Assessing Cognition after Stroke. Who Misses Out? A Systematic Review

Structural brain networks correlating with poststroke cognition

Cognitive deficits are a common and debilitating consequence of stroke, yet our understanding of the structural neurobiological biomarkers predicting recovery of cognition after stroke remains limited. In this longitudinal observational study, we set out to investigate the effect of both focal lesions and structural connectivity on poststroke cognition. Sixty-two patients with stroke underwent advanced brain imaging and cognitive assessment, utilizing the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), at 3-month and 12-month poststroke. We first evaluated the relationship between lesions and cognition at 3 months using voxel-based lesion-symptom mapping. Next, a novel correlational tractography approach, using multi-shell diffusion-weighted magnetic resonance imaging (MRI) data collected at both time points, was used to evaluate the relationship between the white matter connectome and cognition cross-sectionally at 3 months, and longitudinally (12 minus 3 months). Lesion-symptom mapping did not yield significant findings. In turn, correlational tractography analyses revealed positive associations between both MoCA and MMSE scores and bilateral cingulum and the corpus callosum, both cross-sectionally at the 3-month stage, and longitudinally. These results demonstrate that rather than focal neural structures, a consistent structural connectome underpins the performance of two frequently used cognitive screening tools, the MoCA and the MMSE, in people after stroke. This finding should encourage clinicians and researchers to not only suspect cognitive decline when lesions affect these tracts, but also to refine their investigation of novel approaches to differentially diagnosing pathology associated with cognitive decline, regardless of the aetiology.

The Acceptability of post-stroke cognitive testing through the lens of the theory of acceptability, a qualitative study

Background

Cognitive impairment is common after stroke and screening is recommended. However, there is a lack of evidence on the best way to assess cognition after stroke and a tendency to focus on the clinician rather than stroke survivor. The Theoretical Framework of Acceptability (TFA) was developed to better understand the factors that contribute to the acceptability of healthcare interventions from the patient perspective. We aimed to explore the acceptability of post-stroke cognitive assessment from the stroke survivor perspective, using the TFA as a lens.

Methods

We analysed interviews conducted with people admitted to hospital after stroke. Inclusion criteria: ≥18 years, able to provide informed consent. Semi-structured interviews were conducted 1-3 weeks after discharge from hospital in the participant's home to explore the experience of cognitive assessment in hospital. Interviews were audio recorded and transcribed verbatim. Data were analysed using framework analysis, with a framework underpinned by the TFA.

Results

Of the 13 participants interviewed, 8 were male, 6 lived in the most deprived SIMD quintile. Ages were 62-84 years. Five themes were identified that describe the factors that influence acceptability of cognitive screening from the patient perspective: (1) participation motives; (2) trust in health professionals; (3) perceived risks of harm; (4) information provision; (5) burden of testing.

Conclusion

Clinical teams should be confident that stroke survivors expect cognitive testing and understand its rational. However, the provision of information and results of cognitive testing should be person-centred.

Mapping the trajectory of acute mild-stroke cognitive recovery using serial computerised cognitive assessment

INTRODUCTION

Cognitive impairment is common post-stroke. There is a need to understand patterns of early cognitive recovery post-stroke to guide both clinical and research practice. The aim of the study was to map the trajectory of cognitive recovery during the first week to 90-days post-stroke using serial computerised assessment.

METHOD

An observational cohort study recruited consecutive stroke patients admitted to a stroke unit within 48 hours of onset. Cognitive function was assessed using the computerised Cambridge Neuropsychological Test Automated Battery (CANTAB) daily for seven days, then 14, 30 and 90 days post-stroke. The CANTAB measured visual episodic memory and learning, information processing speed, visuo-spatial working memory, complex sustained attention and mental flexibility. Repeated measures MANOVA/ANOVA with Least Squares Difference post-hoc analyses were performed to ascertain significant change over time.

RESULT

Forty-eight participants, mean age 73, primarily mild, ischaemic stroke, completed all assessment timepoints. There was a trajectory of early, global cognitive improvement, indicative of a post-stroke delirium, that largely stabilised between 6 and 14-days post-stroke. Change over time was examined within each cognitive test, with one measure stabilising by day 6 (Reaction Time) and others detecting improving performances up to 14 days post-stroke.

CONCLUSIONS

Serial, computerised cognitive assessment can effectively map post-stroke cognitive recovery and revealed an early phase of global improvement over 14 days that is evidence for an acute post-stroke delirium. Resolution of post-stroke delirium in the second week following mild stroke indicates more extensive neuropsychological testing may be undertaken earlier than previously thought.

