ORCID Profile
0000-0002-7129-6684
Current Organisations
University of South Australia
,
The Francis Crick Institute
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Publisher: Informa UK Limited
Date: 13-10-2023
Publisher: Wiley
Date: 23-04-2014
DOI: 10.1111/EJN.12597
Abstract: Ipsilateral primary motor cortex (M1) reorganisation after unilateral lower-limb utation may degrade function of the utated limb. We hypothesised unilateral lower-limb utees would have a bilateral increase in corticomotor excitability, and increased excitability of ipsilateral M1 would be associated with increased step-time variability during gait. Twenty transtibial utees (16 male) aged 60.1 years (range 45-80 years), and 20 age- and gender-matched healthy adult controls were recruited. Single-pulse transcranial magnetic stimulation assessed corticomotor excitability. Two indices of corticomotor excitability were calculated. An index of corticospinal excitability (ICE) determined relative excitability of ipsilateral and contralateral corticomotor projections to alpha-motoneurons innervating the quadriceps muscle (QM) of the utated limb. A laterality index (LI) assessed relative excitability of contralateral projections from each hemisphere. Spatial-temporal gait analysis was performed to calculate step-time variability. Amputees had lower ICE values, indicating relatively greater excitability of ipsilateral corticomotor projections than controls (P = 0.04). A lower ICE value was associated with increased step-time variability for utated (P = 0.04) and non- utated limbs (P = 0.02). This association suggests corticomotor projections from ipsilateral M1 to alpha-motoneurons innervating the utated limb QM may interfere with gait. Cortical excitability in utees was not increased bilaterally, contrary to our hypothesis. There was no difference in excitability of contralateral M1 between utees and controls (P = 0.10), and no difference in LI (P = 0.71). It appears both hemispheres control one QM, with predominance of contralateral corticomotor excitability in healthy adults. Following lower-limb utation, putative ipsilateral corticomotor excitability is relatively increased in some utees and may negatively impact on function.
Publisher: Elsevier BV
Date: 11-2015
Publisher: SAGE Publications
Date: 12-02-2021
Abstract: In preclinical models, behavioral training early after stroke produces larger gains compared with delayed training. The effects are thought to be mediated by increased and widespread reorganization of synaptic connections in the brain. It is viewed as a period of spontaneous biological recovery during which synaptic plasticity is increased. To look for evidence of a similar change in synaptic plasticity in the human brain in the weeks and months after ischemic stroke. We used continuous theta burst stimulation (cTBS) to activate synapses repeatedly in the motor cortex. This initiates early stages of synaptic plasticity that temporarily reduces cortical excitability and motor-evoked potential litude. Thus, the greater the effect of cTBS on the motor-evoked potential, the greater the inferred level of synaptic plasticity. Data were collected from separate cohorts (Australia and UK). In each cohort, serial measurements were made in the weeks to months following stroke. Data were obtained for the ipsilesional motor cortex in 31 stroke survivors (Australia, 66.6 ± 17.8 years) over 12 months and the contralesional motor cortex in 29 stroke survivors (UK, 68.2 ± 9.8 years) over 6 months. Depression of cortical excitability by cTBS was most prominent shortly after stroke in the contralesional hemisphere and diminished over subsequent sessions ( P = .030). cTBS response did not differ across the 12-month follow-up period in the ipsilesional hemisphere ( P = .903). Our results provide the first neurophysiological evidence consistent with a period of enhanced synaptic plasticity in the human brain after stroke. Behavioral training given during this period may be especially effective in supporting poststroke recovery.
Publisher: American Physiological Society
Date: 05-2020
Abstract: Voluntary force production requires that the brain produces and transmits a motor command to the muscles. It is widely acknowledged that motor commands are executed from the primary motor cortex (M1) located in the contralateral hemisphere. However, involvement of M1 located in the ipsilateral hemisphere during moderate to high levels of unilateral muscle contractions ( % of the maximum) has been disclosed in recent years. This phenomenon has been termed cross-activation. The activation of the ipsilateral M1 relies on complex inhibitory and excitatory interhemispheric interactions mediated via the corpus callosum and modulated according to the contraction level. The regulatory mechanisms underlying these interhemispheric interactions, especially excitatory ones, remain vague, and contradictions exist in the literature. In addition, very little is known regarding the possibility that other pathways could also mediate the cross-activation. In the present review, we will therefore summarize the concept of cross-activation during unilateral voluntary muscle contraction and explore the associated mechanisms and other nervous system pathways underpinning this response. A broader knowledge of these mechanisms would consequently allow a better comprehension of the motor system as a whole, as distant brain networks working together to produce the motor command.
Publisher: Springer Science and Business Media LLC
Date: 16-06-2022
DOI: 10.1038/S41597-022-01401-7
Abstract: Accurate lesion segmentation is critical in stroke rehabilitation research for the quantification of lesion burden and accurate image processing. Current automated lesion segmentation methods for T1-weighted (T1w) MRIs, commonly used in stroke research, lack accuracy and reliability. Manual segmentation remains the gold standard, but it is time-consuming, subjective, and requires neuroanatomical expertise. We previously released an open-source dataset of stroke T1w MRIs and manually-segmented lesion masks (ATLAS v1.2, N = 304) to encourage the development of better algorithms. However, many methods developed with ATLAS v1.2 report low accuracy, are not publicly accessible or are improperly validated, limiting their utility to the field. Here we present ATLAS v2.0 (N = 1271), a larger dataset of T1w MRIs and manually segmented lesion masks that includes training (n = 655), test (hidden masks, n = 300), and generalizability (hidden MRIs and masks, n = 316) datasets. Algorithm development using this larger s le should lead to more robust solutions the hidden datasets allow for unbiased performance evaluation via segmentation challenges. We anticipate that ATLAS v2.0 will lead to improved algorithms, facilitating large-scale stroke research.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.JSTROKECEREBROVASDIS.2022.106789
Abstract: Stroke is a global leading cause of adult disability with survivors often enduring persistent impairments and loss of function. Both intensity and dosage of training appear to be important factors to help restore behavior. However, current practice fails to achieve sufficient intensity and dose of training to promote meaningful recovery. The purpose of this review is to propose therapeutic solutions that can help achieve a higher dose and/or intensity of therapy. Raising awareness of these intensive, high-dose, treatment strategies might encourage clinicians to re-evaluate current practice and optimize delivery of stroke rehabilitation for maximal recovery. Literature that tested and evaluated solutions to increase dose or intensity of training was reviewed. For each therapeutic strategy, we outline evidence of clinical benefit, supporting neurophysiological data (where available) and discuss feasibility of clinical implementation. Possible therapeutic solutions included constraint induced movement therapy, robotics, circuit therapy, bursts of training, gaming technologies, goal-oriented instructions, and cardiovascular exercise. Our view is that clinicians should evaluate current practice to determine how intensive high-dose training can be implemented to promote greater recovery after stroke.
Publisher: MDPI AG
Date: 22-02-2021
DOI: 10.3390/BIOMEDICINES9020223
Abstract: Stroke is a leading cause of death and disability and is responsible for a significant economic burden. Sarcopenia and cognitive dysfunction are common consequences of stroke, but there is less awareness of the concurrency of these conditions. In addition, few reviews are available to guide clinicians and researchers on how to approach sarcopenia and cognitive dysfunction as comorbidities after stroke, including how to assess and manage them and implement interventions to improve health outcomes. This review synthesises current knowledge about the relationship between post-stroke sarcopenia and cognitive dysfunction, including the physiological pathways, assessment tools, and interventions involved.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-05-2021
DOI: 10.1212/WNL.0000000000012187
Abstract: New treatments that can facilitate neural repair and reduce persistent impairments have significant value in promoting recovery following stroke. One technique that has gained interest is transcranial direct current stimulation (tDCS) as early research suggested it could enhance plasticity and enable greater behavioral recovery. However, several studies have now identified substantial intersubject variability in response to tDCS and clinical trials revealed insufficient evidence of treatment effectiveness. A possible explanation for the varied and negative findings is that the physiologic model of stroke recovery that researchers have used to guide the application of tDCS-based treatments in stroke is overly simplistic and does not account for stroke heterogeneity or known determinants that affect the tDCS response. Here, we propose that tDCS could have a more clearly beneficial role in enhancing stroke recovery if greater consideration is given to in idualizing treatment. By critically reviewing the proposed mechanisms of tDCS, stroke physiology across the recovery continuum, and known determinants of tDCS response, we propose a new, theoretical, patient-tailored approach to delivering tDCS after stroke. The proposed model includes a step-by-step principled selection strategy for identifying optimal neuromodulation targets and outlines key areas for further investigation. Tailoring tDCS treatment to in idual neuroanatomy and physiology is likely our best chance at producing robust and meaningful clinical benefit for people with stroke and would therefore accelerate opportunities for clinical translation.
