Frequency and clinical determinants of dementia after ischemic stroke

Vascular cognitive impairment: disease mechanisms and therapeutic implications

The prevalence of vascular cognitive impairment (VCI) is likely to increase as the population ages and cardiovascular disease survival improves. We provide an overview of the definition and disease mechanisms of VCI and present a systematic literature review of the current evidence for the pharmacologic and nonpharmacologic therapies used to treat the VCI symptoms of cognitive dysfunction or to modify VCI through primary and secondary prevention. The Cochrane Database of Systematic Reviews was searched from 2005 to October 2010 using the keywords "vascular dementia" or "vascular cognitive impairment and therapy." MEDLINE was searched for English-language articles published within the last 10 years using the combined Medical Subject Headings (MeSH) "therapeutics and dementia," "vascular" or "vascular cognitive impairment." Although cholinesterase inhibitors and memantine produce small cognitive improvements in patients with VCI, these drugs do not improve global clinical outcomes and have adverse effects and costs. Selective serotonin reuptake inhibitors and dihydropyridine calcium channel blockers may improve short-term cognitive function in patients with VCI. Anti-hypertensive therapy with an ACE inhibitor-based regimen and statins may prevent the major subtype of VCI known as poststroke cognitive decline. Clinical and effectiveness studies with long-term follow-up are needed to determine the benefits and risks of pharmacologic and nonpharmacologic therapies to prevent and treat VCI. Given its growing health, social, and economic burden, the prevention and treatment of VCI are critical priorities for clinical care and research.

Depressive symptoms and executive functioning in stroke patients: a follow-up study

BACKGROUND

Cognitive and emotional sequellae are commonly observed in stroke patients and these symptoms often co-occur. Diagnosis can be difficult since symptoms of depression and executive dysfunction overlap.

OBJECTIVE

To study the longitudinal relationship between depressive symptoms and executive dysfunction in stroke patients.

METHODS

The study comprises of 116 first-ever stroke patients who were followed-up for 2 years and who were assessed for emotional and cognitive sequellae after 1, 6, 12, and 24 months. Emotional disturbances were evaluated using the SCL-90 depression subscale. Executive functions were assessed using compound scores of a combination of the interference scores of the Stroop Colour Word Test and the Concept Shifting Test.

RESULTS

Twenty-five patients suffered from both depressive symptoms and executive dysfunction, 28 patients were depressed with no signs of executive dysfunction, and 13 patients showed executive dysfunction with no depressive symptoms. Patients with executive dysfunction had higher mean SCL-90-D scores compared to patients with no executive dysfunction (30.9 (SD 11.7) versus 26.2 (SD 11.1, p = 0.037). Depressive symptoms were predictive for executive dysfunction in a regression analysis corrected for age, sex, and diabetes mellitus but not after additional correction for pre-existent brain damage and other vascular risk factors. After 2 years 66.6 and 53.3% of patients with both depressive symptoms and executive dysfunction at baseline still had depressive symptoms and executive dysfunctions respectively and had worse prognostic outcome than patients with depressive symptoms or executive dysfunction alone.

CONCLUSIONS

Symptoms of depression and executive dysfunction are highly prevalent in stroke patients and often co-occur. These patients are more at risk for poor stroke outcome, chronic depression, and cognitive deterioration.

Hyperglycaemia, microangiopathy, diabetes and dementia risk

Brain microangiopathy increases in frequency and severity with older age, with the presence of hypertension and to a lesser extent with diabetes. Magnetic resonance imaging is used to provide anatomical descriptions, but at this time only clinical examination and neuropsychological testing can assess white matter functioning. Clinical correlates of microangiopathy appear as subcortical cognitive alterations, but data are controversial about dementia risk. Brain microangiopathy seems to be however a complication of chronic hyperglycaemia, probably due to similar mechanisms occurring in retinopathy and other microvascular complications. To date, many questions have been raised: How can brain microangiopathy progression be monitored? Is there a reversible stage of brain microangiopathy? Which preventive actions should be implemented in aging patients with diabetes? Finally, what type of care should be provided for people with diabetes and mild cognitive impairment or overt dementia to slow down cognitive worsening?

Utility of the Neuropsychological Assessment Battery in detecting cognitive impairment after unilateral stroke

This study evaluated the clinical utility of the Neuropsychological Assessment Battery (NAB) in a stroke sample by examining the NAB's ability to differentiate a chronic stroke group with radiologically confirmed unilateral damage (n = 42) and a demographically matched healthy control (HC) group (n = 36). The stroke group performed more poorly than the control group across NAB Total score and all five Domain scores. Receiver operator curves (ROC) were derived and area under the curve (AUC) showed moderate diagnostic effectiveness (AUC .70 to .90) for NAB Total score, all five Domain scores, a motor composite, and a Global Deficit Score (GDS) that has been shown to closely approximate clinical ratings of neuropsychological impairment. The NAB Total, GDS, and motor composite had comparable clinical utility, whereas the Attention and Executive domain scores demonstrated better classification utility compared with the Memory domain. Because 90.5% of our stroke sample had middle cerebral artery territory strokes, the comparison of motor and cognitive classification utility may be biased. However, follow-up analyses showed that the NAB accounted for additional variance even when motor composite was included in the model. Sensitivity, specificity, and odds ratios at various clinical cutoffs are provided. These results suggest that the NAB is a useful clinical tool for detection of cognitive deficits in individuals with chronic unilateral stroke, although lenient clinical cutoffs appear warranted to maximize sensitivity.

