MRI correlates of executive dysfunction in patients with ischaemic stroke

Same, Same but Different? A Multi-Method Review of the Processes Underlying Executive Control

Attention, working memory, and executive control are commonly considered distinct cognitive functions with important reciprocal interactions. Yet, longstanding evidence from lesion studies has demonstrated both overlap and dissociation in their behavioural expression and anatomical underpinnings, suggesting that a lower dimensional framework could be employed to further identify processes supporting goal-directed behaviour. Here, we describe the anatomical and functional correspondence between attention, working memory, and executive control by providing an overview of cognitive models, as well as recent data from lesion studies, invasive and non-invasive multimodal neuroimaging and brain stimulation. We emphasize the benefits of considering converging evidence from multiple methodologies centred on the identification of brain mechanisms supporting goal-driven behaviour. We propose that expanding on this approach should enable the construction of a comprehensive anatomo-functional framework with testable new hypotheses, and aid clinical neuroscience to intervene on impairments of executive functions.

Meta-analysis of the relationship between the number and location of perivascular spaces in the brain and cognitive function

BACKGROUND

Cerebral perivascular spaces are part of the cerebral microvascular structure and play a role in lymphatic drainage and the removal of waste products from the brain. Relationships of the number and location of such spaces with cognition are unclear.

OBJECTIVE

To meta-analyze available data on potential associations of severity and location of perivascular spaces with cognitive performance.

METHODS

We searched PubMed, EMBASE, Web of Science and the Cochrane Central Registry of Controlled Trials for relevant studies published between January 2000 and July 2023. Performance on different cognitive domains was compared to the severity of perivascular spaces in different brain regions using comprehensive meta-analysis. When studies report unadjusted and adjusted means, we use adjusted means for meta-analysis. The study protocol is registered in the PROSPERO database (CRD42023443460).

RESULTS

We meta-analyzed data from 26 cross-sectional studies and two longitudinal studies involving 7908 participants. In most studies perivascular spaces was using a visual rating scale. A higher number of basal ganglia perivascular spaces was linked to lower general intelligence and attention. Moreover, increased centrum semiovale perivascular spaces were associated with worse general intelligence, executive function, language, and memory. Conversely, higher hippocampus perivascular spaces were associated with enhanced memory and executive function. Subgroup analyses revealed variations in associations among different disease conditions.

CONCLUSIONS

A higher quantity of perivascular spaces in the brain is correlated with impaired cognitive function. The location of these perivascular spaces and the underlying disease conditions may influence the specific cognitive domains that are affected.

SYSTEMATIC REVIEW REGISTRATION

The study protocol has been registered in the PROSPERO database (CRD42023443460).

Exploring Pragmatic Deficits in Relation to Theory of Mind and Executive Functions: Evidence from Individuals with Right Hemisphere Stroke

Research investigating pragmatic deficits in individuals with right hemisphere damage focuses on identifying the potential mechanisms responsible for the nature of these impairments. Nonetheless, the presumed shared cognitive mechanisms that could account for these deficits have not yet been established through data-based evidence from lesion studies. This study aimed to examine the co-occurrence of pragmatic language deficits, Theory of Mind impairments, and executive functions while also exploring their associations with brain lesion sites. Twenty-five patients suffering from unilateral right hemisphere stroke and thirty-seven healthy participants were recruited for this study. The two groups were tested in pragmatics, Theory of Mind, and executive function tasks. Structural imaging data were also obtained for the identification of the lesion sites. The findings of this study suggest a potential convergence among the three aforementioned cognitive mechanisms. Moreover, we postulate a hypothesis for a neural circuitry for communication impairments observed in individuals with right hemisphere damage.

Comparing the Symptomatology of Post-stroke Depression with Depression in the General Population: A Systematic Review

Previous research into the phenomenological differences of post-stroke depression (PSD) has typically focused on comparisons of symptom profiles between stroke and non-stroke population controls. This systematic review aimed to synthesize these findings with results from other methodological approaches that contribute to an understanding of phenomenological differences. Articles were identified via a systematic search of seven databases and additional manual searching. A narrative synthesis approach was adopted because of the high methodological heterogeneity. Twelve articles comparing the symptomatology of depression between stroke and non-stroke controls were included. Three distinct methodological approaches, relevant to the aim, were identified: comparisons of profiles among groups with similar overall depression severity, comparisons of the strengths of correlations between a symptom and depression, and comparisons of latent symptom severity. The symptomatology of depression was generally similar between the groups, including somatic symptoms, despite the hypothesized interference of comorbid physical stroke effects. Despite high heterogeneity, there was a tentative indication that post-stroke depression manifests with comparatively less severe/prevalent anhedonia. Possible mechanisms for the observed similarities and differences are explored, including suggestions for future research.

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.

Machine learning based analysis of stroke lesions on mouse tissue sections

An unbiased, automated and reliable method for analysis of brain lesions in tissue after ischemic stroke is missing. Manual infarct volumetry or by threshold-based semi-automated approaches is laborious, and biased to human error or biased by many false -positive and -negative data, respectively. Thereby, we developed a novel machine learning, atlas-based method for fully automated stroke analysis in mouse brain slices stained with 2% Triphenyltetrazolium-chloride (2% TTC), named "StrokeAnalyst", which runs on a user-friendly graphical interface. StrokeAnalyst registers subject images on a common spatial domain (a novel mouse TTC- brain atlas of 80 average mathematical images), calculates pixel-based, tissue-intensity statistics (z-scores), applies outlier-detection and machine learning (Random-Forest) models to increase accuracy of lesion detection, and produces volumetry data and detailed neuroanatomical information per lesion. We validated StrokeAnalyst in two separate experimental sets using the filament stroke model. StrokeAnalyst detects stroke lesions in a rater-independent and reproducible way, correctly detects hemispheric volumes even in presence of post-stroke edema and significantly minimizes false-positive errors compared to threshold-based approaches (false-positive rate 1.2-2.3%, p < 0.05). It can process scanner-acquired, and even smartphone-captured or pdf-retrieved images. Overall, StrokeAnalyst surpasses all previous TTC-volumetry approaches and increases quality, reproducibility and reliability of stroke detection in relevant preclinical models.

Enlarged Perivascular Spaces Are Negatively Associated With Montreal Cognitive Assessment Scores in Older Adults

Emerging evidence suggests that enlarged perivascular spaces (ePVS) may be a clinically significant neuroimaging marker of global cognitive function related to cerebral small vessel disease (cSVD). We tested this possibility by assessing the relationship between ePVS and both a standardized measure of global cognitive function, the Montreal Cognitive Assessment (MoCA), and an established marker of cSVD, white matter hyperintensity volume (WMH) volume. One hundred and eleven community-dwelling older adults (56-86) underwent neuroimaging and MoCA testing. Quantification of region-specific ePVS burden was performed using a previously validated visual rating method and WMH volumes were computed using the standard ADNI pipeline. Separate linear regression models were run with ePVS as a predictor of MoCA scores and whole brain WMH volume. Results indicated a negative association between MoCA scores and both total ePVS counts (P ≤ 0.001) and centrum semiovale ePVS counts (P ≤ 0.001), after controlling for other relevant cSVD variables. Further, WMH volumes were positively associated with total ePVS (P = 0.010), basal ganglia ePVS (P ≤ 0.001), and centrum semiovale ePVS (P = 0.027). Our results suggest that ePVS burden, particularly in the centrum semiovale, may be a clinically significant neuroimaging marker of global cognitive dysfunction related to cSVD.

