Frontal impairment in subcortical ischemic vascular dementia in comparison to Alzheimer's disease

Neuropsychological differential diagnosis of Alzheimer's disease and vascular dementia: a systematic review with meta-regressions

Introduction

Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them.

Methods

We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots.

Results

We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (β g = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (β g = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (β g = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (β g = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (β g = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (β g = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50).

Conclusion

Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.

The clinical profile of cerebral small vessel disease: Toward an evidence-based identification of cognitive markers

There is no consensus on which test is more suited to outline the cognitive deficits of cerebral small vessel disease (cSVD) patients. We explored the ability of eight cognitive tests, selected in a previous systematic review as the most commonly used in this population, to differentiate among cSVD patients, controls, and other dementing conditions performing a meta-analysis of 86 studies. We found that cSVD patients performed worse than healthy controls in all tests while data on the comparison to neurodegenerative diseases were limited. We outlined a lack of data on these tests' accuracy on the diagnosis. Cognitive tests measuring processing speed were those mostly associated with neuroimaging cSVD markers. There is currently incomplete evidence that a single test could differentiate cSVD patients with cognitive decline from other dementing diseases. We make preliminary proposals on possible strategies to gain information about the clinical definition of cSVD that currently remains a neuroimaging-based one.

Diagnostics and treatment of chronic cerebral ischemia

5560 patients with the diagnosis “Other cerebral vascular diseases” per 100 000 of elderly population were registered in RF in 2017. Usually this is a code for chronic brain ischemia (CBI) – the most popular diagnosis in Russian neurological practice. However, diagnostic criteria of CBI are not well defined and need to be ascertained. Recent studies show that the most reliable clinical feature of CBI could be cognitive impairment. It is developed before other clinical signs and correlate with severity of vascular brain lesions. Typically, cognitive impairment is subcortical with prominent bradyphrenia, attentional, dysexecutive and visuospatial deficit and relative sparing of memory. However clinical diagnosis of CBI could be only hypothetical. Diagnosis should be verified by MRI or other visualization technic. Diagnosis is verified if neuroimaging revealed silent strokes, microbleeds and vascular leukoencephalopathy. The most important objective of chronic brain ischemia management is the control of basic vascular disease. Besides this, pathogenetic therapy should be performed to improve cerebral microcirculation, neuronal metabolism and to provide neuroprotection. There is positive data on dipyridamole usage in chronic brain ischemia. It has desagregative, vasotropic, antioxidative and antiinflammation properties. Dypiridamole treatment in CBI patients lead to decrease of neuropsychiatric symptoms and improvement of well-being.

Update on Vascular Cognitive Impairment Associated with Subcortical Small-Vessel Disease

Subcortical small-vessel disease (SSVD) is a disorder well characterized from the clinical, imaging, and neuropathological viewpoints. SSVD is considered the most prevalent ischemic brain disorder, increasing in frequency with age. Vascular risk factors include hypertension, diabetes, hyperlipidemia, elevated homocysteine, and obstructive sleep apnea. Ischemic white matter lesions are the hallmark of SSVD; other pathological lesions include arteriolosclerosis, dilatation of perivascular spaces, venous collagenosis, cerebral amyloid angiopathy, microbleeds, microinfarcts, lacunes, and large infarcts. The pathogenesis of SSVD is incompletely understood but includes endothelial changes and blood-brain barrier alterations involving metalloproteinases, vascular endothelial growth factors, angiotensin II, mindin/spondin, and the mammalian target of rapamycin pathway. Metabolic and genetic conditions may also play a role but hitherto there are few conclusive studies. Clinical diagnosis of SSVD includes early executive dysfunction manifested by impaired capacity to use complex information, to formulate strategies, and to exercise self-control. In comparison with Alzheimer's disease (AD), patients with SSVD show less pronounced episodic memory deficits. Brain imaging has advanced substantially the diagnostic tools for SSVD. With the exception of cortical microinfarcts, all other lesions are well visualized with MRI. Diagnostic biomarkers that separate AD from SSVD include reduction of cerebrospinal fluid amyloid-β (Aβ)42 and of the ratio Aβ42/Aβ40 often with increased total tau levels. However, better markers of small-vessel function of intracerebral blood vessels are needed. The treatment of SSVD remains unsatisfactory other than control of vascular risk factors. There is an urgent need of finding targets to slow down and potentially halt the progression of this prevalent, but often unrecognized, disorder.