Insulin resistance, diabetes and cognitive function: consequences for preventative strategies

Cognitive decline and dementia both place a heavy burden on patients and their relatives, and any means of preventing such age-related changes are worthy of consideration. Those who have the metabolic syndrome with or without diabetes suffer more often from dysexecutive problems and slower psychomotor speed than do other patients. In epidemiological studies, diabetes has appeared to be a risk factor for all types of dementia, including vascular dementia, although the role of the metabolic syndrome in the risk of Alzheimer's disease is still a matter of debate. The possible mechanisms of cognitive alterations are multiple, and may differ according to age group and duration of diabetes or the metabolic syndrome. Drug interventional trials addressing the prevention of cognitive decline through action on the metabolic syndrome are disappointing-albeit scarce at this time. Lifestyle interventions in middle-aged or younger-elderly subjects should also be implemented in the general population.

VASCULAR DEMENTIA AND ALZHEIMER'S DISEASE: THE UNSOLVED PROBLEM OF CLINICAL AND NEUROPSYCHOLOGICAL DIFFERENTIAL DIAGNOSIS

The definition of clinical criteria for differential diagnosis of Vascular Dementia (VaD) and Alzheimer's disease (AD) remains controversial. A large group of patients selected was affected by chronic cerebrovascular disease classified as VaD or not (VND), according to DSM IV criteria. Neuropsychological performances of VaD patients were compared with a group of patients affected by probable AD, matched for age, education, and severity of disease. The comparison of performances did not reach statistical significance in single neuropsychological tasks. The results suggest that neuropsychological examination might not clearly differentiate between VaD and AD patients; the similar pattern of cognitive impairment is probably indicative of several common pathogenetic mechanisms.

Defining the macroscopic and microscopic findings of experimental focal brain ischemia in rats from a forensic scientist's point of view

Approximately 10% of all deaths in the world occur as a result of stroke. Determination of the time schedule of the pathologic events in a stroke patient is invaluable for a forensic specialist. The aim of this study was to define the schedule of the macroscopic and microscopic changes that occurred in a rat model of permanent focal ischemia for providing useful clues for the evaluation of stroke patients. Male Wistar rats weighing 250 to 350 g were used in this study. Permanent focal brain ischemia was applied by the suture occlusion method. The animals were divided into 7 experimental groups (n = 6) with time schedules including 1.5, 3, 6, 12, 24, 72 hours, and the sham. Brains were harvested at the end of the determined time schedule. Lesions in the frontoparietal cortex were evaluated macroscopically first and later hematoxylin eosin stained sections from the infarct core were investigated microscopically. Macroscopically, enlargement of the ipsilateral hemisphere was mild at 6 hour, apparent at 12 and 24 hours, and mild again at 72 hours. Microscopically, ischemic changes were apparent even at 1.5 hour. Red neurons and infiltration of the parenchyma with neutrophil leukocytes were observed at 12 hours. Pannecrosis and massive leukocyte infiltration were observed at 72 hours. Macroscopic and microscopic findings obtained from a rat model may provide clues for determination of the time-dependent changes due to brain ischemia in human subjects. Finally, the benefits of determination of time course of pathologic changes in the brain for forensic scientists were discussed.

Hyperglycemia in patients undergoing cerebral aneurysm surgery: its association with long-term gross neurologic and neuropsychological function

OBJECTIVE

To evaluate whether elevated intraoperative blood glucose concentrations are associated with an increased risk of long-term neurologic dysfunction in patients at risk for ischemic brain injury.

PATIENTS AND METHODS

Data from 1000 patients were retrieved from the Intraoperative Hypothermia for Aneurysm Surgery Trial database. All patients were recruited between February 2000 and April 2003, and underwent surgery for aneurysm clipping within 14 days of subarachnoid hemorrhage. Gross neurologic and neuropsychological function was evaluated at 3 months after surgery using certified observers and standardized assessment instruments. Intraoperative blood glucose concentrations, measured once when the aneurysm clip was placed, were correlated with neurologic outcome using both univariable and multivariable logistic regression analyses.

RESULTS

Blood glucose concentrations at the time of aneurysm clipping ranged from 59 to 331 mg/dL. At 3 months after surgery, those with blood glucose concentrations of 129 mg/dL or more (upper 2 quartiles) were more likely to have impaired cognition (P=.03). Those with glucose concentrations of 152 mg/dL or more (upper quartile) were more likely to experience deficits in gross neurologic function assessed by the National Institutes of Health Stroke Scale (P<.05), but not other scoring scales. Length of stay in intensive care units was longer in those with glucose concentrations of 129 mg/dL or more, but there was no difference among glucose groups in the duration of overall hospital stay or the fraction of patients discharged to home.

CONCLUSION

In patients at high risk for ischemic brain injury, intraoperative hyperglycemia, of a magnitude commonly encountered clinically, was associated with long-term changes in cognition and gross neurologic function.

"Timing It Right": a conceptual framework for addressing the support needs of family caregivers to stroke survivors from the hospital to the home

OBJECTIVE

Discuss family caregivers of stroke survivors' changing needs for education and support across the care continuum.

METHODS

Conceptual review.