The nonverbal BriefScreen: A cognitive screening method for patients with limited language and motor abilities

Dementia and significant cognitive decline are frequent sequelae of stroke, but are difficult to evaluate when aphasia and/or motor impairment are present. The linguistic and motor requirements of commonly employed screening tests render them problematic for use post-stroke. The present study examines the validity of the Nonverbal BriefScreen, a brief screening method with limited verbal and motor requirements, in groups of patients with known cognitive impairment using the MMSE as a gold standard. Participants were 137 healthy middle aged and older community dwellers, 21 patients with MCI/early dementia and 35 patients with different types of dementia. The sensitivity and specificity of the Nonverbal BriefScreen were calculated for various cutoff scores, with the MMSE as comparison. The Nonverbal BriefScreen was effective in discriminating between healthy controls and patients with dementia, as well as between healthy controls and all patients, with areas under the ROC curve similar to that of the MMSE. ROC analyses with a smaller sample of 35 age-matched healthy controls showed adequate discriminant ability to detect cognitive impairment. The Nonverbal BriefScreen was shown to be a valid method for screening for cognitive impairment that could be employed as a screening method for patients with limited language.

Post-Stroke Environmental Enrichment Improves Neurogenesis and Cognitive Function and Reduces the Generation of Aberrant Neurons in the Mouse Hippocampus

Ischemic lesions stimulate adult neurogenesis in the dentate gyrus, however, this is not associated with better cognitive function. Furthermore, increased neurogenesis is associated with the formation of aberrant neurons. In a previous study, we showed that a running task after a stroke not only increases neurogenesis but also the number of aberrant neurons without improving general performance. Here, we determined whether stimulation in an enriched environment after a lesion could increase neurogenesis and cognitive function without enhancing the number of aberrant neurons. After an ischemic stroke induced by MCAO, animals were transferred to an enriched environment containing a running wheel, tunnels and nest materials. A GFP-retroviral vector was delivered on day 3 post-stroke and a modified water maze test was performed 6 weeks after the lesion. We found that the enriched environment significantly increased the number of new neurons compared with the unstimulated stroke group but not the number of aberrant cells after a lesion. Increased neurogenesis after environmental enrichment was associated with improved cognitive function. Our study showed that early placement in an enriched environment after a stroke lesion markedly increased neurogenesis and flexible learning but not the formation of aberrant neurons, indicating that rehabilitative training, as a combination of running wheel training and enriched environment housing, improved functional and structural outcomes after a stroke.

Fatigue and its relation to general cognition, social cognition and social activity in multiple sclerosis and stroke

INTRODUCTION

The relationship between fatigue and (socio-)cognitive deficits in neurological diseases has sparked increasing research interest in the past years. So far, findings are inconsistent. Most studies focused on general cognitive functioning in specific disorders, particularly cancer or multiple sclerosis (MS).

METHODS

This study aims to examine the relationship between fatigue, social cognition and social activity, also taking into account general cognition, more closely, including a stroke patient group (n = 57), a MS patient group (n = 31) and a healthy control group (n = 20). The participants underwent a comprehensive (socio-)cognitive test battery and completed questionnaires on fatigue and psychopathology which, in addition to fatigue, can also affect (socio-)cognitive performance.

RESULTS

In both MS and stroke patients high fatigue scores were observed. Irrespective of aetiology, patients with high and low fatigue did not differ with regard to general cognition and social cognition. However, high fatigue scores were associated with a reduction of social activities in both patient groups. No other significant relationships were observed between fatigue and (socio-)cognitive measures.

CONCLUSIONS

Future studies ought to further explore the potentially complex nature of fatigue symptoms and their relationship with (socio-)cognitive performance and social activity in neurological populations.

Post-Stroke Cognitive Impairment: Epidemiology, Risk Factors, and Management

Stroke, characterized as a neurological deficit of cerebrovascular cause, is very common in older adults. Increasing evidence suggests stroke contributes to the risk and severity of cognitive impairment. People with cognitive impairment following stroke often face with quality-of-life issues and require ongoing support, which have a profound effect on caregivers and society. The high morbidity of post-stroke cognitive impairment (PSCI) demands effective management strategies, in which preventive strategies are more appealing, especially those targeting towards modifiable risk factors. In this review article, we attempt to summarize existing evidence and knowledge gaps on PSCI: elaborating on the heterogeneity in current definitions, reporting the inconsistent findings in PSCI prevalence in the literature, exploring established or less established predictors, outlining prevention and treatment strategies potentially effective or currently being tested, and proposing promising directions for future research.