Frontal Lobe Dementia and Subcortical Vascular Dementia: A Neuropsychological Comparison

We compared the performance of 40 patients with frontal lobe dementia to that of 40 patients with subcortical vascular dementia (80 patients including, 46 men and 34 women) in a set of tasks assessing attentional, executive, and behavioural tasks. The frontal lobe dementia represents an important cause for degenerative disruption and is increasingly recognised as an important form (up to 25%) of degenerative dementia among individuals of late-middle-age. The main involvement is the frontal-subcortical pathway, which is the final target of impairment even in subcortical vascular dementia. A wider involvement of the cortical (decisional) layers in frontal dementia, in contrast with the prominent and widespread involvement of the subcortical pathways (refinement and corrections programs) creates the different profiles of the two groups. Frontal patients have more difficulties in abstract reasoning, focusing attention, and implementing strategies to solve problems. They exhibit more profound behavioural alterations in personality and social conduct and show only moderate depression, and a total lack of insight concerning their clinical condition. In contrast, the patients with subcortical vascular dementia have poor general cognitive functions, high insight, and important depression and apathy as the principal and most salient characteristic of their behavioral conduct.

Frequency of and risk factors for poor cognitive performance in hemodialysis patients

OBJECTIVE

There are few detailed data on cognition in patients undergoing dialysis. We evaluated the frequency of and risk factors for poor cognitive performance using detailed neurocognitive testing.

METHODS

In this cross-sectional cohort study, 314 hemodialysis patients from 6 Boston-area hemodialysis units underwent detailed cognitive assessment. The neuropsychological battery assessed a broad range of functions, with established age-, sex-, and education-matched normative scores. Principal component analysis was used to derive composite scores for memory and executive function domains. Risk factors for each domain were evaluated using linear regression adjusting for age, sex, race, and education status. Analyses were repeated in those with Mini-Mental State Examination (MMSE) score ≥ 24.

RESULTS

Compared with population norms, patients on dialysis had significantly poorer executive function but not memory performance, a finding that persisted in the subgroup with MMSE score ≥ 24. In adjusted analyses, vascular risk factors and vascular disease were associated with lower executive function (p < 0.01).

CONCLUSIONS

There is a high frequency of poor cognitive performance in hemodialysis patients, primarily affecting executive function. Risk factors for worse executive function include vascular risk factors as well as vascular disease. Normal performance on the MMSE does not preclude impaired cognitive function, because individuals with MMSE score ≥ 24 also have a high frequency of poor cognitive performance.

The additive effects of type-2 diabetes on cognitive function in older adults with heart failure

Background. Medical comorbidity has been theorized to contribute to cognitive impairment in heart failure (HF) patients. Specifically, type-2 diabetes mellitus (T2DM), a common coexisting condition among HF patients, may be an independent predictor of cognitive impairment. Nonetheless, the relationships between T2DM and other risk factors for cognitive impairment among persons with HF are unclear. Methods. Persons with HF (N = 169, 34.3% women, age 68.57 ± 10.28 years) completed neuropsychological testing within a framework of an ongoing study. History of T2DM, along with other medical characteristics, was ascertained through a review of participants' medical charts and self-report. Results. Many participants (34.9%) had a comorbid T2DM diagnosis. After adjustment for demographic and medical characteristics, HF patients with T2DM evidenced significantly greater impairments across multiple cognitive domains than HF patients without T2DM: λ = .92, F(5, 156) = 2.82, P = .018. Post hoc tests revealed significant associations between T2DM and attention (P = .003), executive function (P = .032), and motor functioning (P = .008). Conclusion. The findings suggest additive contributions of T2DM and HF to impairments in attention, executive function, and motor function. Future work is needed to elucidate the mechanisms by which T2DM exacerbates cognitive impairment in HF.