RESULTS

Stroke is a serious, sudden onset illness requiring care across the care continuum. The focus of care, the individuals primarily responsible for providing that care, and patients' self-care abilities change across care environments. Often family members who provide support also experience changes in their caregiving role. To date, however, interventions for family caregivers have not explicitly considered their changing support needs. Our "Timing It Right" framework highlights family caregivers changing experiences and corresponding support needs across the care continuum. Five different phases of caregiver support are discussed: (1) event/diagnosis; (2) stabilization; (3) preparation; (4) implementation; (5) adaptation. The first two phases occur during acute care, the third occurs during acute care and/or in-patient rehabilitation, and the final two phases occur in the community.

CONCLUSIONS

Application of this framework has the potential to benefit future intervention efforts by identifying gaps in caregiver education, training, and support.

PRACTICE IMPLICATIONS

Recognition of family caregivers changing support needs across the care continuum will assist health care professionals to provide more timely and appropriate support.

Diagnosis and management of vascular cognitive impairment

Accurate diagnosis of vascular cognitive impairment (VCI) is important but may be difficult. VCI diagnoses depend on determinations of the presence of both cognitive impairment and cerebrovascular disease (CVD), temporal causal links between cognitive impairment and CVD, and the presence or absence of other potential contributors to cognitive impairment, such as Alzheimer's disease (AD). Diagnostic criteria differ across currently utilized systems, resulting in widely differing VCI prevalence rates. Also, current systems may not be able to differentiate "pure" VCI from "mixed" AD and CVD. National Institute of Neurological Disorders and Stroke harmonization criteria for VCI have been developed for study and validation to help bridge gaps in our understanding of VCI diagnosis. VCI management begins with atherogenic risk factor control. Current VCI treatment options demonstrate statistical improvement but not consistent global clinical efficacy. Future clinical trials should concentrate on both primary risk factor control and development of new therapeutic agents to treat patients already diagnosed with VCI.

Subthreshold depression and cognitive impairment but not demented in stroke patients during their rehabilitation

BACKGROUND

Subthreshold depression (sD) and cognitive impairment but not demented (CIND) in stroke patients are associated with poorer rehabilitative outcomes. Their diagnosis can easily be operationalized using validated scales.

AIM

The aim of the study was to ascertain the prevalence of depressive symptoms and cognitive impairment in stroke patients during three crucial stages of the rehabilitative process, viz. upon admission, upon planned discharges from rehabilitation hospitals and at 6 months post-stroke, using validated scales like the Geriatric Depression Scale and Abbreviated Mental Test (recommended by the British Geriatric Society). Their baseline risk factors were also ascertained.

RESULTS

On admission, the prevalence of depressive symptoms and cognitive impairment was 60% and 54% respectively. The prevalence upon planned discharges and 6 months post-stroke, respectively, of depressive symptoms was 38% and 34% and that of impaired cognition was 33% and 40%. Baseline independent correlates at 6 months post-stroke depressive symptoms were: recurrent stroke (OR 3.34); on admission cognitive impairment (OR 4.78) and ADL dependence (OR 5.28). And that of cognitive impairment were: increasing age (OR 8.07); post-stroke dysphagia (OR 4.58); on admission cognitive impairment (OR 23.95) and on admission depressive symptoms (OR 3.50).

CONCLUSIONS

Continuous screening and appropriate intervention, especially at baseline, would significantly decrease the burden posed by stroke patients with such psychological impairments in the community.

Caregiver burden for impaired elderly Japanese with prevalent stroke and dementia under long-term care insurance system

BACKGROUND

Limited data are available on caregiver burden for stroke and dementia patients. We examined the associations of prevalent stroke and dementia with family caregiver burden in Japanese general populations.

METHODS

A total of 916 Japanese home caregivers, whose family members were covered by long-term care insurance, responded to the caregiver burden questionnaire. The questionnaire included the caregiver's age, sex and employment status, the patient-caregiver relationship, the patient's history of stroke, symptoms of dementia, care levels under long-term care insurance and the Zarit Caregiver Burden Interview.

RESULTS

The mean total score from the Zarit Caregiver Burden Interview was 12% higher in patients with stroke than in those without (p = 0.02) and 40% higher in those with dementia than in those without (p < 0.001). Compared with nonstroke patients without dementia, the mean total score was 21% higher in stroke patients without dementia (p = 0.01), 49% higher in nonstroke patients with dementia (p < 0.001) and 55% higher in stroke patients with dementia (p < 0.001). After adjustment for the caregiver's age, sex and employment status, the patient-caregiver relationship, and the patient's care level and community, the higher scores remained statistically significant for nonstroke patients with dementia and for stroke patients with dementia but not for stroke patients without dementia.

CONCLUSIONS

Prevalent stroke and, more strongly, dementia were associated with increased family caregiver burden. Among patients with dementia, the presence of stroke did not enhance caregiver burden further.

