Longitudinal cognitive decline in subcortical ischemic vascular disease--the LADIS Study.

BACKGROUND: Cross-sectional studies have indicated that subcortical ischemic vascular disease (SIVD), as defined according to imaging criteria, is associated with a specific clinical and cognitive profile. Much less is known about the long-term cognitive consequences of SIVD. The aim of the study was to investigate the longitudinal cognitive performance and incident dementia in subjects with and without SIVD in a sample of older adults with white matter lesions. METHODS: In the Leukoaraiosis and Disability (LADIS) study, 639 participants were examined with annual clinical and neuropsychological evaluations for 3 years. The subjects meeting the MRI criteria of SIVD at baseline were compared to the other subjects of the sample with linear mixed models. RESULTS: The overall level of cognitive performance over the follow-up period was inferior in multiple cognitive domains in SIVD subjects as compared to the reference group. The subjects with SIVD presented significantly steeper decline of performance in the Stroop test (parts I and II), Trail Making A test, Verbal fluency test, and Mini-Mental State Examination. They also had a threefold risk of developing dementia during follow-up independently of age, sex, education and medial temporal lobe atrophy. CONCLUSIONS: SIVD, as a manifestation of cerebral small vessel disease, is related to progressive cognitive impairment and a considerable risk of developing dementia. SIVD seems to specifically contribute to the deterioration of psychomotor speed, executive control, and global cognitive function.

MRI-defined subcortical ischemic vascular disease: baseline clinical and neuropsychological findings. The LADIS Study.

BACKGROUND: Subcortical ischemic vascular disease (SIVD) is a common, but often overlooked cause of vascular cognitive impairment. Diagnostic research criteria for SIVD are based on magnetic resonance imaging (MRI) findings including substantial white matter lesions (WML) and multiple lacunar infarcts. Empirical studies validating these imaging criteria are still few. The purpose of the study was to describe the clinical and cognitive characteristics of the MRI-defined SIVD in a mixed sample of functionally independent elderly subjects with WML. METHODS: The subjects of the Leukoaraiosis and Disability (LADIS) study, aged 65-84 years, underwent comprehensive clinical and neuropsychological examinations, and brain MRI at the baseline assessment. The subjects meeting the SIVD imaging criteria (n = 89) were compared to the other subjects of the sample (n = 524). RESULTS: SIVD was associated with lower education, hypertension and, independently, with obesity. The subjects with SIVD had more often motor impairment, a history of falls, and subtle impairment in activities of daily living, but they did not differ for depressive symptoms. SIVD subjects performed significantly inferiorly in tests of global cognitive function, psychomotor speed, attention and executive functions, verbal fluency, and working memory. CONCLUSION: In this population of nondisabled older adults with WML, SIVD was related to specific clinical and functional characteristics. Neuropsychological features included psychomotor slowing as well as deficits in attention and executive functions.

Corpus callosum atrophy is associated with mental slowing and executive deficits in subjects with age-related white matter hyperintensities: the LADIS Study.

BACKGROUND: Previous research has indicated that corpus callosum atrophy is associated with global cognitive decline in neurodegenerative diseases, but few studies have investigated specific cognitive functions. OBJECTIVE: To investigate the role of regional corpus callosum atrophy in mental speed, attention and executive functions in subjects with age-related white matter hyperintensities (WMH). METHODS: In the Leukoaraiosis and Disability Study, 567 subjects with age-related WMH were examined with a detailed neuropsychological assessment and quantitative magnetic resonance imaging. The relationships of the total corpus callosum area and its subregions with cognitive performance were analysed using multiple linear regression, controlling for volume of WMH and other confounding factors. RESULTS: Atrophy of the total corpus callosum area was associated with poor performance in tests assessing speed of mental processing--namely, trail making A and Stroop test parts I and II. Anterior, but not posterior, corpus callosum atrophy was associated with deficits of attention and executive functions as reflected by the symbol digit modalities and digit cancellation tests, as well as by the subtraction scores in the trail making and Stroop tests. Furthermore, semantic verbal fluency was related to the total corpus callosum area and the isthmus subregion. CONCLUSIONS: Corpus callosum atrophy seems to contribute to cognitive decline independently of age, education, coexisting WMH and stroke. Anterior corpus callosum atrophy is related to the frontal-lobe-mediated executive functions and attention, whereas overall corpus callosum atrophy is associated with the slowing of processing speed.

White matter lesions are related to impaired instrumental activities of daily living poststroke.

