Medial temporal lobe atrophy and memory deficits in elderly stroke patients

MRI factors associated with cognitive functioning after acute onset brain injury: Systematic review and meta-analysis

Impairments of memory, attention, and executive functioning are frequently reported after acute onset brain injury. MRI markers hold potential to contribute to identification of patients at risk for cognitive impairments and clarification of mechanisms. The aim of this systematic review was to summarize and value the evidence on MRI markers of memory, attention, and executive functioning after acute onset brain injury. We included ninety-eight studies, on six classes of MRI factors (location and severity of damage (n = 15), volume/atrophy (n = 36), signs of small vessel disease (n = 15), diffusion-weighted imaging measures (n = 36), resting-state functional MRI measures (n = 13), and arterial spin labeling measures (n = 1)). Three measures showed consistent results regarding their association with cognition. Smaller hippocampal volume was associated with worse memory in fourteen studies (pooled correlation 0.58 [95% CI: 0.46-0.68] for whole, 0.11 [95% CI: 0.04-0.19] for left, and 0.34 [95% CI: 0.17-0.49] for right hippocampus). Lower fractional anisotropy in cingulum and fornix was associated with worse memory in six and five studies (pooled correlation 0.20 [95% CI: 0.08-0.32] and 0.29 [95% CI: 0.20-0.37], respectively). Lower functional connectivity within the default-mode network was associated with worse cognition in four studies. In conclusion, hippocampal volume, fractional anisotropy in cingulum and fornix, and functional connectivity within the default-mode network showed consistent associations with cognitive performance in all types of acute onset brain injury. External validation and cut off values for predicting cognitive impairments are needed for clinical implementation.

Cognitive Profile of Large-Vessel Vascular Dementia—An Observational Study from a Tertiary Care Center in Kolkata

Introduction  Vascular dementia is the second leading cause of dementia worldwide. Its heterogenous presentation along with potential for reversibility at earlier stages makes it unique among all dementias.

Objectives  We aimed to study the cognitive dysfunction in large-vessel vascular dementia. Second, we tried to study the cognitive dysfunction in large-vessel vascular dementia as per the arterial territory involvement. Additionally, we also tried to study the contribution of hemispheric involvement to the dementia severity as evidenced by clinical dementia rating (CDR) scale.

Materials and Methods  We recruited 28 patients of large-vessel vascular dementia and categorized them on the basis of the arterial territories and hemisphere involved. The groups were later studied for the type of cognitive and behavioral dysfunctions as well as the dementia severity.

Results  Among 28 patients of large-vessel vascular dementia, attention (100%), executive function (100%), and behavior (100%) were more impaired in anterior cerebral artery territory infarcts ( p  < 0.05). Language (53.8%) and memory (53.8%) were more impaired in middle cerebral artery territory infarcts, while visuoperceptual (33.3%) domains were more impaired in posterior cerebral artery territory infarcts ( p  > 0.05). The mean CDR was lower in patients of right-sided lesions (1.292) than in those with left-sided (1.750) or bilateral lesions (2.000).

Conclusion  Different arterial territory lesions have different patterns of cognitive impairment in large-vessel vascular dementia. The dementia severity is less in right-sided lesions when compared with left-sided or bilateral lesions.

Medicolegal Implications of Mild Neurocognitive Disorder

INTRODUCTION

The syndromes of mild cognitive impairment (MCI) or mild neurocognitive disorder (MiND), often prodromal to dementia (Major Neurocognitive Disorder), are characterized by acquired clinically significant changes in one or more cognitive domains despite preserved independence. Mild impairment has significant medicolegal consequences for an affected person and their care system. We review the more common etiologies of MiND and provide a systematic review of its medicolegal implications.

METHODS

We conducted a systematic review of the peer-reviewed English literature on medicolegal aspects of MCI or MiND using comprehensive search terms and expanding our review to include sources cited by these reports.

