Emilia Salvadori

Differential impact of cerebral white matter changes, diabetes, hypertension and stroke on cognitive performance among non-disabled elderly. The LADIS study

Background and purpose: Age related white matter changes (ARWMC) are frequent in non-demented old subjects and are associated with impaired cognitive function. Our aim was to study the influence of vascular risk factors and ARWMC on the neuropsychological performance of an independent elderly population, to see if vascular risk factors impair cognition in addition to the effects of ARWMC. Methods: Independent subjects, aged 65–84 years, with any degree of ARWMC were assessed using a comprehensive neuropsychological battery including the Mini-Mental State Examination (MMSE), VADAS-Cog (Alzheimer’s disease assessment scale) and the Stroop and Trail Making test. Vascular risk factors were recorded and ARWMC (measured by MRI) were graded into three classes. The impact of vascular risk factors and ARWMC on neuropsychological performance was assessed by linear regression analyses, with adjustment for age and education. Results: 638 patients (74.1 (5) years old, 55% women) were included. Patients with severe ARWMC performed significantly worse on global tests of cognition, executive functions, speed and motor control, attention, naming and visuoconstructional praxis. Diabetes interfered with tests of executive function, attention, speed and motor control, memory and naming. Arterial hypertension and stroke influenced executive functions and attention. The effect of these vascular risk factors was independent of the severity of ARWMC, age and education. Conclusion: ARWMC is related to worse performance in executive function, attention and speed. Diabetes, hypertension and previous stroke influenced neuropsychological performance, independently of the severity of ARWMC, stressing the need to control vascular risk factors in order to prevent cognitive decline in the elderly.

Whole-Brain Histogram and Voxel-Based Analyses of Diffusion Tensor Imaging in Patients with Leukoaraiosis: Correlation with Motor and Cognitive Impairment

BACKGROUND AND PURPOSE: Cerebral white matter changes, termed leukoaraiosis (LA), appearing as areas of increased signal intensity in T2-weighted MR images, are common in elderly subjects, but the possible correlation of LA with cognitive or motor deficit has not been established. We hypothesized that histogram and voxel-based analyses of whole-brain mean diffusivity (MD) and fractional anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) could be more sensitive tools than visual scales to investigate the clinical correlates of LA. MATERIALS AND METHODS: Thirty-six patients of the Leukoaraiosis and Disability Study were evaluated with fluid-attenuated inversion recovery for LA extension, T1-weighted images for volume, and DTI for MD and FA. The extent of LA was rated visually. The normalized total, gray, and white matter brain volumes were computed, as well as the 25th percentile, 50th percentile, kurtosis, and skewness of the MD and FA maps of the whole brain. Finally, voxel-based analysis on the maps of gray and white matter volume, MD, and FA was performed with SPM2 software. Correlation analyses between visual or computerized data and motor or neuropsychologic scale scores were performed using the Spearman rank test and the SPM2 software. RESULTS: The visual score correlated with some MD and FA histogram metrics (P < .01). However, only the 25th and 50th percentiles, kurtosis, and skewness of the MD and FA histograms correlated with motor or neuropsychologic deficits. Voxel-based analysis revealed a correlation (P < .05 corrected for multiple comparisons) between a large cluster of increased MD in the corpus callosum and pericallosal white matter and motor deficit. CONCLUSIONS: These results are consistent with the hypothesis that histogram and voxel-based analyses of the whole-brain MD and FA maps are more sensitive tools than the visual evaluation for clinical correlation in patients with LA.

Development of a Neuropsychological Battery for the Leukoaraiosis and Disability in the Elderly Study (LADIS): Experience and Baseline Data

The relationship between age-related white matter changes and cognitive performance in independent elderly people is still not clear. The Leukoaraiosis and Disability in the Elderly study (LADIS) involves 11 European centers. It aims to assess the role of the age-related white matter changes as an independent factor in the transition to disability, and in cognitive performance of an independent elderly population. A comprehensive neuropsychological battery was constructed in order to harmonize the cognitive assessment across countries. Patients were evaluated at baseline and during the 3-year follow-up with the Mini-Mental State Examination, a modified version of the VADAS-Cog (Alzheimer’s Dementia Assessment Scale plus tests of Delayed recall, Symbol digit, Digit span, Maze, Digit cancellation and Verbal fluency), Trail making and Stroop test. Six hundred thirty-eight patients (mean age 74 ± 5 years; mean educational level 10 ± 4, F/M: 351/287) were included in this study. Neuropsychological data were analyzed test by test and also grouped in three compound measures (executive, memory and speed/motor control domains). Older subjects (>74 years) performed significantly worse than younger subjects on the ADAS-Mod and on the tests of memory (t631 = 3.25; p = 0.001), executive functions (t581 = 4.68; p = 0.001) and speed/motor control (t587 = 4.01; p = 0.001). Participants with higher educational level (>8 years of school) showed better performances on the compound measures for memory (t631 = 3.25; p = 0.001), executive functions (t581 = 4.68; p = 0.001) and speed/motor control (t587 = 4.01; p = 0.001). Using multiple regression analysis models to study the influence of demographic variables on cognitive performance, age and education remained important variables influencing test performance. In the LADIS population baseline data, older age and lower educational levels negatively influence neuropsychological performance.

