Executive function subdomains are associated with post-stroke functional outcome and permanent institutionalization.

BACKGROUND AND PURPOSE: Impairment of executive functions (EFs) is a common cognitive symptom post-stroke and affects independence in daily activities. Previous studies have often relied on brief cognitive tests not fully considering the wide spectrum of EF subdomains. A detailed assessment of EFs was used to examine which of the subdomains and tests have the strongest predictive value on post-stroke functional outcome and institutionalization in long-term follow-up. METHODS: A subsample of 62 patients from the Helsinki Stroke Aging Memory Study was evaluated with a battery of seven neuropsychological EF tests 3 months post-stroke and compared to 39 healthy control subjects. Functional impairment was evaluated with the modified Rankin Scale (mRS) and Instrumental Activities of Daily Living (IADL) scale at 3 months, and with the mRS at 15 months post-stroke. Institutionalization was reviewed from the national registers of permanent hospital admissions in up to 21-year follow-up. RESULTS: The stroke group performed more poorly than the control group in multiple EF tests. Tests of inhibition, set shifting, initiation, strategy formation and processing speed were associated with the mRS and IADL scale in stroke patients. EF subdomain scores of inhibition, set shifting and processing speed were associated with functional outcome. In addition, inhibition was associated with the risk for earlier institutionalization. CONCLUSIONS: Executive function was strongly associated with post-stroke functional impairment. In follow-up, poor inhibition was related to earlier permanent institutionalization. The results suggest the prognostic value of EF subdomains after stroke.

Post-stroke cognitive impairment is common even after successful clinical recovery.

BACKGROUND AND PURPOSE: Cognitive impairment is common after stroke, but the prevalence and long-term significance of the diverse neuropsychological deficits on functional outcome are still not well known. The frequency and prognostic value of domain-specific cognitive impairments were investigated in a large cohort of ischaemic stroke patients. METHODS: Consecutive patients (n = 409), aged 55-85 years, from the acute stroke unit of the Helsinki University Hospital, Finland, were evaluated with extensive clinical and neuropsychological assessments 3 months post-stroke. Impairments within nine cognitive domains were determined according to age-appropriate normative data from a random healthy population. Functional disability was evaluated with the modified Rankin scale (mRS) 3 and 15 months post-stroke. RESULTS: In all, 83% patients showed impairment in at least one cognitive domain, whereas 50% patients were impaired in multiple (≥3) domains. In cases with excellent clinical recovery at 3 months (mRS = 0-1, no disability), the occurrence of any cognitive impairment was 71%. Memory, visuoconstructional and executive functions were most commonly impaired. A substantially smaller proportion of patients scored below the conventional or more stringent cut-offs in the Mini-Mental State Examination (MMSE). Domain-specific cognitive impairments were associated with functional dependence at 15 months regardless of stroke severity and other confounders. CONCLUSIONS: Cognitive impairment as evaluated with a comprehensive neuropsychological assessment is prevalent in stroke survivors even with successful clinical recovery. Typically multiple domains and complex cognitive abilities are affected. MMSE is not sensitive in detecting these symptoms. Post-stroke cognitive impairment is strongly related to poor functional outcome.

Brain atrophy accelerates cognitive decline in cerebral small vessel disease: the LADIS study.

OBJECTIVE: To examine the independent contributions and combined interactions of medial temporal lobe atrophy (MTA), cortical and subcortical atrophy, and white matter lesion (WML) volume in longitudinal cognitive performance. METHODS: A total of 477 subjects with age-related WML were evaluated with brain MRI and annual neuropsychological examinations in 3-year follow-up. Baseline MRI determinants of cognitive decline were analyzed with linear mixed models controlling for multiple confounders. RESULTS: MTA and subcortical atrophy predicted significantly steeper rate of decline in global cognitive measures as well as compound scores for psychomotor speed, executive functions, and memory after adjusting for age, gender, education, lacunes/infarcts, and WML volume. Cortical atrophy independently predicted decline in psychomotor speed. WML volume remained significantly associated with cognitive decline even after controlling for the atrophy scores. Moreover, significant synergistic interactions were found between WML and atrophy measures in overall cognitive performance across time and the rate of cognitive decline. Synergistic effects were also observed between baseline lacunar infarcts and all atrophy measures on change in psychomotor speed. The main results remained robust after exclusion of subjects with clinical stroke or incident dementia, and after additional adjustments for progression of WML and lacunes. CONCLUSIONS: Brain atrophy and WML are independently related to longitudinal cognitive decline in small vessel disease. MTA, subcortical, and cortical atrophy seem to potentiate the effect of WML and lacunes on cognitive decline.

Corpus callosum atrophy as a predictor of age-related cognitive and motor impairment: a 3-year follow-up of the LADIS study cohort.