RESULTS

Impairment of memory, executive function, social cognition, judgment, insight or abstraction can alter an individual's abilities in a variety of areas that include decision making, informed consent, designation of a surrogate decision-maker such as a health care proxy, understanding and management of financial affairs, execution of a will, or safe driving.

CONCLUSION

Even mild cognitive impairment can have significant behavioral consequences. Clinicians can assist care partners and persons with MCI or MiND by alerting them to the medicolegal concerns that often accompany cognitive decline. Early recognition and discussion can help a care system manage medicolegal risk more effectively and promote thoughtful advance planning.

Preexisting Cerebral Abnormalities and Functional Outcomes After Acute Ischemic Stroke

PURPOSE

The aim of this study was to investigate the association between preexisting cerebral abnormalities in patients with acute ischemic stroke upon their functional outcomes.

METHODS

We recruited 272 patients with first-ever acute ischemic stroke. Cerebral abnormalities on magnetic resonance imaging included infarction, silent brain infarcts (SBI), enlarged perivascular spaces, white matter lesions (WMLs), global brain atrophy, and medial temporal lobe atrophy (MTLA). Functional outcomes were assessed using the instrumental activities of daily living (IADL) scale and basic activities of daily living (BADL) scale, at 3 and 6 months after the index stroke.

RESULTS

Two hundred and fifty patients completed the 3-month follow-up and 246 patients completed the 6-month follow-up. Univariate analyses showed that patients with poor IADL and BADL were older, more likely to be men, had higher National Institutes of Health Stroke Scale (NIHSS) score on admission, more frequent atrial fibrillation, and large artery atherosclerosis subtypes. They also had more frequent cortical infarcts, subcortical infarcts, infratentorial infarcts, larger infarct volume, more frequent presence of SBI, severe WMLs, and MTLA. In multiple regression analyses, NIHSS on admission, subcortical region infarct and MTLA were significant predictors of poor IADL at 3 months. National Institutes of Health Stroke Scale on admission, SBI and MTLA were significant predictors of poor IADL at 6 months. National Institutes of Health Stroke Scale on admission and MTLA were significant predictors of poor BADL at 3 months. National Institutes of Health Stroke Scale on admission and SBI were significant predictors of poor BADL at 6 months.

CONCLUSIONS

In patients with acute ischemic stroke, the presence of SBI, and severe MTLA represent significant predictors of poorer functional outcomes, thus highlighting the importance of preexisting cerebral abnormalities.

The new insights into human brain imaging after stroke

Over the last two decades, developments of human brain stroke imaging have raised several questions about the place of new MRI biomarkers in the acute management of stroke and the prediction of poststroke outcome. Recent studies have demonstrated the main role of perfusion-weighted imaging in the identification of the best cerebral perfusion profile for a better response after reperfusion therapies in acute ischemic stroke. A major issue remains the early prediction of stroke outcome. While voxel-based lesion-symptom mapping emphasized the influence of stroke location, the analysis of the brain parenchyma underpinning the stroke lesion showed the relevance of prestroke cerebral status, including cortical atrophy, white matter integrity, or presence of chronic cortical cerebral microinfarcts. Moreover, besides the evaluation of the visually abnormal brain tissue, the analysis of normal-appearing brain parenchyma using diffusion tensor imaging and magnetization transfer imaging or spectroscopy offered new biomarkers to improve the prediction of the prognosis and new targets to follow in therapeutic trials. The aim of this review was to depict the main new radiological biomarkers reported in the last two decades that will provide a more thorough prediction of functional, motor, and neuropsychological outcome following the stroke. These new developments in neuroimaging might be a cornerstone in the emerging personalized medicine for stroke patients.

