ORCID Profile
0000-0001-7009-6843
Current Organisation
Deakin University
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Publisher: Elsevier BV
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 12-2015
Publisher: Mary Ann Liebert Inc
Date: 06-2015
Abstract: In iduals with nonspecific low back pain (NSLBP) show a decreased sit-to-stand-to-sit (STSTS) performance. This dynamic sensorimotor task requires integration of sensory and motor information in the brain. Therefore, a better understanding of the underlying central mechanisms of impaired sensorimotor performance and the presence of NSLBP is needed. The aims of this study were to characterize differences in sensorimotor functional connectivity in in iduals with NSLBP and to investigate whether the patterns of sensorimotor functional connectivity underlie the impaired STSTS performance. Seventeen in iduals with NSLBP and 17 healthy controls were instructed to perform five consecutive STSTS movements as fast as possible. Based on the center of pressure displacement, the total duration of the STSTS task was determined. In addition, resting-state functional connectivity images were acquired and analyzed on a multivariate level using both functional connectivity density mapping and independent component analysis. In iduals with NSLBP needed significantly more time to perform the STSTS task compared to healthy controls. In addition, decreased resting-state functional connectivity of brain areas related to the integration of sensory and/or motor information was shown in the in iduals with NSLBP. Moreover, the decreased functional connectivity at rest of the left precentral gyrus and lobule IV and V of the left cerebellum was associated with a longer duration of the STSTS task in both in iduals with NSLBP and healthy controls. In summary, in iduals with NSLBP showed a reorganization of the sensorimotor network at rest, and the functional connectivity of specific sensorimotor areas was associated with the performance of a dynamic sensorimotor task.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2009
Publisher: American Society of Neuroradiology (ASNR)
Date: 24-11-2017
DOI: 10.3174/AJNR.A5020
Publisher: Springer Science and Business Media LLC
Date: 02-04-2022
DOI: 10.1007/S11682-022-00655-4
Abstract: Recent neuroimaging studies have reported alterations in brain activation during cognitive tasks in cancer patients who have undergone chemotherapy treatment. However, the location of these altered brain activation patterns after chemotherapy varies considerably across studies. The aim of the present meta-analysis was to quantitatively synthesise this body of evidence using Activation Likelihood Estimation to identify reliable regions of altered brain activation in cancer patients treated with chemotherapy, compared to healthy controls and no chemotherapy controls. Our systematic search identified 12 studies that adopted task-related fMRI on non-central nervous system cancer patients who received chemotherapy relative to controls. All studies were included in the analyses and were grouped into four contrasts. Cancer patients treated with chemotherapy showed reduced activation in the left superior parietal lobe recuneus (family-wise error corrected p .05) compared to no chemotherapy controls. No significant clusters were found in three of our contrasts. The majority of studies did not support an association between altered brain activation and cognitive performance after chemotherapy. Findings point towards a possible chemotherapy-induced alteration, which could inform targeted treatment strategies. With continued work in this field using homogenous task-related protocols and cancer populations, fMRI may be used as a biomarker of cognitive deficits in the future.
Publisher: Mary Ann Liebert Inc
Date: 02-2017
Abstract: Computerized cognitive training programs have previously shown to be effective in improving cognitive abilities in patients suffering from traumatic brain injury (TBI). These studies often focused on a single cognitive function or required expensive hardware, making it difficult to be used in a home-based environment. This pilot feasibility study aimed to evaluate the feasibility of a newly developed, home-based, computerized cognitive training program for adolescents who suffered from TBI. Additionally, feasibility of study design, procedures, and measurements were examined. Case series, longitudinal, pilot, feasibility intervention study with one baseline and two follow-up assessments. Nine feasibility outcome measures and criteria for success were defined, including accessibility, training motivation/user experience, technical smoothness, training compliance, participation willingness, participation rates, loss to follow-up, assessment timescale, and assessment procedures. Five adolescent patients (four boys, mean age = 16 years 7 months, standard deviation = 9 months) with moderate to severe TBI in the chronic stage were recruited and received 8 weeks of cognitive training with BrainGames. Effect sizes (Cohen's d) were calculated to determine possible training-related effects. The new cognitive training intervention, BrainGames, and study design and procedures proved to be feasible all nine feasibility outcome criteria were met during this pilot feasibility study. Estimates of effect sizes showed small to very large effects on cognitive measures and questionnaires, which were retained after 6 months. Our pilot study shows that a longitudinal intervention study comprising our novel, computerized cognitive training program and two follow-up assessments is feasible in adolescents suffering from TBI in the chronic stage. Future studies with larger s le sizes will evaluate training-related effects on cognitive functions and underlying brain structures.
Publisher: Elsevier BV
Date: 2015
Publisher: Public Library of Science (PLoS)
Date: 17-08-2011
Publisher: Wiley
Date: 02-04-2015
DOI: 10.1002/HBM.22796
Publisher: Emerald
Date: 16-10-2017
DOI: 10.1108/AAAJ-07-2015-2144
Abstract: The purpose of this paper is to examine the role of management control systems (MCS) in strategically responding to institutional pressures for sustainability (IPS). Drawing on institutional theory (DiMaggio and Powell, 1983) and strategic responses to institutional pressures framework (Oliver, 1991), the study argues that organisations strategically respond to IPS using MCS. Data were collected by interviewing sustainability managers of a large-scale multinational apparel manufacturing organisation with its headquarters in Sri Lanka. The study finds that organisations actively respond to IPS using acquiescence, compromise, avoidance, defiance, and manipulation strategies. The results not only reveal that formal MCS play a critical role in complying with IPS, but also in more active responses, including compromise, avoidance, defiance, and manipulation. The findings highlight that organisations use MCS as a medium to respond strategically to IPS, and in turn, the use of MCS has important implications for organisational change and improvement. The study has implications for Western organisations, finding that suppliers committed to sustainability in Asia strategically respond to IPS as a means of strengthening outsourcing contracts, instead of blindly accepting. Findings indicate that organisational changes and success seem to be a function of strategically responding to IPS rather than operating an organisation by neglecting sustainability challenges. The organisational ability to use MCS in strategically responding to IPS has the potential for long-term value creation. This study provides novel insights into the MCS, strategy and sustainability literatures by exploring different uses of MCS tools in strategically responding to IPS. More specifically, it shows how the use of MCS tools varies in supporting strategic responses, and with respective IPS. In doing so, it enhances our understanding of the importance of the use of MCS in dynamics of institutional change and practical variances in strategically responding to IPS.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.RIDD.2014.07.059
Abstract: Neurofibromatosis type 1 (NF1) is one of the most common single-gene disorders affecting fine and visual-motor skills. This case-control study investigated motor timing as a possible related performance deficit in children with NF1. A visual-motor reaction time (VRT) test was administered in 20 NF1 children (mean age 9 years 7 months) and 20 age- and gender-matched typically developing (TD) children. Copying and tracing performance were evaluated using the Beery-Buktenica Developmental Test of Visual-Motor Integration (Beery VMI). Children with NF1 responded with an increased reaction time (RT) to temporally predictive stimuli compared to TD children, whereas RT at unpredictive stimuli did not differ between groups. Motor timing indexed by the RT decrease at predictive stimuli significantly associated with the Beery VMI copy and tracing outcomes. Deficient motor timing as an actual symptom may add to further research on the pathogenesis of NF1-associated motor impairment and the development of more effective treatment.
Publisher: MIT Press - Journals
Date: 09-2017
DOI: 10.1162/JOCN_A_01127
Abstract: Adaptive working memory (WM) training may lead to cognitive benefits that are associated with white matter plasticity in parietofrontal networks, but the underlying mechanisms remain poorly understood. We investigated white matter microstructural changes after adaptive WM training relative to a nonadaptive comparison group. Microstructural changes were studied in the superior longitudinal fasciculus, the main parietofrontal connection, and the cingulum bundle as a comparison pathway. MRI-based metrics were the myelin water fraction and longitudinal relaxation rate R1 from multicomponent relaxometry (captured with the mcDESPOT approach) as proxy metrics of myelin, the restricted volume fraction from the composite hindered and restricted model of diffusion as an estimate of axon morphology, and fractional anisotropy and radial diffusivity from diffusion tensor imaging. PCA was used for dimensionality reduction. Adaptive training was associated with benefits in a “WM capacity” component and increases in a microstructural component (increases in R1, restricted volume fraction, fractional anisotropy, and reduced radial diffusivity) that predominantly loaded on changes in the right dorsolateral superior longitudinal fasciculus and the left parahippoc al cingulum. In contrast, nonadaptive comparison activities were associated with the opposite pattern of reductions in WM capacity and microstructure. No group differences were observed for the myelin water fraction metric suggesting that R1 was a more sensitive “myelin” index. These results demonstrate task complexity and location-specific white matter microstructural changes that are consistent with tissue alterations underlying myelination in response to training.
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.NEUROIMAGE.2012.03.067
Abstract: Complex bimanual motor learning causes specific changes in activation across brain regions. However, there is little information on how motor learning changes the functional connectivity between these regions, and whether this is influenced by different sensory feedback modalities. We applied graph-theoretical network analysis (GTNA) to examine functional networks based on motor-task-related fMRI activations. Two groups learned a complex 90° out-of-phase bimanual coordination pattern, receiving either visual or auditory feedback. 3T fMRI scanning occurred before (day 0) and after (day 5) training. In both groups, improved motor performance coincided with increased functional network connectivity (increased clustering coefficients, higher number of network connections and increased connection strength, and shorter communication distances). Day×feedback interactions were absent but, when examining network metrics across all examined brain regions, the visual group had a marginally better connectivity, higher connection strength, and more direct communication pathways. Removal of feedback had no acute effect on the functional connectivity of the trained networks. Hub analyses showed an importance of specific brain regions not apparent in the standard fMRI analyses. These findings indicate that GTNA can make unique contributions to the examination of functional brain connectivity in motor learning.