Potential Biomarkers for Post-Stroke Cognitive Impairment: A Systematic Review and Meta-Analysis

Stroke is a primary debilitating disease in adults, occurring in 15 million individuals each year and causing high mortality and disability rates. The latest estimate revealed that stroke is currently the second leading cause of death worldwide. Post-stroke cognitive impairment (PSCI), one of the major complications after stroke, is frequently underdiagnosed. However, stroke has been reported to increase the risk of cognitive impairment by at least five to eight times. In recent decades, peripheral blood molecular biomarkers for stroke have emerged as diagnostic, prognostic, and therapeutic targets. In this study, we aimed to evaluate some blood-derived proteins for stroke, especially related to brain damage and cognitive impairments, by conducting a systematic review and meta-analysis and discussing the possibility of these proteins as biomarkers for PSCI. Articles published before 26 July 2021 were searched in PubMed, Embase, the Web of Science, and the Cochrane Library to identify all relevant studies reporting blood biomarkers in patients with stroke. Among 1820 articles, 40 were finally identified for this study. We meta-analyzed eight peripheral biomarker candidates: homocysteine (Hcy), high-density lipoprotein cholesterol (HDL-C), C-reactive protein (CRP), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), uric acid, and glycated hemoglobin (HbA1c). The Hcy, CRP, TC, and LDL-C levels were significantly higher in patients with PSCI than in the non-PSCI group; however, the HDL-C, TG, uric acid, and HbA1c levels were not different between the two groups. Based on our findings, we suggest the Hcy, CRP, TC, and LDL-C as possible biomarkers in patients with post-stroke cognitive impairment. Thus, certain blood proteins could be suggested as effective biomarkers for PSCI.

Cognitive impact of cerebral microbleeds in patients with symptomatic small vessel disease

BACKGROUND AND AIM

Whether cerebral microbleeds cause cognitive impairment remains uncertain. We analyzed whether cerebral microbleeds are associated with cognitive dysfunction in patients with symptomatic cerebral small vessel disease, and whether this association is independent of other neuroimaging markers of cerebral small vessel disease.

METHODS

We analyzed consecutive patients with MRI-confirmed lacunar stroke included in DNA-Lacunar-2 multicenter study. Cerebral microbleeds were graded using the Brain Observer Microbleed Rating Scale (BOMBS). Neuropsychological assessment was performed using the Brief Memory and Executive Test (BMET). We analyzed the association between cerebral microbleeds, BMET, and the following subdomains: executive function/processing speed and orientation/memory. We also searched for an independent association between cerebral microbleeds and vascular cognitive impairment, defined as BMET ≤ 13.

RESULTS

Out of 688 included patients, cerebral microbleeds were detected in 192 (27.9%). After adjusting for white matter hyperintensities severity, lacune count, and other confounders, both the presence and the number of cerebral microbleeds were significantly associated with impaired cognitive performance [β = -13.0; 95% CI = (-25.3, -0.6) and β = -13.1; 95% CI = (-19.8, -6.4), respectively]. On analysis of specific cognitive domains, associations were present for executive function/processing speed [β = -5.8; 95% CI = (-9.3, -2.2) and β = -4.3; 95% CI = (-6.2, -2.4), respectively] but not for orientation/memory [β = -0.4; 95% CI = (-4.0, 3.2) and β = -2.1; 95% CI = (-4.0, 0.1), respectively]. We also found an independent association between the presence and the number of cerebral microbleeds and vascular cognitive impairment [adjusted OR = 1.48; 95% CI = (1.01, 2.18) and OR = 1.43; 95% CI = (1.15, 1.79), respectively].

CONCLUSION

In a large cohort of symptomatic cerebral small vessel disease patients, after controlling for other neuroimaging markers of cerebral small vessel disease severity, cerebral microbleeds were associated with cognitive dysfunction. Executive function and processing speed were predominantly impaired. This might suggest a causal role of cerebral microbleeds in determining vascular cognitive impairment.

Combined cognitive and motor training improves the outcome in the early phase after stroke and prevents a decline of executive functions: A pilot study

BACKGROUND

The negative impact of cognitive dysfunction on motor rehabilitation as a relearning-process is well known in stroke patients. However, evidence for combined cognitive and motor training (CMT) is lacking.

OBJECTIVE

To evaluate the effects of combined CMT in early stroke rehabilitation.

METHODS

In a controlled pilot study, 29 moderately affected stroke patients with low-level motor performance and cognitive impairment received motor therapy plus either cognitive (experimental group, EG) or low-frequency ergometer training (control group, CG) for eight days.

RESULTS

Both groups improved their motor functioning significantly. After training, between-group comparison revealed significant differences for cognitive flexibility and trends for set-shifting, working memory, and reaction control in favor of the EG. Within-group effects showed improvement across all cognitive domains in the EG, which correlated with gains in bed-mobility, while the CG showed no significant improvement in cognition. Rather, a trend towards reaction control decline was observed, which correlated with less functional progression and recovery. Furthermore, a decline in cognitive flexibility, set-shifting, and working memory was descriptively observed.

CONCLUSIONS

Combined CMT may enhance cognition and motor relearning early after stroke and is superior to single motor training. Further studies are needed to replicate these results and investigate long-term benefits.

The contribution of cognition to the rehabilitation of language and communication deficits

Background/Aims

There is growing evidence to suggest that cognitive processes, in particular working memory and executive functions, are related to language functions such as syntactic processing, reading comprehension, narration and conversational discourse. This article offers rehabilitation considerations for speech-language pathologists to include cognitive assessment and treatment in their clinical practice. The information presented will also be useful in promoting multidisciplinary rehabilitation.

Methods

A critical review of the literature on the interaction between cognitive processes and linguistic functions in communication disorders was undertaken. Specific key terms including but not limited to executive functioning, working memory, language, assessment, intervention and communication disorders were searched on the Google Scholar database. Relevant literature from the last three decades pertaining to cognitive behavior, assessment and intervention in communication disorders of all age groups and severities is included in the review.

Results

The review presents analyses of the multidimensional and dynamic interaction of language and cognition in children (specific language impairment, attention deficit hyperactivity disorder, stuttering) and adults (traumatic brain injury, stroke, dementia) with communication disorders. The article elaborates on the speech-language pathologist's scope of practice in cognitive assessment and intervention that are consistent with the World Health Organization's International Classification of Functioning, Disability and Health framework.

