ORCID Profile
0000-0002-5190-7038
Current Organisations
Higher Education Academy
,
University of Oxford
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Publisher: Wiley
Date: 06-01-2014
DOI: 10.1002/MDS.25748
Publisher: SAGE Publications
Date: 27-03-2009
Abstract: Abstract The British Association for Psychopharmacology guidelines specify the scope and target of treatment for bipolar disorder. The second version, like the first, is based explicitly on the available evidence and presented, like previous Clinical Practice guidelines, as recommendations to aid clinical decision making for practitioners: they may also serve as a source of information for patients and carers. The recommendations are presented together with a more detailed but selective qualitative review of the available evidence. A consensus meeting, involving experts in bipolar disorder and its treatment, reviewed key areas and considered the strength of evidence and clinical implications. The guidelines were drawn up after extensive feedback from participants and interested parties. The strength of supporting evidence was rated. The guidelines cover the diagnosis of bipolar disorder, clinical management, and strategies for the use of medicines in treatment of episodes, relapse prevention and stopping treatment.
Publisher: Royal College of Psychiatrists
Date: 07-2012
DOI: 10.1192/BJP.BP.111.105361
Abstract: Late-life depression is a common and heterogeneous illness, associated with structural abnormalities in both grey and white matter. To examine the relationship between age at onset and magnetic resonance imaging (MRI) measures of grey and white matter to establish whether they support particular hypotheses regarding the anatomy and aetiology of network disruption in late-life depression. We studied 36 participants with late-life depression. Grey matter was examined using T 1 -weighted MRI and analysed using voxel-based morphometry. The hippoc us was automatically segmented and volume and shape analysis performed. White matter was examined using diffusion tensor imaging and analysed using tract-based spatial statistics. Later age at onset was significantly associated with reduced fractional anisotropy of widespread tracts, in particular the anterior thalamic radiation and superior longitudinal fasciculus. Earlier age at onset was associated with reduced hippoc al volume normalised to whole brain size bilaterally. However, no significant correlations were detected using hippoc al shape analysis or voxel-based morphometry. Overall, the results were compatible with the vascular hypothesis, and provided some support for the glucocorticoid cascade hypothesis.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2002
Abstract: Prefrontal repetitive transcranial magnetic stimulation (rTMS) has been used to induce side-specific mood changes in volunteers and patients. To clarify inconsistencies between reports that used different stimulation frequencies, we conducted a controlled study with a low (1 Hz) frequency, comparing left with right-sided stimulation Nineteen healthy volunteers received randomised left or right prefrontal rTMS at a frequency of 1 Hz and 100% of motor threshold in two sessions two weeks apart. There were significant improvements with TMS for performance in the digit symbol substitution and verbal fluency tests, but no change of mood on a number of measures. There was also a reduction of pulse rate after TMS. The only side-specific TMS-effect was on mean arterial pressure, which decreased pressure after left, but not after right prefrontal TMS. Apart from the unexpected and so far unreplicated effect on mean arterial pressure, there were no side-specific effects on mood in volunteers. It is unlikely that a simple laterality model of mood together with the assumed activating effect of higher and 'quenching' effect of lower stimulation frequency can account for the effects of TMS on mood.
Publisher: Cold Spring Harbor Laboratory
Date: 29-07-2020
DOI: 10.1101/2020.07.28.208579
Abstract: Large scale neuroimaging datasets present the possibility of providing normative distributions for a wide variety of neuroimaging markers, which would vastly improve the clinical utility of these measures. However, a major challenge is our current poor ability to integrate measures across different large-scale datasets, due to inconsistencies in imaging and non-imaging measures across the different protocols and populations. Here we explore the harmonisation of white matter hyperintensity (WMH) measures across two major studies of healthy elderly populations, the Whitehall II imaging sub-study and the UK Biobank. We identify pre-processing strategies that maximise the consistency across datasets and utilise multivariate regression to characterise s le differences contributing to study-level differences in WMH variations. We also present a parser to harmonise WMH-relevant non-imaging variables across the two datasets. We show that we can provide highly calibrated WMH measures from these datasets with: (1) the inclusion of a number of specific standardised processing steps and (2) appropriate modelling of s le differences through the alignment of demographic, cognitive and physiological variables. These results open up a wide range of applications for the study of WMHs and other neuroimaging markers across extensive databases of clinical data. We harmonised measures of WMHs across two studies on healthy ageing Specific pre-processing strategies can increase comparability across studies Modelling of biological differences is crucial to provide calibrated measures
Publisher: Public Library of Science (PLoS)
Date: 14-07-2022
DOI: 10.1371/JOURNAL.PMED.1004039
Abstract: Brain iron deposition has been linked to several neurodegenerative conditions and reported in alcohol dependence. Whether iron accumulation occurs in moderate drinkers is unknown. Our objectives were to investigate evidence in support of causal relationships between alcohol consumption and brain iron levels and to examine whether higher brain iron represents a potential pathway to alcohol-related cognitive deficits. Observational associations between brain iron markers and alcohol consumption ( n = 20,729 UK Biobank participants) were compared with associations with genetically predicted alcohol intake and alcohol use disorder from 2-s le mendelian randomization (MR). Alcohol intake was self-reported via a touchscreen questionnaire at baseline (2006 to 2010). Participants with complete data were included. Multiorgan susceptibility-weighted magnetic resonance imaging (9.60 ± 1.10 years after baseline) was used to ascertain iron content of each brain region (quantitative susceptibility mapping (QSM) and T2*) and liver