Publisher: The Royal Society
Date: 08-2017
DOI: 10.1098/RSOS.170660
Abstract: Restorative brain–computer interfaces (BCIs) have been proposed to enhance stroke rehabilitation. Restorative BCIs are able to close the sensorimotor loop by rewarding motor imagery (MI) with sensory feedback. Despite the promising results from early studies, reaching clinically significant outcomes in a timely fashion is yet to be achieved. This lack of efficacy may be due to suboptimal feedback provision. To the best of our knowledge, the optimal feedback update interval (FUI) during MI remains unexplored. There is evidence that sensory feedback disinhibits the motor cortex. Thus, in this study, we explore how shorter than usual FUIs affect behavioural and neurophysiological measures following BCI training for stroke patients using a single-case proof-of-principle study design. The action research arm test was used as the primary behavioural measure and showed a clinically significant increase (36%) over the course of training. The neurophysiological measures including motor evoked potentials and maximum voluntary contraction showed distinctive changes in early and late phases of BCI training. Thus, this preliminary study may pave the way for running larger studies to further investigate the effect of FUI magnitude on the efficacy of restorative BCIs. It may also elucidate the role of early and late phases of motor learning along the course of BCI training.
Publisher: Peertechz Publications Private Limited
Date: 12-01-2017
Publisher: Frontiers Media SA
Date: 17-01-2023
Publisher: JMIR Publications Inc.
Date: 23-04-2018
Abstract: troke can have devastating consequences for an in idual’s quality of life. Interventions capable of enhancing response to therapy would be highly valuable to the field of neurological rehabilitation. One approach is to use noninvasive brain stimulation techniques, such as transcranial direct current stimulation, to induce a neuroplastic response. When delivered in combination with rehabilitation exercises, there is some evidence that transcranial direct current stimulation is beneficial. However, responses to stimulation are highly variable. Therefore biomarkers predictive of response to stimulation would be valuable to help select appropriate people for this potentially beneficial treatment. he objective of this study is to investigate connectivity of the stimulation target, the ipsilesional motor cortex, as a biomarker predictive of response to anodal transcranial direct current stimulation in people with stroke. his study is a double blind, randomized controlled trial (RCT), with two parallel groups. A total of 68 participants with first ever ischemic stroke with motor impairment will undertake a two week (14 session) treatment for upper limb function (Graded Repetitive Arm Supplementary Program GRASP). Participants will be randomized 2:1 to active:sham treatment groups. Those in the active treatment group will receive anodal transcranial direct current stimulation to the ipsilesional motor cortex at the start of each GRASP session. Those allocated to the sham treatment group will receive sham transcranial direct current stimulation. Behavioural assessments of upper limb function will be performed at baseline, post treatment, 1 month follow-up and 3 months follow-up. Neurophysiological assessments will include magnetic resonance imaging (MRI), electroencephalography (EEG) and transcranial magnetic stimulation (TMS) and will be performed at baseline, post treatment, 1 month follow-up (EEG and TMS only) and 3 months follow-up (EEG and TMS only). articipants will be recruited between March 2018 and December 2018, with experimental testing concluding in March 2019. dentifying a biomarker predictive of response to transcranial direct current stimulation would greatly assist clinical utility of this novel treatment approach. ustralia New Zealand Clinical Trials Registry ACTRN12618000443291 www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12618000443291 (Archived by WebCite at 37QOXXxt) R1-10.2196/10848
Publisher: MDPI AG
Date: 21-05-2020
Abstract: Stroke remains a global leading cause of disability. Novel treatment approaches are required to alleviate impairment and promote greater functional recovery. One potential candidate is transcranial direct current stimulation (tDCS), which is thought to non-invasively promote neuroplasticity within the human cortex by transiently altering the resting membrane potential of cortical neurons. To date, much work involving tDCS has focused on upper limb recovery following stroke. However, lower limb rehabilitation is important for regaining mobility, balance, and independence and could equally benefit from tDCS. The purpose of this review is to discuss tDCS as a technique to modulate brain activity and promote recovery of lower limb function following stroke. Preliminary evidence from both healthy adults and stroke survivors indicates that tDCS is a promising intervention to support recovery of lower limb function. Studies provide some indication of both behavioral and physiological changes in brain activity following tDCS. However, much work still remains to be performed to demonstrate the clinical potential of this neuromodulatory intervention. Future studies should consider treatment targets based on in idual lesion characteristics, stage of recovery (acute vs. chronic), and residual white matter integrity while accounting for known determinants and biomarkers of tDCS response.
Publisher: Informa UK Limited
Date: 30-10-2016
DOI: 10.3109/09638288.2015.1103790
Abstract: Lower limb utee rehabilitation has traditionally focussed on restoration of gait and balance through use of prosthetic limbs and mobility aids. Despite these efforts, some utees continue to experience difficulties with mastering prosthetic mobility. Emerging techniques in rehabilitation, such as non-invasive brain stimulation (NIBS), may be an appropriate tool to enhance prosthetic rehabilitation outcomes by promoting "normal" brain reorganisation and function. The purpose of this review is to highlight the potential of NIBS to improve functional outcomes for lower limb utees. To demonstrate the rationale for applying NIBS to utees, this study will first review literature regarding human motor control of gait, followed by neurophysiological reorganisation of the motor system after utation and the relationship between brain reorganisation and gait function. We will conclude by reviewing literature demonstrating application of NIBS to lower limb muscle representations and evidence supportive of subsequent functional improvements. Imaging, brain stimulation and behavioural evidence indicate that the cortex contributes to locomotion in humans. Following utation both hemispheres reorganise with evidence suggesting brain reorganisation is related to functional outcomes in utees. Previous studies indicate that brain stimulation techniques can be used to selectively promote neuroplasticity of lower limb cortical representations with improvements in function. We suggest NIBS has the potential to transform lower limb utee rehabilitation and should be further investigated. Implications for Rehabilitation Despite extensive rehabilitation some utees continue to experience difficulty with prosthetic mobility Brain reorganisation following utation has been related to functional outcomes and may be an appropriate target for novel interventions Non-invasive brain stimulation is a promising tool which has potential to improve functional outcomes for lower limb utees.
Publisher: JMIR Publications Inc.
Date: 18-10-2018
DOI: 10.2196/10848
Publisher: SAGE Publications
Date: 2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2023
DOI: 10.1161/STROKEAHA.123.043713
Abstract: Integrity of the corticospinal tract (CST) is an important biomarker for upper limb motor function following stroke. However, when structurally compromised, other tracts may become relevant for compensation or recovery of function. We used the ENIGMA Stroke Recovery data set, a multicenter, retrospective, and cross-sectional collection of patients with upper limb impairment during the chronic phase of stroke to test the relevance of tracts in in iduals with less and more severe (laterality index of CST fractional anisotropy ≥0.25) CST damage in an observational study design. White matter integrity was quantified using fractional anisotropy for the CST, the superior longitudinal fascicle, and the callosal fibers interconnecting the primary motor cortices between hemispheres. Optic radiations served as a control tract as they have no a priori relevance for the motor system. Pearson correlation was used for testing correlation with upper limb motor function (Fugl-Meyer upper extremity). From 1235 available data sets, 166 were selected (by imaging, Fugl-Meyer upper extremity, covariates, stroke location, and stage) for analyses. Only in iduals with severe CST damage showed a positive association of fractional anisotropy in both callosal fibers interconnecting the primary motor cortices ( r [21]=0.49 P= 0.025) and superior longitudinal fascicle ( r [21]=0.51 P=0 .018) with Fugl-Meyer upper extremity. Our data support the notion that in iduals with more severe damage of the CST depend on residual pathways for achieving better upper limb outcome than those with less affected CST.
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.JSTROKECEREBROVASDIS.2022.106557
Abstract: To investigate whether cognitive reserve modifies the relationship between functional connectivity, lesion volume, stroke severity and upper-limb motor impairment and recovery in stroke survivors. Ten patients with first-ever ischemic middle cerebral artery stroke completed the Cognitive Reserve Index Questionnaire at baseline. Upper-limb motor impairment and functional connectivity were assessed using the Fugl-Meyer Assessment and electroencephalography respectively at baseline and 3-months post-stroke. A debiased weighted phase lag index was computed to estimate functional connectivity between electrodes. Partial least squares (PLS) regression identified a connectivity model that maximally predicted variance in the degree of upper-limb impairment. Regression models were generated to determine whether cognitive reserve modified the relationship between neural function (functional connectivity), neural injury (lesion volume), stroke severity (National Institutes of Health Stroke Scale) and upper-limb motor impairment at baseline and recovery at 3-months (Fugl-Meyer Assessment). The addition of cognitive reserve to a regression model with a dependent variable of upper-limb motor recovery and independent variables of functional connectivity between the ipsilesional motor cortex and parietal cortex, stroke severity and lesion volume improved model efficiency (∆BIC=-7.07) despite not reaching statistical significance (R Preliminary observations suggest cognitive reserve might modify the relationship between neural function, neural injury, stroke severity and upper-limb motor recovery. Further investigation of cognitive reserve in motor recovery post-stroke appears warranted.
Publisher: Frontiers Media SA
Date: 15-03-2018
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.NEUROSCIENCE.2019.08.038
Abstract: Brain connectivity studies have reported that functional networks change with older age. We aim to (1) investigate whether electroencephalography (EEG) data can be used to distinguish between in idual functional networks of young and old adults and (2) identify the functional connections that contribute to this classification. Two eyes-open resting-state EEG recording sessions with 64 electrodes for each of 22 younger adults (19-37 years) and 22 older adults (63-85 years) were conducted. For each session, imaginary coherence matrices in delta, theta, alpha, beta and gamma bands were computed. A range of machine learning classification methods were utilized to distinguish younger and older adult brains. A support vector machine (SVM) classifier was 93% accurate in classifying the brains by age group. We report decreased functional connectivity with older age in delta, theta, alpha and gamma bands, and increased connectivity with older age in beta band. Most connections involving frontal, temporal, and parietal electrodes, and more than half of connections involving occipital electrodes, showed decreased connectivity with older age. Slightly less than half of the connections involving central electrodes showed increased connectivity with older age. Functional connections showing decreased strength with older age were not significantly different in electrode-to-electrode distance than those that increased with older age. Most of the connections used by the classifier to distinguish participants by age group belonged to the alpha band. Findings suggest a decrease in connectivity in key networks and frequency bands associated with attention and awareness, and an increase in connectivity of the sensorimotor functional networks with aging during a resting state.
