Neuropsychological, psychiatric, and cerebral perfusion correlates of leukoaraiosis in Alzheimer's disease

Strengths and Weaknesses of the Vascular Apathy Hypothesis: A Narrative Review

The vascular apathy hypothesis states that cerebral small vessel disease (CSVD) can cause apathy, even when no other symptoms of CSVD are present. In order to examine this hypothesis, the objectives of this narrative review are to evaluate the evidence for a pathophysiological mechanism linking CSVD to apathy and to examine whether CSVD can be a sole cause of apathy. The nature of the CSVD-apathy relationship was evaluated using the Bradford Hill criteria as a method for research on the distinction between association and causation. Pathological, neuroimaging, and behavioral studies show that CSVD can cause lesions in the reward network, which causes an apathy syndrome. Studies in healthy older individuals, stroke patients and cognitively impaired persons consistently show an association between CSVD markers and apathy, although studies in older persons suffering from depression are inconclusive. A biological gradient is confirmed, as well as a temporal relationship, although the evidence for the latter is still weak. The specificity of this causal relationship is low given there often are other contributing factors in CSVD patients with apathy, particularly depression and cognitive deterioration. Differentiating between vascular apathy and other apathy syndromes on the basis of clinical features is not yet possible, while in-depth knowledge about differences in the prognosis and efficacy of treatment options for apathy caused by CSVD and other apathy syndromes is lacking. Since we cannot differentiate between etiologically different apathy syndromes as yet, it is premature to use the term vascular apathy which would suggest a distinct clinical apathy syndrome.

Macrostructural and Microstructural White Matter Alterations Are Associated with Apathy across the Clinical Alzheimer's Disease Spectrum

Apathy is the commonest neuropsychiatric symptom in Alzheimer's disease (AD). Previous findings suggest that apathy is caused by a communication breakdown between functional neural networks involved in motivational-affective processing. This study investigated the relationship between white matter (WM) damage and apathy in AD. Sixty-one patients with apathy (AP-PT) and 61 without apathy (NA-PT) were identified from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database and matched for cognitive status, age and education. Sixty-one cognitively unimpaired (CU) participants were also included as controls. Data on cognitive performance, cerebrospinal fluid biomarkers, brain/WM hyperintensity volumes and diffusion tensor imaging indices were compared across groups. No neurocognitive differences were found between patient groups, but the AP-PT group had more severe neuropsychiatric symptoms. Compared with CU participants, only apathetic patients had deficits on the Clock Drawing Test. AP-PT had increased WM damage, both macrostructurally, i.e., larger WM hyperintensity volume, and microstructurally, i.e., increased radial/axial diffusivity and reduced fractional anisotropy in the fornix, cingulum, anterior thalamic radiations and superior longitudinal and uncinate fasciculi. AP-PT showed signs of extensive WM damage, especially in associative tracts in the frontal lobes, fornix and cingulum. Disruption in structural connectivity might affect crucial functional inter-network communication, resulting in motivational deficits and worse cognitive decline.

Psychosis as a Treatment Target in Dementia: A Roadmap for Designing Interventions

Psychotic phenomena are among the most severe and disruptive symptoms of dementias and appear in 30% to 50% of patients. They are associated with a worse evolution and great suffering to patients and caregivers. Their current treatments obtain limited results and are not free of adverse effects, which are sometimes serious. It is therefore crucial to develop new treatments that can improve this situation. We review available data that could enlighten the future design of clinical trials with psychosis in dementia as main target. Along with an explanation of its prevalence in the common diseases that cause dementia, we present proposals aimed at improving the definition of symptoms and what should be included and excluded in clinical trials. A review of the available information regarding the neurobiological basis of symptoms, in terms of pathology, neuroimaging, and genomics, is provided as a guide towards new therapeutic targets. The correct evaluation of symptoms is transcendental in any therapeutic trial and these aspects are extensively addressed. Finally, a critical overview of existing pharmacological and non-pharmacological treatments is made, revealing the unmet needs, in terms of efficacy and safety. Our work emphasizes the need for better definition and measurement of psychotic symptoms in dementias in order to highlight their differences with symptoms that appear in non-dementing diseases such as schizophrenia. Advances in neurobiology should illuminate the development of new, more effective and safer molecules for which this review can serve as a roadmap in the design of future clinical trials.