Dysregulation of Autophagy, Mitophagy, and Apoptotic Genes in the Medial Temporal Lobe Cortex in an Ischemic Model of Alzheimer's Disease

Ischemic brain damage is a pathological incident that is often linked with medial temporal lobe cortex injury and finally its atrophy. Post-ischemic brain injury associates with poor prognosis since neurons of selectively vulnerable ischemic brain areas are disappearing by apoptotic program of neuronal death. Autophagy has been considered, after brain ischemia, as a guardian against neurodegeneration. Consequently, we have examined changes in autophagy (BECN 1), mitophagy (BNIP 3), and apoptotic (caspase 3) genes in the medial temporal lobe cortex with the use of quantitative reverse-transcriptase PCR following transient 10-min global brain ischemia in rats with survival 2, 7, and 30 days. The intense significant overexpression of BECN 1 gene was noted on the 2nd day, while on days 7-30 the expression of this gene was still upregulated. BNIP 3 gene was downregulated on the 2nd day, but on days 7-30 post-ischemia, there was a significant reverse tendency. Caspase 3 gene, associated with apoptotic neuronal death, was induced in the same way as BNIP 3 gene after brain ischemia. Thus, the demonstrated changes indicate that the considerable dysregulation of expression of BECN 1, BNIP 3, and caspase 3 genes may be connected with a response of neuronal cells in medial temporal lobe cortex to transient complete brain ischemia.

Discrepancy in Expression of β-Secretase and Amyloid-β Protein Precursor in Alzheimer-Related Genes in the Rat Medial Temporal Lobe Cortex Following Transient Global Brain Ischemia

Brain ischemia may be causally related with Alzheimer's disease. Presumably, β-secretase and amyloid-β protein precursor gene expression changes may be associated with Alzheimer's disease neuropathology. Consequently, we have examined quantitative changes in both β-secretase and amyloid-β protein precursor genes in the medial temporal lobe cortex with the use of quantitative rtPCR analysis following 10-min global brain ischemia in rats with survival of 2, 7, and 30 days. The greatest significant overexpression of β-secretase gene was noted on the 2nd day, while on days 7-30 the expression of this gene was only modestly downregulated. Amyloid-β protein precursor gene was downregulated on the 2nd day, but on days 7-30 postischemia, there was a significant reverse tendency. Thus, the demonstrated alterations indicate that the considerable changes of expression of β-secretase and amyloid-β protein precursor genes may be connected with a response of neurons in medial temporal lobe cortex to transient global brain ischemia. Finally, the ischemia-induced gene changes may play a key role in a late and slow onset of Alzheimer-type pathology.

Cerebral small vessel disease, medial temporal lobe atrophy and cognitive status in patients with ischaemic stroke and transient ischaemic attack

BACKGROUND AND PURPOSE

Small vessel disease (SVD) and Alzheimer's disease (AD) are two common causes of cognitive impairment and dementia, traditionally considered as distinct processes. The relationship between radiological features suggestive of AD and SVD was explored, and the association of each of these features with cognitive status at 1 year was investigated in patients with stroke or transient ischaemic attack.

METHODS

Anonymized data were accessed from the Virtual International Stroke Trials Archive (VISTA). Medial temporal lobe atrophy (MTA; a marker of AD) and markers of SVD were rated using validated ordinal visual scales. Cognitive status was evaluated with the Mini Mental State Examination (MMSE) 1 year after the index stroke. Logistic regression models were used to investigate independent associations between (i) baseline SVD features and MTA and (ii) all baseline neuroimaging features and cognitive status 1 year post-stroke.

RESULTS

In all, 234 patients were included, mean (±SD) age 65.7 ± 13.1 years, 145 (62%) male. Moderate to severe MTA was present in 104 (44%) patients. SVD features were independently associated with MTA (P < 0.001). After adjusting for age, sex, disability after stroke, hypertension and diabetes mellitus, MTA was the only radiological feature independently associated with cognitive impairment, defined using thresholds of MMSE ≤ 26 (odds ratio 1.94; 95% confidence interval 1.28-2.94) and MMSE ≤ 23 (odds ratio 2.31; 95% confidence interval 1.48-3.62).

CONCLUSION

In patients with ischaemic cerebrovascular disease, SVD features are associated with MTA, which is a common finding in stroke survivors. SVD and AD type neurodegeneration coexist, but the AD marker MTA, rather than SVD markers, is associated with post-stroke cognitive impairment.