Publisher: MDPI AG
Date: 21-08-2020
Abstract: Obesity is characterised by excessive body fat and is associated with several detrimental health conditions, including cardiovascular disease and diabetes. There is some evidence that people who are obese have structural and functional brain alterations and cognitive deficits. It may be that these neurophysiological and behavioural consequences are underpinned by altered plasticity. This study investigated the relationship between obesity and plasticity of the motor cortex in people who were considered obese (n = 14, nine males, aged 35.4 ± 14.3 years) or healthy weight (n = 16, seven males, aged 26.3 ± 8.5 years). A brain stimulation protocol known as continuous theta burst transcranial magnetic stimulation was applied to the motor cortex to induce a brief suppression of cortical excitability. The suppression of cortical excitability was quantified using single-pulse transcranial magnetic stimulation to record and measure the litude of the motor evoked potential in a peripheral hand muscle. Therefore, the magnitude of suppression of the motor evoked potential by continuous theta burst stimulation was used as a measure of the capacity for plasticity of the motor cortex. Our results demonstrate that the healthy-weight group had a significant suppression of cortical excitability following continuous theta burst stimulation (cTBS), but there was no change in excitability for the obese group. Comparing the response to cTBS between groups demonstrated that there was an impaired plasticity response for the obese group when compared to the healthy-weight group. This might suggest that the capacity for plasticity is reduced in people who are obese. Given the importance of plasticity for human behaviour, our results add further emphasis to the potentially detrimental health effects of obesity.
Publisher: Frontiers Media SA
Date: 14-07-2022
DOI: 10.3389/FNEUR.2022.869248
Abstract: Approximately one-third of stroke survivors experience post-stroke depression. Repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has shown promise as a treatment for depression with few side effects and high tolerability. However, previous post-stroke depression trials have not considered the effect of lesion location, the persistence of clinical improvements, nor the value of ongoing maintenance treatments. These questions are important to determine the therapeutic value of rTMS as a treatment for post-stroke depression. We report a unique case study of a 71-year-old male who had experienced a left hemispheric ischemic stroke 4 years prior. The patient was screened with the Beck Depression Inventory and Patient Health Questionnaire and found to be experiencing moderate levels of depression. Ten daily sessions of left dorsolateral pre-frontal cortex rTMS were applied over a two-week period. A clinically meaningful reduction in depression was achieved. Approximately 10 weeks following rTMS treatment, improvements in depression were attenuating. Weekly maintenance rTMS was delivered to the left dorsolateral pre-frontal cortex for 10 sessions. At the conclusion of maintenance rTMS, clinical assessments indicated depressive symptoms had reduced to a minimal to nil level. Clinically meaningful improvements in depression were maintained at 3 months after rTMS treatment had ceased. These findings provide novel insight to suggest rTMS may reduce depressive symptoms in stroke survivors with a lesion at the site of stimulation. Ongoing maintenance treatments might prove beneficial to enhance persistence of clinical improvements.
Publisher: Wiley
Date: 06-06-2012
DOI: 10.1002/PRI.1529
Abstract: In iduals with utations are a core group in Australian rehabilitation units that have a long index length of stay. The Repatriation General Hospital (RGH) offers general rehabilitation services to the population of Southern Adelaide (a population of 350,000) and includes an on-site prosthetic manufacturing facility. Using a physiotherapy database at the RGH, we sought to answer the following questions: What are the demographic and clinical characteristics of patients admitted for lower limb prosthetic rehabilitation over 15 years? What are the times to rehabilitation outcomes? How have these changed over 15 years with changes in service delivery? This paper is a retrospective observational study using a physiotherapy clinical database (1996-2010) of 531 consecutive in iduals with lower limb utation at one South Australian hospital (RGH). There were two changes in service delivery: 1) a multidisciplinary interim prosthetic programme (IPP) introduced in 1998 and 2) removable rigid dressings (RRDs) introduced in 2000. Outcome measures were patient demographics, clinical characteristics and time to rehabilitation outcome markers. Mean age was 68 years (standard deviation [SD]: 15), with 69% male, 80% dysvascular and 68% transtibial. The overall median inpatient rehabilitation length of stay (RLOS) was 39 days (interquartile range [IQR]: 26-57). In iduals with utation entering rehabilitation each year had a higher number of co-morbidities (β: 0.08 95% confidence interval: 0.05-0.11). Introduction of the IPP was associated with a significant reduction in time to initial prosthetic casting, independent walking and inpatient RLOS. Introduction of RRDs was associated with a significant reduction in time to wound healing, initial prosthetic casting and independent walking. In iduals with utation were typically elderly dysvascular men with transtibial utations. Introduction of the IPP and RRDs successfully reduced time to rehabilitation outcomes including independent walking, an outcome that is rarely reported but is of significance to patients and physiotherapists.
Publisher: Informa UK Limited
Date: 03-05-2023
Publisher: Informa UK Limited
Date: 07-12-2017
DOI: 10.1080/09638288.2016.1207110
Abstract: This study compared bilateral corticomotor and intracortical excitability of the primary motor cortex (M1), pre- and post-unilateral transtibial utation. Three males aged 45, 55, and 48 years respectively who were scheduled for elective utation and thirteen (10 male, 3 female) healthy control participants aged 58.9 (SD 9.8) were recruited. Transcranial magnetic stimulation assessed corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were performed 10 (SD 7) days prior to surgery and again at 10 (SD 3) days following surgery. Data were analyzed descriptively and objectively compared to 95% confidence intervals from control data. Prior to utation, all three patients demonstrated stronger short-latency intracortical inhibition evoked from M1 ipsilateral to the affected limb and reduced long-latency intracortical inhibition evoked from M1 contralateral to the affected limb compared to control subjects. Following utation, short-latency intracortical inhibition was reduced in both M1s and long-latency intracortical inhibition was reduced for the ipsilateral M1. Single-pulse motor evoked potential litude and motor thresholds were similar pre-to-post utation. Modulation of intracortical excitability shortly following utation indicates that the cortical environment may be optimized for reorganization in the acute post- utation period which might be significant for learning to support prosthetic mobility. Implications for Rehabilitation Amputation of a lower-limb is associated with extensive reorganization at the level of the cortex. Reorganization occurs in the acute post- utation period implying a favorable cortical environment for recovery. Rehabilitation or brain interventions may target the acute pre-prosthetic post- utation period to optimize recovery.
Publisher: Frontiers Media SA
Date: 07-07-2021
DOI: 10.3389/FNAGI.2021.679585
Abstract: Background: Increasing evidence demonstrates that repetitive transcranial magnetic stimulation (rTMS) treatment of the dorsolateral prefrontal cortex is beneficial for improving cognitive function in patients with Alzheimer’s disease (AD) however, the underlying mechanism of its therapeutic effect remains unclear. Objectives/Hypothesis: The aim of this study was to investigate the impact of rTMS to the dorsolateral prefrontal cortex on functional connectivity along with treatment response in AD patients with different severity of cognitive impairment. Methods: We conducted a 2-week treatment course of 10-Hz rTMS over the left dorsolateral prefrontal cortex in 23 patients with AD who were split into the mild or moderate cognitive impairment subgroup. Resting state electroencephalography and general cognition was assessed before and after rTMS. Power envelope connectivity was used to calculate functional connectivity at the source level. The functional connectivity of AD patients and 11 cognitively normal in iduals was compared. Results: Power envelope connectivity was higher in the delta and theta bands but lower in the beta band in the moderate cognitive impairment group, compared to the cognitively normal controls, at baseline ( p & 0.05). The mild cognitive impairment group had no significant abnormities. Montreal Cognitive Assessment scores improved after rTMS in the moderate and mild cognitive impairment groups. Power envelope connectivity in the beta band post-rTMS was increased in the moderate group ( p & 0.05) but not in the mild group. No significant changes in the delta and theta band were found after rTMS in both the moderate and mild group. Conclusion: High-frequency rTMS to the dorsolateral prefrontal cortex modulates electroencephalographic functional connectivity while improving cognitive function in patients with AD. Increased beta connectivity may have an important mechanistic role in rTMS therapeutic effects.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.APMR.2014.11.015
Abstract: To determine whether normalizing spatial-temporal gait data for walking speed obtained from multiple walking trials leads to differences in gait variability parameters associated with a history of falling in people with transtibial utations. Cross-sectional study. Rehabilitation center. People with unilateral transtibial utations (N=45 mean age ± SD, 60.5±13.7y 35 men [78%]) were recruited. Not applicable. Participants completed 10 consecutive walking trials using an instrumented walkway system. Primary gait parameters were walking speed and step-length, step-width, step-time, and swing-time variability. A retrospective 12-month fall history was obtained from participants. Sixteen utees (36%) were classified as fallers. Variation in gait speed across the 10 walking trials was 2.9% (range, 1.1%-12.1%). Variability parameters of normalized gait data were significantly different from variability parameters of nonnormalized data (all P<.01). For nonnormalized data, fallers had greater utated limb step-time (P=.02), step-length (P=.02), swing-time (P=.05), and step-width (P=.03) variability and non utated limb step-length (P=.04) and step-width (P=.01) variability. For normalized data, only 3 variability parameters were significantly greater for fallers. These were utated limb step-time (P=.05), step-length (P=.02), and step-width (P=.01) variability. Normalizing spatial-temporal gait data for walking speed before calculating gait variability parameters may aid in discerning variability parameters related to falls histories in people with transtibial utations. This may help focus on the initial rehabilitation efforts of utees with a fall history.