Publisher: Elsevier BV
Date: 02-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-07-2021
DOI: 10.1212/WNL.0000000000012222
Abstract: Our study addressed aims (1) to test the hypothesis that moderate-severe traumatic brain injury (TBI) in pediatric patients is associated with widespread white matter (WM) disruption, (2) to test the hypothesis that age and sex affect WM organization after injury, and (3) to examine associations between WM organization and neurobehavioral outcomes. Data from 10 previously enrolled, existing cohorts recruited from local hospitals and clinics were shared with the Enhancing NeuroImaging Genetics Through Meta-Analysis (ENIGMA) Pediatric Moderate/Severe TBI (msTBI) working group. We conducted a coordinated analysis of diffusion MRI (dMRI) data using the ENIGMA dMRI processing pipeline. Five hundred seven children and adolescents (244 with complicated msTBI and 263 controls) were included. Patients were clustered into 3 postinjury intervals: acute/subacute, months postacute, 2 to 6 months and chronic, ≥6 months. Outcomes were dMRI metrics and postinjury behavioral problems as indexed by the Child Behavior Checklist. Our analyses revealed altered WM diffusion metrics across multiple tracts and all postinjury intervals (effect sizes range d = −0.5 to −1.3). Injury severity is a significant contributor to the extent of WM alterations but explained less variance in dMRI measures with increasing time after injury. We observed a sex-by-group interaction: female patients with TBI had significantly lower fractional anisotropy in the uncinate fasciculus than controls (β = 0.043), which coincided with more parent-reported behavioral problems (β = −0.0027). WM disruption after msTBI is widespread, persistent, and influenced by demographic and clinical variables. Future work will test techniques for harmonizing neurocognitive data, enabling more advanced analyses to identify symptom clusters and clinically meaningful patient subtypes.
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.RIDD.2010.01.002
Abstract: To examine whether children with a 22q11.2 Deletion syndrome (22q11.2DS) are able to use prospective control, 21 children with 22q11.2DS (mean age=9.6+/-1.9 mean FSIQ=73.05+/-10.2) and 21 control children (mean age=9.6+/-1.9 mean FSIQ=73.38+/-12.0) were asked to perform a visuo-manual tracking task in which they had to track a cursor rhythmically between 2 target zones. Children with 22q11.2DS performed worse than the age- and IQ-matched controls (higher absolute time and distance errors) suggesting that the 22q11.2DS group experiences an additional (syndrome specific) processing deficit that cannot be attributed to their lower intellectual abilities. The 22q11.2DS group neither the control group improved their tracking performance throughout five identical full feedback conditions of the tracking task possibly due to a slow visuo-motor adaptation process, a short span of attention and cognitive flexibility impairments. The results showed that both the 22q11.2DS group and the controls had difficulties anticipating the movement of the target (prospective control) and thus are assumed to rely more on feedback instead of on an internal representation of the movement.
Publisher: Springer Science and Business Media LLC
Date: 26-10-2013
DOI: 10.1007/S00429-013-0654-Z
Abstract: Age-related changes in the microstructural organization of the corpus callosum (CC) may explain declines in bimanual motor performance associated with normal aging. We used diffusion tensor imaging in young (n = 33) and older (n = 33) adults to investigate the microstructural organization of seven specific CC subregions (prefrontal, premotor, primary motor, primary sensory, parietal, temporal and occipital). A set of bimanual tasks was used to assess various aspects of bimanual motor functioning: the Purdue Pegboard test, simultaneous and alternating finger tapping, a choice reaction time test and a complex visuomotor tracking task. The older adults showed age-related deficits on all measures of bimanual motor performance. Correlation analyses within the older group showed that white matter fractional anisotropy of the CC occipital region was associated with bimanual fine manipulation skills (Purdue Pegboard test), whereas better performance on the other bimanual tasks was related to higher fractional anisotropy in the more anterior premotor, primary motor and primary sensory CC subregions. Such associations were less prominent in the younger group. Our findings suggest that structural alterations of subregional callosal fibers may account for bimanual motor declines in normal aging.
Publisher: Elsevier
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 13-06-2013
DOI: 10.1007/S00429-013-0590-Y
Abstract: Diffusion tensor imaging (DTI) characterizes white matter (WM) microstructure. In many brain regions, however, the assumption that the diffusion probability distribution is Gaussian may be invalid, even at low b values. Recently, diffusion kurtosis imaging (DKI) was suggested to more accurately estimate this distribution. We explored the added value of DKI in studying the relation between WM microstructure and upper limb coordination in healthy controls (N = 24). Performance on a complex bimanual tracking task was studied with respect to the conventional DTI measures (DKI or DTI derived) and kurtosis metrics of WM tracts/regions carrying efferent (motor) output from the brain, corpus callosum (CC) substructures and whole brain WM. For both estimation models, motor performance was associated with fractional anisotropy (FA) of the CC-genu, CC-body, the anterior limb of the internal capsule, and whole brain WM (r s range 0.42-0.63). Although DKI revealed higher mean, radial and axial diffusivity and lower FA than DTI (p < 0.001), the correlation coefficients were comparable. Finally, better motor performance was associated with increased mean and radial kurtosis and kurtosis anisotropy (r s range 0.43-0.55). In conclusion, DKI provided additional information, but did not show increased sensitivity to detect relations between WM microstructure and bimanual performance in healthy controls.
Publisher: No publisher found
Date: 2015
Publisher: Informa UK Limited
Date: 28-10-2009
DOI: 10.1080/09297040902740678
Abstract: In the early publications on the 22q11.2 Deletion Syndrome (22q11.2DS) motor abnormalities have been frequently reported. However, systematic studies on the motor performance of children with the 22q11.2DS, and especially of school-age children, are scarce. In this study the motor performance of primary school-age children with a 22q11.2DS (n = 28) was compared with an age- and IQ-matched control group (n = 28) using the Movement Assessment Battery for Children (MABC), the Körperkoordinationstest für Kinder (KTK) and the Beery-Buctenica test of Visual-Motor Integration (Beery). Children with a 22q11.2DS scored significantly lower than the age- and IQ-matched control group on the subsection Manual Dexterity (MABC) and the Visual Perception and Motor Coordination subtests of the Beery. When investigating the correlations between Intelligence quotient (IQ) and motor performance, a specific profile was found in the 22q11.2DS group when compared with the age- and IQ-matched control group. Because an IQ-matched control group was adopted, the deficits in visual-perceptual and visuomotor integration skills cannot fully be attributed to a general developmental delay and thus may be specific for the 22q11.2DS. Future studies that investigate the specificity of the visual-perceptual problems - both on the behavioral and brain level (functional Magnetic Resonance Imaging [fMRI] and Diffusion Tensor Imaging [DTI]) - are necessary to answer this question. Nonetheless, the importance of incorporating motor functioning into the study of the neuropsychological profile of children with a 22q11.2DS has to be stressed.
Publisher: Cold Spring Harbor Laboratory
Date: 26-07-2012
Abstract: The corpus callosum (CC) is the largest white matter tract in the brain. It enables interhemispheric communication, particularly with respect to bimanual coordination. Here, we use diffusion tensor imaging (DTI) in healthy humans to determine the extent to which structural organization of subregions within the CC would predict how well subjects learn a novel bimanual task. A single DTI scan was taken prior to training. Participants then practiced a bimanual visuomotor task over the course of 2 wk, consisting of multiple coordination patterns. Findings revealed that the predictive power of fractional anisotropy (FA) was a function of CC subregion and practice. That is, FA of the anterior CC, which projects to the prefrontal cortex, predicted bimanual learning rather than the middle CC regions, which connect primary motor cortex. This correlation was specific in that FA correlated significantly with performance of the most difficult frequency ratios tested and not the innately preferred, isochronous frequency ratio. Moreover, the effect was only evident after training and not at initiation of practice. This is the first DTI study in healthy adults which demonstrates that white matter organization of the interhemispheric connections between the prefrontal structures is strongly correlated with motor learning capability.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.JPEDS.2015.09.069
Abstract: To extend preliminary findings on associated white matter deficits and structural connectivity in children with developmental coordination disorder (DCD). Diffusion magnetic resonance imaging-based tractography was used to identify abnormal microstructural properties of specific sensorimotor white matter tracts in 21 children with DCD between 8 and 10 years of age and 20 age- and sex-matched typically developing controls. Graph theoretical analyses were applied to evaluate whole brain connectomics. Associations were also calculated between the tractography/connectome results and visual-motor performance, as measured with the Beery-Buktenica Developmental Test of Visual Motor Integration. Significant positive correlations were obtained between visual-motor trace scores and fractional anisotropy (FA) in the retrolenticular limb of the internal capsule within the group with DCD. Moreover, lower FA in sensorimotor tracts and altered structural connectivity were observed for children with DCD. Compared with controls, subjects with DCD showed decreases in clustering coefficient, and global and local efficiency, suggesting weaker structural network segregation and integration. The degree of decreased global efficiency was significantly associated with poor visual-motor tracing outcomes, above and beyond FA reductions. Specifically, nodal efficiency at the cerebellar lobule VI and right parietal superior gyrus were found significant predictors to discriminate between children with DCD and those with typical development. Specific white matter alterations and network topology features associate with visual-motor deficits and DCD diagnosis indicating the clinical potential of diffusion magnetic resonance imaging-based metrics for diagnosing DCD.