BACKGROUND: White matter lesions (WMLs) are frequent in elderly people, and have been associated with impaired activities of daily living (ADL) and cognitive decline. We sought to examine the role of WMLs and their extent, in regard to basic ADL, instrumental ADL (IADL), and cognitive functions, in a large well-defined cohort examined 3 months after an ischemic stroke. METHODS: The study group included 395 of 486 consecutive patients aged 55 to 85 years who, 3 months after an ischemic stroke, completed a neuropsychological test battery and magnetic resonance imaging, and structured medical, neurological, and laboratory evaluations; assessment included an interview with a knowledgeable informant. RESULTS: The patients with the most severe WMLs (n = 213) were older, in comparison with those with moderate (n = 71) or mild/no (n = 111) WMLs. These patients also more often had Diagnostic and Statistical Manual of Mental Disorders, Third Edition dementia; had a lower Mini Mental Status score; were more often women; more often had impaired immediate and delayed memory performance, executive dysfunction, and impaired basic ADL and IADL functions; and had more infarcts and cortical or central atrophy in magnetic resonance imaging. However, there were no significant differences among the 3 groups in stroke severity measured on the Scandinavian Stroke Scale, in stroke-related depression as measured by the Beck Depression Inventory, or in stroke type. According to multiple logistic regression analysis, higher age (odds ratio 1.067, 95% confidence interval 1.036-1.01) and impaired IADL (odds ratio 0.852, 95% confidence interval 0.778-0.931) significantly correlated with severe WMLs. CONCLUSIONS: Although the degree of WMLs was not associated with stroke severity, it was associated with global cognitive function, impaired memory functions, executive dysfunction, sex, and impaired basic ADL. Age and IADL functions were independent correlates of severe WMLs.

Source estimation of spontaneous MEG oscillations in mild cognitive impairment.

Mild cognitive impairment (MCI) is a memory disorder often preceding Alzheimer's disease (AD). AD has been shown to be associated with abnormal generation of spontaneous electromagnetic activity. We investigated whether the cortical generation of spontaneous brain oscillations in MCI shows changes resembling those observed in AD. A minimum current estimates algorithm was applied to identify cortical sources of magnetoencephalographic (MEG) spontaneous brain oscillations in male MCI patients with a clear memory disorder and in healthy elderly controls. This data was subsequently compared to a male subsample of AD patients from an earlier study. While there were clear oscillatory abnormalities in AD patients, there was no evidence of significant changes in the alpha source distribution in MCI patients as compared to healthy controls. Deficits in the distribution of oscillatory sources in the resting state are thus likely to occur at later stages of cognitive impairment than MCI.

Neuropsychological functions in variant Alzheimer's disease with spastic paraparesis.

Few data exist on the effects of specific Alzheimer's disease (AD)-related mutations on cognitive function. We present neuropsychological test results in eight members of a large kindred with variant Alzheimer's disease (VarAD) due to a deletion of the presenilin 1 (PS-1) gene, encompassing exon 9. The disease was neuropathologically characterized by the presence of large, unusual, "cotton wool" plaques (CWP). Four surviving patients were prospectively tested, and retrospective neuropsychological data were collected from additional four deceased patients. The neuropsychological evaluation was based on tests of verbal and visual memory, abstract thinking, and visuoconstructive and spatial functions. In addition, psychiatric symptoms were evaluated. In four patients, brain glucose metabolism was examined by positron emission tomography (PET). PET showed temporoparietal hypometabolism typical of AD. In addition, variable patterns of hypometabolism (hemispherical asymmetry and occipital accentuation) were related to individual deficits of cognitive performance. However, all these early-onset patients (age range 43-63 years) with a deletion mutation of PS-1 gene showed prominent memory impairment and deficits in visuoconstructive and intellectual functions.

Callosal tissue loss parallels subtle decline in psychomotor speed. a longitudinal quantitative MRI study. The LADIS Study.

Cross-sectional studies have suggested that corpus callosum (CC) atrophy is related to impairment in global cognitive function, mental speed, and executive functions in the elderly. Longitudinal studies confirming these findings have been lacking. We investigated whether CC tissue loss is associated with change in cognitive performance over time in subjects with age-related white matter lesions (WML). Two-hundred-fifty-three subjects, aged 65-84 years, were evaluated by using repeated MRI and neuropsychological evaluation at baseline and after 3 years. The effect of overall and regional CC tissue loss on cognitive decline was analyzed with hierarchical linear regression models. After controlling for age, sex, education, and baseline cognitive performance, the rates of tissue loss in the total CC area, and in rostrum/genu and midbody subregions were significantly associated with decline in a compound measure of cognitive speed and motor control, but not in those of executive functions, memory, or global cognitive function. Total CC area and midbody remained significant predictors of speed also after adjusting for baseline WML volume, WML progression, and global brain atrophy. However, the relationship between anterior CC and speed performance was mediated by WML volume. In conclusion, the overall and regional rate of CC tissue loss parallels longitudinal slowing of psychomotor performance. The adverse effect of CC tissue loss on psychomotor function may be driven by altered interhemispheric information transfer between homologous cortical areas.