Cerebrovascular disease and cognition in older adults

The well-established association between advanced age, cerebrovascular pathology, and cognitive decline is receiving greater attention as the population attains new levels of longevity. This chapter will provide an overview of vascular anatomy and age-related cerebrovascular disorders and diseases, including stroke and degenerative dementia. The cognitive and functional sequellae of these cerebrovascular disorders will also be described in detail. Throughout this review, we will emphasize topics that have been relatively underrepresented in the literature, including age-related diseases of the cerebral small vessels, nuanced characterization of cognitive impairment associated with insidious small-vessel vascular dementia, and the real-life functional consequences of cerebrovascular changes in older adults.

The long-term efficacy and tolerability of donepezil in patients with vascular dementia

OBJECTIVE

To determine the long-term tolerability and efficacy of donepezil in patients with vascular dementia (VaD).

METHODS

International, multicentre, open-label, 30-week extension study of two 24-week, randomised, double-blind, placebo-controlled studies. Participants were ambulatory adults (59% female; mean age, 74.7 +/- 0.3) with a diagnosis of possible or probable VaD and without a diagnosis of Alzheimer's disease, who were medically stable and had completed one of two double-blind studies. All patients received donepezil 5 mg/day for the first 6 weeks, then 10 mg/day (clinician approval required). Assessments were performed at week 6 and every 12 weeks thereafter. The main outcome measure was the Alzheimer's disease Assessment Scale-cognitive subscale (ADAS-cog). Safety/tolerability measures included adverse events (AEs) and physical and laboratory evaluations.

RESULTS

Of 1219 eligible patients, 885 (72.6%) were enrolled, of which 707 (79.9%) completed the study; 127 (14.4%) patients discontinued due to AEs. A mean reduction (0.6-1.15 points) from double-blind study baseline score to week 54 (end of open-label study) on the ADAS-cog was observed for patients who received donepezil continuously for 54 weeks. ADAS-cog scores remained stable in the group that initiated donepezil treatment during the extension study. Most common donepezil-related AEs were nausea (occurring in 5.3%) and diarrhoea (8.8%); no unexpected AEs attributable to donepezil occurred.

CONCLUSION

These data suggest that donepezil improves cognition for up to 54 weeks in patients with VaD. Patients initiating donepezil in this extension study did not perform as well on the primary outcome measure as those initiating donepezil in the double-blind study.

Temporal order memory differences in Alzheimer's disease and vascular dementia

Determining the order of events is essential for accurate memory recollection: an ability previously linked to both frontal and medial temporal functioning. Frontal-subcortical and medial temporal dysfunction typify vascular dementia (VaD) and Alzheimer's disease (AD), respectively. Therefore, we assessed patients' ordering abilities using a novel sequencing task that progressively increased memory load. VaD patients made more errors and selected more previously encountered stimuli than did AD. Curve analysis revealed a general decline in ordering for VaD whereas error production in AD is more dependent on memory load. These findings generally support the role of frontal-subcortical functioning in temporal order memory.

Brief screening for mild cognitive impairment in elderly outpatient clinic: validation of the Korean version of the Montreal Cognitive Assessment

The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening tool with high sensitivity for screening patients with mild cognitive impairment (MCI). The authors examined the validity and reliability of the Korean version of the MoCA (MoCA-K) in elderly outpatients. The MoCA-K, a Korean version of the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR) scale, and neuropsychological batteries were administered to 196 elderly persons (mild Alzheimer's disease [AD] = 44, MCI = 37, normal controls [NC] = 115). MoCA-K scores were highly correlated with those of MMSE and CDR. Using a cutoff score of 22/23, the MoCA-K had an excellent sensitivity of 89% and a good specificity of 84% for screening MCI. Internal consistency and test-retest reliability were good. The results obtained show that the MoCA-K is brief, reliable, and suitable for use as a screening tool to screen MCI patients in elderly outpatient clinic settings.