Publisher: Wiley
Date: 11-06-2010
DOI: 10.1002/HBM.20911
Publisher: Elsevier BV
Date: 2010
DOI: 10.1016/J.RIDD.2009.09.004
Abstract: To examine whether children with a learning disorder (LD) are able to use prospective motor control, 30 children with LD (mean age 8 years and 11 months) and an age- and gender-matched control group were asked to smoothly track an accelerating dot presented on a monitor by moving an electronic pen on a digitizer. Children with LD performed worse than controls: the number of drawn circles was smaller, the maximum target velocity lower, and the number of submovements was higher. It is suggested that a decreased ability to predict the movement of the target leads to impaired visuomanual tracking in children with LD. Furthermore, children with LD did not improve from the 1st to the 2nd trial, possibly as a result of slower visuomotor adaptation processes.
Publisher: Oxford University Press (OUP)
Date: 06-08-2016
DOI: 10.1093/BRAIN/AWW194
Abstract: A growing number of studies approach the brain as a complex network, the so-called 'connectome'. Adopting this framework, we examine what types or extent of damage the brain can withstand-referred to as network 'robustness'-and conversely, which kind of distortions can be expected after brain lesions. To this end, we review computational lesion studies and empirical studies investigating network alterations in brain tumour, stroke and traumatic brain injury patients. Common to these three types of focal injury is that there is no unequivocal relationship between the anatomical lesion site and its topological characteristics within the brain network. Furthermore, large-scale network effects of these focal lesions are compared to those of a widely studied multifocal neurodegenerative disorder, Alzheimer's disease, in which central parts of the connectome are preferentially affected. Results indicate that human brain networks are remarkably resilient to different types of lesions, compared to other types of complex networks such as random or scale-free networks. However, lesion effects have been found to depend critically on the topological position of the lesion. In particular, damage to network hub regions-and especially those connecting different subnetworks-was found to cause the largest disturbances in network organization. Regardless of lesion location, evidence from empirical and computational lesion studies shows that lesions cause significant alterations in global network topology. The direction of these changes though remains to be elucidated. Encouragingly, both empirical and modelling studies have indicated that after focal damage, the connectome carries the potential to recover at least to some extent, with normalization of graph metrics being related to improved behavioural and cognitive functioning. To conclude, we highlight possible clinical implications of these findings, point out several methodological limitations that pertain to the study of brain diseases adopting a network approach, and provide suggestions for future research.
Publisher: Mary Ann Liebert Inc
Date: 12-2016
Publisher: Wiley
Date: 04-05-2017
DOI: 10.1002/HBM.23628
Publisher: Wiley
Date: 11-01-2018
DOI: 10.1002/HBM.23947
Publisher: Informa UK Limited
Date: 08-01-2009
DOI: 10.1080/87565640802499183
Abstract: Motor imagery provides a unique window on the integrity of movement representation. How this ability unfolds during development remains unknown, however. It was the aim of this cross-sectional study to chart the development of movement imagery over childhood using validated measures, and to examine its relationship to movement skill. A s le of 58 children aged 7-12 years were recruited from Australian primary schools. Motor imagery ability was assessed using the Radial Pointing Task and a (mental) Hand Rotation Task, whereas visual (or object-related) imagery was measured on a Letter Rotation Task. Motor skill was assessed on the McCarron Assessment of Neuromuscular Development (MAND). Results showed clear age differences on all measures: motor skill, motor imagery, and visual imagery. The relationship between motor imagery and motor skill was shown to become stronger with age, whereas no relationship between visual imagery and motor skill was evident at any age. Taken together, these results show that motor imagery has a distinct developmental trajectory that is entwined with the development of movement skill in children. We argue that movement imagery reflects the unfolding of internal modeling processes providing the foundation for adaptive, goal-directed movements.
Publisher: Springer Science and Business Media LLC
Date: 22-08-2017
DOI: 10.1007/S11682-017-9760-5
Abstract: Previous studies have suggested that neurological factors partly explain the reduced motor competence found in many children with obesity. Accordingly, the aim of this study was to compare motor competence and white matter organization of important pathways for motor control (cerebellar peduncles) in children with and without obesity. Nineteen children with obesity and 25 children with a healthy weight, aged 7-11 years old, were included. Anthropometric measurements were taken and the level of motor competence was assessed using the Movement Assessment Battery for Children (2nd Edition). Children's brain was scanned using diffusion weighted imaging preceded by a standard anatomical scan. Fractional anisotropy and mean diffusivity were extracted from the cerebellar peduncles. Obese children's level of motor competence was significantly lower than that in healthy weight peers (p < 0.05). Additionally, significant group differences (p < 0.05) were found for values of fractional anisotropy, but not for mean diffusivity. Further analyses revealed that lower values of fractional anisotropy in the inferior (p = 0.040) and superior (p = 0.007) cerebellar peduncles were present in children with obesity compared to children with a healthy weight. After controlling for multiple comparisons (p < 0.0167), only significant differences in the superior cerebellar peduncle remained significant. Our results showed that childhood obesity is accompanied by reduced motor competence and alterations in white matter organization. This suggests that the motor difficulties of children with obesity are not solely due to carrying excess weight, which may have implications for prevention and intervention programs.
Publisher: SAGE Publications
Date: 22-03-2011
Abstract: Background. Deterioration of motor function is one of several clinical manifestations following traumatic brain injury (TBI) in children and adolescents. Objective. To investigate the relationship between white matter (WM) integrity using diffusion tensor imaging (DTI) and motor functioning in young TBI patients. Methods. A group with moderate to severe TBI (n = 24) and a control group (n = 17) were scanned using DTI along with standard anatomical scans. Using ExploreDTI software, WM regions/tracts that carry efferent output (motor) from the brain were evaluated, as well as the corpus callosum, brainstem, internal capsule, and subcortical WM structures. Motor function was assessed using the Movement Assessment Battery for Children (M-ABC), consisting of manual dexterity, ball skills, and static and dynamic balance items. Results. TBI patients were less successful on the M-ABC than the controls and showed lower WM fractional anisotropy (FA) in the corpus callosum, anterior corona radiata, corticospinal tract, and cerebellum. Decreased FA was associated with lower motor performance in the TBI group but not in the control group. Conclusion. This study provides evidence for a structural alteration of motor pathways and regions in children and adolescents with TBI that are correlated with motor functioning. Further studies may be able to identify therapeutic targets and monitor the effects of new interventions.
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.RIDD.2013.02.008
Abstract: A dysfunction in predictive motor timing is put forward to underlie DCD-related motor problems. Predictive timing allows for the pre-selection of motor programmes (except 'program' in computers) in order to decrease processing load and facilitate reactions. Using functional magnetic resonance imaging (fMRI), this study investigated the neural correlates of motor timing in DCD (n=17) and typically developing children (n=17). The task involved motor responses to sequences of visual stimuli with predictive or unpredictive interstimulus intervals (ISIs). DCD children responded with a smaller reaction time (RT) advantage to predictive ISIs compared to typically developing children. Typically developing children exhibited higher activation in the right dorsolateral prefrontal cortex (DLPFC) and right inferior frontal gyrus (IFG) for responses at unpredictive as opposed to predictive ISIs, whereas activations in DCD children were non-differentiable. Moreover, DCD children showed less activation than typically developing children in the right DLPFC, the left posterior cerebellum (crus I) and the right temporo-parietal junction (TPJ) for this contrast. Notably, activation in the right temporo-parietal junction (TPJ) positively correlated with RT as an indicator of processing load in both groups. These data indicate that motor performance in DCD children requires extra processing demands due to impaired predictive encoding.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.RIDD.2016.06.014
Abstract: Children with impaired motor coordination (or DCD) have difficulty using motor imagery. We have suggested that this difficulty is explained by the internal modeling deficit (IMD) hypothesis of DCD. Our previous training study lent support for this hypothesis by showing that a computerized imagery training protocol (involving action observation, and mental- and overt-rehearsal) was equally effective to perceptual-motor therapy (PMT) in promoting motor skill acquisition. The study presented here was designed to replicate and extend this finding, targeting a select group of children with moderate-to-severe DCD. All 36 children with DCD who participated were referred to the study and scored below the 10th percentile for their age on the Movement Assessment Battery for Children (MABC). Using a randomized control trial, the referred children were assigned randomly to one of three groups using a blocked procedure: imagery training, perceptual-motor training (PMT), and wait-list control. Motor proficiency was measured using the MABC, pre and post-training. In idual training consisted of 60-min sessions, conducted once a week for 5 weeks. Results showed that the imagery protocol was equally effective as PMT in promoting motor skill acquisition, with moderate-to-large effect sizes. In idual differences showed that the majority of children in the two intervention groups improved their motor performance significantly. Overall, these results further support the use of motor imagery protocols in the treatment of DCD, and tentative support for the IMD hypothesis. Developmental and dose issues in the implementation of imagery-based intervention are discussed.