Self-perceived memory impairment and cognitive performance in an elderly independent population with age-related white matter changes.

Objectives: To determine whether self-perceived memory impairment is associated with the severity of white matter changes (WMC) and is related to cognitive impairment. Methods: Data were drawn from the multinational Leukoaraiosis and Disability Study (LADIS), which investigates the impact of WMC on global functioning. WMC severity was rated using the Fazekas scale. Medial temporal lobe atrophy (MTA) was scored visually and mean values were calculated. The neuropsychological battery consisted of the Mini-Mental State Examination, a modified version of the VADAS-Cog, Trail making and Stroop tests. A question about self-perceived memory impairment was used as a measure for presence of memory complaints. Cognitive performance was analysed test-by-test and in three main domains: memory, executive functions and speed/motor control. The Geriatric Depression Scale (GDS) was used as a measure of depressive symptoms. Results: Six hundred and thirty-eight subjects were included in this study. No association was found between memory complaints and the severity of WMC. Subjects with memory complaints (n = 399) had a higher GDS score [t(637) = −7.15; p<0.02] and performed worse on almost all cognitive tests and on the three cognitive domains. Multiple linear regression showed that the worse performance on the memory domain was associated with memory complaints independently of depressive symptoms, WMC severity and MTA (R2 = 0.183; F = 17.09, β = −0.126; p<0.05). Conclusion: In a sample of non-disabled elderly subjects with WMC, self-perceived memory impairment is significantly associated with objective memory impairment independently of the WMC severity, depressive symptoms and MTA.

Post-Stroke Dementia and Cognitive Impairment

The term post-stroke dementia (PSD) is used to define any dementia occurring after stroke irrespective if the leading cause is vascular, degenerative or mixed. PSD is a frequent condition after stroke and its prevalence ranges from 6 to 32%. However, not all cognitive impairment cases following a stroke are enough severe to fit the criteria for dementia. Indeed, many patients after a stroke develop mild cognitive impairment that in some cases can progress to PSD. There is an urgent need to find sensitive tools to detect post-stroke cognitive impairment as early as possible. The detection of cognitive impairment in the acute phase of stroke can offer valid information to the clinician on whether to set an early cognitive rehabilitation and to plan a more focused follow-up.

The Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy (CADASIL) Scale: a screening tool to select patients for NOTCH3 gene analysis.

Background and Purpose— Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) phenotype is highly variable, and, although the full clinical–neuroimaging picture may be suggestive of the disease, no characteristic is pathognomonic. Thus, a genetic test remains the diagnostic gold standard, but because it is costly and time-consuming, a pregenetic screening appears desirable. We aimed at developing the CADASIL scale, a screening tool to be applied in the clinical setting. Methods— A preliminary scale was created assigning weighted scores to common disease features based on their frequencies obtained in a pooled analysis of selected international CADASIL series. The accuracy of the scale versus the genetic diagnosis was tested with receiver operating characteristic analysis after the application of this scale to 61 CADASIL and 54 NOTCH3-negative patients (no pathogenic mutation on exons 2–23 of the NOTCH3 gene). To improve the scale accuracy, we then developed an ad hoc optimization algorithm to detect the definitive scale. A third group of 39 patients affected by sporadic small-vessel disease was finally included in the algorithm to evaluate the stability of the scale. Results— The cutoff score of the definitive CADASIL scale had a sensitivity of 96.7% and a specificity of 74.2%. This scale was robust to contamination of patients with sporadic small-vessel disease. Conclusions— The CADASIL scale is a simple and sufficiently accurate screening tool to select patients with a high probability to be affected by the disease and therefore to be subjected to the genetic testing.

Comparison of the Alzheimer's Disease Assessment Scale Cognitive Subscale and the Vascular Dementia Assessment Scale in differentiating elderly individuals with different degrees of white matter changes. The LADIS Study.

Background/Aims: The Alzheimer’s Disease Assessment Scale cognitive subscale (ADAS-cog) is a widely used rating instrument. The Vascular Dementia Assessment Scale cognitive subscale (VADAS-cog) includes additional tests reflecting mental speed and executive functions. The objective of this study was to compare the results of the two scales among subjects with various degrees of white matter hyperintensities (WMHs). Methods:In the multicentre, multinational Leukoaraiosis and Disability in the Elderly (LADIS) study, 616 non-disabled subjects between the ages of 65 and 84 were examined using MRI, the ADAS-cog and VADAS-cog. The WMH rating from the MRI divided the patients into groups of mild (n = 280), moderate (n = 187) and severe (n = 149) degrees of change. Results: Covariance analysis controlling for the effect of age and education revealed that the ADAS-cog differentiated only the mild and severe WMH groups, while the differences between all three groups were highly significant with the VADAS-cog. Conclusions:The VADAS-cog significantly differentiated between all the white matter groups. In comparison, the ADAS-cog differentiated only severe changes. Accordingly, the VADAS-cog may be a more sensitive endpoint in studies of patients with white matter load and vascular burden of the brain.