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.YFRNE.2021.100970
Abstract: Resting-state functional magnetic resonance imaging (rs-fMRI) has been actively used in the last decade to investigate brain functional connectivity alterations in Type 2 Diabetes Mellitus (T2DM) to understand the neuropathophysiology of T2DM in cognitive degeneration. Given the emergence of new analysis techniques, this scoping review aims to map the rs-fMRI analysis techniques that have been applied in the literature and reports the latest rs-fMRI findings that have not been covered in previous reviews. Graph theory, the contemporary rs-fMRI analysis, has been used to demonstrate altered brain topological organisations in people with T2DM, which included altered degree centrality, functional connectivity strength, the small-world architecture and network-based statistics. These alterations were correlated with T2DM patients' cognitive performances. Graph theory also contributes to identify unbiased seeds for seed-based analysis. The expanding rs-fMRI analytical approaches continue to provide new evidence that helps to understand the mechanisms of T2DM-related cognitive degeneration.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-05-2022
Abstract: Persistent sensorimotor impairments after stroke can negatively impact quality of life. The hippoc us is vulnerable to poststroke secondary degeneration and is involved in sensorimotor behavior but has not been widely studied within the context of poststroke upper‐limb sensorimotor impairment. We investigated associations between non‐lesioned hippoc al volume and upper limb sensorimotor impairment in people with chronic stroke, hypothesizing that smaller ipsilesional hippoc al volumes would be associated with greater sensorimotor impairment. Cross‐sectional T1‐weighted magnetic resonance images of the brain were pooled from 357 participants with chronic stroke from 18 research cohorts of the ENIGMA (Enhancing NeuoImaging Genetics through Meta‐Analysis) Stroke Recovery Working Group. Sensorimotor impairment was estimated from the FMA‐UE (Fugl‐Meyer Assessment of Upper Extremity). Robust mixed‐effects linear models were used to test associations between poststroke sensorimotor impairment and hippoc al volumes (ipsilesional and contralesional separately Bonferroni‐corrected, P .025), controlling for age, sex, lesion volume, and lesioned hemisphere. In exploratory analyses, we tested for a sensorimotor impairment and sex interaction and relationships between lesion volume, sensorimotor damage, and hippoc al volume. Greater sensorimotor impairment was significantly associated with ipsilesional ( P =0.005 β=0.16) but not contralesional ( P =0.96 β=0.003) hippoc al volume, independent of lesion volume and other covariates ( P =0.001 β=0.26). Women showed progressively worsening sensorimotor impairment with smaller ipsilesional ( P =0.008 β=−0.26) and contralesional ( P =0.006 β=−0.27) hippoc al volumes compared with men. Hippoc al volume was associated with lesion size ( P .001 β=−0.21) and extent of sensorimotor damage ( P =0.003 β=−0.15). The present study identifies novel associations between chronic poststroke sensorimotor impairment and ipsilesional hippoc al volume that are not caused by lesion size and may be stronger in women.
Publisher: Informa UK Limited
Date: 03-10-2022
DOI: 10.1080/09638288.2022.2123053
Abstract: To summarise body awareness assessment tools and interventions relevant for stroke rehabilitation using a framework that categorises key body awareness constructs, disorders and impairments. Online electronic databases and trial registries were searched from inception until July 2021, in addition to hand searching reference lists of included studies and reviews. Study selection included any study design where the investigation involved assessing and/or intervening in body awareness following stroke. Data were extracted based on predefined criteria by two independent reviewers and mapped to the emergent framework. The final analysis included 144 papers that reported 43 assessment tools and 8 types of interventions for body awareness. Consensus was reached on a synthesised body awareness framework. This comprised specific impairments and disorders, constructs, sub-categories and main categories leading to the overarching term of body awareness. Clinical and psychometric properties of the assessment tools were not reported or poorly evaluated, and the interventions lacked robust study designs and rigorous methods. The framework produced will enable future research and clinical practice to be based on consistent concepts and definitions. Clinicians can also use this information to cautiously select assessment tools and/or interventions but are reminded of the limitations identified in this review.Implications for rehabilitationThere is limited understanding, compounded by inconsistent terminology and definitions regarding body awareness after stroke.A synthesized framework to define key constructs and definitions of body awareness is proposed.Assessment tools and interventions reported in the literature are mapped to the proposed framework.Psychometric properties of available tools are reported.Significant work remains to refine concepts of body awareness, develop and evaluate assessment tools and interventions.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.BRS.2016.12.001
Abstract: The potential of non-invasive brain stimulation (NIBS) for both probing human neuroplasticity and the induction of functionally relevant neuroplastic change has received significant interest. However, at present the utility of NIBS is limited due to high response variability. One reason for this response variability is that NIBS targets a diffuse cortical population and the net outcome to stimulation depends on the relative levels of excitability in each population. There is evidence that the relative excitability of complex oligosynaptic circuits (late I-wave circuits) as assessed by transcranial magnetic stimulation (TMS) is useful in predicting NIBS response. Here we examined whether an additional marker of cortical excitability, MEP litude variability, could provide additional insights into response variability following application of the continuous theta burst stimulation (cTBS) NIBS protocol. Additionally we investigated whether I-wave recruitment was associated with MEP variability. Thirty-four healthy subjects (15 male, aged 18-35 years) participated in two experiments. Experiment 1 investigated baseline MEP variability and cTBS response. Experiment 2 determined if I-wave recruitment was associated with MEP variability. Data show that both baseline MEP variability and late I-wave recruitment are associated with cTBS response, but were independent of each other together, these variables predict 31% of the variability in cTBS response. This study provides insight into the physiological mechanisms underpinning NIBS plasticity responses and may facilitate development of more reliable NIBS protocols.
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.NEUROBIOLAGING.2022.09.003
Abstract: Alpha-band oscillatory activity in human electroencephalography (EEG) becomes slower and lower in litude with advanced age. However, the influence of aperiodic activity on these measures has received little consideration. We investigated whether age-related differences in aperiodic activity explains differences in resting EEG peak alpha frequency and power. We assessed aperiodic activity in 85 younger and 92 older adults by fitting the 1/f-like background activity evident in EEG power spectra using the spectral parameterization ("specparam") algorithm. Across the scalp, the aperiodic exponent and offset were smaller in older compared to younger participants, reflecting a flatter 1/f-like slope and a downward broadband shift in power spectra with age. After correcting for aperiodic activity, peak alpha frequency remained slower in older adults however, peak alpha power no longer differed statistically between age groups. The large s le size utilized in this study, as well as the depth of analysis, provides further evidence that the aperiodic component of the resting EEG signal is altered with aging and should be considered when investigating neural oscillatory activity.
Publisher: Cold Spring Harbor Laboratory
Date: 23-06-2023
DOI: 10.1101/2023.06.19.545638
Abstract: Chronic motor impairments are a leading cause of disability after stroke. Previous studies have predicted motor outcomes based on the degree of damage to predefined structures in the motor system, such as the corticospinal tract. However, such theory-based approaches may not take full advantage of the information contained in clinical imaging data. The present study uses data-driven approaches to predict chronic motor outcomes after stroke and compares the accuracy of these predictions to previously-identified theory-based biomarkers. Using a cross-validation framework, regression models were trained using lesion masks and motor outcomes data from 789 stroke patients (293 female/496 male) from the ENIGMA Stroke Recovery Working Group (age 64.9±18.0 years time since stroke 12.2±0.2 months normalised motor score 0.7±0.5 (range [0,1]). The out-of-s le prediction accuracy of two theory-based biomarkers was assessed: lesion load of the corticospinal tract, and lesion load of multiple descending motor tracts. These theory-based prediction accuracies were compared to the prediction accuracy from three data-driven biomarkers: lesion load of lesion-behaviour maps, lesion load of structural networks associated with lesion-behaviour maps, and measures of regional structural disconnection. In general, data-driven biomarkers had better prediction accuracy - as measured by higher explained variance in chronic motor outcomes - than theory-based biomarkers. Data-driven models of regional structural disconnection performed the best of all models tested (R 2 = 0.210, p 0.001), performing significantly better than predictions using the theory-based biomarkers of lesion load of the corticospinal tract (R 2 = 0.132, p 0.001) and of multiple descending motor tracts (R 2 = 0.180, p 0.001). They also performed slightly, but significantly, better than other data-driven biomarkers including lesion load of lesion-behaviour maps (R 2 =0.200, p 0.001) and lesion load of structural networks associated with lesion-behaviour maps (R 2 =0.167, p 0.001). Ensemble models - combining basic demographic variables like age, sex, and time since stroke - improved prediction accuracy for theory-based and data-driven biomarkers. Finally, combining both theory-based and data-driven biomarkers with demographic variables improved predictions, and the best ensemble model achieved R 2 = 0.241, p 0.001. Overall, these results demonstrate that models that predict chronic motor outcomes using data-driven features, particularly when lesion data is represented in terms of structural disconnection, perform better than models that predict chronic motor outcomes using theory-based features from the motor system. However, combining both theory-based and data-driven models provides the best predictions.