Publisher: Oxford University Press (OUP)
Date: 21-01-2009
DOI: 10.1093/BRAIN/AWN344
Abstract: Traumatic brain injury (TBI) is a common form of disability in children. Persistent deficits in motor control have been documented following TBI but there has been less emphasis on changes in functional cerebral activity. In the present study, children with moderate to severe TBI (n = 9) and controls (n = 17) were scanned while performing cyclical movements with their dominant and non-dominant hand and foot according to the easy isodirectional (same direction) and more difficult non-isodirectional (opposite direction) mode. Even though the children with TBI were shown to be less successful on various items of a clinical motor test battery than the control group, performance on the coordination task during scanning was similar between groups, allowing a meaningful interpretation of their brain activation differences. fMRI analysis revealed that the TBI children showed enhanced activity in medial and anterior parietal areas as well as posterior cerebellum as compared with the control group. Brain activation generally increased during the non-isodirectional as compared with the isodirectional mode and additional regions were involved, consistent with their differential degree of difficulty. However, this effect did not interact with group. Overall, the findings indicate that motor impairment in TBI children is associated with changes in functional cerebral activity, i.e. they exhibit compensatory activation reflecting increased recruitment of neural resources for attentional deployment and somatosensory processing.
Publisher: Springer Science and Business Media LLC
Date: 21-04-2014
DOI: 10.1038/ONC.2014.106
Abstract: A feature of many gliomas is the lification of the epidermal growth factor receptor (EGFR), resulting in its overexpression. Missense mutations or deletions within the extracellular domain are associated with this lification and can lead to constitutive activation of the receptor, with the Domain I/II deletion, EGFRvIII, being the most common. These changes have also been associated with increased sensitivity to EGFR inhibition using small molecule inhibitors. We have expressed, in human glioma cells, EGFR containing four glioma-specific EGFR missense mutations within Domain IV (C620Y, C624F, C628Y and C636Y) to analyze their biological properties and sensitivity to EGFR inhibition. One of these mutants, C620Y, exhibited an enhanced basal phosphorylation, which was partially dependent on an EGFR-ligand autocrine loop. All Domain IV mutants responded equally as well as wildtype EGFR (wtEGFR) to ligand stimulation. Biochemical analysis revealed that a pre-formed, disulfide-bonded dimer associated with these mutations was underglycosylated, inactive and cytoplasmically retained. Ligand stimulation resulted in the formation of a tyrosine-phosphorylated, disulfide-bonded dimer for all Domain IV mutants but not for wtEGFR. Following treatment with the next-generation, irreversible pan-ErbB inhibitor dacomitinib, the C620Y, C624F and EGFRvIII mutants were inactivated, covalently dimerized and were retained in the cytoplasm, resulting in cell-surface receptor loss and, for C620Y and C624F, decreased binding of EGF. Dacomitinib treatment significantly reduced the in vivo growth of human glioma xenografts bearing C620Y, but not wtEGFR. Collectively, these data indicate that the unique biochemical traits of Domain IV EGFR cysteine mutants can be exploited for enhanced sensitivity to EGFR small molecule inhibitors, with potential clinical applications.
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.RIDD.2014.10.013
Abstract: For children with Developmental Coordination Disorder (DCD), the real-time coupling between frontal executive function and online motor control has not been explored despite reported deficits in each domain. The aim of the present study was to investigate how children with DCD enlist online control under task constraints that compel the need for inhibitory control. A total of 129 school children were s led from mainstream primary schools. Forty-two children who met research criteria for DCD were compared with 87 typically developing controls on a modified double-jump reaching task. Children within each skill group were ided into three age bands: younger (6-7 years), mid-aged (8-9), and older (10-12). Online control was compared between groups as a function of trial type (non-jump, jump, anti-jump). Overall, results showed that while movement times were similar between skill groups under simple task constraints (non-jump), on perturbation (or jump) trials the DCD group were significantly slower than controls and corrected trajectories later. Critically, the DCD group was further disadvantaged by anti-jump trials where inhibitory control was required however, this effect reduced with age. While coupling online control and executive systems is not well developed in younger and mid-aged children, there is evidence of age-appropriate coupling in older children. Longitudinal data are needed to clarify this intriguing finding. The theoretical and applied implications of these results are discussed.
Publisher: Springer Science and Business Media LLC
Date: 12-12-2012
DOI: 10.1007/S00429-012-0494-2
Abstract: Recent research on traumatic brain injury (TBI) has shown that impairments in cognitive and executive control functions are accompanied by a disrupted neural connectivity characterized by white matter damage. We constructed binary and weighted brain structural networks in 21 patients with chronic TBI and 17 healthy young adults utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. Executive function was assessed with the local global task and the trail making task, requiring inhibition, updating, and switching. The results revealed that TBI patients were less successful than controls on the executive tasks, as shown by the higher reaction times, higher switch costs, and lower accuracy rates. Moreover, both TBI patients and controls exhibited a small world topology in their white matter networks. More importantly, the TBI patients demonstrated increased shortest path length and decreased global efficiency of the structural network. These findings suggest that TBI patients have a weaker globally integrated structural brain network, resulting in a limited capacity to integrate information across brain regions. Furthermore, we showed that the white matter networks of both groups contained highly connected hub regions that were predominately located in the parietal cortex, frontal cortex, and basal ganglia. Finally, we showed significant correlations between switching performance and network property metrics within the TBI group. Specifically, lower scores on the switching tasks corresponded to a lower global efficiency. We conclude that analyzing the structural brain network connectivity provides new insights into understanding cognitive control changes following brain injury.
Publisher: Wiley
Date: 10-09-2018
DOI: 10.1002/HBM.24360
Publisher: No publisher found
Date: 2018
DOI: 10.1002/HBM.24041
Publisher: Mary Ann Liebert Inc
Date: 06-2011
Abstract: Bimanual actions are ubiquitous in daily life. Many coordinated movements of the upper extremities rely on precise timing, which requires efficient interhemispheric communication via the corpus callosum (CC). As the CC in particular is known to be vulnerable to traumatic brain injury (TBI), furthering our understanding of its structure-function association is highly valuable for TBI diagnostics and prognosis. In this study, 21 young adults with TBI and 17 controls performed object manipulation tasks (insertion of pegs with both hands and bilateral daily life activities) and cognitive control tasks (i.e., switching maneuvers during spatially and temporally coupled bimanual circular motions). The structural organization of 7 specific subregions of the CC (prefrontal, premotor/supplementary motor, primary motor, primary sensory, parietal, temporal, and occipital) was subsequently investigated in these subjects with diffusion tensor imaging (DTI). Findings revealed that bimanual coordination was impaired in TBI patients as shown by elevated movement time values during daily life activities, a decreased number of peg insertions, and slower response times during the switching task. Furthermore, the DTI analysis demonstrated a significantly decreased fractional anisotropy and increased radial diffusivity in prefrontal, primary sensory, and parietal regions in TBI patients versus controls. Finally, multiple regression analyses showed evidence of the high specificity of callosal subregions accounting for the variance associated with performance of the different bimanual coordination tasks. Whereas disruption in commissural pathways between occipital areas played a role in performance on the clinical tests of bimanual coordination, deficits in the switching task were related to disrupted interhemispheric communication in prefrontal, sensory, and parietal regions. This study provides evidence that structural alterations of several subregional callosal fibers in adults with TBI are associated with differential behavioral manifestations of bimanual motor functioning.
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.BANDC.2008.07.001
Abstract: Motor disorders are a frequent consequence of acquired brain injury (ABI) in children and much effort is currently invested in alleviating these deficits. The aim of the present study was to test motor imagery (MI) capabilities in children with ABI (n=25) and an age- and gender-matched control group (n=25). A computerized Virtual Radial Fitts Task (VRFT) was used to investigate the speed-accuracy trade-offs (or Fitts' law) that occur as target size is varied for both executed and imagined performance. In the control group, the speed for accuracy trade-off for both executed and imagined performance conformed to Fitts' law. In the ABI group, only executed movements conformed to Fitts' law. These findings suggest that children with ABI show an inferior ability to imagine the time needed to complete goal-directed movements with differential difficulty levels.
Publisher: Wiley
Date: 02-08-2013
DOI: 10.1002/HBM.22341
Publisher: Wiley
Date: 30-03-2009
DOI: 10.1111/J.1467-7687.2008.00803.X
Abstract: Motor imagery (MI) has become a principal focus of interest in studies on brain and behavior. However, changes in MI across development have received virtually no attention so far. In the present study, children (N = 112, 6 to 16 years old) performed a new, computerized Virtual Radial Fitts Task (VRFT) to determine their MI ability as well as the age-related confluence between performance in executed and imagined movement conditions. Participants aimed at five targets, which were positioned along radial axes from a central target circle. The targets differed in width (2.5, 5, 10, 20 or 40 mm), resulting in an index of difficulty (ID) that varied from 6.9 to 2.9 bits. Performance was indexed by the linear relationship between ID and Movement Time (MT). The findings showed that executed task performance was slower than imagined performance. Moreover, conformance to Fitts' Law during executed movement performance was obtained from a very young age. Most importantly, correlations between imagined and executed movements were low in the young participants but gradually increased across age. These age-related changes in MI are hypothesized to reflect the children's emerging ability to represent internal models for prospective actions, consistent with the gradual unfolding of feedforward control processes.