Prevalence and cognitive impact of medial temporal atrophy in a hospital stroke service: retrospective cohort study

BACKGROUND

Cerebrovascular disease and neurodegeneration cause cognitive impairment and frequently coexist.

AIMS

Our objectives were to investigate the prevalence and cognitive impact of medial temporal lobe atrophy - a radiological marker often associated with Alzheimer's disease - in a hospital stroke service.

METHODS

Retrospective cohort study of patients from a hospital stroke service. Patients assessed for suspected ischemic stroke or transient ischemic attack, irrespective of final diagnosis, underwent neuropsychological testing and magnetic resonance imaging. medial temporal lobe atrophy, white matter hyperintensities, lacunes, and cerebral microbleeds were rated using established criteria and validated scales. The associations between medial temporal lobe atrophy and cognition were tested using multivariable logistic regression analyses, adjusted for age and imaging markers of cerebrovascular disease.

RESULTS

Three hundred and ninety-three patients were included, of whom 169 (43%; 95% confidence interval: 38·1-48·1%) had medial temporal lobe atrophy; in 38 patients (9·7%), medial temporal lobe atrophy was severe (mean score ≥2). In unadjusted logistic regression analyses in the whole cohort, mean medial temporal lobe atrophy score was associated with verbal memory, nominal and perceptual skills, executive function, and speed and attention. After adjustment for age, white matter hyperintensities, number of lacunes, presence of cerebral microbleeds, previous ischemic stroke or transient ischemic attack, and premorbid intelligence quotient, mean medial temporal lobe atrophy score remained associated with impairment in verbal memory (odds ratio: 1·64; 95% confidence interval 1·04-2·58) and nominal skills (odds ratio: 1·61; 95% confidence interval 1·04-2·48).

CONCLUSIONS

Medial temporal lobe atrophy is common and has an independent impact on cognitive function in a stroke service population, independent of confounding factors including age and magnetic resonance imaging markers of cerebrovascular disease. Medial temporal lobe atrophy is independently related to verbal memory and nominal skills, while small vessel pathology also contributes to speed and attention, and executive and perceptual functions.

Is poststroke depression a major depression?

BACKGROUND

Poststroke depression (PSD) is the most common neuropsychiatric consequence of stroke. A large number of studies have focused on the pathogenesis of PSD, but only a few aimed to characterize its psychopathology; these studies yielded results that are difficult to compare because of the different methods utilized. The current study aimed to characterize the symptom profile of PSD in an attempt to better understand the disease and allow a more accurate diagnosis.

METHODS

The study sample comprised 64 patients divided into three groups: stroke patients without diagnosis of depression (n = 33), stroke patients diagnosed with PSD (PSD group, n = 14) and patients diagnosed with major depression (MD) but with no clinical comorbidity (MD group, n = 17). All patients were diagnosed using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I). The initial diagnostic interview was complemented by the Mini Mental State Examination (MMSE), the Rankin Scale, and four scales for the assessment of the intensity of symptoms of anxiety and depression: the Beck Depression Inventory (BDI), the Hospital Anxiety and Depression General Scale (HADS), the Hamilton Depression Rating Scale (HAM-D) and the Hamilton Rating Scale for Anxiety (HAM-A). The Star Plot, a graphical method of data visualization, was used to analyze the results. The t test was used for independent samples (two-tailed analysis).

RESULTS

As measured by the BDI, HAM-D and HAM-A scales and HADS depression subscale, the average total scores of symptoms for the sample of patients diagnosed with MD without clinical comorbidity was significantly higher than that of the PSD patients (p < 0.05). Similar results were obtained by plotting the BDI data on Star Plot. The PSD patients showed mild typical depressive symptoms such as less depressed mood, anhedonia, disinterest, guilt, negative thoughts, depreciation, suicidal ideation and anxiety, when evaluated by the HAM-A scale. Moreover, the somatic symptoms of depression did not lead to increased diagnosis of major depression in stroke patients.