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.

Depression-executive dysfunction syndrome in stroke patients.

OBJECTIVE: It has been suggested that executive dysfunction could be the core defect in patients with geriatric or vascular depression, and that this depression-dysexecutive syndrome (DES) might be related to frontal-subcortical circuit dysfunction. The authors tested this hypothesis in 158 poststroke patients, of whom 21 had both depression and executive dysfunction. METHODS: In this cross-sectional cohort study, a neurological, psychiatric, and neuropsychological examination was carried out 3 months after ischemic stroke, and brain infarcts, white-matter changes, and brain atrophy were recorded by MRI. RESULTS: The 21 patients with DES had significantly more brain infarcts affecting their frontal-subcortical circuit structures than the 137 patients without DES, or the 41 patients with depression but without executive dysfunction. Patients with DES also had more severe depressive symptoms and worse psychosocial functioning, and they coped less well in complex activities of daily living. CONCLUSIONS: DES is a valid concept and may define a subgroup of poststroke patients with frontal-subcortical pathology and with distinct prognosis and treatment options.

Assessment of executive function in clinical trials.

Cerebrovascular disease and stroke are related to high risk of cognitive impairment. One of the main neuropsychological features in vascular cognitive impairment and vascular dementia is executive dysfunction. Definition of the essential subcomponents and concepts of executive function is important before determining the methodology in clinical trials. The scientific research and new methods on this topic are rapidly growing. We present some most commonly used neuropsychological tests and discuss the methodological aspects in light of clinical trials.

Clinical features of MRI-defined subcortical vascular disease.

BACKGROUND AND PURPOSE: Vascular cognitive impairment and vascular dementia are now seen to extend much beyond the traditional multi-infarct dementia.A more homogeneous subtype is the subcortical ischemic vascular disease (SIVD). We applied magnetic resonance imaging (MRI) criteria based on research criteria for SIVD in a large cohort of patients with ischemic stroke. We compared clinical features of patients with SIVD and patients with other stroke type. SUBJECT AND METHODS: The study group comprised 337 of 486 consecutive patients aged 55 to 85 years who 3 months after ischemic stroke completed a comprehensive neuropsychological test battery and MRI, including structured medical, neurologic, and laboratory evaluations; clinical mental status examination; interview of a knowledgeable informant; detailed history of risk factors; and evaluation of stroke type, localization, and syndrome. RESULTS: Patients with SIVD (n = 86) more often had a history of progressive cognitive decline (22.8% vs. 6.9%, P = 0.0002), walking disorder before stroke (27.9% vs. 2.0%, P = 0.02), and urinary difficulties (12.8% vs. 5.6%, P = 0.028) in comparison with patients with other stroke type (n = 251). Of the study population, 107 (31.8%) had DSM-III dementia. The patients with SIVD more often had DSM-III dementia (40.7% vs. 28.7%, P = 0.04), had less severe stroke as measured by Scandinavian Stroke Scale (56.6 vs. 55.1, P = 0.03), were more dependent in activities of daily living (ADL) functions as measured by FAQ scale (8.9 vs. 5.4, P = 0.001), were more dependent in instrumental activities of daily living (IADL) functions as measured by the Lawton scale (5.5 vs. 6.3, P = 0.01), and were more depressed as measured by the Beck Depression Inventory (11.8 vs. 8.4, P = 0.0003) poststroke than the patients without SIVD. The main cognitive domain that differentiated the patients with SIVD from those without was executive dysfunction (51.2% vs. 38.7%, P = 0.04). According to multiple regression model, apractic-atactic gait disorder (odds ratio 2.82, 95% confidence interval 1.21-6.53), ADL functions (odds ratio 1.04, 95% confidence interval 1.01-1.08), and the Beck Depression Inventory (odds ratio 1.05, 95% confidence interval 1.02-1.09) related to SIVD. CONCLUSIONS: The most significant clinical features of MRI-defined SIVD were found to be apractic-atactic gait, impaired ADL functions, and depression.