Publisher: MDPI AG
Date: 25-03-2014
DOI: 10.3390/S140405845
Publisher: MDPI AG
Date: 07-06-2018
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.NEUROSCIENCE.2016.02.012
Abstract: Transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) exhibit considerable trial-to-trial variability, potentially reducing the sensitivity and reproducibility of this measure. While increasing the number of trials will improve accuracy, prolonged recording blocks are not always feasible. In this study, we investigated the minimum number of trials required to provide a measure of human corticospinal excitability that is stable both within and between sessions. Single-pulse TMS was applied to the left primary motor cortex, and MEPs were recorded from the right first dorsal interosseous muscle. Approximately 20-30 trials were required to provide a stable measure of MEP litude with high within- and between-session reliability. Extending the number of trials beyond 30 provided no additional benefit. Collecting 30 trials may be optimal for reliably estimating corticospinal excitability using TMS. These findings may have significant implications for using TMS to measure corticospinal excitability in both basic and clinical research settings.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JSTROKECEREBROVASDIS.2019.104452
Abstract: Motor evoked potentials obtained with transcranial magnetic stimulation (TMS) can provide valuable information to inform stroke neurophysiology and recovery but are difficult to obtain in all stroke survivors due to high stimulation thresholds. To determine whether transcranial magnetic stimulation evoked potentials (TEPs) evoked using a lower stimulus intensity, below that necessary for recording motor evoked potentials, could serve as a marker of poststroke upper-limb motor function and were different compared to healthy adults. Eight chronic stroke survivors (66 ± 21 years) and 15 healthy adults (53 ± 10 years) performed a motor function task using a customized grip-lift manipulandum. TMS was applied to the lesioned motor cortex, with TEPs recorded using simultaneous high-definition electroencephalography (EEG). Stroke participants demonstrated greater hold ratio with the manipulandum. Cluster-based statistics revealed larger P30 litude in stroke participants, with significant clusters over frontal (P = .016) and parietal-occipital electrodes (P = .023). There was a negative correlation between the N45 peak litude and hold ratio in stroke participants (r = -.83, P = .02), but not controls. TEPs can be recorded using lower stimulus intensities in chronic stroke. The global P30 TEP response differed between stroke participants and healthy controls, with results suggesting that the TEP can be used as a biomarker of upper-limb behavior.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.HUMOV.2016.06.002
Abstract: The purpose of this study was to manipulate psychological stress and anxiety to investigate effects on ensuing perceptual-motor learning. Thirty-six participants attended two experimental sessions separated by 24h. In the first session, participants were randomized to either a mental arithmetic task known to increase stress and anxiety levels or a control condition and subsequently completed training on a speeded precision pinch task. Learning of the pinch task was assessed at the second session. Those exposed to the high stress-anxiety mental arithmetic task prior to training reported elevated levels of both stress and anxiety and demonstrated shorter movement times and improved retention of movement accuracy and movement variability. Response execution processes appear to benefit from elevated states of stress and anxiety immediately prior to training even when elicited by an unrelated task.
Publisher: Cold Spring Harbor Laboratory
Date: 05-08-1970
DOI: 10.1101/385302
Abstract: Metrics of brain network organization can be derived from neuroimaging data using graph theory. We explored the test-retest reliability of graph metrics of functional networks derived from resting-state electroencephalogram (EEG) recordings. Data were collected within two designs: (1) within sessions (WS) design where EEG data were collected from 18 healthy participants in four trials within a few hours and (2) between sessions (BS) design where EEG data were collected from 19 healthy participants in three trials on three different days at least one week apart. Electrophysiological source activity was reconstructed and functional connectivity between pairs of sensors or brain regions was determined in different frequency bands. We generated undirected binary graphs and used intra-class correlation coefficient (ICC) to estimate reliability. We showed that reliabilities ranged from poor to good. Reliability at the sensor-level was significantly higher than source-level. The most reliable graph metric at the sensor-level was cost efficiency and at the source-level was global efficiency. At the sensor-level: WS reliability was significantly higher than BS reliability high beta band in WS design had the highest reliability in WS design reliability in gamma band was significantly lower than reliability in low and high beta bands. At the source-level: low beta band in BS design had the highest reliability there was no significant main effect of frequency band on reliability reliabilities of WS and BS designs were not significantly different. These results suggest that these graph metrics can provide reliable outcomes, depending on how the data were collected and analysed.
Publisher: Springer Science and Business Media LLC
Date: 27-05-2021
DOI: 10.1007/S00429-021-02299-4
Abstract: A patterned repetitive transcranial magnetic stimulation protocol, known as continuous theta burst stimulation (cTBS), can suppress corticospinal excitability via mechanisms that appear similar to long-term depression synaptic plasticity. Despite much potential, this technique is currently limited by substantial response variability. The purpose of this study was to investigate whether baseline resting state functional connectivity is a determinant of response to cTBS. Eighteen healthy young adults participated in up to three experimental sessions. Single-pulse transcranial magnetic stimulation was used to quantify change in corticospinal excitability following cTBS. Three minutes of resting electroencephalographic activity was recorded, and functional connectivity was estimated using the debiased weighted phase lag index across different frequency bands. Partial least squares regression identified models of connectivity between a seed region (C3) and the whole scalp that maximally accounted for variance in cTBS responses. There was no group-level effect of a single cTBS train or spaced cTBS trains on corticospinal excitability (p = 0.092). A low beta frequency band model of connectivity accounted for the largest proportion of variance in spaced cTBS response (R
Publisher: SAGE Publications
Date: 04-03-2022
DOI: 10.1177/02692155221083492
Abstract: Impairments in body awareness are common after stroke and are associated with decreased participation and performance in everyday activities. To explore the feasibility and safety of a body awareness program after stroke, and identify the preliminary efficacy of class-based lessons compared to home-based lessons on sensation, body awareness, motor impairment and quality of life. A two-armed pilot randomized controlled trial with a nested qualitative descriptive study was conducted. In iduals with a diagnosis of stroke (at least three months post injury) were randomized to either class-based face-to-face body awareness lessons or home-based in idually performed body awareness lessons. Outcome measures were safety, feasibility, sensation, body awareness, motor impairment, self-efficacy and quality of life. Semi-structured interviews were used to allow greater exploration and understanding of participants’ experience of the program. Twenty participants were randomized, 16 participants completed the program. Feasibility was greater in the class-based group. No adverse events were detected. The class-based group led to improvement in body awareness (p = 0.002), quality of life (p = 0.002), and the arm (p = 0.025) and leg (p = 0.005) motor impairment scores. Qualitative data similarly indicated that the class-based group experienced a stronger sense of awareness, achievement and connection than the home-based group. Body awareness training was safe, feasible and acceptable in people with stroke. In iduals in the class-based group showed greater benefit compared to those receiving home-based therapy.
Publisher: Wiley
Date: 28-09-2020
DOI: 10.1002/EJP.1657
Publisher: SAGE Publications
Date: 21-05-2020
Abstract: Background. Resting state functional connectivity (RSFC) is a developmental priority for stroke recovery. Objective. To determine whether (1) RSFC differs between stroke survivors based on integrity of descending motor pathways (2) RSFC is associated with upper-limb behavior in chronic stroke and (3) the relationship between interhemispheric RSFC and upper-limb behavior differs based on descending motor pathway integrity. Methods. A total of 36 people with stroke (aged 64.4 ± 11.1 years, time since stroke 4.0 ± 2.8 years) and 25 healthy adults (aged 67.3 ± 6.7 years) participated in this study. RSFC was estimated from electroencephalography (EEG) recordings. Integrity of descending motor pathways was ascertained using transcranial magnetic stimulation to determine motor-evoked potential (MEP) status and magnetic resonance imaging to determine lesion overlap and fractional anisotropy of the corticospinal tract (CST). For stroke participants, upper-limb motor behavior was assessed using the Fugl-Meyer test, Action Research Arm Test and grip strength. Results. β-Frequency interhemispheric sensorimotor RSFC was greater for MEP+ stroke participants compared with MEP− ( P = .020). There was a significant positive correlation between β RSFC and upper-limb behavior ( P = .004) that appeared to be primarily driven by the MEP+ group. A hierarchical regression identified that the addition of β RSFC to measures of CST integrity explained greater variance in upper-limb behavior ( R 2 change = 0.13 P = .01). Conclusions. This study provides insight to understand the role of EEG-based measures of interhemispheric network activity in chronic stroke. Resting state interhemispheric connectivity was positively associated with upper-limb behavior for stroke survivors where residual integrity of descending motor pathways was maintained.