The burden of microstructural damage modulates cortical activation in elderly subjects with MCI and leuko-araiosis. A DTI and fMRI study

The term leuko‐araiosis (LA) describes a common chronic affection of the cerebral white matter (WM) in the elderly due to small vessel disease with variable clinical correlates. To explore whether severity of LA entails some adaptive reorganization in the cerebral cortex we evaluated with functional MRI (fMRI) the cortical activation pattern during a simple motor task in 60 subjects with mild cognitive impairment and moderate or severe (moderate‐to‐severe LA group, n = 46) and mild (mild LA group, n = 14) LA extension on visual rating. The microstructural damage associated with LA was measured on diffusion tensor data by computation of the mean diffusivity (MD) of the cerebral WM and by applying tract based spatial statistics (TBSS). Subjects were examined with fMRI during continuous tapping of the right dominant hand with task performance measurement. Moderate‐to‐severe LA group showed hyperactivation of left primary sensorimotor cortex (SM1) and right cerebellum. Regression analyses using the individual median of WM MD as explanatory variable revealed a posterior shift of activation within the left SM1 and hyperactivation of the left SMA and paracentral lobule and of the bilateral cerebellar crus. These data indicate that brain activation is modulated by increasing severity of LA with a local remapping within the SM1 and increased activity in ipsilateral nonprimary sensorimotor cortex and bilateral cerebellum. These potentially adaptive changes as well lack of contralateral cerebral hemisphere hyperactivation are in line with sparing of the U fibers and brainstem and cerebellar WM tracts and the emerging microstructual damage of the corpus callosum revealed by TBSS with increasing severity of LA. Hum Brain Mapp 35:819–830, 2014.

A pathogenic mutation on exon 21 of the NOTCH3 gene causing CADASIL in an octogenarian paucisymptomatic patient.

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is an inherited small vessel disease causing migraine, early strokes, cognitive impairment and premature death. The disease is caused by NOTCH3 gene puntiform mutations on one of the exons coding for the epidermal-growth factor (EGF)-like repeats of the extracellular domain of the NOTCH3 receptor. Mutations have been reported with higher frequency on some exons, and never on 6 out of a total of 23. We report for the first time a mutation (c.3471C>G) on exon 21 of the NOTCH3 gene that leads to a cysteine substitution (p.1131C>W) in the EGF-like repeat 29 of the NOTCH3 receptor extracellular domain, and that is responsible for CADASIL in a functionally independent elderly man who came to our attention at the age of 79 because of a minor stroke. CADASIL suspicion aroused only from the finding of severe white matter changes extended to the temporopolar region on cerebral magnetic resonance imaging. This case report underlines that, when CADASIL is suspected, molecular analysis should be performed on all the NOTCH3 exons coding for EGF-like repeats and not be limited to those where mutations have been found with higher frequency, and that the disease may be encountered also in mildly symptomatic elderly patients. The newly reported mutation might sustain a milder expressivity of the disease.

White matter microstructural damage in small vessel disease is associated with montreal cognitive assessment but not with mini mental state examination performances: Vascular mild cognitive impairment tuscany study

Background and Purpose— Montreal Cognitive Assessment (MoCA) has been proposed as a screening tool in vascular cognitive impairment. Diffusion tensor imaging is sensitive to white matter microstructural damage. We investigated if diffusion tensor imaging-derived indices are more strongly associated with performances on MoCA or on the widely used mini mental state examination in patients with mild cognitive impairment and small vessel disease. Methods— Mild cognitive impairment patients with moderate/severe degrees of white matter hyperintensities on MRI were enrolled. Lacunar infarcts, cortical atrophy, medial temporal lobe atrophy and median values of mean diffusivity and fractional anisotropy of the cerebral white matter were studied and correlated with cognitive tests performances. Results— Seventy-six patients (mean age 75.1±6.8 years, mean years of education 8.0±4.3) were assessed. In univariate analyses, a significant association of both MoCA and mini mental state examination scores with age, education, cortical atrophy, and medial temporal lobe atrophy was found, whereas mean diffusivity and fractional anisotropy were associated with MoCA. In partial correlation analyses, adjusting for all demographic and neuroimaging variables, both mean diffusivity and fractional anisotropy were associated only with MoCA (mean diffusivity: r= −0.275, P=0.023; fractional anisotropy: r=0.246, P=0.043). Conclusions— In patients with mild cognitive impairment and small vessel disease, diffusion tensor imaging-measured white matter microstructural damage is more related to MoCA than mini mental state examination performances. MoCA is suited for the cognitive screening of patients with small vessel disease.