Neuromodulation for Apathy in Alzheimer's Disease: A Double-Blind, Randomized, Sham-Controlled Pilot Study

BACKGROUND

Apathy, a profound loss of motivation, initiation, and goal directed cognition, is a common comorbidity of Alzheimer's disease (AD). The presence of apathy is associated with rapid progression of AD, long-term impairment, disability, and higher mortality. Pharmacological treatments of apathy are limited.

OBJECTIVE

The primary objective was to evaluate the efficacy of repetitive transcranial magnetic stimulation (rTMS) for apathy in AD.

METHODS

A randomized, double-blind, parallel-arm, sham-controlled pilot study was conducted in subjects with AD and apathy (N = 20). Subjects were randomized to rTMS or sham treatment (5 days/week) for four weeks. Primary outcome, apathy evaluation scale-clinician version (AES-C), and secondary outcome measures, modified-Mini Mental State Examination (3MS), instrumental activities of daily living (IADL), and clinical global impression (CGI), were assessed at baseline and four weeks. Follow-up visits were conducted at 8 and 12 weeks to test the durability of effects of intervention.

RESULTS

Mean age was 77.3 (±7.2) years, 80% were Caucasians and 10% were females. After adjusting for baseline, there was a significantly greater improvement in the AES-C with rTMS compared to sham treatment (-10.1 (-15.9 to -4.3); t (16)  = -3.69; p = 0.002) at 4 weeks. There was also significantly greater improvement in 3MS (6.9 (1.7 to 12.0); t (15)  = 2.85; p = 0.012), IADL (3.4 (1.0 to 5.9); χ21 = 7.72; p = 0.006), CGI-S (1.4 (0.5 to 2.3), t (16)  = 3.29; p = 0.005), and CGI-I (-2.56 (-3.5 to -1.6), t (17)  = -5.72; p < 0.001) for rTMS compared to the sham at 4 weeks. The effects of rTMS were durable at 12 weeks.

CONCLUSION

rTMS may be safely used in subjects with AD and may improve apathy, function, and some aspects of cognition.

White matter hyperintensity topography in Alzheimer's disease and links to cognition

Introduction

White matter hyperintensities (WMH) are often described in Alzheimer's disease (AD), but their topography and specific relationships with cognition remain unclear.

Methods

Regional WMH were estimated in 54 cognitively impaired amyloid beta–positive AD (Aβpos‐AD), compared to 40 cognitively unimpaired amyloid beta–negative older controls (Aβneg‐controls) matched for vascular risk factors. The cross‐sectional association between regional WMH volume and cognition was assessed within each group, controlling for cerebral amyloid burden, global cortical atrophy, and hippocampal atrophy.

Results

WMH volume was larger in Aβpos‐AD compared to Aβneg‐controls in all regions, with the greatest changes in the splenium of the corpus callosum (S‐CC). In Aβpos‐AD patients, larger total and regional WMH volume, especially in the S‐CC, was strongly associated with decreased cognition.

Discussion

WMH specifically contribute to lower cognition in AD, independently from amyloid deposition and atrophy. This study emphasizes the clinical relevance of WMH in AD, especially posterior WMH, and most notably S‐CC WMH.

Neuropsychiatric symptoms associated with cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease, a common cause of vascular dementia, is often considered clinically silent before dementia or stroke become apparent. However, some individuals have subtle symptoms associated with acute MRI lesions. We aimed to determine whether neuropsychiatric and cognitive symptoms vary according to small vessel disease burden.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and PsycINFO for articles published in any language from database inception to Jan 24, 2020. We searched for studies assessing anxiety, apathy, delirium, emotional lability, fatigue, personality change, psychosis, dementia-related behavioural symptoms or cognitive symptoms (including subjective memory complaints), and radiological features of cerebral small vessel disease. We extracted reported odds ratios (OR), standardised mean differences (SMD), and correlations, stratified outcomes by disease severity or symptom presence or absence, and pooled data using random-effects meta-analyses, reporting adjusted findings when possible. We assessed the bias on included studies using the Risk of Bias for Non-randomized Studies tool. This study is registered with PROSPERO, CRD42018096673.