Conceptualizing Functional Cognition in Stroke

Background. Up to 65% of individuals demonstrate poststroke cognitive impairments, which may increase hospital stay and caregiver burden. Randomized stroke clinical trials have emphasized physical recovery over cognition. Neuropsychological assessments have had limited utility in randomized clinical trials. These issues accentuate the need for a measure of functional cognition (the ability to accomplish everyday activities that rely on cognitive abilities, such as locating keys, conveying information, or planning activities). Objective. The aim of the study was to present the process used to establish domains of functional cognition for development of computer adaptive measure of functional cognition for stroke. Methods. Functional cognitive domains involved in identifying relevant neuropsychological constructs from the literature were conceptualized and finalized after advisory panel feedback from experts in neurology, neuropsychology, aphasiology, clinical trials, and epidemiology. Results. The following 17 domains were proposed: receptive aphasia, expressive aphasia, agraphia, alexia, calculation, visuospatial, visuoperceptual, visuoconstruction, attention, language usage, executive functions, orientation, processing speed, memory, working memory, mood, awareness and abstract reasoning. The advisory panel recommended retaining the first 12 domains. Recommended changes included: to address only encoding and retrieval of recent information in the memory domain; to add domains for limb apraxia and poststroke depression; and to keep orientation as a separate domain or reclassify it under memory or attention. The final 10 domains included: language, reading and writing, numeric/calculation, limb praxis, visuospatial function, social use of language, emotional function, attention, executive function, and memory. Conclusion. Conceptualizing domains of functional cognition is the first step in developing a computer adaptive measure of functional cognition for stroke. Additional steps include developing, refining, and field-testing items, psychometric analysis, and computer adaptive test programming.

Hypertension, cognitive decline, and dementia: an epidemiological perspective

Hypertension is a known risk factor for stroke, and thus for vascular dementia. However, recent large observational studies have suggested that high blood pressure may also play a role in Alzheimer's disease. The mechanisms linking hypertension to Alzheimer's disease remain to be elucidated, but white matter lesions seen on cerebral magnetic resonance imaging appear to be a good marker of this association. It is not yet clearly established whether lowering blood pressure reduces the risk of white matter lesions and dementia, so large trials dealing with this question are eagerly awaited. These future trials could confirm the hope that, by lowering blood pressure, we may have a preventive treatment for dementia. This issue is of major importance, as the number of cases of dementia is expected to rise sharply in the near future.

Incidence of dementia and associated risk factors in Japan: The Osaki-Tajiri Project

The incidence of dementia and risk factors has not been fully investigated in Japan. Following a prevalence study in 1998, we investigated the incidence and associated factors in the same population in 2003 and 2005. Randomly selected 771 residents in Tajiri were targeted. The final participants included 204 (65.2%) healthy older adults (Clinical Dementia Rating, CDR 0) and 335 (73.1%) people with questionable dementia (CDR 0.5). We analyzed the incidence of dementia and dementing diseases, and possible risk factors. The risk factors included demographics, lifestyle-related factors, vascular risk factors, cognitive functions, and MRI findings. Overall, 3.9% of the CDR 0 and 37.0% of the CDR 0.5 participants developed dementia during the 5-year period, whereas 40.2% of the CDR 0.5 participants developed dementia during the 7-year period. Older adults had a higher incidence. Higher CDR Box scores had a higher incidence. Of the dementing diseases, 60.8% of participants developed Alzheimer' disease (AD), followed by vascular dementia (VaD), 17.9%. Logistic regression analyses showed that age, MMSE, cognitive functions such as recent memory, and generalized atrophy were significant predictors of progression to AD. Similarly, predictive factors for progression to VaD were age, MMSE, cognitive functions such as frontal function, and white matter lesions and cerebrovascular diseases. A comprehensive system including CDR, cognitive tests, and MRI, is recommended in community-based health policy planning.

Short-term evolution as a marker of vascular dementia versus Alzheimer's disease

The diagnosis of vascular dementia (VaD) remains a controversial issue in many aspects and concepts. These nosologic problems are caused both by the methods, insufficient to ascertain the diagnosis, as well as by the weak consistency of the clinical concept of VaD itself. One of the most intriguing issues on VaD, and in particular on post-stroke dementia (PSD), is related to the time of development of cognitive decline. In clinical practice, the 3-month time threshold is usually chosen to enable resolution of a possible acute post-stroke delirium, and to obtain a more reliable cognitive assessment with a complete regression of acute neuropsychological stroke-related deficits. Another relevant issue is the possibility to predict which patient will develop PSD. In this regard, recent data indicate an overlap between Alzheimer's disease (AD) and PSD, which seems to share risk factors and neuropathology. In most population samples these two disorders appear together, and the consensus is growing that a degenerative component has a more important role in determining PSD onset shortly after stroke than previously recognized. Therefore, anamnestic data have a fundamental role in this prognostic approach.

Executive Function Deficits in Acute Stroke

OBJECTIVES

To establish the frequency of executive dysfunction during acute hospitalization for stroke and to examine the relationship of that dysfunction to stroke severity and premorbid characteristics.

DESIGN

Inception cohort study.

SETTING

Inpatient wards at a Veterans Affairs hospital.

PARTICIPANTS

Consecutive sample of inpatients with radiologically or neurologically confirmed stroke. Final sample included 47 patients screened for aphasia and capable of neuropsychologic testing. Two nonstroke inpatient control samples (n=10 each) with either transient ischemic attack (TIA) or multiple stroke risk factors were administered the same research procedure and tests.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Composite cognitive impairment ratio (CIR), calculated from 8 scores indicative of executive function on 6 neuropsychologic tests by dividing number of tests completed into the number of scores falling below cutoff point, defined as 1.5 standard deviations below normative population mean.

RESULTS

Stroke patients had a mean CIR of .61, compared with .48 for TIAs and .44 for stroke-risk-only. Analysis of variance revealed that CIRs of stroke-risk-only patients but not TIAs were lower than those of the stroke patients (P=.02). Impairment frequencies were at least 50% for stroke patients on most test scores. The Symbol Digit Modalities Test (75% impairment) and a design fluency measure distinguished stroke from nonstroke patients. CIR was not related to stroke severity in the stroke patient sample, but was related to estimated premorbid intelligence.