CONCLUSIONS

The results indicate that the PSD clinical picture comprised, in general, symptoms of mild/moderate intensity, especially those considered as pillars for the diagnosis of depression: depressed mood, loss of pleasure and lack of interest. Given the imprecision of boundaries that separate the clinical forms of depression from subclinical and nonpathological forms, or even from the concepts of demoralization and adjustment disorders, we situate PSD in a complex biopsychosocial context in which a better understanding of its psychopathological profile could provide diagnostic and therapeutic alternatives best suited to the difficult reality experienced by stroke patients.

Medial temporal atrophy and memory dysfunction in poststroke cognitive impairment-no dementia

Background and Purpose

It was recently reported that the prevalence of poststroke memory dysfunction might be higher than previously thought. Stroke may exist concomitantly with underlying Alzheimer's disease (AD), and so we determined whether post-stroke memory dysfunction indicates manifestation of underlying subclinical AD.

Methods

Of 1201 patients in a prospective cognitive assessment database, we enrolled subjects with poststroke amnestic vascular cognitive impairment-no dementia (aVCIND; n=48), poststroke nonamnestic vascular cognitive impairment-no dementia (naVCIND; n=50), and nonstroke amnestic mild cognitive impairment (aMCI; n=65). All subjects had cognitive deficits, but did not meet the criteria for dementia. A standardized neuropsychological test battery and magnetic resonance imaging were performed at least 90 days after the index stroke (mean, 473 days). Visual assessment of medial temporal atrophy (MTA) was used as a measure of underlying AD pathology.

Results

The MTA score was significantly lower in the naVCIND group (0.64±0.85, mean±SD) than in the aVCIND (1.10±1.08) and aMCI (1.45±1.13; p<0.01) groups. Multivariable ordinal logistic regression analysis revealed that compared with naVCIND, aVCIND [odds ratio (OR)=2.69; 95% confidence interval (CI)=1.21-5.99] and aMCI (OR=5.20; 95% CI=2.41-11.23) were significantly associated with increasing severity of MTA.

Conclusions

Our findings show that compared with poststroke naVCIND, the odds of having more-severe MTA were increased for poststroke aVCIND and nonstroke aMCI.

Cognitive dysfunction and depression in adult kidney transplant recipients: baseline findings from the FAVORIT Ancillary Cognitive Trial (FACT)

OBJECTIVE

Hyperhomocysteinemia and B-vitamin deficiency may be treatable risk factors for cognitive impairment and decline. Hyperhomocysteinemia, cognitive impairment, and depression are all common in individuals with kidney disease, including kidney transplant recipients. Accordingly, we assessed the prevalence of cognitive impairment and depressive symptoms in transplant recipients and their association with kidney function, plasma total homocysteine, and B-vitamin concentrations.

SETTING

Cross-sectional analysis of baseline data from the Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) Ancillary Cognitive Trial (FACT), which included 183 participants in FAVORIT who underwent detailed neuropsychological assessment before the study intervention.

RESULTS

The mean age was 54.0 ± 9.5 years (range: 7 to 386 months). Men comprised 55.2% of the cohort, and the mean time between the current transplant and cognitive testing was 7.0 ± 5.8 years. Twenty-four percent of participants reported neurological or psychiatric complaints, and 30% exhibited symptoms of mild to severe depression. Testing revealed evidence of significant and selective deficits in this population: 33% performed more than 1 standard deviation (SD) below normed means on a memory test, 58% fell lower than 1 SD below the norms on a test of attention and mental processing speed, and 33% to 42% fell lower than 1 SD below the norms on several tests of executive function. Lower estimated glomerular filtration rate and lower folate were associated with poorer performance on tests of memory and executive function.

CONCLUSIONS

These observations confirm previous reports of mood and cognitive impairments in adult kidney transplant recipients. Further research is needed to determine the benefit of B-vitamin supplementation and other interventions in this patient population.

