Volumetric MRI and cognitive measures in Alzheimer disease : comparison of markers of progression

Background Both cognitive tests and MRI-based measures have been suggested as outcomes in trials assessing disease-modifying therapies in Alzheimer's disease (AD). Objective To compare changes in longitudinal MRI measures with changes in performance on cognitive tests routinely used in AD clinical trials. Method Fifty-two subjects from the placebo-arm of a clinical trial in mild-to-moderate AD had volumetric T-1-weighted scans and cognitive tests including the Mini-Mental State Examination (MMSE), AD Assessment Scale-Cognitive Subscale, Disability Assessment for Dementia, AD Cooperative Study-Clinical Global Impression of Change and Clinical Dementia Rating at baseline and one-year later. Rates of brain atrophy and ventricular enlargement were measured using the boundary shift integral. Hippocampal (Hc) atrophy was calculated from manual volume measurements. The relationships between MRI and cognitive measures were investigated. Results Rates of brain atrophy and/or ventricular enlargement were correlated with declining performance on cognitive scales. The strongest association was between brain atrophy rate and MMSE decline (r = 0.59, p < 0.0001). Hc atrophy rate was not significantly correlated with any of the cognitive scales. Conclusion The lack of correlation between Hc atrophy and cognitive scales may reflect a combination of: the extensive functional damage to the Hc by the time AD is clinically established, the greater influence of ongoing cortical degeneration, and errors in Hc outlining. The strong correlations between brain atrophy and ventricular enlargement, and cognitive scales probably reflect the correspondence between these measures of overall cerebral loss and global cognitive measures in the moderate stages of AD

Benefit of Repetitive Intrathecal Triamcinolone Acetonide Therapy in Predominantly Spinal Multiple Sclerosis: Prediction By Upper Spinal Cord Atrophy

Intrathecal injection of triamcinolone acetonide (TCA) has been shown to provide substantial benefit in a subset of progressive multiple sclerosis (MS) patients with predominant spinal symptoms. We examined whether atrophy of the upper spinal cord (USC) as measured by MRI can serve as a predictive marker for response to repetitive intrathecal TCA application. Repetitive administration of 40 mg TCA was performed in 31 chronic progressive MS patients up to six times within 3 weeks. Expanded Disability Status Scale (EDSS) and maximum walking distance (WD) were assessed before and after the treatment cycle. Cervical 3D T1-weighted images were acquired on a 1.5T scanner at baseline. Mean cross-sectional area of the USC was determined using a semi-automated volumetry method. Results were compared with a group of 29 healthy controls to group patients into those with and without atrophy. Results show a negative correlation between the degree of USC atrophy and treatment benefit. A higher treatment benefit in patients with little USC atrophy but short initial maximum WD was observed. Absence of USC atrophy as measured on MRI is a predictive marker for intrathecal TCA therapy outcome in progressive MS. Patients with initial poor walking abilities, but only little or no atrophy, benefited most from TCA therapy

Antemortem volume loss mirrors TDP-43 staging in older adults with non-frontotemporal lobar degeneration

Over the past decade, the transactive response DNA-binding protein of 43 kDa (TDP-43) has been recognized as a major protein in normal and pathological ageing, increasing the risk of cognitive impairment and dementia. In conditions distinct from the frontotemporal lobar degenerations, TDP-43 appears to progress in a stereotypical pattern. In the present study, we aimed at providing a better understanding of the effects of TDP-43 and other age-related neuropathologies on cross-sectional grey matter volume in a cohort of non-FTLD subjects. We included 407 individuals with an antemortem MRI and post-mortem brain tissue from the Mayo Clinic Alzheimer's Disease Research Center, Mayo Clinic Alzheimer's Disease Patient Registry, or the Mayo Clinic Study of Aging. All individuals were assigned pathological stages for TDP-43, tau, amyloid-\u3b2, Lewy bodies, argyrophilic grain disease and vascular pathologies. Robust regressions were performed in regions of interest and voxel-wise to explore the relationships between TDP-43 stages and grey matter volume while controlling for other pathologies. Grey matter volumes adjusted for pathological and demographic variables were also computed for each TDP-43-positive case to further characterize the sequential involvement of brain structures associated with TDP-43, irrespective of the TDP-43 staging scheme. Robust regressions showed that the extent of TDP-43 pathology was associated with the extent of grey matter atrophy. Specifically, we found that the volume in medial temporal regions (i.e. amygdala, entorhinal cortex, hippocampus) decreased progressively with advancing TDP-43 stages. Importantly, these effects were of similar magnitude to those related to tau stages. Additional analyses using adjusted grey matter volume demonstrated a sequential pattern of volume loss associated with TDP-43, starting within the medial temporal lobe, followed by early involvement of the temporal pole, and eventually encompassing additional temporal and frontal regions. Altogether, this study demonstrates the major and independent contribution of TDP-43 pathology on neurodegeneration and provides further insight into the regional distribution of TDP-43 in non-FTLD subjects. Along with previous studies, these findings emphasized the importance of targeting TDP-43 in future clinical trials to prevent its detrimental effect on grey matter volume and, eventually, cognition