FINDINGS

Of 7119 papers identified, 81 studies including 79 cohorts in total were eligible for inclusion (n=21 730 participants, mean age 69·2 years). Of these 81 studies, 45 (8120 participants) reported effect estimates. We found associations between worse white matter hyperintensity (WMH) severity and apathy (OR 1·41, 95% CI 1·05-1·89) and the adjusted SMD in apathy score between WMH severities was 0·38 (95% CI 0·15-0·61). Worse WMH severity was also associated with delirium (adjusted OR 2·9, 95% CI 1·12-7·55) and fatigue (unadjusted OR 1·63, 95% CI 1·20-2·22). WMHs were not consistently associated with subjective memory complaints (OR 1·34, 95% CI 0·61-2·94) and unadjusted SMD for WMH severity between these groups was 0·08 (95% CI -0·31 to 0·47). Anxiety, dementia-related behaviours, emotional lability, and psychosis were too varied or sparse for meta-analysis; these factors were reviewed narratively. Overall heterogeneity varied from 0% to 79%. Only five studies had a low risk of bias across all domains.

INTERPRETATION

Apathy, fatigue, and delirium associated independently with worse WMH, whereas subjective cognitive complaints did not. The association of anxiety, dementia-related behaviours, emotional lability, and psychosis with cerebral small vessel disease require further investigation. These symptoms should be assessed longitudinally to improve early clinical detection of small vessel disease and enable prevention trials to happen early in the disease course, long before cognition declines.

FUNDING

Chief Scientist Office of the Scottish Government, UK Dementia Research Institute, Fondation Leducq, Stroke Association Garfield-Weston Foundation, Alzheimer's Society, and National Health Service Research Scotland.

Specific Dimensions of Depression Have Different Associations With Cognitive Decline in Older Adults With Type 2 Diabetes

OBJECTIVE

Depression is highly frequent in older adults with type 2 diabetes and is associated with cognitive impairment, yet little is known about how various depression dimensions differentially affect cognition. We investigated longitudinal associations of specific depression dimensions with cognitive decline.

RESEARCH DESIGN AND METHODS

Participants (N = 1,002) were from the Israel Diabetes and Cognitive Decline study, were ≥65 years of age, had type 2 diabetes, and were not experiencing dementia at baseline. Participants underwent a comprehensive neuropsychological battery at baseline and every 18 months thereafter, including domains of episodic memory, attention/working memory, semantic categorization/language, and executive function, and Z-scores of each domain were averaged and further normalized to calculate global cognition. Depression items from the 15-item Geriatric Depression Scale were measured at each visit and subcategorized into five dimensions: dysphoric mood, withdrawal-apathy-vigor (entitled apathy), anxiety, hopelessness, and memory complaint. Random coefficients models examined the association of depression dimensions with baseline and longitudinal cognitive functioning, adjusting for sociodemographics and baseline characteristics, including cardiovascular risk factors, physical activity, and use of diabetes medications.

RESULTS

In the fully adjusted model at baseline, all dimensions of depression, except for anxiety, were associated with some aspect of cognition (P values from 0.01 to <0.001). Longitudinally, greater apathy scores were associated with faster decline in executive function (P = 0.004), a result that withstood adjustment for multiple comparisons. Associations of other depression dimensions with cognitive decline were not significant (P > 0.01).

CONCLUSIONS

Apathy was associated with a faster cognitive decline in executive function. These findings highlight the heterogeneity of depression as a clinical construct rather than as a single entity and point to apathy as a specific risk factor for cognitive decline among older adults with type 2 diabetes.

