White matter changes and gait decline in cerebral small vessel disease.

The relation between progression of cerebral small vessel disease (SVD) and gait decline is uncertain, and diffusion tensor imaging (DTI) studies on gait decline are lacking. We therefore investigated the longitudinal associations between (micro) structural brain changes and gait decline in SVD using DTI. 275 participants were included from the Radboud University Nijmegen Diffusion tensor and Magnetic resonance imaging Cohort (RUN DMC), a prospective cohort of participants with cerebral small vessel disease aged 50-85 years. Gait (using GAITRite) and magnetic resonance imaging measures were assessed during baseline (2006-2007) and follow-up (2011 - 2012). Linear regression analysis was used to investigate the association between changes in conventional magnetic resonance and diffusion tensor imaging measures and gait decline. Tract-based spatial statistics analysis was used to investigate region-specific associations between changes in white matter integrity and gait decline. 56.2% were male, mean age was 62.9 years (SD8.2), mean follow-up duration was 5.4 years (SD0.2) and mean gait speed decline was 0.2 m/s (SD0.2). Stride length decline was associated with white matter atrophy (ß = 0.16, p = 0.007), and increase in mean white matter radial diffusivity and mean diffusivity, and decrease in mean fractional anisotropy (respectively, ß = - 0.14, p = 0.009; ß = - 0.12, p = 0.018; ß = 0.10, p = 0.049), independent of age, sex, height, follow-up duration and baseline stride length. Tract-based spatial statistics analysis showed significant associations between stride length decline and fractional anisotropy decrease and mean diffusivity increase (primarily explained by radial diffusivity increase) in multiple white matter tracts, with the strongest associations found in the corpus callosum and corona radiata, independent of traditional small vessel disease markers. White matter atrophy and loss of white matter integrity are associated with gait decline in older adults with small vessel disease after 5 years of follow-up. These findings suggest that progression of SVD might play an important role in gait decline.

Diffusion tensor imaging of the hippocampus predicts the risk of dementia; the RUN DMC study.

INTRODUCTION: Cerebral small vessel disease is one of the most important risk factors for dementia, and has been related to hippocampal atrophy, which is among the first observed changes on conventional MRI in patients with dementia. However, these volumetric changes might be preceded by loss of microstructural integrity of the hippocampus for which conventional MRI is not sensitive enough. Therefore, we investigated the relation between the hippocampal diffusion parameters and the risk of incident dementia, using diffusion tensor imaging, independent of hippocampal volume. METHODS: The RUNDMC study is a prospective study among 503 elderly with small vessel disease, without dementia, with 5 years follow-up in 2012 (99.6% response-rate). Cox regression analysis was performed to calculate hazard ratios for dementia, of fractional anisotropy and mean diffusivity within the hippocampus, adjusted for demographics, hippocampal volume, and white matter. This was repeated in participants without evident hippocampal volume loss, because in these participants the visible damage might not yet have already started, whereas damage might have started on a microstructural level. RESULTS: 43 participants developed dementia (8.6%), resulting in a 5.5-year cumulative risk of 11.1% (95%CI 7.7-14.6). Higher mean diffusivity was associated with an increased 5-year risk of dementia. In the subgroup of participants with the upper half hippocampal volume, higher hippocampal mean diffusivity, more than doubled the 5-year risk of dementia. CONCLUSION: This is the first prospective study showing a relation between a higher baseline hippocampal mean diffusivity and the risk of incident dementia in elderly with small vessel disease at 5-year follow-up, independent of hippocampal volume and white matter volume.

Removal of valproic acid by plasmapheresis in a patient treated for multiple sclerosis.

We present a case of a patient with multiple sclerosis who was treated with plasmapheresis and valproic acid. We used therapeutic drug monitoring to determine whether plasma concentrations of valproic acid were kept within the therapeutic window and to determine the amount of valproic acid that was removed by plasmapheresis.

Microstructural integrity of the cingulum is related to verbal memory performance in elderly with cerebral small vessel disease: the RUN DMC study.