The aim of this 3-year follow-up study was to investigate whether corpus callosum (CC) atrophy may predict future motor and cognitive impairment in an elderly population. On baseline MRI from 563 subjects with age-related white matter changes (ARWMC) from the Leukoaraiosis And DISability (LADIS) study, the CC was segmented and subdivided into five anterior-posterior regions (CC1-CC5). Associations between the CC areas and decline in motor performance and cognitive functions over a 3-year period were analyzed. CC atrophy at baseline was significantly associated with impaired cognitive performance (p<0.01 for CC1, p<0.05 for CC5), motor function (p<0.05 for CC2 and CC5), and walking speed (p<0.01 for CC2 and CC5, p<0.05 for CC3 and total CC), and with development of dementia at 3 years (p<0.05 for CC1) after correction for appropriate confounders (ARWMC volume, atrophy, age, gender and handedness). In conclusion, CC atrophy, an indicator of reduced functional connectivity between cortical areas, seems to contribute, independently of ARWMC load, to future cognitive and motor decline in the elderly.

Incident lacunes influence cognitive decline: the LADIS study.

BACKGROUND: In cerebral small vessel disease, the core MRI findings include white matter lesions (WML) and lacunar infarcts. While the clinical significance of WML is better understood, the contribution of lacunes to the rate of cognitive decline has not been established. This study investigated whether incident lacunes on MRI determine longitudinal cognitive change in elderly subjects with WML. METHODS: Within the Leukoaraiosis and Disability Study (LADIS), 387 subjects were evaluated with repeated MRI and neuropsychological assessment at baseline and after 3 years. Predictors of change in global cognitive function and specific cognitive domains over time were analyzed with multivariate linear regression. RESULTS: After controlling for demographic factors, baseline cognitive performance, baseline lacunar and WML lesion load, and WML progression, the number of new lacunes was related to subtle decrease in compound scores for executive functions (p = 0.021) and speed and motor control (p = 0.045), but not for memory or global cognitive function. Irrespective of lacunes, WML progression was associated with decrease in executive functions score (p = 0.016). CONCLUSION: Incident lacunes on MRI parallel a steeper rate of decline in executive functions and psychomotor speed. Accordingly, in addition to WML, lacunes determine longitudinal cognitive impairment in small vessel disease. Although the individual contribution of lacunes on cognition was modest, they cannot be considered benign findings, but indicate a risk of progressive cognitive impairment.

Cognitive impairment predicts poststroke death in long-term follow-up.

BACKGROUND: Poststroke global cognitive decline and dementia have been related to poor long-term survival. Whether deficits in specific cognitive domains are associated with long-term survival in patients with ischaemic stroke is not known in detail. METHODS: Patients with acute stroke subjected to comprehensive neuropsychological evaluation were included in the study (n = 409) and followed up for up to 12 years. RESULTS: In Kaplan-Meier analysis, impairments in following cognitive domains predicted poor poststroke survival (estimated years): executive functions (48.2%) (5.8 vs 10.1 years, p<0.0001), memory (59.9%) (6.8 vs 9.3 years, p = 0.009), language (28.9%) (5.3 vs 8.6 years, p = 0.004) and visuospatial/constructional abilities (55.2%) (5.6 vs 10.1 years, p<0.0001). Low Mini Mental Status Examination (MMSE)

Poststroke dementia predicts poor survival in long-term follow-up: influence of prestroke cognitive decline and previous stroke.

BACKGROUND: The aim of this study was to investigate the influence of poststroke dementia on long-term survival after acute stroke and also to assess the possible influence of prestroke cognitive decline and previous stroke on this relationship. METHODS: A total of 451 consecutive patients with acute ischaemic stroke admitted to hospital were included in the study and followed up for 12 years. Dementia was diagnosed 3 months after stroke in 115 patients (25.5%). RESULTS: In Kaplan-Meier analysis, poststroke dementia predicted poor long-term survival (5.1 years vs 8.8 years in patients who did not have poststroke dementia; p<0.001). Prestroke cognitive decline had a negative influence on survival in patients with poststroke dementia (3.8 years vs 5.8 years; p<0.001); however, previous stroke did not affect survival in these patients (p = 0.676). In stepwise Cox regression proportional hazards analysis adjusted for significant covariates, poststroke dementia (hazard ratio (HR) 1.53; p = 0.003), advanced age (HR 1.07; p<0.001), severity of stroke (HR 1.91; p<0.001), smoking (HR 1.35; p = 0.035), cardiac failure (HR 1.61; p = 0.003) and atrial fibrillation (HR 1.89; p = 0.035) were all independent predictors of poor long-term survival. Poststroke dementia (HR 2.33; p<0.001), advanced age (HR 1.07; p<0.001) and poor Rankin score (HR 2.15; p = 0.001) were associated with death from brain-related causes, including infarction, haemorrhage and dementia. CONCLUSIONS: Long-term follow-up of our large well-defined poststroke cohort indicated that in patients with acute stroke, dementia is a significant predictor of poor long-term survival and death from brain-associated causes. Prestroke cognitive decline seems to have an additional negative influence on survival, but previous stroke does not seem to affect survival.

Clinical significance of corpus callosum atrophy in a mixed elderly population.