Publisher: IEEE
Date: 06-2015
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2018
Publisher: Brill
Date: 2016
DOI: 10.1163/22134808-00002526
Abstract: Processing proprioceptive information in the brain is essential for optimal postural control and can be studied with proprioceptive stimulation, provided by muscle vibration, during functional magnetic resonance imaging (fMRI). Classic electromagnetic muscle vibrators, however, cannot be used in the high-strength magnetic field of the fMRI scanner. Pneumatic vibrators offer an fMRI-compatible alternative. However, whether these devices produce reliable and valid proprioceptive stimuli has not been investigated, although this is essential for these devices to be used in longitudinal research. Test–retest reliability and concurrent validity of the postural response to muscle vibration, provided by custom-made fMRI-compatible pneumatic vibrators, were assessed in a repeated-measures design. Mean center of pressure (CoP) displacements during, respectively, ankle muscle and back muscle vibration (45–60 Hz, 0.5 mm) provided by an electromagnetic and a pneumatic vibrator were measured in ten young healthy subjects. The test was repeated on the same day and again within one week. Intraclass correlation coefficients (ICC) were calculated to assess (a) intra- and interday reliability of the postural responses to, respectively, pneumatic and electromagnetic vibration, and (b) concurrent validity of the response to pneumatic compared to electromagnetic vibration. Test–retest reliability of mean CoP displacements during pneumatic vibration was good to excellent (ICCs = 0.64–0.90) and resembled that of responses to electromagnetic vibration (ICCs = 0.64–0.94). Concurrent validity of the postural effect of pneumatic vibration was good to excellent (ICCs = 0.63–0.95). In conclusion, the proposed fMRI-compatible pneumatic vibrator can be used with confidence to stimulate muscle spindles during fMRI to study central processing of proprioception.
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.RIDD.2010.01.019
Abstract: The present study focused on the mechanism subserving the production of kinematic patterns in 21 children with 22q11.2DS (mean age=9.6+/-1.9 mean FSIQ=73.05+/-10.2) and 21 age- and IQ-matched control children (mean age=9.6+/-1.9 mean FSIQ=73.38+/-12.0) when performing a visuo-manual tracking task in which they had to track a cursor rhythmically between 2 target zones. Children with 22q11.2DS moved faster (overall) and reached their maximum velocity sooner when compared to controls. However, the number of corrective submovements to attain the target did not differ. Children with 22q11.2DS seem to adopt a young ballistic movement strategy, with a fast ballistic first movement phase, followed by a second movement phase with very little online corrections to attain the target. Children with 22q11.2DS are not able to process the incoming feedback during the second movement phase to maximize the accuracy of the ongoing movement and use this phase to prepare the following. The fact that the parietal cortex and cerebellum are involved in action prediction and internal representation and are implicated in children with 22q11.2DS provides a possible neurological basis for their problems with prospective control and tracking behavior.
Publisher: MIT Press
Date: 2023
DOI: 10.1162/NETN_A_00277
Abstract: Graph theoretical analysis of the structural connectome has been employed successfully to characterize brain network alterations in patients with traumatic brain injury (TBI). However, heterogeneity in neuropathology is a well-known issue in the TBI population, such that group comparisons of patients against controls are confounded by within-group variability. Recently, novel single-subject profiling approaches have been developed to capture inter-patient heterogeneity. We present a personalized connectomics approach that examines structural brain alterations in five chronic patients with moderate to severe TBI who underwent anatomical and diffusion magnetic resonance imaging. We generated in idualized profiles of lesion characteristics and network measures (including personalized graph metric GraphMe plots, and nodal and edge-based brain network alterations) and compared them against healthy reference cases (N = 12) to assess brain damage qualitatively and quantitatively at the in idual level. Our findings revealed alterations of brain networks with high variability between patients. With validation and comparison to stratified, normative healthy control comparison cohorts, this approach could be used by clinicians to formulate a neuroscience-guided integrative rehabilitation program for TBI patients, and for designing personalized rehabilitation protocols based on their unique lesion load and connectome.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-03-2013
DOI: 10.1212/WNL.0B013E31828C2EE5
Abstract: To examine the relation between measures of whole-brain white matter connectivity and cognitive performance in patients with early Alzheimer disease (AD) using a network-based approach and to assess whether network parameters provide information that is complementary to conventional MRI markers of AD. Fifty patients (mean age 78.8 ± 7.1 years) with early AD were recruited via a memory clinic. In addition, 15 age-, sex-, and education-matched control participants were used as a reference group. All participants underwent a 3-T MRI scan and cognitive assessment. Diffusion tensor imaging–based tractography was used to reconstruct the brain network of each in idual, followed by graph theoretical analyses. Overall network efficiency was assessed by measures of local (clustering coefficient, local efficiency) and global (path length, global efficiency) connectivity. Age-, sex-, and education-adjusted cognitive scores were related to network measures and to conventional MRI parameters (i.e., degree of cerebral atrophy and small-vessel disease). The structural brain network of patients showed reduced local efficiency compared to controls. Within the patient group, worse performance in memory and executive functioning was related to decreased local efficiency ( r = 0.434 p = 0.002), increased path length ( r = −0.538 p 0.001), and decreased global efficiency ( r = 0.431 p = 0.005). Measures of network efficiency explained up to 27% of the variance in cognitive functioning on top of conventional MRI markers ( p 0.01). This study shows that network-based analysis of brain white matter connections provides a novel way to reveal the structural basis of cognitive dysfunction in AD.
Publisher: Cold Spring Harbor Laboratory
Date: 17-10-2023
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.CORTEX.2013.10.009
Abstract: Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, le evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus. To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions. Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit.
Publisher: Wiley
Date: 07-2008
DOI: 10.1111/J.1467-8624.2008.01163.X
Abstract: To examine the development of feedforward control during manual tracking, 117 participants in 5 age groups (6 to 7, 8 to 9, 10 to 11, 12 to 14, and 15 to 17 years) tracked an accelerating dot presented on a monitor by moving an electronic pen on a digitizer. To remain successful at higher target velocities, they had to create a predictive model of the target's motion. The ability to track the target at higher velocities increased, and the application of a feedback-based step-and-hold strategy decreased with age, as shown by increases in maximum target velocity and decreases in number of stops between ages 6-7 and 8-9 and between ages 8-9 and 10-11. The ability to exploit feedforward control in a dynamic tracking task improves significantly with age.
Publisher: Mary Ann Liebert Inc
Date: 09-2015
Abstract: Traumatic brain injury (TBI) can lead to deficits in gait and posture, which are often asymmetric. A possible factor mediating these deficits may be asymmetry in strength of the leg muscles. However, muscle strength in the lower extremities has rarely been investigated in (young) TBI patients. Here, we investigated associations between lower-extremity muscle weakness, strength asymmetry, and impairments in gait and posture in young TBI patients. A group of young patients with moderate-to-severe TBI (n=19 age, 14 years 11 months ±2 years) and a group of typically developing subjects (n=31 age, 14 years 1 month±3 years) participated in this study. A force platform was used to measure postural sway to quantify balance control during normal standing and during conditions of compromised visual and/or somatosensory feedback. Spatiotemporal gait parameters were assessed during comfortable and fast-speed walking, using an electronic walkway. Muscle strength in four lower-extremity muscle groups was measured bilaterally using a handheld dynamometer. Findings revealed that TBI patients had poorer postural balance scores across all sensory conditions, as compared to typically developing subjects. During comfortable and fast gait, TBI patients demonstrated a lower gait velocity, longer double-support phase, and increased step-length asymmetry. Further, TBI patients had a reduced strength of leg muscles and an increased strength asymmetry. Correlation analyses revealed that asymmetry in muscle strength was predictive of a poorer balance control and a more variable and asymmetric gait. To the best of our knowledge, this is the first study to measure strength asymmetry in leg muscles of a s le of TBI patients and illustrate the importance of muscular asymmetry as a potential marker and possible risk factor of impairments in control of posture and gait.
Publisher: Public Library of Science (PLoS)
Date: 29-04-2013
Publisher: Wiley
Date: 06-06-2021
DOI: 10.1111/PSYP.13871
Abstract: Attentional lapses interfere with goal‐directed behaviors, which may result in harmless (e.g., not hearing instructions) or severe (e.g., fatal car accident) consequences. Task‐related functional MRI (fMRI) studies have shown a link between attentional lapses and activity in the frontoparietal network. Activity in this network is likely to be mediated by the organization of the white matter fiber pathways that connect the regions implicated in the network, such as the superior longitudinal fasciculus I (SLF‐I). In the present study, we investigate the relationship between susceptibility to attentional lapses and relevant white matter pathways in 36 healthy adults (23 females, M age = 31.56 years). Participants underwent a diffusion MRI (dMRI) scan and completed the global–local task to measure attentional lapses, similar to previous fMRI studies. Applying the fixel‐based analysis framework for fiber‐ specific analysis of dMRI data, we investigated the association between attentional lapses and variability in microstructural fiber density (FD) and macrostructural (morphological) fiber‐bundle cross section (FC) in the SLF‐I. Our results revealed a significant negative association between higher total number of attentional lapses and lower FD in the left SLF‐I. This finding indicates that the variation in the microstructure of a key frontoparietal white matter tract is associated with attentional lapses and may provide a trait‐like biomarker in the general population. However, SLF‐I microstructure alone does not explain propensity for attentional lapses, as other factors such as sleep deprivation or underlying psychological conditions (e.g., sleep disorders) may also lead to higher susceptibility in both healthy people and those with neurological disorders.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 2012
Publisher: Mary Ann Liebert Inc
Date: 09-2015
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.NEUROSCIENCE.2011.07.030
Abstract: We recently found that spontaneous eye movements occur during motor imagery of hand movements, which are similar to those made during physical execution. In physical execution, eye movements have been shown to play an important role during training. In motor imagery practice, however, their effect remains unclear. Therefore, in the present study, we examined the role of eye movements during motor imagery practice with specific interest in the impact of task complexity and effector specificity. Thirty-six young healthy participants were tested before and after 4 days of visual motor imagery training on a Virtual Radial Fitts' task with different indices of difficulty. Training was performed with the nondominant hand only. Subjects were ided into a group that trained while spontaneous eye movements were allowed, one that kept the eyes fixed during training, and a control group. Electro-oculography and electromyography signals were monitored to guarantee task compliance during imagery. The results indicated that eye movements during imagery did not affect the temporal parameters of the trained movement. They did, however, help to achieve maximal gains in movement accuracy and efficiency. These positive effects on the spatial parameters were most pronounced during conditions with high accuracy demands and were present for both the trained and the untrained hand. These findings contribute to guidelines for optimizing training protocols based on motor imagery.