Conclusions

By documenting cognitive-communication behaviour, speech-language pathologists are able to effectively contribute to the clinical assessment and management of cognitive deficits. However, future research efforts are required to develop clinically reliable tests of cognitive functioning in communication disorders and promote evidence-based cognitive treatment practices.

Microstructural degeneration and cerebrovascular risk burden underlying executive dysfunction after stroke

Executive dysfunction affects 40% of stroke patients, but is poorly predicted by characteristics of the stroke itself. Stroke typically occurs on a background of cerebrovascular burden, which impacts cognition and brain network structural integrity. We used structural equation modelling to investigate whether measures of white matter microstructural integrity (fractional anisotropy and mean diffusivity) and cerebrovascular risk factors better explain executive dysfunction than markers of stroke severity. 126 stroke patients (mean age 68.4 years) were scanned three months post-stroke and compared to 40 age- and sex-matched control participants on neuropsychological measures of executive function. Executive function was below what would be expected for age and education level in stroke patients as measured by the organizational components of the Rey Complex Figure Test, F(3,155) = 17, R2 = 0.25, p < 0.001 (group significant predictor at p < 0.001) and the Trail-Making Test (B), F(3,157) = 3.70, R2 = 0.07, p < 0.01 (group significant predictor at p < 0.001). A multivariate structural equation model illustrated the complex relationship between executive function, white matter integrity, stroke characteristics and cerebrovascular risk (root mean square error of approximation = 0.02). Pearson's correlations confirmed a stronger relationship between executive dysfunction and white matter integrity (r = - 0.74, p < 0.001), than executive dysfunction and stroke severity (r = 0.22, p < 0.01). The relationship between executive function and white matter integrity is mediated by cerebrovascular burden. White matter microstructural degeneration of the superior longitudinal fasciculus in the executive control network better explains executive dysfunction than markers of stroke severity. Executive dysfunction and incident stroke can be both considered manifestations of cerebrovascular risk factors.

Dissociating spatial attention from neglect dyslexia: A single case study

Word-centred neglect dyslexia is generally thought to be caused by a visuospatial neglect-like attentional deficit which impacts orientation-canonical representations of visual stimuli. However, the relationship between word-centred neglect dyslexia and more general attentional processes is not well described. Here, we investigated the impact of attentional load manipulations within a case of word-centred neglect dyslexia. This study presents data from a single case, Patient CD, who exhibited ipsilesional word-centred neglect dyslexia in conjunction with severe, contralesional allocentric neglect. CD demonstrated an intact ability to name all letters in visually presented words, but committed neglect dyslexia errors when subsequently asked to read the same word as a whole. The severity of patient CD's neglect dyslexia was not found to be impacted by attentional manipulations. We found no effect of exposure time or visual crowding on the frequency of neglect dyslexia errors. This absence of an apparent, right-lateralised perceptual deficit, comorbid left-lateralised object-centred neglect, and insensitivity to attentional load manipulations suggests that the deficit underlying word-centred neglect dyslexia is not related to broad visuo-spatial attention. These findings suggest that neglect dyslexia and domain-general visuospatial neglect may not be as related as previously asserted.

Normative data of neuropsychological tests of attention and executive functions in Ecuadorian adult population

OBJECTIVE

The purpose of this study was to generate normative data for five tests of attention and executive functions (M-WCST, Stroop test, TMT, BTA, and SDMT), in a group of 322 Ecuadorian adults from Quito between the ages of 18 and 85.

METHOD

Multiple regression analyzes taking into account age, education, and gender were used to generate the normative data.

RESULTS

Age and education were significantly related to test performance such that scores decreased with age and improved as a function of education. An online calculator is provided to generate normative test scores.

CONCLUSIONS

This is the first study that presents normative data for tests of executive functions and attention in an Ecuadorian adult population. This data will improve the clinical practice of neuropsychology and help to develop the field in the country.

Normative data for tests of attention and executive functions in a sample of European Portuguese adult population

OBJECTIVE

The main goal of this study was to produce normative data for the Portuguese population on five neuropsychological tests frequently used to assess executive functions and attention: the Modified Wisconsin Card Sorting Test (M-WCST), the Stroop Color and Word Test, the Trail Making Test (TMT), the Brief Test of Attention (BTA), and the Symbol Digit Modalities Test (SDMT).

METHOD

The study included 300 individuals aged between 18 and 93 years, who had educational backgrounds ranging from 3 to 25 years.

RESULTS

The influence of age, education, and sex was explored for each measure, as well as their contribution to explain the performance variance.

CONCLUSIONS

The normative data are presented as regression-based algorithms to adjust direct and derived test scores for sex, age, and education. This study provides a calculator of normative data, derived from the results of the regression models.

Cerebral Microbleed Burdens in Specific Brain Regions Are Associated With Disease Severity of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, caused by NOTCH3 mutations, is characterized by recurrent ischemic strokes and progressive cognitive decline. It remains unclear whether cerebral microbleeds (CMBs) can serve as a surrogate marker for disease progression in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. We aimed to investigate the CMB burdens in NOTCH3 mutation carriers at different disease stages and test their associations with cognitive performance.

Methods and Results

Forty‐nine individuals carrying NOTCH3 cysteine‐altering mutations received brain magnetic resonance imaging with T1‐weighted and susceptibility‐weighted images. Whole brain images were segmented into 14 regions using Statistical Parametric Mapping and FreeSurfer software, and semiautomatic methods were used to locate and quantify the number and volume of CMBs. In our study participants, the median of CMB counts was 13, with a wide individual variation (range, 0–286). CMBs were most frequently present in thalamus, followed by temporal lobe. In the whole brain, the CMB counts and CMB volume ratios (ie, CMB volume divided by the volume of corresponding brain region) gradually increased as the disease advanced. CMB counts in the thalamus and temporal and frontal lobes increased more rapidly than other brain regions as disease progressed. There were significant associations between Mini‐Mental State Examination scores and CMB counts in the frontal lobe, temporal lobe, and pons.

Conclusions

CMBs may have an influential role in the clinical manifestations of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. CMB burdens and their distribution in different brain regions may be capable to serve as a disease marker for monitoring the disease severity of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

The Impact of Covert Lacunar Infarcts and White Matter Hyperintensities on Cognitive and Motor Outcomes After Stroke

BACKGROUND AND AIMS

In addition to overt stroke lesions, co-occurring covert lesions, including white matter hyperintensities (WMH) and covert lacunar infarcts (CLI), contribute to poststroke outcome. The purpose of this study was to examine the relationship between covert lesions, and motor and cognitive outcomes in individuals with chronic stroke.

METHODS

Volumetric quantification of clinically overt strokes, covert lesions (periventricular and deep: pWMH, dWMH, pCLI, dCLI), ventricular and sulcal CSF (vCSF, sCSF), and normal appearing white (NAWM) and gray matter (NAGM) was performed using structural magnetic resonance imaging. We assessed motor impairment and function, and global cognition, memory, and other cognitive domains. When correlation analysis identified more than one MR parameter relating to stroke outcomes, we used regression modeling to identify which factor had the strongest impact.