tissues (T2*), a marker of systemic iron. Main outcomes were susceptibility (χ) and T2*, measures used as indices of iron deposition. Brain regions of interest included putamen, caudate, hippoc i, thalami, and substantia nigra. Potential pathways to alcohol-related iron brain accumulation through elevated systemic iron stores (liver) were explored in causal mediation analysis. Cognition was assessed at the scan and in online follow-up (5.82 ± 0.86 years after baseline). Executive function was assessed with the trail-making test, fluid intelligence with puzzle tasks, and reaction time by a task based on the “Snap” card game. Mean age was 54.8 ± 7.4 years and 48.6% were female. Weekly alcohol consumption was 17.7 ± 15.9 units and never drinkers comprised 2.7% of the s le. Alcohol consumption was associated with markers of higher iron (χ) in putamen (β = 0.08 standard deviation (SD) [95% confidence interval (CI) 0.06 to 0.09], p 0.001), caudate (β = 0.05 [0.04 to 0.07], p 0.001), and substantia nigra (β = 0.03 [0.02 to 0.05], p 0.001) and lower iron in the thalami (β = −0.06 [−0.07 to −0.04], p 0.001). Quintile-based analyses found these associations in those consuming units (56 g) alcohol weekly. MR analyses provided weak evidence these relationships are causal. Genetically predicted alcoholic drinks weekly positively associated with putamen and hippoc us susceptibility however, these associations did not survive multiple testing corrections. Weak evidence for a causal relationship between genetically predicted alcohol use disorder and higher putamen susceptibility was observed however, this was not robust to multiple comparisons correction. Genetically predicted alcohol use disorder was associated with serum iron and transferrin saturation. Elevated liver iron was observed at just units (88 g) alcohol weekly c.f. units (56 g). Systemic iron levels partially mediated associations of alcohol intake with brain iron. Markers of higher basal ganglia iron associated with slower executive function, lower fluid intelligence, and slower reaction times. The main limitations of the study include that χ and T2* can reflect changes in myelin as well as iron, alcohol use was self-reported, and MR estimates can be influenced by genetic pleiotropy. To the best of our knowledge, this study represents the largest investigation of moderate alcohol consumption and iron homeostasis to date. Alcohol consumption above 7 units weekly associated with higher brain iron. Iron accumulation represents a potential mechanism for alcohol-related cognitive decline.
Publisher: Wiley
Date: 08-2016
Publisher: Elsevier BV
Date: 09-2021
DOI: 10.1016/J.BBR.2021.113510
Abstract: Loneliness is linked to increased risk for Alzheimer's disease, but little is known about factors potentially contributing to adverse brain health in lonely in iduals. In this study, we used data from 24,867 UK Biobank participants to investigate risk factors related to loneliness and estimated brain age based on neuroimaging data. The results showed that on average, in iduals who self-reported loneliness on a single yes/no item scored higher on neuroticism, depression, social isolation, and socioeconomic deprivation, performed less physical activity, and had higher BMI compared to in iduals who did not report loneliness. In line with studies pointing to a genetic overlap of loneliness with neuroticism and depression, permutation feature importance ranked these factors as the most important for classifying lonely vs. not lonely in iduals (ROC AUC = 0.83). While strongly linked to loneliness, neuroticism and depression were not associated with brain age estimates. Conversely, objective social isolation showed a main effect on brain age, and in iduals reporting both loneliness and social isolation showed higher brain age relative to controls - as part of a prominent risk profile with elevated scores on socioeconomic deprivation and unhealthy lifestyle behaviours, in addition to neuroticism and depression. While longitudinal studies are required to determine causality, this finding may indicate that the combination of social isolation and a genetic predisposition for loneliness involves a risk for adverse brain health. Importantly, the results underline the complexity in associations between loneliness and adverse health outcomes, where observed risks likely depend on a combination of interlinked variables including genetic as well as social, behavioural, physical, and socioeconomic factors.
Publisher: Springer Science and Business Media LLC
Date: 30-05-2014
Publisher: Cambridge University Press (CUP)
Date: 05-2001
DOI: 10.1192/APT.7.3.181
Abstract: One hundred years ago, D'Arsonval and Beer first described the effects of magnetic fields on human brain function. Placing one's head into a powerful magnet produced phosphenes, vertigo or even syncopes (George & Belmaker, 2000). However, only since 1985 has the technology of fast discharging capacitors developed sufficiently to generate reproducible effects across the intact skull, with peak magnetic field strengths of about 1–2 tesla (Barker et al , 1985). The headline-grabbing news has been about therapeutic applications of transcranial magnetic stimulation (TMS), but in the meantime a revolution in functional brain research has taken place, based on the manipulation of brain activity by focused magnetic fields. TMS applied in this way is, in a manner of speaking, brain imaging in the reverse. While common modes of functional brain imaging, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), demonstrate associations between brain metabolic activity and ‘brain tasks', the causal interpretation of such associations can be difficult. Is the frontal lobe activation observed during a memory task, for ex le, necessary for performing the task, or does it correspond to monitoring activity that runs parallel to task performance proper? If, on the other hand, focal brain activation during TMS results in a muscle twitch, there is no doubt that stimulation of at least some of the neurons within the magnetic field is sufficient cause for the observed movement. Functional neuroimaging is now often combined with TMS, carried out in the same session in order to exploit the complementary strengths of the methods. Although direct stimulation of association (as opposed to motor or sensory) cortex does not usually result in an observable response, TMS applied in repetitive trains can produce reversible ‘lesions'. By interfering with tasks that are dependent on the functioning of the stimulated neurons, it can thus contribute to the localisation of brain function.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
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 Klaus Ebmeier.