Publisher: Oxford University Press (OUP)
Date: 16-03-2012
DOI: 10.1093/BRAIN/AWS048
Abstract: Patients with traumatic brain injury show clear impairments in behavioural flexibility and inhibition that often persist beyond the time of injury, affecting independent living and psychosocial functioning. Functional magnetic resonance imaging studies have shown that patients with traumatic brain injury typically show increased and more broadly dispersed frontal and parietal activity during performance of cognitive control tasks. We constructed binary and weighted functional networks and calculated their topological properties using a graph theoretical approach. Twenty-three adults with traumatic brain injury and 26 age-matched controls were instructed to switch between coordination modes while making spatially and temporally coupled circular motions with joysticks during event-related functional magnetic resonance imaging. Results demonstrated that switching performance was significantly lower in patients with traumatic brain injury compared with control subjects. Furthermore, although brain networks of both groups exhibited economical small-world topology, altered functional connectivity was demonstrated in patients with traumatic brain injury. In particular, compared with controls, patients with traumatic brain injury showed increased connectivity degree and strength, and higher values of local efficiency, suggesting adaptive mechanisms in this group. Finally, the degree of increased connectivity was significantly correlated with poorer switching task performance and more severe brain injury. We conclude that analysing the functional brain network connectivity provides new insights into understanding cognitive control changes following brain injury.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.NEUBIOREV.2018.05.019
Abstract: In addition to the burden of a life-threatening diagnosis, cancer patients are struggling with adverse side-effects from cancer treatment. Chemotherapy has been linked to an array of cognitive impairments and alterations in brain structure and function ("chemobrain"). In this review, we summarized the existing evidence that evaluate the changes in cognitive functioning and brain with chemotherapy, as assessed using structural and functional MRI-based techniques in a longitudinal design. This review followed the latest PRISMA guidelines using Embase, Medline, PsychINFO, Scopus, and Web of Science databases with date restrictions from 2012 to 2017. Fourteen research articles met the key inclusion criteria: (i) the studies involved adult cancer patients (mean age ≥ 18) (ii) the use of chemotherapy in the treatment of cancer (iii) pre-post assessment of behavioral and brain-based outcomes and (iv) abstracts written in English. Effect sizes of subjective and objective cognitive impairments from the reviewed studies were estimated using Cohen's d or z-scores. We calculated percentage of mean change or effect sizes for main neuroimaging findings when data were available. Strength of the correlations between brain alterations and cognitive changes was obtained using squared correlation coefficients. Small to medium effect sizes were shown? on in idual tests of attention, processing speed, verbal memory, and executive control and medium effect sizes on self-report questionnaires. Neuroimaging data showed reduced grey matter density in cancer patients in frontal, parietal, and temporal regions. Changes in brain function (brain activation and cerebral blood flow) were observed with cancer across functional networks involving (pre)frontal, parietal, occipital, temporal, and cerebellar regions. Data from diffusion-weighted MRI suggested reduced white matter integrity involving the superior longitudinal fasciculus, corpus callosum, forceps major, and corona radiate, and altered structural connectivity across the whole brain network. Finally, we observed moderate-to-strong correlations between worsening cognitive function and morphological changes in frontal brain regions. While MRI is a powerful tool for detection of longitudinal brain changes in the 'chemobrain', the underlying biological mechanisms are still unclear. Continued work in this field will hopefully detect MRI metrics to be used as biomarkers to help guide cognitive treatment at the in idual cancer patient level.
Publisher: Society for Neuroscience
Date: 06-04-2016
DOI: 10.1523/JNEUROSCI.1973-15.2016
Abstract: Brain region-specific changes have been demonstrated with a variety of cognitive training interventions. The effect of cognitive training on brain subnetworks in humans, however, remains largely unknown, with studies limited to functional networks. Here, we used a well-established working memory training program and state-of-the art neuroimaging methods in 40 healthy adults (21 females, mean age 26.5 years). Near and far-transfer training effects were assessed using computerized working memory and executive function tasks. Adaptive working memory training led to improvement on (non)trained working memory tasks and generalization to tasks of reasoning and inhibition. Graph theoretical analysis of the structural (white matter) network connectivity (“connectome”) revealed increased global integration within a frontoparietal attention network following adaptive working memory training compared with the nonadaptive group. Furthermore, the impact on the outcome of graph theoretical analyses of different white matter metrics to infer “connection strength” was evaluated. Increased efficiency of the frontoparietal network was best captured when using connection strengths derived from MR metrics that are thought to be more sensitive to differences in myelination (putatively indexed by the [quantitative] longitudinal relaxation rate, R 1 ) than previously used diffusion MRI metrics (fractional anisotropy or fiber-tracking recovered streamlines). Our findings emphasize the critical role of specific microstructural markers in providing important hints toward the mechanisms underpinning training-induced plasticity that may drive working memory improvement in clinical populations. SIGNIFICANCE STATEMENT This is the first study to explore training-induced changes in the structural connectome using a well-controlled design to examine cognitive training with up-to-date neuroimaging methods. We found changes in global integration based on white matter connectivity within a frontoparietal attention network following adaptive working memory training compared with a nonadaptive comparison group. Furthermore, the impact of different diffusion MR metrics and more specific markers of white matter on the graph theoretical findings was evaluated. An increase in network global efficiency following working memory training was best captured when connection strengths were weighted by MR relaxation rates (influenced by myelination). These results are important for the optimization of cognitive training programs for healthy in iduals and people with brain disease.
Publisher: Wiley
Date: 05-09-2017
DOI: 10.1111/DMCN.13530
Abstract: To better understand the neural and performance factors that may underlie developmental coordination disorder (DCD), and implications for a multi-component account. A systematic review of the experimental literature published between June 2011 and September 2016 was conducted using a modified PICOS (population, intervention, comparison, outcomes, and study type) framework. A total of 106 studies were included. Behavioural data from 91 studies showed a broad cluster of deficits in the anticipatory control of movement, basic processes of motor learning, and cognitive control. Importantly, however, performance issues in DCD were often shown to be moderated by task type and difficulty. As well, we saw new evidence of compensatory processes and strategies in several studies. Neuroimaging data (15 studies, including electroencephalography) showed reduced cortical thickness in the right medial orbitofrontal cortex and altered brain activation patterns across functional networks involving prefrontal, parietal, and cerebellar regions in children with DCD than those in comparison groups. Data from diffusion-weighted magnetic resonance imaging suggested reduced white matter organization involving sensorimotor structures and altered structural connectivity across the whole brain network. Taken together, results support the hypothesis that children with DCD show differences in brain structure and function compared with typically developing children. Behaviourally, these differences may affect anticipatory planning and reduce automatization of movement skill, prompting greater reliance on slower feedback-based control and compensatory strategies. Implications for future research, theory development, and clinical practice are discussed.
Publisher: Wiley
Date: 30-01-2012
DOI: 10.1002/HBM.21508
Abstract: The ability to suppress and flexibly adapt motor behavior is a fundamental mechanism of cognitive control, which is impaired in traumatic brain injury (TBI). Here, we used a combination of functional magnetic resonance imaging and diffusion weighted imaging tractography to study changes in brain function and structure associated with motor switching performance in TBI. Twenty‐three young adults with moderate‐severe TBI and twenty‐six healthy controls made spatially and temporally coupled bimanual circular movements. A visual cue signaled the right hand to switch or continue its circling direction. The time to initiate the switch (switch response time) was longer and more variable in the TBI group and TBI patients exhibited a higher incidence of complete contralateral (left hand) movement disruptions. Both groups activated the basal ganglia and a previously described network for task‐set implementation, including the supplementary motor complex and bilateral inferior frontal cortex (IFC). Relative to controls, patients had significantly increased activation in the presupplementary motor area (preSMA) and left IFC, and showed underactivation of the subthalamic nucleus (STN) region. This altered functional engagement was related to the white matter microstructural properties of the tracts connecting preSMA, IFC, and STN. Both functional activity in preSMA, IFC, and STN, and the integrity of the connections between them were associated with behavioral performance across patients and controls. We suggest that damage to these key pathways within the motor switching network because of TBI, shifts the patients toward the lower end of the existing structure‐function‐behavior spectrum. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Publisher: Wiley
Date: 22-10-2011
DOI: 10.1002/HBM.21429
Publisher: Mary Ann Liebert Inc
Date: 03-2017
Abstract: Traumatic brain injury (TBI) often leads to impairments in gait performance. However, the underlying neurostructural pathology of these gait deficits is poorly understood. We aimed to investigate regional gray matter (GM) volume in young moderate-to-severe TBI participants (n = 19 age 13 years 11 months ±3 years 1 month), compared with typically developing (TD) participants (n = 30 14 years 10 months ±2 years 2 months), and assess whether reduced volume was related to impaired gait performance in TBI participants. Cortical and subcortical GM structures involved in the neural control of gait were selected as regions of interest (ROIs) and their volume was extracted using Freesurfer. Moreover, established spatiotemporal markers of gait impairments in TBI participants, including step length asymmetry, step length variability, and double support time, were obtained using an electronic walkway. Compared with TD participants, TBI participants showed increased double support time, step length asymmetry, and step length variability, suggesting a reduced gait control. Secondly, in TBI participants, reduced volumes were demonstrated in overall subcortical GM and in idual subcortical ROIs, including the hippoc us, cerebellar cortex, putamen, and thalamus. Moreover, in the TBI group, volume losses in subcortical ROIs were highly inter-correlated, indicating that atrophy tends to occur in combined subcortical structures. Finally, it was demonstrated, for the first time, that gait abnormalities in TBI subjects were associated with reduced volume in specific GM structures, including the hippoc us, thalamus, and the cerebellar, superior frontal, paracentral, posterior cingulate, and superior parietal cortices. The present study is an important first step in the understanding of the neurostructural pathology underlying impaired gait in TBI patients.