CONCLUSIONS

Executive function deficits are common in stroke patients. The data suggest that limitations in information processing due to these deficits may require environmental and procedural accommodations to increase rehabilitation benefit.

Diabetes mellitus and dementia

Alzheimer's disease (AD) and diabetes mellitus (DM) are two of the most common and devastating health problems in the elderly. They share a number of common features amongst which high prevalence after 65 years, important impact of patient's quality of life, substantial health care costs. Reviews on the epidemiological studies on cognitive impairment in patients with DM found evidence of cross-sectional and prospective associations between type 2 DM and moderate cognitive impairment, on memory and executive functions. There is also evidence for an elevated risk of both vascular dementia and AD in patients with type 2 DM, albeit with strong interaction of other factors such as hypertension, dyslipidaemia and ApoE genotype. DM is an independent predictor of post-stroke dementia. DM being an atherogenic risk factor, it may increase the risk of dementia through associations with stroke, causing vascular dementia. In addition, vascular reactivity may be adversely affected by advanced glycosylation end products resulting in more subtle perfusion abnormalities. Cerebrovascular disease may exacerbate AD through direct interactions between the two pathological processes or through cognitive impairment secondary to cerebrovascular disease "unmasking" AD at an earlier stage than it would otherwise become apparent. The increased risk of AD may also be mediated by the exacerbation of B-amyloid neurotoxicity by advanced glycosylation end products identified in the matrix of neurofibrillary tangles and amyloid plaques in AD brains, or associations with insulin functions. Decreased cholinergic transport across the blood-brain barrier observed in diabetic animals may exacerbate cognitive impairment in AD. Many interventions could reduce the cognitive decline associated with DM, yet not enough are taken into account so far.

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.

Executive function is independently associated with performances of balance and mobility in community-dwelling older adults after mild stroke: implications for falls prevention

BACKGROUND

Stroke survivors have a high incidence of falls. Impaired executive-controlled processes are frequent in stroke survivors and are associated with falls in this population. Better understanding of the independent association between executive-controlled processes and physiological fall risk (i.e. performances of balance and mobility) could enhance future interventions that aim to prevent falls and to promote an independent lifestyle among stroke survivors.

METHODS

Cross-sectional analysis of 63 adults who suffered a mild stroke >1 year prior to the study, aged > or =50 years.

RESULTS

Cognitive flexibility was independently associated with performances of balance and mobility in community-dwelling older adults after mild stroke, after accounting for age, quadriceps strength of the paretic side and current physical activity level.

CONCLUSIONS

Clinicians may need to consider cognitive function when assessing and treating impaired balance and mobility in community-dwelling older adults after mild stroke.

Predictors of poststroke dementia: results of a hospital-based study in poland

Dementia affects up to 30% of stroke survivors 3 months after stroke. The goal of this study was to determine the risk factors of poststroke dementia (PSD) in a cohort of consecutive stroke patients in Poland. A standard stroke evaluation was conducted on admission in 220 consecutive patients with ischemic/hemorrhagic stroke after excluding 30 (12%) patients with prestroke dementia. After 3 months, the survivors completed a comprehensive neuropsychological examination. The DSM-IV definition was used for diagnosis of dementia. Dementia was diagnosed in 44 (22.6%) patients 3 months after stroke. In logistic regression analysis, age (OR 1.08, 95% CI 1.04-1.14, p < 0.001), diabetes mellitus (OR 2.67, 95% CI 1.06-6.57, p = 0.03) and neurological deficit on admission (OR 0.92, 95% CI 0.89-0.96, p < 0.001) were independently associated with PSD in the Polish hospital-based population.

Clinical determinants of dementia and mild cognitive impairment following ischaemic stroke: the Sydney Stroke Study

BACKGROUND

Dementia following stroke is common but its determinants are still incompletely understood.

METHODS

In the Sydney Stroke Study, we performed detailed neuropsychological and medical-psychiatric assessments on 169 patients aged 50-85 years, 3-6 months after a stroke, and 103 controls with a majority of both groups undergoing MRI brain scans. Stroke subjects were diagnosed as having vascular mild cognitive impairment (VaMCI) or vascular dementia (VaD) or no cognitive impairment by consensus. Demographic, functional, cerebrovascular risk factors and neuroimaging parameters were examined as determinants of dementia using planned logistic regression.

RESULTS

21.3% of subjects were diagnosed with VaD, with one case in those aged 50-59 years, 24% in those aged 60-69 years and 23% in those 70-79 years. There was no difference by sex. The prevalence of VaMCI was 36.7%. VaD subjects had lower premorbid intellectual functioning and had 0.9 years less education than controls. The VaD and VaMCI groups did not differ from the no cognitive impairment group on any specific cerebrovascular risk factor, however overall those with impairment had a greater number of risk factors. They did not differ consistently on depression severity, homocysteine levels and neuroimaging parameters (atrophy, infarct volume and number of infarcts) except for an excess of white matter lesions on MRI and greater number of infarcts in the VaD and VaMCI groups. On a series of logistic regression analyses, stroke volume and premorbid function were significant determinants of cognitive impairment in stroke patients.