RESULTS

Neuropsychological and brain imaging data were collected from 30 participants at least 6 months following a clinically diagnosed stroke. Memory performance related to vCSF (r = -0.52, P = .004). The strongest predictor of nonmemory domains was pCLI (r² = 0.28, P = .004). Motor impairment and function were most strongly predicted by the volume of stroke and NAWM (r² = 0.36; P = .001), and dWMH (r² = 0.39; P = .001) respectively.

CONCLUSIONS

Covert lesion type and location have important consequences for post-stroke cognitive and motor outcome. Limiting the progression of covert lesions in aging populations may enhance the degree of recovery post-stroke.

Dysexecutive disorders and their diagnosis: A position paper

Although executive function disorders are among the most prevalent cognitive impairments a consensus on diagnostic criteria has yet to be reached. With a view to harmonizing these criteria, the present position paper (i) focuses on the main dysexecutive disorders, (ii) examines recent approaches in both the behavioral and cognitive domains, (iii) defines diagnostic boundaries for frontal syndrome, (iv) reports on the frequency and profile of the executive function disorders observed in the main brain diseases, and (v) proposes an operationalization of diagnostic criteria. Future work must define the executive processes involved in human adaptive behavior, characterize their impairment in brain diseases, and improve the management of these conditions (including remediation strategies and rehabilitation).

Can a tablet-based cancellation test identify cognitive impairment in older adults?

Background and objective

There has been a growing interest in using computerized cognitive assessment to detect age-related cognitive disorders. We have developed a tablet-based cancellation test (e-CT), previously shown as a reliable measure of executive functions and free of effect of familiarity with computer-based devices in healthy older adults. This study aimed to investigate the influence of demographics and current daily use of computer-based devices in older adults with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD). We further studied the ability of the e-CT to discriminate MCI and AD patients from older adults with normal cognition (NC).

Methods

The e-CT was administered to 325 older adults (NC = 112, MCI = 129, AD = 84). Subjects also performed the K-T test, a paper-and-pencil cancellation test from which the e-CT was developed. Multiple linear regression analyses were conducted to assess the contribution of demographics and current daily use of computer-based devices on the e-CT in patient groups. The Receiver Operating Characteristic (ROC) curves and the Area Under the Curve (AUC) were established to compare the efficacy of the e-CT and the K-T test to classify subjects into diagnostic groups.

Results

In the MCI group, age (B = -0.37, p<0.001) and current daily use of computer-based devices (B = 5.85, p<0.001) were associated with the number of correct cancellations of the e-CT. In the AD group, only current daily use of a computer-based device was a significant contributor (B = 6.28, p<0.001). The e-CT (AUC = 0.811; 95% confidence interval [CI]: 0.756–0.867) and the K-T (AUC = 0.837; CI: 0.787–0.887) showed good and comparable diagnostic accuracy to discriminate between MCI and NC subjects. To discriminate between NC and AD, both tests showed high diagnostic accuracy, with the AUC values of 0.923 (CI: 0.876–0.971) and 0.929 (95%CI: 0.886–0.972) for the e-CT and the K-T, respectively.

Conclusion

The e-CT presents satisfying discriminative validity and is a promising tool for detection of early cognitive impairment in older adults.

Prevalence of Brain MRI Markers of Hemorrhagic Risk in Patients with Stroke and Atrial Fibrillation

Background and purpose

Cerebral microbleeds (CMBs), cortical superficial siderosis, white matter lesions (WML), and cerebral atrophy may signify greater bleeding risk particularly in patients in whom anticoagulation is to be considered. We investigated their prevalence and associations with stroke type in patients with stroke and atrial fibrillation (AF).

Materials and Methods

Cross-sectional sample, Monash Medical Centre (Melbourne, Australia) between 2010 and 2013, with brain MRI. MRI abnormalities were rated using standardized methods. Logistic regression was used to study associations adjusting for age and sex.

Results

There were 170 patients, mean age 78 years (SD 9.8), 154 (90.6%) with ischemic stroke. Prevalence of MRI markers were any microbleed 49%, multiple (≥2) microbleeds 30%, confluent WMLs 18.8%, siderosis 8.9%, severe cerebral atrophy 37.7%. Combinations of the severe manifestations of these markers were much less prevalent (2.9–12.4%). Compared with ischemic stroke, those with hemorrhagic stroke were more likely to have ≥10 microbleeds (OR 5.50 95% CI 1.46–20.77, p = 0.012) and siderosis (OR 6.24, 95% CI 1.74–22.40, p = 0.005). Siderosis was associated with multiple microbleeds (OR 8.14, 95% CI 2.38–27.86, p = 0.001). Patients admitted with hemorrhagic stroke and multiple microbleeds were more frequently anticoagulated prior to stroke (6/7, 85.7%) than in those with single (1/2, 50%) or no microbleeds (4/7, 57%).

Conclusion

Multiple CMBs, severe WML, and severe cerebral atrophy were common individually in hospitalized patients with stroke and AF, but less so in combination. A higher burden of CMBs may be associated with intracerebral hemorrhage in stroke patients with AF.

Stroke injury, cognitive impairment and vascular dementia

The global burden of ischaemic strokes is almost 4-fold greater than haemorrhagic strokes. Current evidence suggests that 25–30% of ischaemic stroke survivors develop immediate or delayed vascular cognitive impairment (VCI) or vascular dementia (VaD). Dementia after stroke injury may encompass all types of cognitive disorders. States of cognitive dysfunction before the index stroke are described under the umbrella of pre-stroke dementia, which may entail vascular changes as well as insidious neurodegenerative processes. Risk factors for cognitive impairment and dementia after stroke are multifactorial including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischaemic attack or recurrent stroke and depressive illness. Neuroimaging determinants of dementia after stroke comprise silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Until recently, the neuropathology of dementia after stroke was poorly defined. Most of post-stroke dementia is consistent with VaD involving multiple substrates. Microinfarction, microvascular changes related to blood–brain barrier damage, focal neuronal atrophy and low burden of co-existing neurodegenerative pathology appear key substrates of dementia after stroke injury. The elucidation of mechanisms of dementia after stroke injury will enable establishment of effective strategy for symptomatic relief and prevention. Controlling vascular disease risk factors is essential to reduce the burden of cognitive dysfunction after stroke. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

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Ischaemic injury is common among long-term stroke survivors

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About 25% stroke survivors develop dementia with a much greater proportion developing cognitive impairment

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Risk factors of dementia after stroke include older age, vascular comorbidities, prior stroke and pre-stroke impairment

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Current imaging and pathological studies suggest 70% of dementia after stroke is vascular dementia

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Severe white matter changes and medial temporal lobe atrophy as sequelae after ischaemic injury are substrates of dementia

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Controlling vascular risk factors and prevention strategies related to lifestyle factors would reduce dementia after stroke

Effect of olfactory impairment and white matter hyperintensities on cognition in Parkinson's disease

INTRODUCTION

Although white matter hyperintensities (WMH) and olfactory dysfunction are independently associated with the cognitive impairments in Parkinson's disease (PD), the effects of simultaneous presence of these abnormalities remain unknown. Thus, we investigated the different effects of deep WMH and periventricular WMH on olfactory and cognitive performance and evaluated the additive effects of the concurrent presence of WMH and olfactory dysfunction on cognitive performance in PD.