Relationship between lesion location and cognitive domains in acute ischemic stroke patients

Localization of brain lesions in acute ischemic stroke has a significant effect on performance in various cognitive domains. The aim of the study was to determine whether there is association between different locations of ischemic brain lesions and different cognitive domains. The study included 40 acute ischemic stroke patients (26 male and 14 female, aged 45-78 years, with 8-16 years of education). Lesion location was visualized using brain computerized tomography, whereas performance in different cognitive domains was assessed using an extensive neuropsychological test battery. The following domains were evaluated: executive function, language, immediate recall, delayed recall, attention, divergent reasoning, and visual-constructive performance in two dimensions. A series of categorical regression analyses were applied. The results showed a significant association between the domains of executive function and language and a set of predictors related to lesion location. Global brain atrophy was found to be a significant partial predictor of performance in all cognitive domains, with higher degrees of global brain atrophy correlating with poorer performance in each of the studied domains. Combined (cortical-subcortical) lesions and unilateral lesions were both found to be significant partial predictors for language, with a higher lesion load being associated with poorer language performance. Combined lesions were also a significant partial predictor for delayed recall, with a higher lesion load correlating with poorer performance in the delayed recall domain.

Medial temporal lobe atrophy in vascular dementia: visual temporal lobe rating scale

Medial temporal lobe atrophy (MTA) as assessed by magnetic resonance imaging (MRI) can be measured in several ways. First of all, visual rating scale is a quick and easy measurement. MTA is a sensitive marker for Alzheimer's disease (AD), but not specific. It has been documented in other dementias including vascular dementia (VD). This study is to evaluate the degree of MTA in VD patients using a standardized visual rating scale and to suggest the importance of the possible role of MTA in VD. Twenty-five VD, 33 AD and 27 non-demented patients underwent a coronal three-dimensional magnetization prepared rapid gradient echo brain MRI sequence. MTA was rated visually using a 5-point rating scale from 0 (no atrophy) to 4 (severe atrophy). The mean summed MTA score was 5.39 in AD, 2.16 in VD and 0.56 in non-demented patients. Most of the VD patients (80%) showed MTA. They were greater in bilateral sides compared with the non-demented group, but milder than in AD. Additionally, MTA of left side score was significantly associated with age. Medial temporal lobe volumes measured visually are smaller in size in patients with VD, although not to the same extent as in AD. This suggests that MTA in VD patients may be associated with pre-existing AD.

Hippocampal size and dementia in stroke patients: the Sydney stroke study

BACKGROUND

Hippocampal atrophy is an early feature of Alzheimer's disease (AD) but it has also been reported in vascular dementia (VaD). It is uncertain whether hippocampal size can help differentiate the two disorders.

METHODS

We assessed 90 stroke/TIA patients 3-6 months after the event, and 75 control subjects, with neuropsychological tests, medical and psychiatric examination and brain MRI scans. A diagnosis of VaD, vascular mild cognitive impairment (VaMCI) or no cognitive impairment (NCI) was reached by consensus on agreed criteria. T1-weighted MRI was used to obtain total intracranial volume (TICV), gray and white matter volume, CSF volume, hippocampus and amygdala volumes, and T2-weighted scans for white matter hyperintensity (WMH) ratings.

RESULTS

Stroke/TIA patients had more white matter hyperintensities (WMHs), larger ventricle-to-brain ratios and smaller amygdalae than controls, but hippocampus size and gray and white matter volumes were not different. WMHs and amygdala but not hippocampal volume distinguished stroke/TIA patients with VaD and VaMCI and without NCI and amygdala volumes. Right hippocampus volume significantly correlated with new visual learning.

CONCLUSIONS

Stroke/TIA patients and patients with post-stroke VaMCI or mild VaD do not have hippocampal atrophy. The amygdala is smaller in stroke/TIA patients, especially in those with cognitive impairment, and this may be accounted for by white matter lesions. The hippocampus volume relates to episodic memory, especially right hippocampus and new visual learning. A longitudinal study of these subjects will determine whether hippocampal atrophy is a late development in VaD.