BACKGROUND: Cerebral small vessel disease (SVD) is related to verbal memory failures. It is suggested that early white matter damage, is located, among others, in the (posterior) cingulum at an early stage in neurodegeneration. Changes in the microstructural integrity of the cingulum assessed with diffusion tensor imaging (DTI), beyond detection with conventional MRI, may precede macrostructural changes and be related to verbal memory failures. OBJECTIVE: To investigate the relation between cingular microstructural integrity and verbal memory performance in 503 non-demented elderly with cerebral SVD. METHODS: The RUN DMC study is a prospective cohort study in elderly (50-85 years) with cerebral SVD. All participants underwent T1 MPRAGE, FLAIR and DTI scanning and the Rey Auditory Verbal Learning Test. Mean diffusivity (MD) and fractional anisotropy (FA) were assessed in six different cingular regions of interests (ROIs). Linear regression analysis was used to assess the relation between verbal memory performance and cingular DTI parameters, with appropriate adjustments. Furthermore a TBSS analysis of the whole brain was performed to investigate the specificity of our findings. RESULTS: Both our ROI-based and TBSS analysis showed that FA was positively related to immediate memory, delayed recall, delayed recognition and overall verbal memory performance of the cingulum, independent of confounders. A similar distribution was seen for the inverse association with MD and verbal memory performance with TBSS analysis. No significant relations were found with psychomotor speed, visuospatial memory and MMSE. When stratified on hippocampal integrity, the MD and FA values of the cingular ROIs differed significantly between participants with a good and poor hippocampal integrity. CONCLUSION: Microstructural integrity of the cingulum, assessed by DTI, is specifically related to verbal memory performance, in elderly with SVD. Furthermore we found that when the integrity of the hippocampus is disrupted, the cingulum integrity is impaired as well.

Depressive Symptoms and Amygdala Volume in Elderly with Cerebral Small Vessel Disease: The RUN DMC Study.

Introduction. Late onset depressive symptoms (LODSs) frequently occur in elderly with cerebral small vessel disease (SVD). SVD cannot fully explain LODS; a contributing factor could be amygdala volume. We investigated the relation between amygdala volume and LODS, independent of SVD in 503 participants with symptomatic cerebral SVD. Methods. Patients underwent FLAIR and T1 scanning. Depressive symptoms were assessed with structured questionnaires; amygdala and WML were manually segmented. The relation between amygdala volume and LODS/EODS was investigated and adjusted for age, sex, intracranial volume, and SVD. Results. Patients with LODS had a significantly lower left amygdala volume than those without (P = 0.02), independent of SVD. Each decrease of total amygdala volume (by mL) was related to an increased risk of LODS (OR = 1.77; 95% CI 1.02-3.08; P = 0.04). Conclusion. Lower left amygdala volume is associated with LODS, independent of SVD. This may suggest differential mechanisms, in which individuals with a small amygdala might be vulnerable to develop LODS.

Subjective cognitive failures and hippocampal volume in elderly with white matter lesions.

BACKGROUND: Subjective cognitive failures (SCF) and subjective memory failures (SMF) have been reported to be an early predictor of Alzheimer disease (AD) and have been attributed to white matter lesions (WML). Since AD is characterized by hippocampal degeneration, it is surprising that its relation with hippocampal atrophy has been investigated only sparsely. Previous studies on this are rare, limited in sample size, and did not adjust for WML. OBJECTIVE: To determine the relation between SCF and hippocampal volume in strata of objective cognitive performance among elderly without dementia with incidental WML. METHODS: The Radboud University Nijmegen Diffusion tensor and MRI Cohort study is a prospective cohort study among 503 subjects with WML aged between 50 and 85 years. All subjects underwent FLAIR and T1 MRI scanning. The amount of SCF and SMF was rated by the Cognitive Failure Questionnaire. Cognitive function was assessed by a cognitive screening battery. Volumetric measures of hippocampus and WML were manually performed. We assessed the relation between hippocampal volume and SCF and SMF adjusted for age, sex, education, depression, intracranial volume, and WML volume. RESULTS: Subjects with SCF and SMF had lower hippocampal volumes than those without (p = 0.01 and p = 0.02). This was most noteworthy in subjects with good objective cognitive performance (p(trend) = 0.007 and p(trend) = 0.03), and not in those with poor objective cognitive performance. CONCLUSION: Subjective cognitive failures (SCF) are associated with lower hippocampal volume, even in subjects without objective cognitive impairment and independent of white matter lesions. SCF has a radiologic detectable pathologic-anatomic substrate.