Cognitive-behavioral profiles of neurodegenerative dementias: beyond Alzheimer's disease

The neurocognitive and behavioral profiles of vascular dementia and vascular cognitive impairment, dementia with Lewy bodies and Parkinson's disease with dementia, and dementia syndromes associated with frontotemporal lobar degenerations are compared and contrasted with Alzheimer's dementia (AD). Vascular dementia/vascular cognitive impairment is characterized by better verbal memory performance, worse quantitative executive functioning, and prominent depressed mood. Dementia with Lewy bodies and Parkinson's disease with dementia are equally contrasted with AD by defective processing of visual information, better performance on executively supported verbal learning tasks, greater attentional variability, poorer qualitative executive functioning, and the presence of mood-congruent visual hallucinations. The frontal variant of frontotemporal lobar degeneration (frontotemporal dementia) differs from AD by better multimodal retention on learning tasks, different patterns of generative word fluency, defective qualitative executive functioning, and by markedly impairment of comportment. For temporal variants of frontotemporal lobar degenerations, progressive aphasia and semantic dementia, worse language performance relative to AD is typically characteristic.

Japanese version of the Frontal Assessment Battery for dementia

The Frontal Assessment Battery (FAB) was developed as a short bedside cognitive and behavioral battery to assess frontal lobe functions. The purpose of this study was to evaluate the validity and reliability of a Japanese version of the FAB to measure cognitive dysfunction in patients with dementia. We studied 25 normal subjects and 105 patients with Alzheimer's disease, n=58, vascular dementia, n=24, and frontotemporal dementia, n=23. The neuropsychological test battery included the FAB, the Mini Mental State Examination (MMSE), a memory test, and the Wisconsin Card Sorting Test (Keio version: KWCST). Patients with dementia performed significantly more poorly than controls on all tests. The FAB showed a good correlation with other cognitive measures: MMSE (r=0.725), KWCST number of categories completed (r=0.654), KWCST number of perseveration errors (r=-0.484), and memory test (r=0.643). Patients with more severe Clinical Dementia Rating scores showed lower scores on the FAB. There was good inter-rater reliability (r=0.972), test-retest reliability (r=0.769), and internal consistency (Cronbach's coefficient alpha=0.715). The FAB is a valid and reliable screening test to evaluate cognitive dysfunction among patients with dementia.

Subcortical cognitive impairment in dialysis patients

Given the high burden of atherosclerotic cardiovascular disease in dialysis patients, we hypothesized that cognitive testing would reveal subtle abnormalities in subcortical brain function, a measure frequently associated with cerebrovascular disease. Detailed neurocognitive testing was performed in 25 hemodialysis patients. All patients had Mini-Mental State Examination (MMSE) scores >24 and had no history of cerebrovascular disease. Where appropriate, scores were normalized for age, gender, and education. One-sample t tests were used to compare differences in cognitive function between dialysis patients and normative data. The mean age was 57 years, and the mean MMSE was 27.5. Fourteen subjects (56%) were females, and 15 white (60%). Results of the North American Adult Reading Test, a measure of verbal intelligence, were comparable with the general population. Similarly, measures of cortical function, namely retention and recognition scores from the Word List Learning subtest of the Wechsler Memory Scale-III, were preserved when compared with normative data where reference = 10. Significant deficits were seen on tests assessing subcortical function: scores (mean+/-standard deviation) for block design, and symbol coding subtests of the Wechsler Adult Intelligence Scale-III were 7.0+/-1.7 and 7.7+/-3.1, respectively (p<0.001 for both comparisons with normative data). Similarly, adjusted scores on the trails A and B tests were 40.5+/-8.3 and 41.8+/-11.3, respectively (p<0.001 for both comparisons with normative data where reference= 50). These results suggest that, despite relatively normal MMSE scores, mild cognitive impairment may be prevalent in hemodialysis patients. The pattern of cognitive dysfunction is primarily subcortical in nature.