METHODS

We enrolled 171 patients with non-demented PD whose WMH scores were assessed using a semi-quantitative visual rating system. The olfactory and cognitive performance was assessed using the Cross-Cultural Smell Identification (CCSI) test and the Seoul Neuropsychological Screening Battery. Additionally, the additive effects of concurrent WMH and olfactory dysfunction on cognitive performance were investigated using binary logistic regression.

RESULTS

The deep WMH score exhibited a significant negative correlation with the CCSI score (p = 0.026) but the total WMH and periventricular WMH did not. A multiple regression analysis revealed that the total WMH (β = -0.109, p = 0.011) and deep WMH (β = -0.153, p = 0.020) severities had significant negative correlations with semantic fluency. A logistic regression analysis revealed that the simultaneous presence of severe olfactory dysfunction and deep WMH was associated with a greater risk for the semantic fluency impairments (odds ratio = 15.909, p = 0.0005) compared to patients with mild deep WMH or high CCSI scores.

CONCLUSIONS

These data indicate that deep WMH was closely coupled with olfactory impairments and cognitive decline in PD. Moreover, the concurrent presence of severe deep WMH and olfactory impairments has a greater influence on semantic fluency.

Frontal white matter hyperintensities, clasmatodendrosis and gliovascular abnormalities in ageing and post-stroke dementia

White matter hyperintensities as seen on brain T ₂ -weighted magnetic resonance imaging are associated with varying degrees of cognitive dysfunction in stroke, cerebral small vessel disease and dementia. The pathophysiological mechanisms within the white matter accounting for cognitive dysfunction remain unclear. With the hypothesis that gliovascular interactions are impaired in subjects with high burdens of white matter hyperintensities, we performed clinicopathological studies in post-stroke survivors, who had exhibited greater frontal white matter hyperintensities volumes that predicted shorter time to dementia onset. Histopathological methods were used to identify substrates in the white matter that would distinguish post-stroke demented from post-stroke non-demented subjects. We focused on the reactive cell marker glial fibrillary acidic protein (GFAP) to study the incidence and location of clasmatodendrosis, a morphological attribute of irreversibly injured astrocytes. In contrast to normal appearing GFAP+ astrocytes, clasmatodendrocytes were swollen and had vacuolated cell bodies. Other markers such as aldehyde dehydrogenase 1 family, member L1 (ALDH1L1) showed cytoplasmic disintegration of the astrocytes. Total GFAP+ cells in both the frontal and temporal white matter were not greater in post-stroke demented versus post-stroke non-demented subjects. However, the percentage of clasmatodendrocytes was increased by >2-fold in subjects with post-stroke demented compared to post-stroke non-demented subjects ( P = 0.026) and by 11-fold in older controls versus young controls ( P < 0.023) in the frontal white matter. High ratios of clasmotodendrocytes to total astrocytes in the frontal white matter were consistent with lower Mini-Mental State Examination and the revised Cambridge Cognition Examination scores in post-stroke demented subjects. Double immunofluorescent staining showed aberrant co-localization of aquaporin 4 (AQP4) in retracted GFAP+ astrocytes with disrupted end-feet juxtaposed to microvessels. To explore whether this was associated with the disrupted gliovascular interactions or blood–brain barrier damage, we assessed the co-localization of GFAP and AQP4 immunoreactivities in post-mortem brains from adult baboons with cerebral hypoperfusive injury, induced by occlusion of three major vessels supplying blood to the brain. Analysis of the frontal white matter in perfused brains from the animals surviving 1–28 days after occlusion revealed that the highest intensity of fibrinogen immunoreactivity was at 14 days. At this survival time point, we also noted strikingly similar redistribution of AQP4 and GFAP+ astrocytes transformed into clasmatodendrocytes. Our findings suggest novel associations between irreversible astrocyte injury and disruption of gliovascular interactions at the blood–brain barrier in the frontal white matter and cognitive impairment in elderly post-stroke survivors. We propose that clasmatodendrosis is another pathological substrate, linked to white matter hyperintensities and frontal white matter changes, which may contribute to post-stroke or small vessel disease dementia.

Diversity of approaches in assessment of executive functions in stroke: limited evidence?

Stroke is a leading cause of disability worldwide. Cognitive functions and, in particular, executive function, are commonly affected after stroke, leading to impairments in performance of daily activities, decrease in social participation and in quality of life. Appropriate assessment and understanding of executive dysfunction are important, firstly to develop better rehabilitation strategies for executive functions per se and secondly to consider executive function abilities on rehabilitation strategies in general. The purpose of this review was to identify the most widely used assessment tools of executive dysfunction for patients with stroke, and their psychometric properties.

We systematically reviewed manuscripts published in English in databases from 1999 to 2015. We identified 35 publications. The most frequently used instruments were the Stroop, Digit Span and Trail making tests. Psychometric properties were described for the Executive Function Performance Test, Executive Clock Drawing Task, Chinese Frontal Assessment Battery and Virtual Action Planning — Supermarket, and two subtests of the Cambridge Cognitive Examination — Revised.

There is a paucity of tools to reliably measure executive dysfunction after stroke, despite the fact that executive dysfunction is frequent. Identification of the best tools for executive dysfunction assessment is necessary to address important gaps in research and in clinical practice.

Secondary damage in left-sided frontal white matter detected by diffusion tensor imaging is correlated with executive dysfunction in patients with acute infarction at the ipsilateral posterior corona radiata

BACKGROUND

Executive dysfunction has been observed in patients with left-sided anterior corona radiata infarction. However, whether left-sided posterior corona radiata infarction could cause executive dysfunction is unclear. Also, whether secondary damage in the left frontal white matter following ipsilateral posterior corona radiata infarct is causal or not and contributes to the occurrence and development of executive dysfunction, is still uncertain.

METHODS

Twelve patients with posterior corona radiata infarction underwent diffusion tensor imaging (DTI) and an executive functional assessment at week 1 (W1), week 4 (W4), and week 12 (W12) after onset. Color duplex sonography and Transcranial Duplex Scanning (TCD) were performed at W1 and W12. Twelve healthy volunteers of similar ages and educational histories were examined as controls and assessed once.

RESULTS

In the patients, we observed an increased mean diffusivity (MD) and a decreased fractional anisotropy (FA) in the left frontal white matter from W1 to W12. There were no significant changes in cerebral blood flow in patients between W1 and W12 according to the result of Color duplex sonography and TCD. Patients showed progressively impaired executive function during 12 weeks. Significant correlations were found between increased MD and decreased FA in the left frontal white matter with impaired degree of executive function.