Publisher: Oxford University Press (OUP)
Date: 10-2021
DOI: 10.1093/BRAINCOMMS/FCAB254
Abstract: Up to two-thirds of stroke survivors experience persistent sensorimotor impairments. Recovery relies on the integrity of spared brain areas to compensate for damaged tissue. Deep grey matter structures play a critical role in the control and regulation of sensorimotor circuits. The goal of this work is to identify associations between volumes of spared subcortical nuclei and sensorimotor behaviour at different timepoints after stroke. We pooled high-resolution T1-weighted MRI brain scans and behavioural data in 828 in iduals with unilateral stroke from 28 cohorts worldwide. Cross-sectional analyses using linear mixed-effects models related post-stroke sensorimotor behaviour to non-lesioned subcortical volumes (Bonferroni-corrected, P & 0.004). We tested subacute (≤90 days) and chronic (≥180 days) stroke subgroups separately, with exploratory analyses in early stroke (≤21 days) and across all time. Sub-analyses in chronic stroke were also performed based on class of sensorimotor deficits (impairment, activity limitations) and side of lesioned hemisphere. Worse sensorimotor behaviour was associated with a smaller ipsilesional thalamic volume in both early (n = 179 d = 0.68) and subacute (n = 274, d = 0.46) stroke. In chronic stroke (n = 404), worse sensorimotor behaviour was associated with smaller ipsilesional putamen (d = 0.52) and nucleus accumbens (d = 0.39) volumes, and a larger ipsilesional lateral ventricle (d = −0.42). Worse chronic sensorimotor impairment specifically (measured by the Fugl-Meyer Assessment n = 256) was associated with smaller ipsilesional putamen (d = 0.72) and larger lateral ventricle (d = −0.41) volumes, while several measures of activity limitations (n = 116) showed no significant relationships. In the full cohort across all time (n = 828), sensorimotor behaviour was associated with the volumes of the ipsilesional nucleus accumbens (d = 0.23), putamen (d = 0.33), thalamus (d = 0.33) and lateral ventricle (d = −0.23). We demonstrate significant relationships between post-stroke sensorimotor behaviour and reduced volumes of deep grey matter structures that were spared by stroke, which differ by time and class of sensorimotor measure. These findings provide additional insight into how different cortico-thalamo-striatal circuits support post-stroke sensorimotor outcomes.
Publisher: SAGE Publications
Date: 24-02-2020
Abstract: Stroke is a leading cause of death and disability. It is a complex and largely heterogeneous condition. Prognosis for variations in impairment and recovery following stroke continues to be challenging and inaccurate, highlighting the need to examine the influence of other currently unknown variables to better predict and understand interin idual differences in stroke impairment and recovery. The concept of “cognitive reserve,” a feature of brain function said to moderate the relationship between brain pathology and clinical outcomes, might provide a partial explanation. This review discusses the potential significance of cognitive reserve in the context of stroke, with reference to reduced burden of disability poststroke, health promotion, intervention and secondary prevention of cognitive impairment, ease and challenges of translation into clinical practice, prognosis and prediction of recovery, and clinical decisions and trial stratification. Discussions from the review aim to encourage stroke clinicians and researchers to better consider the role of premorbid, lifestyle-related variables, such as cognitive reserve, in facilitating successful neurological outcomes and recovery following stroke.
Publisher: Frontiers Media SA
Date: 30-04-2019
Publisher: Springer Science and Business Media LLC
Date: 15-05-2019
Publisher: Wiley
Date: 10-03-2017
DOI: 10.1113/JP274089
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AH13232
Abstract: Objective The aim of the present study was to investigate a change in physiotherapy provision from a 5- to 7-days-a-week service on both physiotherapy and hospital length of stay (LOS) after total knee (TKR) and total hip (THR) replacement. Methods A retrospective analysis of a clinical database was conducted for patients who received either a TKR or THR between July 2010 and June 2012 in one regional hospital. Results There was a significant decrease in physiotherapy LOS from 5.0 days (interquartile range (IQR) 5.0–6.0 days) for a 5-day physiotherapy service, to 5.0 days (IQR 4.0–5.0 days) for 7-day physiotherapy service (U = 1443.5, z = –4.62, P = 0.001). However, hospital LOS was not reduced (P = 0.110). For TKR, physiotherapy LOS decreased significantly by 1 day with a 7-day physiotherapy service (U = 518.0, z = –4.20, P = 0.001). However, hospital LOS was again no different (P = 0.309). For THR there was no difference in physiotherapy LOS (P = 0.060) or hospital LOS (P = 0.303) between the 5- and 7-day physiotherapy services. Where physiotherapy LOS was less than hospital LOS, delayed discharge was due primarily to non-medical issues (72%) associated with hospital organisational aspects. Conclusions Increasing the provision of physiotherapy service after TKR provides an increase in physiotherapy sessions and has the potential to reduce hospital LOS. To be effective this must align with other administrative aspects of hospital discharge. What is known about the topic? Previous studies have investigated the effect of increasing physiotherapy services following total hip replacement (THR) and total knee replacement (TKR) surgery, with varying reports of decreased or unaffected hospital length of stay (LOS). What does this paper add? This study investigates both hospital and physiotherapy LOS in idually for THR and TKR patients following an increase from a 5- to 7-day physiotherapy service. Where physiotherapy LOS decreased and hospital LOS did not, delays in hospital discharge were investigated. What are the implications for practitioners? Additional physiotherapy services decrease physiotherapy LOS for TKR patients, but administrative aspects of hospital discharge must improve to reduce hospital LOS.
Publisher: BMJ
Date: 12-12-2015
Publisher: Wiley
Date: 18-01-2017
DOI: 10.1111/EJN.13508
Abstract: Responses to non-invasive brain stimulation are highly variable between subjects. Resting state functional connectivity was investigated as a marker of plasticity induced by anodal transcranial direct current stimulation (tDCS). Twenty-six healthy adults (15 male, 26.4 ± 6.5 years) were tested. Experiment 1 investigated whether functional connectivity could predict modulation of corticospinal excitability following anodal tDCS. Experiment 2 determined test-retest reliability of connectivity measures. Three minutes of electroencephalography was recorded and connectivity was quantified with the debiased weighted phase lag index. Anodal (1 mA, 20 min) or sham tDCS was applied to the left primary motor cortex (M1), with a change in motor evoked potential litude recorded from the right first dorsal interosseous used as a marker of tDCS response. Connectivity in the high beta frequency (20-30 Hz) between an electrode approximating the left M1 (C3) and electrodes overlying the left parietal cortex was a strong predictor of tDCS response (cross-validated R
Publisher: Elsevier BV
Date: 03-2014
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/AH11138
Abstract: Objective. Examine demographics, clinical characteristics and rehabilitation outcomes of lower-limb utees, using the Australasian Rehabilitation Outcomes Centre (AROC) database. Methods. Lower-limb utee rehabilitation separations between 2004 and 2010 were identified using AROC impairment codes 5.3–5.7.1 Analysis was conducted by year, impairment code, Australian National Sub-acute and Non-Acute Patient (AN-SNAP) classification (S2–224, Functional Independence Measure (FIM) motor(Mot) score 72–91 S2–225, FIM (Mot) score 14–71) and states of Australia. Results. Mean length of stay (LOS) for all lower-limb utee episodes was 36.1 days (95% confidence interval (CI): 35.4–36.9). Majority of episodes were unilateral below knee (63.6%), males (71.8%) with a mean age of 67.9 years (95% CI: 67.6–68.3). Year-on-year analysis revealed a trend for increasing LOS and decreasing age. Analysis by impairment code demonstrated no significant difference in rehabilitation outcomes. Analysis by AN-SNAP found that LOS was 16.2 days longer for S2–225 than for S2–224 (95% CI: 14.7–17.8, P 0.001), and FIM (Mot) change was 12.0 points higher for S2–225 than for S2–224 (95% CI: 11.5–12.6, P 0.001). Analysis by states revealed significant variation in LOS, FIM (Mot) change and FIM (Mot) efficiency which may be associated with variations in organisation of rehabilitation services across states. Conclusion. Although utees represented a comparatively small proportion of all rehabilitation episodes in Australia, their LOS was significant. Unlike many other rehabilitation conditions, there was no evidence of decreasing LOS over time. AN-SNAP classes were effective in distinguishing rehabilitation outcomes, and could potentially be used more effectively in planning rehabilitation programs. What is known about the topic? Literature reporting on the rehabilitation outcomes of cohorts of lower-limb utees in Australia is limited to in idual sites. No previous literature was identified that reported national data. What does this paper add? This study investigates utee rehabilitation at a national level over a 7-year observation period (2004–10) and comprises 6588 episodes. It reports the national demographics, clinical characteristics and rehabilitation outcomes, with the aim of identifying findings that have implications for practitioners. What are the implications for practitioners? Although only a small proportion of all episodes in the AROC database, this subset of lower-limb utee episodes has provided a useful snapshot of the current state of utee rehabilitation in Australia. We believe these findings have significant implications for practitioners in delivery of utee rehabilitation services across Australia. Practitioners may benefit from adjusting service delivery based upon the decreasing age of lower limb utees. Findings from this study also indicate that AN-SNAP classifications are effective in discriminating utee rehabilitation outcomes and may be used to streamline rehabilitation services and provide a more efficient and effective rehabilitation service to prevent further increases in LOS.