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.BANDC.2016.08.001
Abstract: Previous research indicates that children with Developmental Coordination Disorder (DCD) show deficits performing online corrections, an issue exacerbated by adding inhibitory constraints however, cross-sectional data suggests that these deficits may reduce with age. Using a longitudinal design, the aim of the study presented here was to model the coupling that occurs between inhibitory systems and (predictive) online control in typically developing children (TDC) and in those with Developmental Coordination Disorder (DCD) over an extended period of time, using a framework of interactive specialization. We predicted that TDC would show a non-linear growth pattern, consistent with re-organisation in the coupling during the middle childhood period, while DCD would display a developmental lag. A group of 196 children (111 girls and 85 boys) aged between 6 and 12years participated in the study. Children were classified as DCD according to research criteria. Using a cohort sequential design, both TDC and DCD groups were ided into age cohorts. Predictive (online) control was defined operationally by performance on a Double-Jump Reaching Task (DJRT), which was assessed at 6-month intervals over two years (5 time points in total). Inhibitory control was examined using an anti-jump condition of the DJRT paradigm whereby children were instructed to touch a target location in the hemispace opposite a cued location. For the TDC group, model comparison using growth curve analysis revealed that a quadratic trend was the most appropriate fit with evidence of rapid improvement in anti-reach performance up until middle childhood (around 8-9years of age), followed by a more gradual rate of improvement into late childhood and early adolescence. This pattern was evident on both chronometric and kinematic measures. In contrast, for children with DCD, a linear function provided the best to fit on the key metrics, with a slower rate of improvement than controls. We conclude that children with DCD require a more extended period of development to effectively couple online motor control and executive systems when completing anti-reach movements, whereas TDC show rapid improvement in early and middle childhood. These group differences in growth curves are likely to reflect a maturational lag in the development of motor-cognitive networks in children with DCD.
Publisher: SAGE Publications
Date: 22-01-2018
Abstract: Acquired brain injury (ABI) is associated with a range of cognitive and motor deficits, and poses a significant personal, societal, and economic burden. Rehabilitation programs are available that target motor skills or cognitive functioning. In this review, we summarize the existing evidence that training may enhance structural neuroplasticity in patients with ABI, as assessed using structural magnetic resonance imaging (MRI)–based techniques that probe microstructure or morphology. Twenty-five research articles met key inclusion criteria. Most trials measured relevant outcomes and had treatment benefits that would justify the risk of potential harm. The rehabilitation program included a variety of task-oriented movement exercises (such as facilitation therapy, postural control training), neurorehabilitation techniques (such as constraint-induced movement therapy) or computer-assisted training programs (eg, Cogmed program). The reviewed studies describe regional alterations in white matter architecture and/or gray matter volume with training. Only weak-to-moderate correlations were observed between improved behavioral function and structural changes. While structural MRI is a powerful tool for detection of longitudinal structural changes, specific measures about the underlying biological mechanisms are lacking. Continued work in this field may potentially see structural MRI metrics used as biomarkers to help guide treatment at the in idual patient level.
Publisher: Frontiers Media SA
Date: 2013
Publisher: Wiley
Date: 06-10-2015
DOI: 10.1002/HBM.22958
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.NEUROIMAGE.2016.12.003
Abstract: Traumatic brain injury (TBI) is associated with cognitive and motor deficits, and poses a significant personal, societal, and economic burden. One mechanism by which TBI is thought to affect cognition and behavior is through changes in functional connectivity. Graph theory is a powerful framework for quantifying topological features of neuroimaging-derived functional networks. The objective of this paper is to review studies examining functional connectivity in TBI with an emphasis on graph theoretical analysis that is proving to be valuable in uncovering network abnormalities in this condition. We review studies that have examined TBI-related alterations in different properties of the functional brain network, including global integration, segregation, centrality and resilience. We focus on functional data using task-related fMRI or resting-state fMRI in patients with TBI of different severity and recovery phase, and consider how graph metrics may inform rehabilitation and enhance efficacy. Moreover, we outline some methodological challenges associated with the examination of functional connectivity in patients with brain injury, including the s le size, parcellation scheme used, node definition and subgroup analyses. The findings suggest that TBI is associated with hyperconnectivity and a suboptimal global integration, characterized by increased connectivity degree and strength and reduced efficiency of functional networks. This altered functional connectivity, also evident in other clinical populations, is attributable to diffuse white matter pathology and reductions in gray and white matter volume. These functional alterations are implicated in post-concussional symptoms, posttraumatic stress and neurocognitive dysfunction after TBI. Finally, the effects of focal lesions have been found to depend critically on topological position and their role in the network. Graph theory is a unique and powerful tool for exploring functional connectivity in brain-injured patients. One limitation is that its results do not provide specific measures about the biophysical mechanism underlying TBI. Continued work in this field will hopefully see graph metrics used as biomarkers to provide more accurate diagnosis and help guide treatment at the in idual patient level.
Publisher: Springer International Publishing
Date: 2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2018
Publisher: Wiley
Date: 27-02-2020
DOI: 10.1002/ACN3.50984
Publisher: Elsevier BV
Date: 04-2010
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2010.01.017
Abstract: Traumatic brain injury (TBI) patients have a high incidence of eye-hand coordination deficits. Diffuse axonal injury is common in TBI and is presumed to contribute to persistent motor problems. Using Diffusion Tensor Imaging (DTI), this study sought to identify changes in (sensori)motor white matter (WM) pathways/regions in a TBI group during the chronic recovery stage. A secondary objective was to examine the relationship between WM integrity and upper-limb visuomotor tracking performance. A young TBI (n=17) and control (n=14) group performed a dynamic tracking task, characterized by increasing information processing speed and predictive movement control. DTI scans were administered along with standard anatomical scans. The TBI group was found to perform inferior to the control group on the tracking task. Decreased fractional anisotropy was found in the TBI group in dedicated pathways involved in transmission of afferent and efferent information, i.e., corticospinal tract, posterior thalamic radiation, and optic radiation, due to increased diffusivity parallel and perpendicular to axonal fibre direction. This decrease in WM integrity was associated with inferior visuomotor tracking performance. Moreover, discriminant function analysis demonstrated that the model, based on the combined application of DTI and behavioral measures, was the most effective in distinguishing between TBI patients and controls. This study shows that specific eye-hand coordination deficits in a young TBI group are related to microstructural abnormalities in task-specific cerebral WM structures. Measures of white matter integrity are potentially important biomarkers for TBI that may support prognosis of motor deficits.
Publisher: Springer Science and Business Media LLC
Date: 11-03-2021
Publisher: Public Library of Science (PLoS)
Date: 20-06-2014
Publisher: Cold Spring Harbor Laboratory
Date: 04-03-2022
DOI: 10.1101/2022.03.02.22271654
Abstract: Graph theoretical analysis of the structural connectome has been employed successfully to characterise brain network alterations in patients with traumatic brain injury (TBI). However, heterogeneity in neuropathology is a well-known issue in the TBI population, such that group comparisons of patients against controls are confounded by within-group variability. Recently, novel single-subject profiling approaches have been developed to capture inter-patient heterogeneity. We present a personalised connectomics approach that examines structural brain alterations in six chronic patients with moderate-to-severe TBI who underwent anatomical and diffusion magnetic resonance imaging (MRI). We generated in idualised profiles of lesion characteristics and network measures (including personalised graph metric ‘GraphMe’ plots, and nodal and edge-based brain network alterations) and compared them against healthy reference cases (N=12) to assess brain damage qualitatively and quantitatively at the in idual level. Our findings revealed clinically significant alterations of brain networks with high variability between patients. Our profiling can be used by clinicians to formulate a neuroscience-guided integrative rehabilitation program for TBI patients, and for designing personalised rehabilitation protocols based on their unique lesion load and connectome.