CONCLUSIONS

This study demonstrates that DTI detected secondary damage in left-sided frontal white matter in patients with acute infarction at the ipsilateral posterior corona radiata. This change may be correlated with executive functional changes in these patients.

Understanding and preventing the development of post-stroke dementia

Post-stroke dementia (PSD) is a clinical entity but it now appears that most of PSD may be categorized as vascular dementia. The well-established relationship between vascular factors and dementia provides a rationale for the implementation of intervention and prevention efforts. Larger primary prevention trials related to lifestyle factors are warranted in association with dementia. Published clinical trials have not been promising and there is meager information on whether PSD can be prevented through the use of pharmacological agents. Control of vascular disease risk and prevention of recurrent strokes are obviously key to reducing the burden of cognitive decline and dementia after stroke. However, modern imaging and analysis techniques will help to elucidate the mechanism of PSD and establish better treatment.

Stroke, cognitive deficits, and rehabilitation: still an incomplete picture

Cognitive impairment after stroke is common and can cause disability with major impacts on quality of life and independence. There are also indirect effects of cognitive impairment on functional recovery after stroke through reduced participation in rehabilitation and poor adherence to treatment guidelines. In this article, we attempt to establish the following: ● whether there is a distinct profile of cognitive impairment after stroke; ● whether the type of cognitive deficit can be associated with the features of stroke-related damage; and ● whether interventions can improve poststroke cognitive performance. There is not a consistent profile of cognitive deficits in stroke, though slowed information processing and executive dysfunction tend to predominate. Our understanding of structure-function relationships has been advanced using imaging techniques such as lesion mapping and will be further enhanced through better characterization of damage to functional networks and identification of subtle white matter abnormalities. Effective cognitive rehabilitation approaches have been reported for focal cortical deficits such as neglect and aphasia, but treatments for more diffusely represented cognitive impairment remain elusive. In the future, the hope is that different techniques that have been shown to promote neural plasticity (e.g., exercise, brain stimulation, and pharmacological agents) can be applied to improve the cognitive function of stroke survivors.

Depressive symptoms in late life and cerebrovascular disease: the importance of intelligence and lesion location

BACKGROUND

The influence of white matter lesions on depressive symptoms in healthy ageing populations remains unclear. In this study, we examined the relationship between depressive symptoms and magnetic resonance imaging (MRI) detected cerebrovascular disease in a normal population living independently in the community, and measured the influence of location of brain abnormalities, fluid intelligence, living alone, and sex.

METHODS

Prospective cohort: 497 community dwelling individuals all born in 1936, who took part in the Scottish Mental Survey of 1947, were followed up in 2000 and at biannual intervals in a longitudinal study of health and cognitive aging. Two hundred forty-four volunteered for brain MRI in 2004-2006. Suitable data were available in 219/244, of whom 115 were men. Brain hyperintensities in lobar white matter, basal ganglia , periventricular, and infratentorial regions were measured using Scheltens' scale. Depressed mood was assessed using the Hospital Anxiety and Depression Scale (HADS) on three biannual intervals. Relationships between Scheltens' scores, HADS-D scores, fluid intelligence, living alone, and sex were assessed using general linear modeling.

RESULTS

The main predictor of depressive symptom scores was poorer fluid intelligence (partial η(2) =0.023-0.028, P < .05). Ischemic change in the brainstem (partial η(2) = 0.026, P ≤.05) and basal ganglia (partial η(2) =0.018, P ≤ .05) also predicted HADS-D scores. There was no relationship with sex or living alone.

CONCLUSIONS

Hyperintensities in the brainstem and basal ganglia are associated with depressive symptoms. Higher fluid intelligence is associated with lower depressive symptoms in this normal, ageing population.

Correlation between cognitive function and the association fibers in patients with Alzheimer's disease using diffusion tensor imaging

White matter (WM) changes, along with well-characterized cortical abnormalities, occur in patients with Alzheimer's disease (AD). We investigated the integrity of WM tracts within association fibers by the use of fractional anisotropy (FA), and the relationship between FA values and cognitive function in patients with AD. Neuropsychological examination and conventional MRI, as well as diffusion tensor imaging, (DTI) were conducted on 12 patients with mild to moderate AD and 18 cognitively healthy volunteers. DTI was performed to measure FA in the bilateral inferior fronto-occipital fasciculus (IFOF) and the superior longitudinal fasciculus (SLF). Mini-Mental State Examination (MMSE) scores and Montreal Cognitive Assessment (MoCA) values were used to evaluate cognitive function and the Clinical Dementia Rating (CDR) scale was used as a staging tool for dementia severity. FA measures were analyzed and correlated with neuropsychological data. No patient showed any WM tract abnormality on either T1-weighted or T2-weighted MRI. However, the FA values in the bilateral IFOF and SLF and the MoCA scores in patients with AD were significantly decreased (p<0.05) compared to the controls. Furthermore, the decreased FA values in the SLF were positively correlated with cognitive function (MMSE scores - right: r=0.672, p=0.033, left: r=0.919, p<0.01; MoCA values - right: r=0.747, p=0.013, left: r=0.679, p=0.031). Our findings confirmed that the loss of integrity of microstructural WM connectivity has a role in the cognitive decline of patients with AD. The data also suggest that the FA values of the SLF may be used as a clinical marker of cognitive function.

Ankle brachial pressure index as a marker of apathy in a community-dwelling population

BACKGROUND

Apathy is defined as a lack of interest or emotion. Several studies have shown the relationship between apathy and atherosclerotic change in poststroke patients. Although apathy is confused with depression, it might be a specific neuropsychiatric syndrome separate from depression.

OBJECTIVE

To clarify the relationship between atherosclerotic change and apathy in a community-dwelling population, which does not include the psychologic factors associated with stroke events.

METHODS

The ankle brachial pressure index (ABI) was measured using a volume-plethymographic apparatus in 860 volunteers (315 males and 545 females) who participated in the Iwaki Health Promotion Project 2008. Starkstein's apathy score and the Center for Epidemiologic Studies Depression Scale (CES-D) were used to assess the psychologic status. The association between the ABI and apathy was assessed by a multiple linear regression analysis.

RESULTS

Gender and low-density lipoprotein (LDL)-cholesterol were independently and significantly associated with the CES-D score. We did not find any association between CES-D score and the ABI. In addition, the extent of education and the ABI were independently and significantly associated with the apathy scale (AS).

CONCLUSION

In a community-dwelling population, a lower ABI score was an independent risk factor for a higher AS score, but not for a higher CES-D score. Apathy and depression may have different etiologies in vascular factors.