CONCLUSION

Post-stroke dementia and MCI are common, especially in older individuals. Cerebrovascular risk factors are not independent risk factors for VaD, but stroke volume is a significant determinant of dementia. Premorbid functioning is a determinant of post- stroke impairment.

Neuroprotection in Vascular Dementia

Vascular dementia (VaD) is the second most common form of dementia after Alzheimer's disease (AD), and one of the major causes of mental and physical disability in developed countries. As such, the identification and implementation of strategies which prevent the development of the condition or enable improvements in patients with VaD are healthcare objectives of the first order. VaD is now regarded as a combined group of clinical-pathological entities rather than one disease, that is, multiple pathogenic mechanisms and lesion types underlie a cognitive impairment of vascular origin. The clinical diagnosis of VaD is complex and difficult because of the heterogeneous nature of its clinical presentation and progression and the low sensitivity of existing clinical criteria. Moreover, there is growing evidence of the epidemiological significance of mixed forms of dementia, and that ischemic processes may precipitate and exacerbate cognitive impairment in AD. Numerous compounds have been proposed as potentially useful in the treatment of patients with VaD, comprising vasodilatative, antithrombotic, hemorrheological, nootropic, antiserotoninergic and, most recently, antiglutamatergic and cholinergic approaches. In spite of some initially favorable reports based on the use of memantine, donepezil and galantamine, there is as yet no conclusive evidence of a definitive treatment for VaD. Unsatisfactory results from VaD drug trials may be attributed in part to the diversity of the patients included (underlying pathogenic mechanisms, number, type, and location of vascular lesions), and to methodological limitations in the design of the trials (outcome measures, end-points, size, follow-up period). The treatment of modifiable vascular risk factors - hypertension, diabetes mellitus, hypercholesterolemia and heart disease - is an important strategy for the reduction of the risk of dementia, and is likely to slow the progress of cognitive decline.

Changes in Mini Mental State Examination score after stroke: lacunar infarction predicts cognitive decline

Stroke and cognitive impairment are inter-related. The purpose of this study was to show the natural evolution of cognitive performance during the first year after a stroke, and to show which factors that predict cognitive decline. Subjects were patients with a first-ever stroke who were treated in a stroke unit. A total of 160 patients were included. At baseline patients were evaluated with regard to stroke type, stroke severity, pre-stroke dementia and other risk factors. Mini Mental State Examinations (MMSE) were performed after 1 week and after 1 year. Patients had a median increase of 1 point (range -8 to +9) on the MMSE. Thirty-two pre cent of the patients deteriorated, 13% were unchanged, and 55% improved. Lacunar infarction (LI) and left-sided stroke were associated with a failure to exhibit improvement. Patients with LI had an average decline of 1.7 points, whilst patients with other stroke types had an average increase of 1.8 points. Most stroke survivors improve cognitively during the first year after the event. The outcome for LI patients is worse, which suggests that LI may serve as a marker for concomitant processes that cause cognitive decline.

Poststroke Dementia

The association between stroke and dementia is frequent. The prevalence of poststroke dementia (PSD) ranges from 6 to 32%, depending on the population studied, the criteria used for the diagnosis of dementia, and the time interval between the stroke and the neuropsychological assessment. The risk of PSD is high immediately after stroke and remains higher than in controls in stroke patients nondemented 3 months after stroke. Not all cases of PSD are vascular in origin, with about one third of demented patients diagnosed as having Alzheimer's disease plus stroke. The pathophysiology of PSD is probably multifactorial, with an influence of vascular lesions, associated Alzheimer's lesions and white matter changes. The risk of dementia is higher in older patients and in patients with preexisting cognitive decline - no dementia, severe stroke, a history of stroke, white matter changes and cerebral atrophy. The influence of stroke location, vascular risk factors and silent infarcts remains to be determined. PSD adversely influences the outcome in stroke patients.

Predictors of a successful driver evaluation in stroke patients after discharge based on an acute rehabilitation hospital evaluation

OBJECTIVE

One of the most common concerns of a stroke patient is the ability to drive. We aimed to determine which neurologic impairments on an acute rehabilitation admission evaluation predict the likelihood of a successful driver evaluation after discharge.

DESIGN

Prospective study in an acute stroke rehabilitation unit.

RESULTS

A total of 45 stroke patients undertook a driver evaluation at our institution. The mean age +/- standard deviation was 71.0 +/- 9.8 yrs, Mini-Mental State Examination score was 22.7 +/- 8.1, upper limb and lower limb Motricity Index scores were 63.7 +/- 34.8 and 71.8 +/- 24.3, Limb Placement Task was 4.6 +/- 3.6 inches, and admission total FIM score was 68.5 +/- 18. The admission variables differed between those who failed (n = 10) vs. those who passed the in-clinic driver evaluation (n = 29, 75%): Mini-Mental State Examination (17.5 +/- 9.7 vs. 24.6 +/- 6.7, P = 0.004), and upper limb (82 +/- 23.7 vs. 57.4 +/- 36.1, P = 0.05) and lower limb (87.6 +/- 11.8 vs. 66.4 +/- 25.2, P = 0.01) Motricity Index scores.

CONCLUSIONS

Patients who undertook and passed the in-clinic driver evaluation had, at admission, higher Mini-Mental State Examination and Motricity Index scores with normal visual field defects.

Focal Wallerian degeneration of the corpus callosum in large middle cerebral artery stroke: Serial diffusion tensor imaging

PURPOSE

To detect lesion-related focal Wallerian degeneration (WD) changes in different segments of the corpus callosum (CC) in patients with large middle cerebral arterial (MCA) territory stroke using diffusion tensor imaging (DTI).