Early Mobilization After Stroke Is Not Associated With Cognitive Outcome

Background and Purpose- We aimed to determine whether early mobilization after stroke affects subsequent cognitive function. Methods- AVERT (A Very Early Rehabilitation Trial) was an international, 56-site, phase 3 randomized controlled trial, conducted from 2006 to 2015. Participants were included if they were aged 18+, presented within 24 hours of stroke, and satisfied physiological limits for blood pressure, heart rate, and temperature. Participants were randomized to receive either usual stroke unit care or very early and more frequent mobilization in addition to usual stroke unit care. The Montreal Cognitive Assessment, scored 0 to 30, was introduced as a 3-month outcome during 2008. Results- Of the 2104 patients included in AVERT, 317 were assessed before the Montreal Cognitive Assessment's introduction. Of the remaining 1787, 1189 (66.5%) had complete Montreal Cognitive Assessment data, 456 (25.5%) had partially or completely missing data, 136 (7.6%) had died, and 6 (0.3%) were lost to follow-up. In surviving participants with complete data, adjusting for age and stroke severity, total Montreal Cognitive Assessment score was no different in the intervention (n=595; median, 23; interquartile range, 19-26; mean, 21.9; SD, 5.9) and usual care (n=594; median, 23; interquartile range, 19-26; mean, 21.8; SD, 5.9) groups ( P=0.68). Conclusions- Exposure to earlier and more frequent mobilization in the acute stage of stroke does not influence cognitive outcome at 3 months. This stands in contrast to the primary outcome from AVERT (modified Rankin Scale), where the intervention group had less favorable outcomes than controls. Clinical Trial Registration- URL: https://www.anzctr.org.au . Unique identifier: ACTRN12606000185561.

Executive control in frontal lesion aphasia: Does verbal load matter?

Executive control impairments in aphasia resulting from frontal lesions are expected, given that integrity of frontal regions is critical to executive control task performance. Yet the consistency of executive control impairments in aphasia is poorly understood. This is due to previous studies using only a brief set of measures or failing to account for the high language processing demands of many executive control tasks. This study investigated performance across a series of specific and broad executive control task, whilst comparing differences between low or high verbal task versions. Ten participants with aphasia secondary to left inferior frontal lesions and fifteen age matched controls completed a battery of verbal and low verbal executive control tasks tapping into the three core domains of inhibiting, switching, and updating of working memory. For both controls and participants with aphasia, there was no consistent influence of verbal load on either reaction time or accuracy performance. When compared to controls, participants with aphasia demonstrate a general slowing of responses across all reaction time tasks, and are less accurate on switching and updating tasks. These findings do suggest that language processing is not essential for executive control task performance, given that verbal load does not matter. Furthermore, tasks which involve holding multiple sources of information in mind, such as during switching or updating, are particularly vulnerable in aphasia.

Longitudinal evaluation of cognition after stroke - A systematic scoping review

BACKGROUND

Cognitive impairment affects up to 80 percent of the stroke population, however, both the available evidence about post-stroke cognition and the measures used to evaluate it longitudinally have not been well described. The aims of this systematic scoping review were: to identify and characterize studies evaluating cognition longitudinally after stroke; to summarize the cognitive instruments used and the domains they target; and to organize cognitive domains assessed using the International Classification of Functioning, Disability and Health (ICF).

METHODS

We used a systematic scoping approach to search for peer-reviewed articles involving adults with stroke that evaluated cognition longitudinally. Screening of titles, abstracts, and full reports was completed independently by two reviewers, across six electronic databases (PubMed, PsycInfo, Medline, Cinahl Plus, Embase, and Web of Science). Cognitive domains were mapped to an ICF function independently by the same two reviewers, using a previously tested, standardized approach.