Wisconsin card sorting test as a measure of executive function impairments in stroke patients

The Wisconsin Card Sorting Test (WCST) is among the most frequently administered neuropsychological tests. It is assumed that successful completion of this test requires engagement of executive functions (EF). One of the most common origins of EF impairments is ischemic stroke. The present study intends to evaluate the diagnostic use of the WCST as a measure of these impairments in poststroke patients. Forty-four patients (8 women and 36 men) who had recent unilateral stroke (22 left hemisphere, 22 right hemisphere) participated in the study. The overall accuracy of the WCST in classifying stroke survivors as having executive disorders was poor. Nevertheless, statistical analysis revealed its negative predictive power to be greater than positive predictive power (i.e., normal scores on the WCST reliably indicated the absence of executive disorders in 8 or more out of 10). Performance on the WCST is clearly influenced by severity of the executive disorders. Namely, patients with severe impairment of EF (as measured by go/no-go, fluency, and other EF tests) performed more poorly on the WCST than patients with lesser impairment or those with no impairment at all, the latter group's results being indistinguishable. In addition, this study highlights a three-factor solution to the WCST, which accounted for 90.3% of the variance. The scores that most strongly loaded on Factors 1 to 3 were, in order: percentage of conceptual-level responses, number of trials to complete the first category, and failures to maintain the set of responses. Finally, an analysis using multivariate analysis of variance, with the anterior versus posterior site and left versus right side of the lesion as independent variables, revealed a relatively weak effect of lesion location on the WCST performance. In particular, with respect to all test scores, there is only one significant interaction between the site and side of lesion was obtained (F(₁(,)₂₄) = 4.12; p < .05; i.e., the number of categories achieved was significantly smaller after damage to the frontal lobe on the left than on the right side, whereas the laterality effect was not significant after nonfrontal lesions). In conclusion, to ascertain the cerebral substrates of poststroke executive dysfunction, there is a need to apply more accurate tests than the WCST. The study highlights the importance of a multicomponent approach to executive functioning in stroke patients.

Importance of symptomatic cerebral infarcts on cognitive performance in patients with Alzheimer's disease

The coexistence of cerebral infarcts and Alzheimer's disease (AD) is common, but the influence of symptomatic cerebral infarcts on cognition is uncertain in AD. We hypothesize that symptomatic cerebral infarcts may provide an additive cognitive factor contributing to dementia in the AD population. We studied 1,001 clinically probable or possible AD patients in the Alzheimer Disease Research Center (ADRC) database. Linear regression was used to evaluate for an association between symptomatic cerebral infarcts and memory, language, executive function, abstract reasoning, and visuospatial performance, separately. Models were adjusted for covariates including age, gender, education, ethnicity, hypertension, diabetes mellitus, heart disease, clinical dementia rating, the presence of silent cerebral infarcts, and multiplicity or location of infarcts. Clinical history of stroke was present in 107 patients, radiological infarcts in 308 patients, and 68 patients with both were considered to have symptomatic infarcts. Adjusting for all covariates, AD patients with symptomatic infarcts had more impairment of executive function (P < 0.05). The influence of cerebral infarcts is neither general nor diffuse, and the presence of clinical history may have a more important influence on executive performance in AD.

Post-stroke cognitive impairment at 3 months

BACKGROUND

Vascular cognitive impairment, being the only treatable cause of dementia in the early stages, and having a diverse etiology, requires sensitive criteria for definition.

AIM

This study aimed to study cognitive functions at 3 months post-stroke, utilising the Mini mental scale examination (MMSE) and the Frontal assessment battery (FAB), and to correlate the same with subgroups of ischemic stroke.

RESULTS

164 patients were studied, 108 of these having multiple infarcts. Pure cortical infarcts were seen in 41 patients. At 3 months, 112/164 patients had MMSE more than 24, with no frontal executive dysfunction. MMSE score less than 24 was seen in 24 patients, all of them having FAB score below 10. Normal MMSE with impaired FAB was seen in 28 patients.

CONCLUSIONS

Impairment on either the MMSE or the FAB was thus seen in 31.7% patients (52/164), at 3 months after stroke. FAB impairment alone, with MMSE in normal range, was seen in 28/52 (53.8%) patients. Memory was significantly more commonly affected in muti-infarct strokes as compared to single infarcts. Frontal executive dysfunction was not significantly different when single and multiple infarcts, or cortical and subcortical infarcts, were compared.

Heterogeneity in mild cognitive impairment: differences in neuropsychological profile and associated white matter lesion pathology

This study examined whether distinct neuropsychological profiles could be delineated in a sample with Mild Cognitive Impairment (MCI) and whether white matter lesion (WML) burden contributed to MCI group differences. A heterogeneous, clinical sample of 70 older adults diagnosed with MCI was assessed using cognitive scores, and WML was quantified using a semi-automated, volumetric approach on T2-weighted fluid-attenuated inversion recovery (FLAIR) images. Using cluster and discriminant analyses, three distinct groups (Memory/Language, Executive/Processing Speed, and Pure Memory) were empirically derived based on cognitive scores. Results also showed a dose dependent relationship of WML burden to MCI subgroup, with the Executive/Processing Speed subgroup demonstrating significantly higher levels of WML pathology when compared to the other subgroups. In addition, there was a dissociation of lesion type by the two most impaired subgroups (Memory/Language and Executive/Processing Speed) such that the Memory/Language subgroup showed higher periventricular lesion (PVL) and lower deep white matter lesion (DWML) volumes, whereas the Executive/Processing Speed demonstrated higher DWML and lower PVL volumes. Results demonstrate that distinct MCI subgroups can be empirically derived and reliably differentiated from a heterogeneous MCI sample, and that these profiles differ according to WML burden. Overall, findings suggest different underlying pathologies within MCI and contribute to our understanding of MCI subtypes.

The Brixton Spatial Anticipation Test as a test for executive function: validity in patient groups and norms for older adults

Impairments in executive functioning frequently occur after acquired brain damage, in psychiatric disorders, and in relation to aging. The Brixton Spatial Anticipation Test is a relatively new measure for assessing the ability to detect and follow a rule, an important aspect of executive functioning. To date, normative data on this task are limited, particularly concerning the elderly. This study presents age- and education-adjusted regression-based norms obtained in a group of healthy older participants (n = 283; mean age 67.4 +/- 8.5 years). The applicability and validity of these norms were further examined in different groups of patients with stroke (n = 106), diabetes mellitus (n = 376), MCI/early dementia (n = 70), psychiatric disorders (n = 63), and Korsakoff's syndrome (n = 41). The results showed that patients with Korsakoff's syndrome, stroke, and psychiatric disorders performed significantly worse than healthy controls. Test-retest correlation (n = 83), learning effects, and correlations with other neuropsychological tests were also explored. Based on the present study, the Brixton test appears a useful addition to existing measures of executive functioning. Moreover, the test can be reliably applied in different groups of clinical patients.

Clinical characteristics in subcortical ischemic white matter disease

BACKGROUND: Vascular white matter lesions (WML) represent one of the main neuroimage findings in individuals older than 65 years and its clinical significance is still partially understood. OBJECTIVE: To describe and analyze the clinical profile of a high severity sample with WML focusing on the frontal executive control. METHOD: Outpatients (n=20) with high severity WML evaluated with magnetic resonance imaging were selected using the Fazekas scale. RESULTS: Most patients (n=17; 85%) presented an altered Trail Making Test ratio (section B/section A); on verbal fluency, 15 individuals (75%) performed below the cutoff score. Apathy (5.9 ± 4.65) and depression (3.05±3.67) were frequent as assessed by the Neuropsychiatric Inventory. The impairment in functional activities strongly correlated with apathy (r=0.814, p<0.001) and verbal fluency (r=0.744, p<0.001). CONCLUSION: Executive dysfunction, apathy, and ratio depression were the main characteristics found. Extension of WML may have distinct impact on the clinical picture, but further studies with methodological adjustments are necessary to provide more definitive conclusions.