The Longitudinal Assessment of Neuropsychiatric Symptoms in Mild Cognitive Impairment and Alzheimer's Disease and Their Association With White Matter Hyperintensities in the National Alzheimer's Coordinating Center's Uniform Data Set

BACKGROUND

Neuropsychiatric symptoms (NPSs) are common in Alzheimer's disease (AD). NPSs contribute to patients' distress, caregiver burden, and institutionalization. White matter hyperintensities (WMHs) appear on magnetic resonance imaging, usually indicative of cerebrovascular disease. WMHs have been associated with certain NPSs. We aimed to assess the relationship between WMH and NPS severity in mild cognitive impairment (MCI) due to AD (MCI-AD) and in AD and to assess the ability of WMHs to predict NPS progression. Data were obtained from the National Alzheimer's Coordinating Center.

METHODS

A total of 252 participants (114 with MCI-AD and 138 with AD) were used in this study. Baseline WMHs were quantified using an automated segmentation technique. NPSs were measured using the Neuropsychiatric Inventory. Mixed-effect models and correlations were used to determine the relationship between WMHs and NPSs.

RESULTS

Longitudinal mixed-effect models revealed a significant relationship between increase in Neuropsychiatric Inventory total scores and baseline WMHs (p = .014). There was a significant relationship between baseline WMHs and an increase in delusions (p = .023), hallucinations (p = .040), agitation (p = .093), depression (p = .017), and irritability (p = .002). Correlation plot analysis showed that baseline whole-brain WMHs predicted change in future Neuropsychiatric Inventory total scores (r = .169, p = .008) and predicted change in future agitation severity scores (r = .165, p = .009). WMHs in the temporal lobes (r = .169, p = .008) and frontal lobes (r = .153, p = .016) contributed most to this change.

CONCLUSIONS

Depression, irritability, and agitation are common NPSs and very distressful to patients and caregivers. Our findings of increased NPS severity over time in MCI-AD and AD with increased WMHs have important implications for treatment, arguing for aggressive treatment of vascular risk factors in patients with MCI-AD or AD.

Network neuroscience of apathy in cerebrovascular disease

Apathy is a reduction in motivated goal-directed behavior (GDB) that is prevalent in cerebrovascular disease, providing an important opportunity to study the mechanistic underpinnings of motivation in humans. Focal lesions, such as those seen in stroke, have been crucial in developing models of brain regions underlying motivated behavior, while studies of cerebral small vessel disease (SVD) have helped define the connections between brain regions supporting such behavior. However, current lesion-based models cannot fully explain the neurobiology of apathy in stroke and SVD. To address this, we propose a network-based model which conceptualizes apathy as the result of damage to GDB-related networks. A review of the current evidence suggests that cerebrovascular disease-related pathology can lead to network changes outside of initially damaged territories, which may propagate to regions that share structural or functional connections. The presentation and longitudinal trajectory of apathy in stroke and SVD may be the result of these network changes. Distinct subnetworks might support cognitive components of GDB, the disruption of which results in specific symptoms of apathy. This network-based model of apathy may open new approaches for investigating its underlying neurobiology, and presents novel opportunities for its diagnosis and treatment.

Lack of a Sense of Threat and Higher Emotional Lability in Patients With Chronic Microvascular Ischemia as Measured by Non-linear EEG Parameters

We aimed to investigate the non-linear features of the electroencephalogram (EEG) findings in patients with chronic microvascular ischemia (CMI) in order to determine the brain correlates of emotional impairment that could impact the risk of developing acute ischemia. We compared the EEG responses of patients with CMI and age-matched healthy volunteers to non-verbal emotionally charged sounds. We analyzed the EEG data, the psychological assessment of the stimuli, and the results of neuropsychological and behavioral testing. We assessed the (in)stability of the envelope's amplitude by calculating its average frequency and the ratio of its standard deviation to its mean. The non-linear features were lower in the patient group in the resting state. The emotional stimulation induced a decrease in the frequency of the envelope's amplitude in all subjects. Changes in the fractal dimension during stimulation were only seen in the patient group, and they correlated with symptoms of emotional lability. The lower ratio of the alpha-rhythm envelope's standard deviation to its mean in the right hemisphere correlated with a higher sense of threat. The EEG and behavioral correlates of emotional impairment in patients with CMI were found.