The enigma of vascular cognitive disorder and vascular dementia

The prevalence, morphology and pathogenesis of vascular dementia (VaD), recently termed vascular cognitive impairment, are a matter of discussion, and currently used clinical diagnostic criteria show moderate sensitivity (average 50%) and variable specificity (range 64-98%). In Western clinic-based series, VaD is suggested in 8-10% of cognitively impaired aged subjects. Its prevalence in autopsy series varies from 0.03 to 58%, with reasonable values of 8-15%, while in Japan it is seen in 22-35%. Neuropathologic changes associated with cognitive impairment include multifocal and/or diffuse disease and focal lesions: multi-infarct encephalopathy, white matter lesions or arteriosclerotic subcortical (leuko)encephalopathy, multilacunar state, mixed cortico-subcortical type, borderline/watershed lesions, rare granular cortical atrophy, post-ischemic encephalopathy and hippocampal sclerosis. They result from systemic, cardiac and local large or small vessel disease. Recent data indicate that cognitive decline is commonly associated with widespread small ischemic/vascular lesions (microinfarcts, lacunes) throughout the brain with predominant involvement of subcortical and functionally important brain areas. Their pathogenesis is multifactorial, and their pathophysiology affects neuronal networks involved in cognition, memory, behavior and executive functioning. Vascular lesions often coexist with Alzheimer disease (AD) and other pathologies. Minor cerebrovascular lesions, except for severe amyloid angiopathy, appear not essential for cognitive decline in full-blown AD, while both mild Alzheimer pathology and small vessel disease may interact synergistically. The lesion pattern of "pure" VaD, related to arteriosclerosis and microangiopathies, differs from that in mixed-type dementia (AD with vascular encephalopathy), more often showing large infarcts, which suggests different pathogenesis of both types of lesions. Due to the high variability of cerebrovascular pathology and its causative factors, no validated neuropathologic criteria for VaD are available, and a large variability across laboratories still exists in the procedures for morphologic examination and histology techniques.

Callosal neglect in hydrocephalus

A functional disconnection of the corpus callosum (CC) can induce a form of spatial neglect where each hand (e.g., left) when attempting to bisect lines in the opposite (e.g., right) hemispace deviates toward its own (e.g., left) hemispace. Patients with hydrocephalus often show thinning of the CC but callosal neglect has not been reported in this condition. Two right-handed patients with hydrocephalus and thinning of the CC, as well as six matched controls, were assessed for neglect by performing the line bisection task in left, right and center space with their right and left hands. When compared to controls neither patient, using either their right or left hands, demonstrated a bias in the center or left space conditions, but with lines in right space both subjects' left hand deviated significantly to the left. Thus, patients with hydrocephalic interhemispheric functional disconnection might show a form of callosal neglect. This hemispatial-hand asymmetry of deviation, however, also might be related to the disinhibition of the attentionally dominant right hemisphere.

Vascular determinants of cholinergic deficits in Alzheimer disease and vascular dementia

Alzheimer's disease (AD) and vascular dementia (VaD) are widely accepted as the most common forms of dementia. Cerebrovascular lesions frequently coexist with AD, creating an overlap in the clinical and pathological features of VaD and AD. This review assembles evidence for a role for cholinergic mechanisms in the pathogenesis of VaD, as has been established for AD. We first consider the anatomy and vascularization of the basal forebrain cholinergic neuronal system, emphasizing its susceptibility to the effects of arterial hypertension, sustained hypoperfusion, and ischemic cerebrovascular disease. The impact of aging and consequences of disruption of the cholinergic system in cognition and in control of cerebral blood flow are further discussed. We also summarize preclinical and clinical evidence supporting cholinergic deficits and the use of cholinesterase inhibitors in patients with VaD. We postulate that vascular pathology likely plays a common role in initiating cholinergic neuronal abnormalities in VaD and AD.

Cognitive impairment in the lateralized phenotype of corticobasal degeneration

Corticobasal degeneration (CBD) is a rare disorder, which normally includes a combination of neurobehavioural features, movement disorders and other manifestations. It is now recognized that CBD patients usually present with two phenotypes: the lateralized phenotype and the dementia phenotype. The aim of our work was to determine the nature and the progression of cognitive and behavioural impairment in 10 lateralized CBD patients. In our patients, the most salient aspects of cognitive impairment were: an evident alteration of rapid alternating operative strategies, associated with the evident impairment of set shifting, of executive operations, of operative and sequential procedure and of implementation of judgement and abstract reasoning. The self-activation of retrieval processes is partly preserved in CBD. As all the other types of subcortical impairments, even CBD encompasses both cognitive impairment as well as a wide range of behaviour disturbances, such as progressive alterations of sleep, depression, and of anxiety (with a remarkable incidence of somatic pain). This suggests that in addition to neuropsychological assessment, quantification of the personality behaviour disorder is important for standardizing the diagnosis of subcortical vascular dementia and distinguishing it from any other dementias.