RESULTS

A total of 5,540 records were found; 257 were included, representing a total pooled sample of 120,860 stroke survivors. Of these studies, 200 (78%) provided specific cognitive outcomes from the longitudinal evaluations, 57 (22%) reported model predictions, and 77 (30%) included interventions. Cognition was evaluated with 356 unique instruments, targeting 95 distinct cognitive domains, and 17 mental functions from the ICF. The Mini-Mental State Examination was the most frequently used instrument (117 reports, 46%). Other tools used longitudinally were the Trail Making Test (17% of reports), tests of verbal fluency (14%), the Functional Independence Measure (14%), the Montreal Cognitive Assessment (13%), the Digit Span (11%), and the Stroop test (10%). Global cognition was evaluated in 170 reports (66%), followed by higher-level cognitive functioning (29%), memory (28%), language (21%), attention (21%), and perceptual skills (14%). Studies using functional (or performance-based) cognitive assessments over time were scarce (< 1%).

CONCLUSION

Our findings indicate that whilst there is a substantial number of studies available that report longitudinal evaluations of cognition after stroke, there is large variability in the measures used and the cognitive domains they target. Nonetheless, the available data for evaluation of cognition over time after stroke can be organized and described systematically.

Cardiovascular Risk and Neurocognitive Assessment in Young Adults and Their Relationship to Body Adiposity

BACKGROUND We assessed body composition, adiposity, cardiovascular risk, and cognitive functions in healthy young adult females and investigated the possible correlation between neurocognitive decline, adiposity, and cardiovascular risk markers. MATERIAL AND METHODS This cross-sectional study was conducted on 83 healthy, young adult, Saudi women (age 19-23 years). Subjects were classified into group (A) with 19 non-obese subjects and negative family history (FH) of cardiovascular diseases (CVD), group (B) with 38 non-obese subjects with a positive FH of CVD, and group (C) with 18 obese subjects with positive FH of CVD. Body composition was analyzed by bioelectrical impedance analysis. Cognitive functions were evaluated using the Cambridge Neuropsychological Automated Battery (CANTAB). The blood samples were tested for lipoprotein(a) [Lp(a)] and high-sensitivity C-reactive Protein (hs-CRP). RESULTS There was significantly prolonged Attention-Switching Task (AST) latency in obese subjects with negative family history of CVD (p=0.014) and those with positive family history of CVD (p=0.026) compared to controls, but the difference in AST Percent Correct Trials, Intra-Extra Dimensional Set Shift (IED) Total Errors, and Simple Reaction Time (SRT) was not significant. Simple response time had a weak but significant inverse correlation with BMI (r=-0.227, p<0.05). BMI was correlated positively with Lp(a) and hs-CRP, while BF% was correlated with hs-CRP only. No correlation was observed between the CANTAB tests, Lp(a), and hs-CRP. CONCLUSIONS Cardiovascular risk increases with higher adiposity and the presence of a positive family history of cardiovascular disease. Neurocognitive function may decline with higher adiposity; however, no relationship was observed between neurocognitive functions and cardiovascular risk markers.

Investigating post-stroke fatigue: An individual participant data meta-analysis

OBJECTIVE

The prevalence of post-stroke fatigue differs widely across studies, and reasons for such divergence are unclear. We aimed to collate individual data on post-stroke fatigue from multiple studies to facilitate high-powered meta-analysis, thus increasing our understanding of this complex phenomenon.

METHODS

We conducted an Individual Participant Data (IPD) meta-analysis on post-stroke fatigue and its associated factors. The starting point was our 2016 systematic review and meta-analysis of post-stroke fatigue prevalence, which included 24 studies that used the Fatigue Severity Scale (FSS). Study authors were asked to provide anonymised raw data on the following pre-identified variables: (i) FSS score, (ii) age, (iii) sex, (iv) time post-stroke, (v) depressive symptoms, (vi) stroke severity, (vii) disability, and (viii) stroke type. Linear regression analyses with FSS total score as the dependent variable, clustered by study, were conducted.

RESULTS

We obtained data from 14 of the 24 studies, and 12 datasets were suitable for IPD meta-analysis (total n = 2102). Higher levels of fatigue were independently associated with female sex (coeff. = 2.13, 95% CI 0.44-3.82, p = 0.023), depressive symptoms (coeff. = 7.90, 95% CI 1.76-14.04, p = 0.021), longer time since stroke (coeff. = 10.38, 95% CI 4.35-16.41, p = 0.007) and greater disability (coeff. = 4.16, 95% CI 1.52-6.81, p = 0.010). While there was no linear association between fatigue and age, a cubic relationship was identified (p < 0.001), with fatigue peaks in mid-life and the oldest old.

CONCLUSION

Use of IPD meta-analysis gave us the power to identify novel factors associated with fatigue, such as longer time since stroke, as well as a non-linear relationship with age.