Publisher: SERDI
Date: 2016
Abstract: Background: Despite advances in vascular surgery techniques, ageing populations and increasing rates of vascular disease and diabetes have contributed to relatively steady utation rates. Older utees have limited life expectancies and often require expensive rehabilitation interventions on top of vascular procedures. Services warrant scrutiny with view to reducing clinical practice variations, improving hospital performance and securing the best patient outcomes. Objective: This study employed a novel methodology to assess 12-month hospital performance associated with provision of lower-limb utee services at three neighbouring hospitals. Design and Setting: Routinely collected data on in iduals having an initial lower-limb utation from July 2001 to June 2008 at three hospital networks in Adelaide, South Australia were analysed. Observed and expected lengths of stay and patient outcomes were generated, from which relative performance across hospitals were compared. Results: Following utation we observed a short time-to-death (0.8 years, IQR 0.21-2.12) and 12-month mortality rate of 25% (unadjusted). Risk-adjusted analyses indicated that one hospital with co-located vascular and rehabilitation services had greater performance with lower re- utation rates and fewer deaths. However, length of stay at this hospital was longer than expected. Conclusion: The risk-adjusted performance analysis provided an approach which could inform further investigations around variation in hospital performance to inform best practice service delivery.
Publisher: Wiley
Date: 14-04-2018
DOI: 10.1002/HBM.24079
Publisher: Frontiers Media SA
Date: 02-12-2016
Publisher: Frontiers Media SA
Date: 19-05-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 30-09-2020
Publisher: Springer Science and Business Media LLC
Date: 11-07-2015
Publisher: Human Kinetics
Date: 02-2022
Abstract: Research addressing lower limb utee gait and prosthetic design often focuses on men, despite female lower limb utees having different risk factors and lower success with their prosthetics overall. It is widely agreed that sex differences exist in able-bodied gait, but research analyzing sex differences in utee gait is rare. This study compared male and female transtibial utee gait to ascertain potential sex differences. Forty-five transtibial utees were asked to walk at their self-selected speed, and spatiotemporal gait data were obtained. Both the mean and variability metric of parameters were analyzed for 10 male and 10 female participants. For all participants, utated limbs had a shorter stance time, longer swing time, and larger step length. Females had a 10% shorter stance time and 26% larger normalized step and stride length than males. Female participants also walked over 20% faster than male participants. Finally, significant interactions were found in the mean and variability metric of stride velocity, indicating greater variability in women. These findings suggest that sex differences exist in transtibial utee gait, offering possible explanations for the different comorbidities experienced by female lower limb utees. These results have major implications for female utees and for sex-specific research, rehabilitation, and prosthetic design.
Publisher: Frontiers Media SA
Date: 29-11-2021
DOI: 10.3389/FNEUR.2021.745964
Abstract: Background: Body awareness (BA) is a process that involves sensory awareness originating from the body's physiological states, processes and actions, and is shaped by one's attitudes, perceptions, beliefs and experience of social and cultural context. Impairments in body awareness after stroke are believed to be common and may be an important influence on recovery outcomes. However, recovery of body awareness is poorly understood and receives little consideration in rehabilitation. Aims: To investigate if body awareness changes over time following stroke and identify if body awareness after stroke is associated with sensation, motor impairment, self-efficacy and quality of life. Methods: An exploratory longitudinal observational study was performed. Participants with a stroke diagnosis and associated motor impairment were recruited from an acute stroke unit. An assessment battery consisting of sensory and motor impairment and function, body awareness, self-efficacy and quality of life measures were used at baseline, 1, 3 and 6 months. Results: A total of 105 people with stroke were recruited. Most recovery in sensation and body awareness occurred within the first month after stroke (all p & 0.01). Sensation and body awareness were correlated with other clinical outcomes (motor impairment, self-efficacy and quality of life), demographics, and stroke specific clinical characteristics (all p & 0.01). Conclusions: This is the first study to track recovery of body awareness after stroke and investigate the relationship it may have in recovery of sensation, motor impairment and function, self-efficacy and quality of life. Further research is now warranted to continue investigation of body awareness and to develop effective stroke-specific assessment and intervention strategies.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2020
Publisher: Cold Spring Harbor Laboratory
Date: 09-2021
DOI: 10.1101/2021.08.31.458328
Abstract: Previous research using electroencephalography (EEG) and magnetoencephalography (MEG) has shown that neural oscillatory activity within the alpha band (8-12 Hz) becomes slower and lower in litude with advanced age. However, most studies have focused on quantifying age-related differences in periodic oscillatory activity with little consideration of the influence of aperiodic activity on these measures. The aim of this study was to investigate age differences in aperiodic activity inherent in the resting EEG signal. We assessed aperiodic activity in 85 healthy younger adults (mean age: 22.2 years, SD: 3.9, age range: 18–35, 37 male) and 92 healthy older adults (mean age: 66.1 years, SD: 8.2, age range 50–86, 53 male) by fitting the 1/f-like background activity evident in EEG power spectra using the fitting oscillations & one over f (FOOOF) toolbox. Across the scalp, the aperiodic exponent and offset were smaller in older compared to younger participants, reflecting a flatter 1/f-like slope and a downward broadband shift in the power spectra with age. Before correcting for aperiodic activity, older adults showed slower peak alpha frequency and reduced peak alpha power relative to younger adults. After correcting for aperiodic activity, peak alpha frequency remained slower in older adults however, peak alpha power no longer differed statistically between age groups. The large s le size utilized in this study, as well as the depth of analysis, provides further evidence that the aperiodic component of the resting EEG signal is altered with aging and should be considered when investigating neural oscillatory activity.
Publisher: Springer Science and Business Media LLC
Date: 12-05-2022
DOI: 10.1007/S00062-022-01170-1
Abstract: Chronic subjective tinnitus is the constant perception of a sound that has no physical source. Brain imaging studies show alterations in tinnitus patients’ resting-state networks (RSNs). This scoping review aims to provide an overview of resting-state fMRI studies in tinnitus, and to evaluate the evidence for changes in different RSNs. A total of 29 studies were included, 26 of which found alterations in networks such as the auditory network, default mode network, attention networks, and visual network however, there is a lack of reproducibility in the field which can be attributed to the use of different regions of interest and analytical methods per study, and tinnitus heterogeneity. Future studies should focus on replication by using the same regions of interest in their analysis of resting-state data, and by controlling adequately for potential confounds. These efforts could potentially lead to the identification of a biomarker for tinnitus in the future.
Publisher: Elsevier BV
Date: 2021
Publisher: Informa UK Limited
Date: 30-03-2023
DOI: 10.1080/10749357.2022.2058294
Abstract: Noninvasive electrical stimulation (ES) could have therapeutic potential in stroke recovery. However, there is no comprehensive evaluation of adverse events. This study systematically searched the literature to document frequency and prevalence of adverse events. A secondary aim was to explore associations between adverse events and ES parameters or participant characteristics. Seventy-five studies were included. Adverse events were minor in nature. The most frequently reported adverse events were tingling (37.3% of papers), burning (18.7%), headaches (14.7%) and fatigue (14.7%). Cathodal stimulation was associated with greater frequency of itching (p = .02), intensities of 1-2 mA with increased tingling (p = .04) and discomfort (p = .03), and current density <0.4mA/cm2 with greater discomfort (p = .03). Tingling was the most prevalent adverse event (18.1% of participants), with prevalence data not differing between active and control conditions (all p ≥ 0.37). In idual participants were more likely to report adverse events with increasing current density (r = 0.99, p = .001). Two severe adverse events were noted (a seizure and percutaneous endoscopic gastrostomy placement). ES appears safe in people with stroke as reported adverse events were predominantly minor in nature. An adverse events questionnaire is proposed to enable a more comprehensive and nuanced analysis of the frequency and prevalence of adverse events.