Pharmacological interventions for apathy in Alzheimer's disease

BACKGROUND

Despite the high prevalence of apathy in Alzheimer's disease (AD), and its harmful effects, there are currently no therapies proven to treat this symptom. Recently, a number of pharmacological therapies have been investigated as potential treatments for apathy in AD.

OBJECTIVES

Objective 1: To assess the safety and efficacy of pharmacotherapies for the treatment of apathy in Alzheimer's disease (AD).Objective 2: To assess the effect on apathy of pharmacotherapies investigated for other primary outcomes in the treatment of AD.

SEARCH METHODS

We searched the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (ALOIS), MEDLINE, Embase, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov and the World Health Organization (WHO) portal, ICTRP on 17 May 2017.

SELECTION CRITERIA

Eligible studies were double-blind, randomized, placebo-controlled trials (RCTs) investigating apathy as a primary or secondary outcome in people with AD.

DATA COLLECTION AND ANALYSIS

Three review authors extracted data. We assessed the risks of bias of included studies using Cochrane methods, and the overall quality of evidence for each outcome using GRADE methods. We calculated mean difference (MD), standardized mean difference (SMD) or risk ratio (RR) with 95% confidence intervals on an intention-to-treat basis for all relevant outcome measures.

MAIN RESULTS

We included 21 studies involving a total of 6384 participants in the quantitative analyses. Risk of bias is very low to moderate. All studies reported appropriate methods of randomization and blinding. Most studies reported appropriate methods of allocation concealment. Four studies, three with methylphenidate and one with modafinil, had a primary aim of improving apathy. In these studies, all participants had clinically significant apathy at baseline. Methylphenidate may improve apathy compared to placebo. This finding was present when apathy was assessed using the apathy evaluation scale (AES), which was used by all three studies investigating methylphenidate: MD -4.99, 95% CI -9.55 to -0.43, n = 145, 3 studies, low quality of evidence, but not when assessed with the neuropsychiatric inventory (NPI)-apathy subscale, which was used by two of the three studies investigating methylphenidate: MD -0.08, 95% CI -3.85 to 3.69, n = 85, 2 studies, low quality of evidence. As well as having potential benefits for apathy, methylphenidate probably also slightly improves cognition (MD 1.98, 95% CI 1.06 to 2.91, n = 145, 3 studies, moderate quality of evidence), and probably improves instrumental activities of daily living (MD 2.30, 95% CI 0.74 to 3.86, P = 0.004, n = 60, 1 study, moderate quality of evidence), compared to placebo. There may be no difference between methylphenidate and placebo in the risk of developing an adverse event: RR 1.28, 95% CI 0.67 to 2.42, n = 145, 3 studies, low quality of evidence. There was insufficient evidence from one very small study of modafinil to determine the effect of modafinil on apathy assessed with the FrSBe-apathy subscale: MD 0.27, 95% CI -3.51 to 4.05, n = 22, 1 study, low quality of evidence. In all other included studies, apathy was a secondary outcome and participants were not selected on the basis of clinically significant apathy at baseline. We considered the evidence on apathy from these studies to be indirect and associated with publication bias. There was low or very low quality of evidence on cholinesterase inhibitors (ChEIs) (six studies), ChEI discontinuation (one study), antipsychotics (two studies), antipsychotic discontinuation (one study), antidepressants (two studies), mibampator (one study), valproate (three studies) and semagacestat (one study).

AUTHORS' CONCLUSIONS

Methylphenidate may demonstrate a benefit for apathy and may have slight benefits for cognition and functional performance in people with AD, but this finding is associated with low-quality evidence. Our meta-analysis is limited by the small number of studies within each drug class, risk of bias, publication bias, imprecision and inconsistency between studies. Additional studies should be encouraged targeting people with AD with clinically significant apathy which investigate apathy as a primary outcome measure, and which have a longer duration and a larger sample size. This could increase the quality of evidence for methylphenidate, and may confirm whether or not it is an effective pharmacotherapy for apathy in AD.