Working memory and learning in early Alzheimer's disease

Cognitive deficits associated with early Alzheimer's disease (AD) have been recently operationalised in terms of an acquisition deficit and the research supporting this view is presented. However, there is still debate concerning the nature of this deficit and how underlying cognitive processes may be detrimentally affecting the ability to acquire new information in early AD. This review argues that the pattern of cognitive deficits contributing to the acquisition impairment in early AD patients may be readily interpreted within the context of a working memory model. Isolating the component processes of working memory that underlie the acquisition deficit in early AD patients will aid in the design of clinical applications that are focussed at enhancing the ability to acquire new information in everyday life.

Understanding the pathology of vascular cognitive impairment

The prevalence, morphology and pathogenesis of vascular dementia (VaD), recently termed vascular cognitive impairment (VCI), and of mixed dementia (Alzheimer disease+vascular encephalopathy) are a matter of discussion and no validated neuropathologic criteria for these disorders are currently available. In Western memory clinic-based series, VaD/CVI is suggested in 8-10% of cognitively impaired elderly; its prevalence in autopsy series ranges from 0.03% to 58% (mean 5-15%). Fairly unusual as an isolated nosological entity, CVI appears to correlate with focal, multifocal or diffuse cortical and/or subcortical microinfarcts and lacunes often affecting strategically important brain areas (thalamus, frontobasal, limbic system), hemispheric white matter and, less often, large brain areas. They result from systemic, cardiac or local large or small vessel disease. The lesion pattern in "pure" VCI with predominant multiple small (subcortical) lesions related to microangiopathies differs from that in "mixed dementia" (AD+VaD), more often associated with large infarcts, suggesting different pathogenesis. In very old subjects, selective hippocampal sclerosis may be accompanied by multiple other vascular pathologies. Minor cerebrovascular lesions (CVL), except for severe amyloid angiopathy, appear not essential for cognitive decline in full-blown AD, while both mild AD-type pathology and small vessel disease may interact synergistically in "unmasking" or promoting dementia. AD pathology is significantly less severe in the presence of cerebrovascular lesions. Further studies are needed to validate diagnostic criteria for VCI and to clarify the impact of vascular lesions on cognitive impairment.

Patterns of memory impairment and perseverative behavior discriminate early Alzheimer's disease from subcortical vascular dementia

Previous research suggests that the neuropsychological deficits in Alzheimer's disease (AD) are different from that of vascular dementia (VaD), especially with respect to memory, language and executive functions, but negative findings were reported. Our objective was to clarify the cognitive syndrome in AD and VaD in the early stage of these disorders. We investigated 45 patients with early AD, 23 patients with subcortical VaD and 35 normal controls. All subjects were assessed with neuropsychological battery designed to measure memory, language, praxis and executive functions. Patients with AD had significantly worse scores on Story Recall (p<0.02) and on all measures of the Free and Cued Selective Reminding Test (p<0.03 to 0.001) than did patients with VaD, as well as greater number of perseverations (p<0.02) on category fluency. Conversely, VaD patients had more perseverations (p<0.02) on the Modified Card Sorting Test. Despite the similar degree of overall cognitive deterioration, the findings show more impaired retrieval from long-term storage in AD than in VaD. Moreover, the data suggest that AD and subcortical VaD affect perseverative behavior in a different fashion. These results may be helpful in differentiating AD from VaD in the early stage of these disorders, when mental impairments are not pervasive yet.

