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We investigated the association between the degree of lesion overlap with the corticospinal tract and walking performance before and after 4-weeks of partial body weight support (PBWS) treadmill training in 18 individuals (ten male, eight female) with a mean age 59 ± 13 years (mean ± SD), range 32–74 years, who were ambulant and 6 months from a subcortical ischaemic stroke. Lesion volumes were manually defined on high resolution T1-weighted 3T-MRI scans and a probabilistic map of the corticospinal tract created using diffusion tensor imaging data collected previously in healthy subjects. The percentage overlap between the lesion and the corticospinal tract was calculated for each patient. Walking performance was determined by measures of 10 m speed, spatiotemporal parameters, percentage recovery of centre of mass (CoM), walking symmetry and 2-min endurance walk prior to and following 4 weeks of treadmill training with PBWS that emphasised normal fast walking. Lesion overlap measures weakly correlated with walking performance measures. Spatiotemporal and performance measures changed in response to training, but spatial symmetry and mechanical energy recovery did not. Walking speed at entry to the study predicted change in response to training of 10 m walk time and swing time asymmetry. Age and lesion overlap did not add to prediction of outcome models. The extent of lesion overlap with the corticospinal tract was not strongly associated with either walking performance or response to gait retraining, despite the correlation of these parameters with upper limb recovery. [ABSTRACT FROM AUTHOR]

The Faces Symbol Test (FST) has recently been proposed as a brief and patient-friendly screening instrument for the assessment of cognitive dysfunction in patients with multiple sclerosis (MS). However, in contrast to well-established MS screening tests such as the Paced Auditory Serial Addition Test, the neural correlates of the FST have not been investigated so far. In the present study, we developed a functional MRI (fMRI) version of the FST to provide first data on brain regions and networks involved in this test. A sample of 19 healthy participants completed a version of the FST adapted for fMRI, requiring matching of faces and symbols in a multiple choice test and two further experimental conditions drawing on cognitive subcomponents (face matching and symbol matching). Imaging data showed a differential involvement of a fronto-parieto-occipital network in the three conditions. The most demanding FST condition elicited brain activation patterns related with sustained attention and executive control. These results suggest that the FST recruits brain networks critical for higherorder cognitive functions often impaired in MS patients. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) techniques such as magnetization transfer imaging and magnetic resonance spectroscopy (MRS) may reveal otherwise undetectable tissue damage in multiple sclerosis (MS) and can serve to explain more severe disability than expected from conventional MRI. That an inverse situation may exist where non-conventional quantitative MRI and MRS metrics would indicate less abnormality than expected from T2 lesion load to explain preserved clinical functioning was hypothesized. Quantitative MRI and MRS were obtained in 13 consecutive patients with clinically benign MS (BMS; mean age 44 ± 9 years) despite large T2 lesion load and in 15 patients with secondary progressive MS (SPMS; mean age 47± 6 years) matched for disease duration. The magnetization transfer ratio (MTR), magnetization transfer rate (kfor), brain parenchymal fraction (BPF) and brain metabolite concentrations from proton MRS were determined. BMS patients were significantly less disabled than their SPMS counterparts (mean expanded disability status score: 2.1 ± 1.1 versus 6.2 ± 1.1; P < 0.001) and had an even somewhat higher mean T2 lesion load (41.2 ± 27.1 versus 27.9 ± 24.8 cm3; P = 0.19). Normal appearing brain tissue histogram metrics for MTR and kfor, mean MTR and kfor of MS lesions and mean BPF were similar in BMS and SPMS patients. Levels of N-acetylaspartate, choline and myoinositol were comparable between groups. This study thus failed to explain the preservation of function in our BMS patients with large T2 lesion load by a higher morphologic or metabolic integrity of the brain parenchyma. Functional compensation must come from other mechanisms such as brain plasticity. [ABSTRACT FROM AUTHOR]

We performed a prospective multi-centre study using functional magnetic resonance imaging (fMRI) to better characterize the relationships between clinical expression and brain function in patients with multiple sclerosis (MS) at eight European sites (56 MS patients and 60 age-matched, healthy controls). Patients showed greater task-related activation bilaterally in brain regions including the pre- and post-central, inferior and superior frontal, cingulate and superior temporal gyri and insula ( P < 0.05, all statistics corrected for multiple comparisons). Both patients and healthy controls showed greater brain activation with increasing age in the ipsilateral pre-central and inferior frontal gyri ( P < 0.05). Patients, but not controls, showed greater brain activation in the anterior cingulate gyrus and the bilateral ventral striatum ( P < 0.05) with less hand dexterity. An interaction between functional activation changes in MS and age was found. This large fMRI study over a broadly selected MS patient population confirms that movement for patients demands significantly greater cognitive ‘resource allocation’ and suggests age-related differences in brain responses to the disease. These observations add to evidence that brain functional responses (including potentially adaptive brain plasticity) contribute to modulation of clinical expression of MS pathology and demonstrate the feasibility of a multi-site functional MRI study of MS. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) plaques and age related white matter lesions (WML) are of similar morphological appearance on T2 weighted MRI. Therefore their differentiation is sometimes crucial. Proton magnetic resonance spectroscopy (1H–MRS) adds metabolic information to conventional imaging and may help to distinguish inflammatory MS plaques from vascular related WML. This study was performed to evaluate the metabolite pattern in MS plaques and WML. 15 MS patients, 14 elderly individuals with WML and 16 controls were investigated by conventional MRI and short echo quantitative 1H–MRS (TE: 30ms, TR: 3000ms). The mean metabolite concentrations in normal control white matter (NCWM), MS plaques and WML were: t–NAA: 8.96 mmol/l (SD:0.93) vs 6.79 mmol/l (SD: 1.99) vs 7.18 mmol/l (SD: 1.41); Cho: 1.66 mmol/l (SD: 0.4) vs 1.49 mmol/l (SD: 0.45) vs 1.46 mmol/l (SD: 0.34); PCr: 5.64 mmol/l (SD: 0.83) vs 4.9mmol/l (SD: 1.3) vs 4.95 mmol/l (SD: 0.86); myo– Ins: 4.57 mmol/l (SD:1.05) vs 6.34 mmol/l (SD: 2.03) vs 4.5 mmol/l (SD: 0.96). t–NAA reduction in MS plaques and WML was significant compared with controls (p ≤ 0.001). MS plaques showed significantly elevated myo– Ins concentrations compared with controls (p = 0.002) and to WML (p = 0.003). In summary MS plaques and WML show a decrease in their t–NAA concentrations compared with controls. Elevated concentrations of myo–Ins in MS plaques but not in WML makes this metabolite of special interest for their differentiation. [ABSTRACT FROM AUTHOR]

Abstract: Background: Electroconvulsive therapy (ECT) has been used as an effective treatment option in severe and treatment resistant cases of depression for decades. However the mode of action of ECT is still not fully understood. Advances in neuroimaging created new possibilities to understand the functional changes of the human brain. Methods: Literature review of studies assessing possible changes in cerebral glucose metabolism pre- and post-ECT by PET, identified by PubMed. Results: Studies were limited by small sample size, inhomogeneous study population with uni- and bipolar depressive patients and methodological inconsistencies. Despite considerable variance, reduction in glucose metabolism after ECT in bilateral anterior and posterior frontal areas represented the most consistent findings. Conclusions: Future research into this issue should include larger and more consistent cohorts of patients. Assessing clinical improvement of depression after ECT should allow to correlate changes in brain glucose metabolism with functional scores. Follow up PET scans after six or twelve months should be performed to test if changes in brain metabolism are persistent. [Copyright &y& Elsevier]