Repetitive transcranial magnetic stimulation for apathy in mild cognitive impairment: A double-blind, randomized, sham-controlled, cross-over pilot study

Apathy is a common and disabling behavioral concomitant of many neurodegenerative conditions. The presence of apathy with Mild Cognitive Impairment (MCI) is linked with heightened rates of conversion to Alzheimer's disease. Improving apathy may slow the neurodegenerative process. The objective was to establish the efficacy of repetitive transcranial magnetic stimulation (rTMS) in improving apathy in older adults with MCI. An 8-week, double-blind, randomized, sham-controlled cross-over study was conducted in nine subjects (66 ± 9 years) with apathy and MCI. Subjects were randomized to rTMS or sham treatment (5 days/week) for 2 weeks following which they underwent a 4-week treatment-free period. Subjects then crossed-over to receive the other treatment for 2 weeks. The primary (apathy (AES-C)) and secondary (cognition (3MS & MMSE), executive function (TMT-A & TMT-B), and clinical global impression (CGI)) outcomes were assessed at baseline, 2, 6, and 8 weeks. After adjusting for baseline, there was a significantly greater improvement in the AES-C with rTMS compared to sham treatment at 2 weeks. There was significantly greater improvement in 3MS, MMSE, TMT-A, and CGI-I with rTMS compared to the sham treatment. This study establishes that rTMS is efficacious in improving apathy in subjects with MCI.

Structural correlates of apathy in Alzheimer's disease: a multimodal MRI study

OBJECTIVE

Apathy is one of the most frequent symptoms of dementia, whose underlying neurobiology is not well understood. The objective was to analyze the correlations of apathy and its dimensions with gray and white matter damage in the brain of patients with advanced Alzheimer's disease (AD).

METHODS

The setting of the study was at the Alzheimer Center Reina Sofía Foundation Research Unit. Participants include 37 nursing home patients with moderate to severe AD, 78.4% were women, and mean Standard Deviation (SD) age is 82.7 (5.8). Several measurements were taken: severe mini-mental state examination and Global Deterioration Scale for cognitive and functional status, Neuropsychiatric Inventory for behavioral problems, and Apathy In Dementia-Nursing Home Version Scale for apathy, including total score and subscores of emotional blunting, deficit of thinking, and cognitive inertia. 3T magnetic resonance imaging measures (voxel-based morphometry, fluid-attenuated inversion recovery, and diffusion tensor imaging) were also conducted.

RESULTS

Moderate levels of apathy (mean Apathy In Dementia-Nursing Home Version Scale: 31.1 ± 18.5) were found. Bilateral damage to the corpus callosum and internal capsule was associated with apathy severity (cluster size 2435, p < 0.0005, family-wise error [FWE]-corrected). A smaller and more anteriorly located region of the right internal capsule and corpus callosum was associated with higher emotional blunting (cluster size 334, p < 0.0005, FWE-corrected). Ischemic damage in the right periventricular frontal region was associated with higher deficit of thinking (cluster size 3805, p < 0.005, FWE-corrected).

CONCLUSIONS

Brain damage related to apathy may have different features in the advanced stages of AD and differs between the three apathy dimensions. Besides atrophy, brain connectivity and vascular lesions are relevant in the study of apathy, especially in the more severe stages of dementia. Further magnetic resonance imaging studies should include multimodal techniques. Copyright © 2016 John Wiley & Sons, Ltd.