Effects of arousing emotional scenes on the distribution of visuospatial attention: changes with aging and early subcortical vascular dementia

BACKGROUND

The modulation of attention by emotionally arousing stimuli is highly important for each individual's social function. Disturbances of emotional processing are a supportive feature for the diagnosis of subcortical vascular dementia (SVD). We address here whether these disturbances might be useful as an early disease marker.

METHODS

In order to examine the modulation of visual attention by emotionally arousing stimuli of different valence, 12 elderly patients with early SVD, 12 age-comparable healthy adults and 12 young healthy subjects were studied while looking at pairs of pictures from the International Affective Picture Battery that were either neutral-neutral, neutral-positive or neutral-negative in terms of emotional content. Eye movements were recorded with an infrared eye-tracking system. The direction of the first saccade and the dwell time during the 10 s of presentation were measured and compared among groups with parametric tests.

RESULTS

All subjects showed a modulation of initial attentional orienting as well as a higher percentage of dwell time towards the pictures containing emotional material. Patients with SVD and old controls did not differ in either experimental measure. Young patients showed a stronger bias towards emotionally negative material than both groups of older individuals.

CONCLUSIONS

Modulation of visuospatial attention is preserved in early SVD. This might have implications for therapeutic interventional approaches. A weakened sustained attention towards negative but not positive emotional pictures in the elderly is in accordance with the socioemotional selectivity theory, describing a relative selection of positive stimuli with aging.

Neuropsychological performance in Alzheimer's disease and vascular dementia: comparisons in a memory clinic population

OBJECTIVES

To compare the performances of two matched groups of patients with Alzheimer's disease (AD) and vascular dementia (VaD) on a battery of neuropsychological tests.

METHODS

325 patients attending a memory clinic were given a detailed multi-disciplinary diagnostic assessment, including a battery of neuropsychological tests administered by a psychologist and a speech and language therapist. The performances of two groups of patients meeting ICD-10 criteria for AD (n = 103) and VaD (n = 68) were compared, adjusting for age, gender, dementia severity and pre-morbid IQ. Patients with co-morbid depression and mixed AD+VaD were excluded.

RESULTS

After adjustment, the AD and VaD groups differed significantly on the Graded Naming Test (VaD superior), AMIPB Complex Design immediate and delayed recall (VaD superior), the Trail Making Test error score (Part B) (VaD superior), and Verbal Picture Description (VaD superior).

CONCLUSIONS

These findings support previous evidence that language function and non-verbal memory are selectively more impaired in AD. The better performance by VaD patients on the Trail Making Test (B) runs counter to previous suggestions that there is an excess of frontal executive dysfunction in this disorder. It may be that this test is more sensitive to the early impairment of concurrent manipulation of information in AD.

Patient populations in clinical trials of the efficacy and tolerability of donepezil in patients with vascular dementia

There is increasing evidence to suggest that patients with vascular dementia (VaD) exhibit a cholinergic deficit. These patients may therefore benefit from treatment with cholinesterase (ChE) inhibitors such as donepezil. However, there are difficulties in accurately defining patients with VaD. Clinical trials to assess the efficacy and tolerability of donepezil in patients with VaD have been completed. National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria were used to establish inclusion and exclusion criteria: evidence of dementia (impaired memory and two other cognitive domains), and evidence of cerebrovascular disease (CVD) from neuroimaging and physical examination and a possible or probable relationship between dementia and CVD were required for enrollment. Patients with a diagnosis of Alzheimer's disease (AD) or dementia caused by other conditions not associated with the cardiovascular system (e.g., MS, chronic infections, hypothyroidism) were excluded. These criteria ensured that only patients with probable or possible VaD were enrolled. Enrolled patients had a mean Hachinski score of 9.7, with memory impairment the most prominent feature of their dementia. Sixty percent of patients had a history of at least one stroke and 18% of patients had a history of transient ischemic attack (TIA) pre-dementia. Cortical and subcortical infarcts were among the lesions observed on computer-assisted tomography and magnetic resonance imaging scans with significant white matter lesions also present in some patients. Placebo-treated patients demonstrated stable cognitive and global function over the 24 weeks of the study. These observations suggest that the patients enrolled in these trials have a broad range of CVD, and are different from those enrolled in AD trials.