MATERIALS AND METHODS

Eight patients underwent DTI scans at three different time points: six to eight weeks, 10-12 weeks, and beyond six months of stroke onset. Eight healthy age-matched controls were also scanned using the same protocol at three different time points. Region-of-interest (ROI) analysis was performed on seven segments of the CC to determine the fractional anisotropy (FA), mean diffusivity (MD), and corresponding callosal cross-sectional areas.

RESULTS

On repeated-measures analysis of variance (ANOVA), a significant reduction in the FA values was observed from the first to the third study compared to controls, reflecting temporal degeneration in the rostrum, genu, rostral body, anterior midbody, and splenium of the CC. However, a significant temporal elevation in MD values was observed in only the rostral body and anterior midbody of the CC. This was associated with a significant region-specific reduction in the cross-sectional areas at time points beyond six months, and appears to be consistent with the loss of callosal structural components due to interruption of the cortico-callosal fibers secondary to WD.

CONCLUSION

These results indicate that cortico-callosal topographical changes exhibit a significant temporal decline in observed FA values that is suggestive of cortico-callosal WD in patients with large MCA territory stroke.

Vascular dementia: prevention and treatment

BACKGROUND

Vascular dementia (VaD) is the most common cause of dementia in the elderly, second only to Alzheimer's disease (AD). Between 1% and 4% of people of 65 years of age suffer from VaD and the prevalence appears to double every 5-10 years after the age of 65.

SUMMARY

Prevention aims to reduce the disease by eliminating its cause or main risk factors, particularly hypertension as well as diabetes mellitus, atherosclerosis, coronary artery disease, smoking, lipid abnormalities, and hyperhomocystinemia. Initial studies of several agents for symptomatic treatment were disappointing. However, there is growing evidence for cholinergic involvement in VaD and recent studies with cholinesterase inhibitors have shown improvement in cognitive, global function, and activities of daily living as compared with placebo and have been well tolerated.

CONCLUSION

VaD is a common condition and its prevalence is likely to increase. As physicians we need to be diligent with regards to recognition of risk factors and vigorous intervention. Promising results have been seen in several clinical trials of cholinesterase inhibitors and no safety of tolerability issues have been noted.

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.

Evolution of cognitive impairment after stroke and risk factors for delayed progression

BACKGROUND AND PURPOSE

Cognitive decline occurs in approximately 30% of stroke patients. Acute risk factors have been identified, but long-term risk has not been examined in large samples. The purpose of this research was to determine factors associated with the progression of cognitive impairment after stroke.

METHODS

Consecutive stroke patients (193) without previous dementia were assessed 3 months after stroke with an extensive neuropsychological battery and diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition criteria and the Clinical Dementia Rating as normal (139), cognitive decline without dementia (18), or dementia (18 mild, 10 moderate, and 8 severe). After a 24-month follow-up, they were classified as stable, progressing, or improving, according to change in Clinical Dementia Rating score. The determinants of progression of cognitive decline were ascertained by logistic regression analysis of all clinical, neuroimaging, and complementary data.

RESULTS

Cognitive status at 24 months was stable in most cases (151; 78.2%), decline progressed in 27 (14%; 6 demented and 21 nondemented), and improved in 15 (7.8%; 7 demented and 8 nondemented). Seven nondemented patients became demented at 24 months, and 5 demented became nondemented. The age (odds ratio [OR], 1.05; 95% CI, 1.01 to 1.1), mental decline before stroke (OR, 1.14; 95% CI, 1.02 to 1.27), number of prescribed drugs (OR, 1.34; 95% CI, 1.05 to 1.72), diastolic blood pressure on admission (OR, 0.96; 95% CI, 0.93 to 0.99), and episodes of hypotension during admission (OR, 7.61; 95% CI, 1.11 to 52.1) were significantly associated with cognitive deterioration.

CONCLUSIONS

Cognition is rather stable for 2 years after stroke. Both progression and improvement of cognitive impairment are frequent in demented patients. Age, previous cognitive decline, polypharmacy, and hypotension during admission are risk factors for progression.

Pre-existing hypertension and the impact of stroke on cognitive function

Hypertension has been associated with subclinical injury in the brain and may therefore increase the impact of an incident stroke on cognitive function. The Study of Osteoporotic Fractures (SOF) is a prospective, observational study of 9,704 women aged 65 years and older recruited from four U.S. metropolitan areas. Blood pressure was measured at study entry, and cognitive decline was defined by the change from prestroke to poststroke cognitive testing. During an average follow-up of 6.8 years, incident stroke occurred in 260 participants (3.1%) who had previously completed baseline cognitive testing. Among participants with stroke, 119 completed follow-up cognitive testing a median of 1.9 years after the stroke, 80 died before the next study visit, and 61 did not complete further cognitive testing. After adjustment for demographic factors and other confounders, pre-existing hypertension was a strong predictor of cognitive decline when a stroke occurred (odds ratio [OR], 4.07; 95% confidence interval [CI], 1.37-12.1). In contrast, hypertension was only weakly associated with cognitive decline in the absence of stroke (OR, 1.13; 95% CI, 1.04-1.22) (p for interaction = 0.032). Pre-existing hypertension in women is associated with a greater impact of stroke on cognitive function, possibly by influencing the ability to tolerate or recover from brain injury.