Publisher: Springer Science and Business Media LLC
Date: 02-09-2023
Publisher: Springer Science and Business Media LLC
Date: 08-2017
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.JSTROKECEREBROVASDIS.2022.106494
Abstract: Interhemispheric inhibition is an important cortical mechanism to support motor control. Altered interhemispheric inhibition has been the target of neuromodulation interventions. This systematic review investigated the evidence for altered interhemispheric inhibition in adults with unilateral neurological conditions: stroke, amyotrophic lateral sclerosis, cerebral palsy, complex regional pain syndrome, traumatic brain injury, and cerebral palsy METHODS: We pre-registered the protocol and followed PRISMA guidelines. Five databases were systematically searched to identify studies reporting interhemispheric inhibition measures in unilateral neurological conditions and healthy controls. Data were grouped according to the measure (ipsilateral silent period and dual-coil), stimulated hemisphere, and stage of the condition (subacute and chronic). 1372 studies were identified, of which 14 were included (n = 226 adults with stroke and 161 age-matched controls). Ipsilateral silent period-duration was longer in people with stroke than in controls (stimulation of dominant hemisphere) regardless of stroke stage. Motor evoked potential was less suppressed in people with sub-acute stroke (stimulation of the unaffected hemisphere) than controls (stimulation of dominant hemisphere) and this reversed in chronic stroke. Detection of altered interhemispheric inhibition appears to be dependent on the measure of interhemispheric inhibition and the stage of recovery. Rebalancing interhemispheric inhibition using neuromodulation is considered a promising line of treatment for stroke rehabilitation. Our results did not find compelling evidence to support consistent alterations in interhemispheric inhibition in adults with stroke.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.SLEEP.2021.10.017
Abstract: Accumulating evidence suggests that low frequency repetitive transcranial magnetic stimulation (rTMS), which generally decreases cortical excitability and remodels plastic connectivity, improves sleep quality in patients with insomnia disorder. However, the effects of rTMS vary substantially across in iduals and treatment is sometimes unsatisfactory, calling for biomarkers for predicting clinical outcomes. This study aimed to investigate whether functional connectivity of the target network in electroencephalography is associated with the clinical response to low frequency rTMS in patients with insomnia disorder. Twenty-five patients with insomnia disorder were subjected to 10 sessions of treatment with 1 Hz rTMS over the right dorsolateral prefrontal cortex. Resting-state electroencephalography was collected before rTMS. Pittsburgh Sleep Quality Index, Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and Mini-Mental State Exam were performed before and after rTMS treatment, with a follow-up after one month. Electroencephalographic connectivity was measured by the power envelope connectivity at the source level. Partial least squares regression identified models of connectivity that maximally accounted for the rTMS response. Scores of Pittsburgh Sleep Quality Index, Hamilton Depression Rating Scale, and Hamilton Anxiety Rating Scale were decreased after rTMS and one-month later. Baseline weaker connectivity of a network in the beta and alpha bands between a brain region approximating the stimulated right dorsolateral prefrontal cortex and areas located in the frontal, insular, and limbic cortices was associated with a greater change in Pittsburgh Sleep Quality Index and Hamilton Depression Rating Scale following rTMS. Low frequency rTMS could improve sleep quality and depressive moods in patients with insomnia disorder. Moreover, electroencephalographic functional connectivity would potentially be a robust biomarker for predicting the therapeutic effects.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 16-05-2023
DOI: 10.1212/WNL.0000000000207219
Abstract: Functional outcomes after stroke are strongly related to focal injury measures. However, the role of global brain health is less clear. In this study, we examined the impact of brain age, a measure of neurobiological aging derived from whole-brain structural neuroimaging, on poststroke outcomes, with a focus on sensorimotor performance. We hypothesized that more lesion damage would result in older brain age, which would in turn be associated with poorer outcomes. Related, we expected that brain age would mediate the relationship between lesion damage and outcomes. Finally, we hypothesized that structural brain resilience, which we define in the context of stroke as younger brain age given matched lesion damage, would differentiate people with good vs poor outcomes. We conducted a cross-sectional observational study using a multisite dataset of 3-dimensional brain structural MRIs and clinical measures from the ENIGMA Stroke Recovery. Brain age was calculated from 77 neuroanatomical features using a ridge regression model trained and validated on 4,314 healthy controls. We performed a 3-step mediation analysis with robust mixed-effects linear regression models to examine relationships between brain age, lesion damage, and stroke outcomes. We used propensity score matching and logistic regression to examine whether brain resilience predicts good vs poor outcomes in patients with matched lesion damage. We examined 963 patients across 38 cohorts. Greater lesion damage was associated with older brain age (β = 0.21 95% CI 0.04–0.38, p = 0.015), which in turn was associated with poorer outcomes, both in the sensorimotor domain (β = −0.28 95% CI −0.41 to −0.15, p 0.001) and across multiple domains of function (β = −0.14 95% CI −0.22 to −0.06, p 0.001). Brain age mediated 15% of the impact of lesion damage on sensorimotor performance (95% CI 3%–58%, p = 0.01). Greater brain resilience explained why people have better outcomes, given matched lesion damage (odds ratio 1.04, 95% CI 1.01–1.08, p = 0.004). We provide evidence that younger brain age is associated with superior poststroke outcomes and modifies the impact of focal damage. The inclusion of imaging-based assessments of brain age and brain resilience may improve the prediction of poststroke outcomes compared with focal injury measures alone, opening new possibilities for potential therapeutic targets.
Publisher: Wiley
Date: 31-03-2018
DOI: 10.1113/JP275841
Publisher: JMIR Publications Inc.
Date: 11-12-2020
DOI: 10.2196/23369
Abstract: Behavior change apps can develop iteratively, where the app evolves into a complex, dynamic, or personalized intervention through cycles of research, development, and implementation. Understanding how existing users engage with an app (eg, frequency, amount, depth, and duration of use) can help guide further incremental improvements. We aim to explore how simple visualizations can provide a good understanding of temporal patterns of engagement, as usage data are often longitudinal and rich. This study aims to visualize behavioral engagement with Drink Less, a behavior change app to help reduce hazardous and harmful alcohol consumption in the general adult population of the United Kingdom. We explored behavioral engagement among 19,233 existing users of Drink Less. Users were included in the s le if they were from the United Kingdom were 18 years or older were interested in reducing their alcohol consumption had a baseline Alcohol Use Disorders Identification Test score of 8 or above, indicative of excessive drinking and had downloaded the app between May 17, 2017, and January 22, 2019 (615 days). Measures of when sessions begin, length of sessions, time to disengagement, and patterns of use were visualized with heat maps, timeline plots, k-modes clustering analyses, and Kaplan-Meier plots. The daily 11 AM notification is strongly associated with a change in engagement in the following hour reduction in behavioral engagement over time, with 50.00% (9617/19,233) of users disengaging (defined as no use for 7 or more consecutive days) 22 days after download identification of 3 distinct trajectories of use, namely engagers (4651/19,233, 24.18% of users), slow disengagers (3679/19,233, 19.13% of users), and fast disengagers (10,903/19,233, 56.68% of users) and limited depth of engagement with 85.076% (7,095,348/8,340,005) of screen views occurring within the Self-monitoring and Feedback module. In addition, a peak of both frequency and amount of time spent per session was observed in the evenings. Visualizations play an important role in understanding engagement with behavior change apps. Here, we discuss how simple visualizations helped identify important patterns of engagement with Drink Less. Our visualizations of behavioral engagement suggest that the daily notification substantially impacts engagement. Furthermore, the visualizations suggest that a fixed notification policy can be effective for maintaining engagement for some users but ineffective for others. We conclude that optimizing the notification policy to target both effectiveness and engagement is a worthwhile investment. Our future goal is to both understand the causal effect of the notification on engagement and further optimize the notification policy within Drink Less by tailoring to contextual circumstances of in iduals over time. Such tailoring will be informed from the findings of our micro-randomized trial (MRT), and these visualizations were useful in both gaining a better understanding of engagement and designing the MRT.
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Physiological Society
Date: 11-2018
Abstract: Transcranial magnetic stimulation (TMS) is a technique that enables noninvasive manipulation of neural activity and holds promise in both clinical and basic research settings. The effect of TMS on the motor cortex is often measured by electromyography (EMG) recordings from a small hand muscle. However, the details of how TMS generates responses measured with EMG are not completely understood. We aim to develop a biophysically detailed computational model to study the potential mechanisms underlying the generation of EMG signals following TMS. Our model comprises a feed-forward network of cortical layer 2/3 cells, which drive morphologically detailed layer 5 corticomotoneuronal cells, which in turn project to a pool of motoneurons. EMG signals are modeled as the sum of motor unit action potentials. EMG recordings from the first dorsal interosseous muscle were performed in four subjects and compared with simulated EMG signals. Our model successfully reproduces several characteristics of the experimental data. The simulated EMG signals match experimental EMG recordings in shape and size, and change with stimulus intensity and contraction level as in experimental recordings. They exhibit cortical silent periods that are close to the biological values and reveal an interesting dependence on inhibitory synaptic transmission properties. Our model predicts several characteristics of the firing patterns of neurons along the entire pathway from cortical layer 2/3 cells down to spinal motoneurons and should be considered as a viable tool for explaining and analyzing EMG signals following TMS. NEW & NOTEWORTHY A biophysically detailed model of EMG signal generation following transcranial magnetic stimulation (TMS) is proposed. Simulated EMG signals match experimental EMG recordings in shape and litude. Motor-evoked potential and cortical silent period properties match experimental data. The model is a viable tool to analyze, explain, and predict EMG signals following TMS.
Publisher: Frontiers Media SA
Date: 08-09-2021
DOI: 10.3389/FNHUM.2021.718662
Abstract: Non-invasive brain stimulation is a useful tool to probe brain function and provide therapeutic treatments in disease. When applied to the right posterior parietal cortex (PPC) of healthy participants, it is possible to temporarily shift spatial attention and mimic symptoms of spatial neglect. However, the field of brain stimulation is plagued by issues of high response variability. The aim of this study was to investigate baseline functional connectivity as a predictor of response to an inhibitory brain stimulation paradigm applied to the right PPC. In fourteen healthy adults (9 female, aged 24.8 ± 4.0 years) we applied continuous theta burst stimulation (cTBS) to suppress activity in the right PPC. Resting state functional connectivity was quantified by recording electroencephalography and assessing phase consistency. Spatial attention was assessed before and after cTBS with the Landmark Task. Finally, known determinants of response to brain stimulation were controlled for to enable robust investigation of the influence of resting state connectivity on cTBS response. We observed significant inter-in idual variability in the behavioral response to cTBS with 53.8% of participants demonstrating the expected rightward shift in spatial attention. Baseline high beta connectivity between the right PPC, dorsomedial pre-motor region and left temporal-parietal region was strongly associated with cTBS response ( R 2 = 0.51). Regression analysis combining known cTBS determinants (age, sex, motor threshold, physical activity, stress) found connectivity between the right PPC and left temporal-parietal region was the only significant variable ( p = 0.011). These results suggest baseline resting state functional connectivity is a strong predictor of a shift in spatial attention following cTBS. Findings from this study help further understand the mechanism by which cTBS modifies cortical function and could be used to improve the reliability of brain stimulation protocols.
Publisher: Elsevier BV
Date: 09-2013
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Brenton Hordacre.