Poststroke memory function in nondemented patients: a systematic review on frequency and neuroimaging correlates

BACKGROUND AND PURPOSE

Poststroke memory dysfunction is a prerequisite for the diagnosis of poststroke dementia. This diagnosis is made within months after a stroke, apparently assuming a relatively stable course of the poststroke memory function. Clinical experience added to anecdotal evidence from the literature suggests that poststroke memory function may be reversible. The aim of the present study was to systematically review the available data on the time course of poststroke memory function in nondemented stroke survivors. In addition, we wanted to investigate the role of (pre-)stroke characteristics on poststroke memory function.

METHODS

We performed systematic literature search of PubMed with the following medical subject heading terms: memory and stroke. The search strategy yielded 798 articles of which 65 fulfilled our inclusion criteria and went on to the data extraction stage.

RESULTS

Five studies reported the prevalence of poststroke memory dysfunction at different poststroke intervals. The prevalence of poststroke memory dysfunction varied from 23% to 55% 3 months poststroke, which declined from 11% to 31% 1 year poststroke. Larger stroke volume, prestroke medial temporal lobe atrophy, and white matter lesions were related with decreased poststroke memory function.

CONCLUSIONS

Not all patients with poststroke memory dysfunction 3 months after a stroke had memory dysfunction 1 year poststroke. Consequently, not all criteria for the dementia diagnosis were fulfilled any more. This may indicate that poststroke dementia may be reversible in a substantial proportion of patients with stroke. Preferably, standardized reassessment of cognitive function should be performed in each patient diagnosed with poststroke dementia.

Medial temporal atrophy rather than white matter hyperintensities predict cognitive decline in stroke survivors

Stroke is an important risk factor for dementia, but the exact mechanisms involved in cognitive decline remain unclear. In this study, we related baseline MRI brain measures with later cognitive decline. Seventy-nine stroke survivors aged 75+ years without dementia were recruited 3-month post-stroke. They underwent yearly neuropsychological assessments and had an MRI at baseline and 2 years. Medial temporal lobe atrophy (MTA) was scored and volume of white matter hyperintensities (WMH) was measured at baseline. The rate of ventricular enlargement was measured by comparing the baseline and repeat images. Linear regression indicated that memory loss was related to both baseline memory and MTA (p=0.001; standardized regression coefficient beta=-0.35) but not WMH volume. The only independent predictor of ventricular enlargement was MTA (p=0.003; beta=0.47). However, no baseline MRI variable differed between those who did (18%) and did not (82%) develop dementia. The association of MTA but not WMH with subsequent cognitive decline and increasing brain atrophy suggests a greater role for Alzheimer type than vascular pathology in delayed cognitive impairment after stroke.

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.

Poststroke dementia

Dementia is one of the major causes of dependency after stroke. The prevalence of poststroke dementia (PSD)-defined as any dementia occurring after stroke-is likely to increase in the future. In community-based studies, the prevalence of PSD in stroke survivors is about 30% and the incidence of new onset dementia after stroke increases from 7% after 1 year 48% after 25 years. Having a stroke doubles the risk of dementia. Patient-related variables associated with an increased risk of PSD are increasing age, low education level, dependency before stroke, prestroke cognitive decline without dementia, diabetes mellitus, atrial fibrillation, myocardial infarction, epileptic seizures, sepsis, cardiac arrhythmias, congestive heart failure, silent cerebral infarcts, global and medial-temporal-lobe atrophy, and white-matter changes. Stroke-related variables associated with an increased risk of PSD are stroke severity, cause, location, and recurrence. PSD might be the result of vascular lesions, Alzheimer pathology, white-matter changes, or combinations of these. The cause of PSD differs among studies in relation to the mean age of patients, ethnicity, criteria used, and time after stroke. In developed countries, the proportion of patients with presumed Alzheimer's disease among those with PSD is between 19% and 61%. Patients with PSD have high mortality rates and are likely to be functionally impaired. These patients should be treated according to the current guidelines for stroke prevention.

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.