Cognitive Dysfunction After Acute Lacunar Infarct

Vascular dementia and vascular cognitive impairment have attracted more attention recently due to their association with increased risk of death and institutionalization. The purpose of the present study was to detect and identify the characteristics of cognitive impairments during the early stage of lacunar stroke. The subjects consisted of 23 consecutive first-ever acute lacunar infarction patients who were admitted to the Department of Neurology, Kaohsiung Municipal Hsiao-Kang Hospital, Taiwan, from November 2001 to October 2002. The National Institutes of Health Stroke Scale and Cognitive Abilities Screening Instrument (CASI) were used to evaluate stroke severity and cognitive function, and assessments were performed by a neurologist and psychologist, within 10 days of stroke onset. Of the 23 patients, 21 (91.3%) had CASI scores below their respective cutoff values and all patients had cognitive impairment in at least one cognitive domain in CASI. There were no significant correlations between CASI abnormality (below the cutoff value) and patient age, education, or the interval from stroke onset. Recent memory impairment was the most often impaired cognitive domain on CASI (19 patients, 82.6%). There were significant correlations between recent memory and "attention or concentration"(correlation coefficient, 0.52; p < 0.05), and "abstraction and judgment" (correlation coefficient, 0.44; p < 0.05). The correlations between recent memory and other domains were not significant. It was concluded that cognitive impairment after acute lacunar infarct is quite common and recent memory is the most often impaired cognitive domain. This may have been caused by the location of the specific lesion as well as by the impairment in "attention or concentration" or "abstraction and judgment".

NINDS AIREN neuroimaging criteria do not distinguish stroke patients with and without dementia

OBJECTIVE

To determine the utility of the neuroimaging component within the National Institute of Neurological Disorders and Stroke (NINDS) Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN) criteria for vascular dementia for distinguishing between patients with and without dementia in the context of cerebrovascular disease.

METHOD

One hundred twenty-five poststroke patients age > or =75 (27 with and 98 without poststroke dementia) from representative hospital-based stroke registers in the North East of England were evaluated using a 1.5 T MR scanner. The proportion of patients with and without poststroke dementia meeting the imaging component of the NINDS AIREN criteria was determined, and hippocampal atrophy (measured using the Schelten scale) was compared between the two groups.

RESULTS

There were no significant differences between the patients with and without poststroke dementia on any criteria of the imaging parameters within the NINDS AIREN criteria. In addition, there were no significant differences in the number or size of cortical or subcortical infarcts between the two groups, with 13 patients without dementia having cortical infarcts >50 mm. Patients with dementia had greater hippocampal atrophy (right: Mann-Whitney U test, Z = 2.5, p = 0.01; left: Mann-Whitney U test, Z = 2.5, p = 0.01).

CONCLUSION

The neuroimaging component of the NINDS AIREN criteria does not distinguish between older patients with and without poststroke dementia.

Admission ambulation velocity predicts length of stay and discharge disposition following stroke in an acute rehabilitation hospital

BACKGROUND AND PURPOSE

Poststroke functional outcome and discharge disposition are influenced by age, lesion location and size, severity of neurological insult, prior functional ability, and social support. The effect of admission ambulation velocity on length of stay and discharge disposition has not been previously reported.

DESIGN

Prospective, cohort study.

SETTING

Designated acute stroke rehabilitation unit.

METHOD

373 patients consecutively admitted to a designated inpatient stroke rehabilitation unit were studied. The study sample was divided into 2 groups, based on admission ambulation velocity (meters/second) during a 2-min timed walk test. Fast ambulators had an ambulation velocity of greater than 0.15 m/s, whereas slow ambulators had an ambulation velocity of 0.15 m/s or less, and also included nonambulators.

INTERVENTIONS

None.

OUTCOME MEASURES

Primary outcome measures were length of stay and discharge disposition. Secondary outcome measures were change in the Functional Independence Measure (FIM) scores and change in ambulation velocity per week. Continuous, ordinal, and nominal variables were analyzed using the Student t test, Mann-Whitney U test, and chi-square test, respectively. Sensitivity, specificity, and positive and negative predictive values assessed admission ambulation velocity as a predictor of discharge disposition.

RESULTS

Patient variables for slow ambulators (n = 226) versus fast ambulators (n = 147) were as follows: age (68 +/- 13 SD vs. 69 +/- 12, P = 0.32), male-female ratio (100:126 vs. 78:69, P = 0.09), admission total FIM score (52 +/- 17 vs. 77 +/- 16, P < 0.0001), change in total FIM score (20 +/- 12 vs. 16 +/- 12, P < 0.003), change in ambulation velocity per week (0.05 +/- 0.06 vs. 0.13 +/- 0.30, P < 0.0001), length of stay in days (30 +/- 28 vs. 17 +/- 19, P < 0.0001), and discharge disposition: home/skilled nursing facility (133/91 vs. 133/13, P < 0.0001). Sensitivity, specificity, and positive and negative predictive values (based on chi-square analyses) for admission fast ambulators as a predictor of home discharge were 0.5, 0.87, 0.91, and 0.41, respectively. Admission ambulation velocity alone correctly identified discharge disposition in 78% of the patient population, based on logistic regression analysis (P < 0.0001).

CONCLUSION

Admission ambulation velocity can predict length of stay and discharge disposition poststroke. This effect is independent of age and admission total FIM score.