Construct validity of the NIH Toolbox Cognition Battery in individuals with stroke

OBJECTIVE

The National Institutes of Health (NIH) Toolbox (NIHTB) for the Assessment of Behavior and Neurological Function Cognition Battery (NIHTB-CB) provides a brief assessment (approximately 30 min) of key components of cognition. This article examines construct validity to support the clinical utility of the NIHTB-CB in individuals with stroke.

RESEARCH METHOD

A total of 131 individuals with stroke (n = 71 mild stroke; n = 60 moderate/severe stroke) completed the NIHTB-CB. Univariate analyses were conducted to examine the cognitive profiles of the two different stroke groups (mild vs. moderate/severe stroke) on NIHTB-CB measures and composite scores. Pearson correlations were conducted between NIHTB-CB and established measures to examine convergent and discriminant validity. Effect sizes and clinical impairment rates for the different NIHTB-CB measures and composite scores were also examined.

RESULTS

Participants experiencing moderate to severe stroke had poorer performance than did individuals with mild stroke on several of the NIHTB cognition measures. Evidence of convergent validity was provided by moderate to strong correlations between the NIHTB measures and the corresponding standard neuropsychological test (Pearson rs ranged from 0.31 to 0.88; median = .60). Evidence of discriminant validity was provided by smaller correlations between different cognitive domains than correlations of measures within the same domain. Effect sizes for composite and subtest scores regarding stroke severity were generally moderate-to-large. In addition, 42% of the sample were exhibiting mild cognitive impairment (i.e., ≥2 low scores on fluid tests).

CONCLUSIONS

Findings provide support for the construct validity of the NIHTB-CB in individuals with stroke. (PsycINFO Database Record

Cognitive assessment in stroke: feasibility and test properties using differing approaches to scoring of incomplete items

OBJECTIVES

Cognitive screening is recommended in stroke, but test completion may be complicated by stroke related impairments. We described feasibility of completion of three commonly used cognitive screening tools and the effect on scoring properties when cognitive testing was entirely/partially incomplete.

METHODS

We performed a cross-sectional study, recruiting sequential stroke patient admissions from two University Hospital stroke rehabilitation services. We assessed Folstein's mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA) and Addenbrooke's cognitive examination (ACE-III). The multidisciplinary team gave an independent diagnostic formulation. We recorded numbers fully/partially completing tests, assistance and time required for testing. We calculated test discrimination metrics in relation to clinical assessment using four differing statistical approaches to account for incomplete testing.

RESULTS

We recruited 51 patients. Direct assistance to complete cognitive tests was required for 33 (63%). At traditional cut-offs, the majority screened "positive" for cognitive impairment (ACE-III: 98%; MoCA: 98%; MMSE: 81%). Comparing against a clinical diagnosis, ACE-III and MoCA had excellent sensitivity but poor specificity. Partial completion of cognitive tests was common (ACE-III: 14/51, MMSE: 22/51; MoCA: 20/51 fully complete); greatest non completion was for test items that required copying or drawing. Adapting analyses to account for these missing data gave differing results; MMSE sensitivity ranged from 0.66 to 0.85, and specificity ranged from 0.44 to 0.71 depending on the approach employed.

CONCLUSIONS

For cognitive screening in stroke, even relatively brief tools are associated with substantial incompletion. The way these missing data are accounted for in analyses impacts on apparent test properties. When choosing a cognitive screening tool, feasibility should be considered and approaches to handling missing data made explicit. Copyright © 2016 John Wiley & Sons, Ltd.

Cognitive function in stroke survivors: A 10-year follow-up study

OBJECTIVES

Post-stroke cognitive impairment (PSCI) has considerable impact on patients and society. However, long-term studies on PSCI are scarce and may be influenced by assessment methods and selection bias. We aimed to (i) assess the prevalence of long-term PSCI; (ii) compare two common cognitive assessment instruments; and (iii) compare cognitive function of long-term stroke survivors with non-stroke persons.

METHODS

Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were administered to 10-year survivors from a population-based cohort of first-ever stroke patients included in the Lund Stroke Register, Sweden, in 2001-2002. PSCI was defined as MMSE<27 and/or MoCA<25 and severe cognitive impairment as MMSE<23. Age- and sex-matched non-stroke control subjects who had performed MMSE (but not MoCA) were recruited from the longitudinal population study "Good Ageing in Skåne." The odds of having cognitive impairment for stroke survivors compared to controls were examined with logistic regression analyses adjusting for education.