Alzheimer's disease (AD) and executive dysfunction. A case-control study on the significance of frontal white matter changes detected by diffusion tensor imaging (DTI)

White matter (WM) changes are frequently seen on structural imaging in AD but the clinical relevance of these changes is uncertain. Frontal WM pathology is often observed upon neuropathological examination in AD. Since frontal cortical/sub-cortical pathology is known to relate to executive dysfunction, the aim was to elucidate if frontal WM changes in AD correlated with executive dysfunction. In all, 15 AD patients and 15 age-matched control cases were investigated in the study, which covered conventional magnetic resonance imaging (MRI), DTI, neuropsychiatric and neuropsychological examinations. Reduced performance on neuropsychological testing of executive function correlated significantly with an increasing degree of frontal WM changes detected by DTI in the AD group, while no such correlation was observed for the controls. Conventional semi-quantitative MRI assessment did not correlate with results on neuropsychological testing of executive function in any of the groups. The structural correlate to certain dimensions of executive dysfunction in AD patients could be related to changes in the deep frontal WM. DTI appears to be more sensitive in the detection of clinically significant WM alterations than conventional semi-quantitative MRI.

Emotional incontinence and executive function in ischemic stroke: a case-controlled study

Frontal and basal ganglia infarcts and executive dysfunction are thought to be involved in the pathophysiology of poststroke emotional incontinence (PSEI). The study examined whether patients with PSEI have more frontal and/or basal ganglia infarcts and impairment in executive function. A total of 516 Chinese patients with acute ischemic stroke consecutively admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong were screened for PSEI 3 months after the index stroke. According to Kim's criteria, 39 (7.6%) had PSEI. Thirty-nine stroke patients without PSEI served as matched control group. The PSEI group had significantly more frontal and/or basal ganglia infarcts, had lower Chinese Frontal Assessment Battery scores, required more time to complete the Stroop Test, and made more omission and commission errors in the Go-NoGo test. There was no significant correlation between frontal or basal ganglia infarcts and executive function. The correlation between frontal infarct and severity of PSEI was .420. Further follow-up and functional imaging studies are warranted to explore the relationship between PSEI, brain infarcts, and executive dysfunction. (JINS, 2009, 15, 62-68.).

Vascular disease and apathy in old age. The Leiden 85-Plus Study

BACKGROUND

Apathy is defined as an important loss of motivation in all domains of daily functioning. Especially in old age, apathy might be a specific neuropsychiatric syndrome separate from depression. There are indications that apathy in elderly subjects is related to vascular disease.

OBJECTIVE

To assess the relation between vascular disease and apathy in subjects aged 85 years and older.

METHODS

The Leiden 85-plus Study is a prospective, population-based study of 500 elderly subjects. Vascular disease including myocardial infarction, angina pectoris or myocardial ischemia, claudicatio intermittens, and arterial surgery was determined at baseline. Symptoms of apathy were assessed annually from age 85 through 90 years using the apathy questions of the 15-item Geriatric Depression Rating Scale (GDS). Diagnostic accuracy of the apathy questions was validated using the Apathy Scale at age 90 years. The association between vascular disease and apathy was estimated both at baseline and longitudinally.

RESULTS

The apathy items of the GDS showed a sensitivity of 69% and a specificity of 85%. At baseline, 69 subjects with apathy but free of depression had significantly more cardiovascular pathologies compared to 287 subjects without apathy. In the 287 subjects who were free of apathy and depression, increase of apathy but not depression during follow-up was significantly higher for each additional cardiovascular pathology at baseline.

CONCLUSION

In community dwelling elderly, those with vascular disease were at higher risk of developing apathy but not depression. This suggests that apathy and depression in old age have different etiologies.

Regional white matter pathology in mild cognitive impairment: differential influence of lesion type on neuropsychological functioning

BACKGROUND AND PURPOSE

Associations between regional white matter lesion pathology and neuropsychological performance across the aging spectrum are not well understood and, to date, research has been largely contradictory and inconclusive. The current study set out to clarify some of the inconsistencies in the literature by relating volumetric analyses of white matter lesions (deep white matter lesions and periventricular lesions) to neuropsychological performance in a large clinical sample of older adults diagnosed with mild cognitive impairment.

METHODS

Seventy older adults with mild cognitive impairment were administered a comprehensive neuropsychological battery. White matter lesions identified on T2-weighted FLAIR images were quantified using a semi-automated volumetric approach (pixel thresholding).

RESULTS

Results showed that, in contrast to performance on memory and naming tasks, total white matter lesions strongly predicted executive impairments, slowed processing speed, and visuospatial/construction difficulties. In addition, separate regression analyses demonstrated that results were primarily accounted for by deep white matter lesions (but not periventricular lesions), most likely due to frontal-subcortical circuitry disruption. Moreover, deep white matter lesions, but not periventricular lesions, significantly predicted overall poorer neuropsychological functioning after controlling for age, education, and level of depression.

CONCLUSIONS

Taken together, findings demonstrate a differential influence of lesion type on cognitive impairment in mild cognitive impairment and implicate deep white matter lesions as being most detrimental in terms of neuropsychological functioning. Clinical, theoretical, and methodological implications of these results are discussed.

The neuro-behavioural syndrome of brainstem disease

We describe two patients with isolated brainstem lesions who exhibited behavioural and cognitive changes that are commonly associated with frontal lobe pathology, as leading clinical features. These cases illustrate the role of distributed neural networks in cognitive and behavioural processes. The brainstem, frontal-subcortical and limbic systems are extensively and reciprocally linked via neurotransmitter projection pathways. We argue that cognitive and behavioural features in patients with brainstem lesions reflect remote effects of brainstem structures on frontal lobe and limbic regions, as a consequence of disruption to ascending neurotransmitter pathways.

Neuroimaging of white matter in aging and dementia

Clinical neuroscientists have focused increasing attention on white matter connections in the brain and on the effects of aging and disease on these connections. Recent advances in magnetic resonance imaging (MRI) analysis have given researchers new tools for quantifying and visualizing white matter to better relate white matter structure and function. The goals of this article are (a) to acquaint the reader with both established and newer methods for imaging and quantifying white matter anatomy and pathology; and (b) to review recent findings on white matter pathology in aging and dementia. Computer-assisted quantification appears to offer better statistical power than visual rating scales for detecting these relationships. New MR modalities such as diffusion imaging can detect white matter abnormalities not shown with conventional acquisition sequences. These newer techniques hold promise for early detection of disease and for delineating functional connections between brain areas.