Publisher: BMJ
Date: 07-2021
DOI: 10.1136/BMJOPEN-2020-046830
Abstract: There are no well-established biomedical treatments for the core symptoms of autism spectrum disorder (ASD). A small number of studies suggest that repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique, may improve clinical and cognitive outcomes in ASD. We describe here the protocol for a funded multicentre randomised controlled clinical trial to investigate whether a course of rTMS to the right temporoparietal junction (rTPJ), which has demonstrated abnormal brain activation in ASD, can improve social communication in adolescents and young adults with ASD. This study will evaluate the safety and efficacy of a 4-week course of intermittent theta burst stimulation (iTBS, a variant of rTMS) in ASD. Participants meeting criteria for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ASD (n=150, aged 14–40 years) will receive 20 sessions of either active iTBS (600 pulses) or sham iTBS (in which a sham coil mimics the sensation of iTBS, but no active stimulation is delivered) to the rTPJ. Participants will undergo a range of clinical, cognitive, epi/genetic, and neurophysiological assessments before and at multiple time points up to 6 months after iTBS. Safety will be assessed via a structured questionnaire and adverse event reporting. The study will be conducted from November 2020 to October 2024. The study was approved by the Human Research Ethics Committee of Monash Health (Melbourne, Australia) under Australia’s National Mutual Acceptance scheme. The trial will be conducted according to Good Clinical Practice, and findings will be written up for scholarly publication. Australian New Zealand Clinical Trials Registry (ACTRN12620000890932).
Publisher: Elsevier BV
Date: 08-2006
DOI: 10.1016/J.NBD.2006.03.009
Abstract: alpha-Mannosidosis is a lysosomal storage disorder caused by lysosomal alpha-mannosidase (LAMAN) deficiency that leads to neurocognitive dysfunctions, psychotic symptoms and emotional changes in human patients. A murine mannosidosis model, LAMAN-deficient mice, was examined on a behavioral task battery that included test for neuromotor, exploratory and neurocognitive (spatial learning and memory) abilities, and multivariate statistical analyses were used to identify behavioral and neurocognitive domains that are most heavily affected by LAMAN deficiency. In addition, we further investigated synaptic plasticity recordings on hippoc al slices that may relate to these behavioral alterations. Correlation analysis revealed significant intra- and intertask correlations and factor analysis that included all 21 behavioral variables identified three main factors (exploration/emotionality, locomotion and learning/memory abilities). Significant correlations were observed between genotype, and factor 1 (exploration/emotionality) and factor 3 (learning/memory abilities). Discriminant function analysis showed that "path length in the open field test" and "time spent in the target quadrant during the water maze probe trial" were the most decisive variables to distinguish between the genotypes. We therefore suggest that these variables would be especially important in forthcoming therapy assessment experiments using this murine mannosidosis model. LAMAN-deficient mice displayed severe changes in synaptic plasticity, which may have contributed to the neurocognitive impairments observed. The present report further shows that targeted deletion of the LAMAN gene in mice mimics many aspects of human alpha-mannosidosis, and these data provide a basis for future therapeutic experiments.
Publisher: Wiley
Date: 07-04-2014
DOI: 10.1002/HBM.22524
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.BANDC.2016.04.010
Abstract: Recent research suggests that children with Developmental Coordination Disorder (DCD) often show deficits in executive functioning (EF) and, more specifically, the ability to use inhibitory control in 'hot', emotionally rewarding contexts. This study optimized the assessment of sensitivity of children with DCD to emotionally significant stimuli by using easily discriminable emotional expressions in a go/no-go task. Thirty-six children (12 with DCD), aged 7-12years, completed an emotional go/no-go task in which neutral facial expressions were paired with either happy or sad ones. Each expression was used as both, a go and no-go target in different runs of the task. There were no group differences in omission errors however, the DCD group made significantly more commission errors to happy no-go faces. The particular pattern of performance in DCD confirms earlier reports of (hot) EF deficits. Specifically, a problem of inhibitory control appears to underlie the atypical pattern of performance seen in DCD on both cold and hot EF tasks. Disrupted coupling between cognitive control and emotion processing networks, such as fronto-parietal and fronto-striatal networks, may contribute to reduced inhibitory control in DCD. The implications for a broader theoretical account of DCD are discussed, as are implications for intervention.
Publisher: Wiley
Date: 04-05-2016
DOI: 10.1111/DESC.12424
Abstract: Children with autism spectrum disorders (ASD) often exhibit motor clumsiness (Developmental Coordination Disorder, DCD), i.e. they struggle with everyday tasks that require motor coordination like dressing, self-care, and participating in sport and leisure activities. Previous studies in these neurodevelopmental disorders have demonstrated functional abnormalities and alterations of white matter microstructural integrity in specific brain regions. These findings suggest that the global organization of brain networks is affected in DCD and ASD and support the hypothesis of a 'dys-connectivity syndrome' from a network perspective. No studies have compared the structural covariance networks between ASD and DCD in order to look for the signature of DCD independent of comorbid autism. Here, we aimed to address the question of whether abnormal connectivity in DCD overlaps that seen in autism or comorbid DCD-autism. Using graph theoretical analysis, we investigated differences in global and regional topological properties of structural brain networks in 53 children: 8 ASD children with DCD (DCD+ASD), 15 ASD children without DCD (ASD), 11 with DCD only, and 19 typically developing (TD) children. We constructed separate structural correlation networks based on cortical thickness derived from Freesurfer. The children were assessed on the Movement-ABC and the Beery Test of Visual Motor Integration. Behavioral results demonstrated that the DCD group and DCD+ASD group scored on average poorer than the TD and ASD groups on various motor measures. Furthermore, although the brain networks of all groups exhibited small-world properties, the topological architecture of the networks was significantly altered in children with ASD compared with DCD and TD. ASD children showed increased normalized path length and higher values of clustering coefficient. Also, paralimbic regions exhibited nodal clustering coefficient alterations in singular disorders. These changes were disorder-specific, and included alterations in clustering coefficient in the isthmus of the right cingulate gyrus and the pars orbitalis of the right inferior frontal gyrus in ASD children, and DCD-related increases in the lateral orbitofrontal cortex. Children meeting criteria for both DCD and ASD exhibited topological changes that were more widespread from those seen in children with only DCD, i.e. children with DCD+ASD showed alterations of clustering coefficient in (para)limbic regions, primary areas, and association areas. The DCD+ASD group showed changes in clustering coefficient in the left association cortex relative to the ASD group. Finally, the DCD+ASD group shared ASD-specific abnormalities in the pars orbitalis of right inferior frontal gyrus, which was hypothesized to reflect atypical emotional-cognitive processing. Our results provide evidence that DCD and ASD are neurodevelopmental disorders with a low degree of overlap in abnormalities in connectivity. The co-occurrence of DCD+ASD was also associated with a distinct topological pattern, highlighting the unique neural signature of comorbid neurodevelopmental disorders.
Publisher: Wiley
Date: 10-2018
DOI: 10.1002/HBM.24384
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.JPAIN.2016.04.005
Abstract: Compelling evidence has shown chronic widespread and exaggerated pain experience in chronic musculoskeletal pain (MSKP) conditions. In addition, neuroimaging research has revealed morphological and functional brain alterations in these patients. It is hypothesized that brain alterations play a role in the persistent pain complaints of patients with chronic MSKP. Nevertheless, lack of overview exists regarding the relations between brain alterations and clinical measures of pain. The present systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, to investigate the relations between structural or functional brain alterations, using magnetic resonance imaging scans, and clinical pain measures in patients with chronic MSKP. PubMed, Web of Science, Cinahl, and Cochrane databases were searched. First, the obtained articles were screened according to title and abstract. Second, the screening was on the basis of full-text. Risk of bias in included studies was investigated according to the modified Newcastle-Ottawa Scale. Twenty studies met the inclusion criteria. Moderate evidence shows that higher pain intensity and pressure pain sensitivity are related to decreased regional gray matter (GM) volume in brain regions encompassing the cingulate cortex, the insula, and the superior frontal and temporal gyrus. Further, some evidence exists that longer disease duration in fibromyalgia is correlated with decreased total GM volume. Yet, inconclusive evidence exists regarding the association of longer disease duration with decreased or increased regional GM volume in other chronic MSKP conditions. Inconclusive evidence was found regarding the direction of the relation of pain intensity and pressure pain sensitivity with microstructural white matter and functional connectivity alterations. In conclusion, preliminary to moderate evidence demonstrates relations between clinical pain measures, and structural and functional connectivity alterations within brain regions involved in somatosensory, affective, and cognitive processing of pain in chronic MSKP. Nevertheless, inconclusive results exist regarding the direction of these relations. Further research is warranted to unravel whether these brain alterations are positively or negatively correlated to clinical pain measures. Structural and functional brain alterations within regions involved in somatosensory, affective, and cognitive pain processing play a crucial role in the persistent pain of chronic MSKP patients. Accordingly, these brain alterations have to be taken into account when assessing and treating patients with chronic MSKP.
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.NEUBIOREV.2018.01.002
Abstract: Recent neuroimaging studies have reported atypical neural activation in children with Developmental Coordination Disorder (DCD) during tasks assessing manual dexterity. However, small s le sizes and subtle differences in task parameters have led to inconsistent findings, rendering interpretation difficult. The aim of the present meta-analysis was to quantitatively summarize this body of evidence using activation likelihood estimation (ALE) analysis to identify reliable regions of differential neural activation in children with DCD, compared to age-matched controls. Seven studies that adopted fMRI to compare children with and without DCD during manual performance were identified following a literature search. All were included in the ALE analysis. Compared to controls, children with DCD showed reduced activation during a manual dexterity task in the middle frontal gyrus, superior frontal gyrus, cerebellum, supramarginal gyrus, and inferior parietal lobule. Children with DCD showed greater activation in parts of the thalamus. Findings provide much needed clarification into the possible neural contributors to atypical manual dexterity in DCD and highlight the need for neuroimaging studies to include manual performance outcomes.
Publisher: Wiley
Date: 06-10-2016
DOI: 10.1002/HBM.23297
No related grants have been discovered for Karen Caeyenberghs.