Corpus callosum (CC) is the main tract connecting the hemispheres, but the clinical significance of CC atrophy is poorly understood. The aim of this work was to investigate clinical and functional correlates of CC atrophy in subjects with age-related white matter changes (ARWMC). In 569 elderly subjects with ARWMC from the Leukoaraiosis And DISability (LADIS) study, the CC was segmented on the normalised mid-sagittal magnetic resonance imaging (MRI) slice and subdivided into five regions. Correlations between the CC areas and subjective memory complaints, mini mental state examination (MMSE) score, history of depression, geriatric depression scale (GDS) score, subjective gait difficulty, history of falls, walking speed, and total score on the short physical performance battery (SPPB) were analyzed. Significant correlations between CC atrophy and MMSE, SPPB, and walking speed were identified, and the CC areas were smaller in subjects with subjective gait difficulty. The correlations remained significant after correction for ARWMC grade. In conclusion, CC atrophy was independently associated with impaired global cognitive and motor function in subjects with ARWMC.

Cognitive profile of subcortical ischaemic vascular disease.

OBJECTIVES: Subcortical ischaemic vascular disease (SIVD) is a subtype of vascular cognitive impairment characterised by extensive white matter lesions and multiple lacunar infarcts. Radiologically defined diagnostic criteria for SIVD have been introduced, but only a few studies have presented empirical data on its clinical and cognitive features. The aim of this study is to describe in detail the neuropsychological characteristics of patients with SIVD from a large well defined stroke cohort. METHODS: A sample of 323 consecutive patients with ischaemic stroke, aged 55-85 years, was investigated using neuropsychological examination and magnetic resonance imaging (MRI). Patients fulfilling the MRI criteria of SIVD (n = 85) were compared to the other stroke patients (n = 238) and to normal control subjects (n = 38). RESULTS: Cognitive performance of the SIVD group was inferior to that of the normal control group throughout all domains. As compared to the other stroke patients, the SIVD group performed significantly worse in tests measuring executive functions and delayed memory recall. Adjusting for depression had no effect on these results. Instead, after controlling for medial temporal lobe atrophy, the differences disappeared for delayed memory but remained significant for executive functions. CONCLUSION: Executive deficits are the most prominent cognitive characteristic associated with SIVD. Patients with SIVD also exhibit subtle deficits in delayed memory, which is explained in part by medial temporal lobe atrophy. Cognitive and mood changes seem to be parallel but independent processes related to SIVD. The results support the concept of SIVD as a separate clinical entity.

White matter hyperintensities as a predictor of neuropsychological deficits post-stroke.

OBJECTIVES: Cerebral white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) are a recognised risk factor for post-stroke dementia. Their specific relations to cognitive impairment are still not well known. The purpose of this study was to explore how the severity and location of WMHs predict neuropsychological test performance in the context of other brain lesions in elderly stroke patients. METHODS: In the Helsinki Stroke Aging Memory Study, 323 patients, aged from 55 to 85 years, completed a detailed neuropsychological test battery and MRI 3 months after an ischaemic stroke. The demographic and MRI predictors of cognition were studied with sequential linear regression analyses. RESULTS: After age, education and total infarct volume were controlled for, the overall degree of WMHs predicted poor performance in tests of mental speed, executive functions, memory, and visuospatial functions, but not in those of short term memory storage or verbal conceptualisation. However, the contribution of separate white matter regions was relatively low. Only the lesions along the bodies of lateral ventricles were independently associated with speed and executive measures. Additionally, general cortical atrophy clearly predicted a wide range of cognitive deficits while infarct volume had less relevance. Further analyses revealed that executive functions act as a strong mediator between the relationship of WMHs to memory and visuospatial functions. CONCLUSIONS: The degree of WMHs is independently related to post-stroke cognitive decline. The most affected cognitive domains seem to be executive functions and speed of mental processing, which may lead to secondary deficits of memory and visuospatial functions.

Medial temporal lobe atrophy and memory deficits in elderly stroke patients.

Medial temporal lobe atrophy (MTA) and its role in memory deficits have been studied extensively in patients with various dementias and non-degenerative neurologic diseases. In stroke patients MTA is a significant risk factor for dementia. However, its role in memory decline in non-demented stroke patients is not yet known. Our aim was to evaluate the relationship between MTA and cognitive functions in a large cohort of elderly patients, who underwent a comprehensive neuropsychologic examination and magnetic resonance imaging 3 months after an ischemic stroke. The study sample (n = 260) was divided into three groups according to the severity of MTA. After adjusting for age, volume of infarcts and cortical atrophy, we found that patients with moderate to severe MTA performed significantly worse in tests of learning, story recall, visual reproduction, block design and mental speed. In contrast, the groups did not differ in tests of digit span, flexibility, verbal fluency and conceptualization. Our conclusion is that in aged stroke patients, MTA is associated with poor performance in specific cognitive domains. The most vulnerable domains are memory and visuospatial functions, whereas verbal and executive functions seem to be unrelated to MTA.