RESULTS

Of 145 stroke survivors after 10 years, 127 participated. MMSE showed PSCI in 46%, whereas MoCA displayed PSCI in 61%. Among the stroke survivors with MoCA<25, 35% had MMSE≥27 (P<.001). The odds of having severe cognitive impairment defined as MMSE<23 were higher among the stroke survivors compared to 354 controls (education-adjusted; OR=2.5; P=.004).

CONCLUSIONS

Post-stroke cognitive impairment was prevalent among 10-year stroke survivors, and the odds of having severe cognitive impairment were higher among the stroke survivors compared to non-stroke persons. The burden of long-term PSCI might have been underestimated previously, and MoCA may be more suitable than MMSE to detect long-term PSCI.

Determining the Association between Language and Cognitive Tests in Poststroke Aphasia

BACKGROUND

Individuals with aphasia are often excluded from studies exploring poststroke cognition because so many of the standard cognitive assessments rely on language ability. Our primary objective was to examine the association between performance on cognitive tests and performance on comprehension and naming tests in poststroke aphasia. Second, we aimed to determine the association between language performance and a real-life measure of cognition (Kettle Test). Third, we explored the feasibility of administering cognitive tests in aphasia.

METHODS

Thirty-six participants with poststroke aphasia and 32 controls were assessed on a battery of pen-and-paper cognitive tests recommended in stroke. Auditory comprehension was measured using the Comprehensive Aphasia Test and naming was measured using the Boston Naming Test. Twenty-two community dwelling participants with aphasia and controls were also asked to complete the Kettle Test. Multiple linear regressions were used to explore the relationship between language performance and performance on the cognitive tests. Feasibility was determined by quantifying missing data.

RESULTS

The cognitive tests with the highest variance accounted for by auditory comprehension and naming were animal fluency (R2 = 0.67, R2 = 0.78) and the Hopkins Verbal Learning Test (recognition discrimination index) (R2 = 0.65, R2 = 0.78). All cognitive tests were significantly associated with auditory comprehension and naming, except for the Star Cancellation Test and the Kettle Test. Thirty-three percent of participants with aphasia were unable to complete all the cognitive tests.

CONCLUSION

Language and non-linguistic cognitive processes are often interrelated. Most pen-and-paper cognitive tests were significantly associated with both auditory comprehension and naming, even in tests that do not require a verbal response. Language performance was not significantly associated with a real-life cognitive performance measure. Task instructions, stimuli, and responses for completion need to be tailored for individuals with aphasia to minimize the influence of language deficits when testing non-linguistic cognitive performance.

Methodological Factors in Determining Risk of Dementia After Transient Ischemic Attack and Stroke: (III) Applicability of Cognitive Tests

BACKGROUND AND PURPOSE

Cognitive assessment is recommended after stroke but there are few data on the applicability of short cognitive tests to the full spectrum of patients. We therefore determined the rates, causes, and associates of untestability in a population-based study of all transient ischemic attack (TIA) and stroke.

METHODS

Patients with TIA or stroke prospectively recruited (2002-2007) into the Oxford Vascular Study had ≥1 short cognitive test (mini-mental state examination, telephone interview of cognitive status, Montreal cognitive assessment, and abbreviated mental test score) at baseline and on follow-up to 5 years.

RESULTS

Among 1097 consecutive assessed survivors (mean: age/SD, 74.8/12.1 years; 378 TIA), numbers testable with a short cognitive test at baseline, 1, 6, 12, and 60 months were 835/1097 (76%), 778/947 (82%), 756/857 (88%), 692/792 (87%), and 472/567 (83%). Eighty-eight percent (331/378) of assessed patients with TIA were testable at baseline compared with only 46% (133/290) of major stroke (P<0.001). Untestability was also associated with older age, premorbid dependency, death on follow-up, and with both pre- and postevent dementia (all P<0.01). Untestability (and problems with testing) were commonly caused by acute stroke effects at baseline (153/262 [58%]: dysphasia/anarthria/hemiparesis=84 [32%], drowsiness=58 [22%], and acute confusion=11 [4%]), whereas sensory deficits caused relatively more problems with testing at later time points (24/63 [38%] at 5 years).

CONCLUSIONS

Substantial numbers of patients with TIA and stroke are untestable with short cognitive tests. Future studies should report data on untestable patients and those with problems with testing in whom the likelihood of dementia is high.