Neural Correlates for Apathy: Frontal-Prefrontal and Parietal Cortical- Subcortical Circuits

Apathy is an uncertain nosographical entity, which includes reduced motivation, abulia, decreased empathy, and lack of emotional involvement; it is an important and heavy-burden clinical condition which strongly impacts in everyday life events, affects the common daily living abilities, reduced the inner goal directed behavior, and gives the heaviest burden on caregivers. Is a quite common comorbidity of many neurological disease, However, there is no definite consensus on the role of apathy in clinical practice, no definite data on anatomical circuits involved in its development, and no definite instrument to detect it at bedside. As a general observation, the occurrence of apathy is connected to damage of prefrontal cortex (PFC) and basal ganglia; “emotional affective” apathy may be related to the orbitomedial PFC and ventral striatum; “cognitive apathy” may be associated with dysfunction of lateral PFC and dorsal caudate nuclei; deficit of “autoactivation” may be due to bilateral lesions of the internal portion of globus pallidus, bilateral paramedian thalamic lesions, or the dorsomedial portion of PFC. On the other hand, apathy severity has been connected to neurofibrillary tangles density in the anterior cingulate gyrus and to gray matter atrophy in the anterior cingulate (ACC) and in the left medial frontal cortex, confirmed by functional imaging studies. These neural networks are linked to projects, judjing and planning, execution and selection common actions, and through the basolateral amygdala and nucleus accumbens projects to the frontostriatal and to the dorsolateral prefrontal cortex. Therefore, an alteration of these circuitry caused a lack of insight, a reduction of decision-making strategies, and a reduced speedness in action decision, major responsible for apathy. Emergent role concerns also the parietal cortex, with its direct action motivation control. We will discuss the importance of these circuits in different pathologies, degenerative or vascular, acute or chronic.

Structural MRI correlates of apathy symptoms in older persons without dementia: AGES-Reykjavik Study

OBJECTIVE

We aimed to investigate the relation between apathy symptoms and structural brain changes on MRI, including white matter lesions (WMLs) and atrophy, in a large cohort of older persons.

METHODS

Cross-sectional analyses are based on 4,354 persons without dementia (aged 76 ± 5 years) participating in the population-based Age, Gene/Environment Susceptibility-Reykjavik Study. Apathy symptoms were assessed with 3 items from the 15-item Geriatric Depression Scale. Brain volumes and total WML volume were estimated on 1.5-tesla MRI using an automated segmentation program; regional WML load was calculated using a semiquantitative scale. Regression analyses were adjusted for age, sex, education, intracranial volume, vascular risk factors, physical activity, brain infarcts, depressive symptoms, antidepressants, and cognitive status.

RESULTS

Compared to those with <2 apathy symptoms, participants with ≥ 2 apathy symptoms (49% of the cohort) had significantly smaller gray matter volumes (mean adjusted difference -3.6 mL, 95% confidence interval [CI] -6.2 to -1.0), particularly in the frontal and temporal lobes; smaller white matter volumes (mean adjusted difference -1.9 mL, 95% CI -3.6 to -0.3), mainly in the parietal lobe; and smaller thalamus volumes. They were also more likely to have WMLs in the frontal lobe (adjusted odds ratio = 1.08, 95% CI 0.9-1.3). Excluding participants with a depression diagnosis did not change the associations.

CONCLUSIONS

In this older population without dementia, apathy symptoms are associated with a more diffuse loss of both gray and white matter volumes, independent of depression.

Vascular factors and epigenetic modifications in the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is a debilitating illness with no known cure. Nowadays accumulating evidence suggested that the vascular endothelium and chronic hypoperfusion may play important role in pathobiology of AD. The vascular endothelium which regulates the passage of macromolecules and circulating cells from blood to tissue, is a major target of oxidative stress, playing a critical role in the pathophysiology of vascular diseases. Since the vascular endothelium, neurons and glia are all able to synthesize, store and release reactive oxygen species (ROS) and vascular active substances in response to certain stimuli, their contribution to the pathophysiology of AD can be very important. New evidence indicates that continuous formation of free ROS induces cellular damage and decreases antioxidant defenses. Specifically, oxidative stress increases vascular endothelial permeability and promotes leukocyte adhesion. We summarize the reports that sporadic, late-onset of AD results from vascular etiology. Recently an involvement of epigenetic alterations in the etiology of AD is also intensively investigated. Gaining a more complete understanding of the essential components and underlying mechanisms involved in epigenetic regulation could lead to novel treatments for a number of neurological and psychiatric conditions.

Association between subcortical lesions and behavioral and psychological symptoms in patients with Alzheimer's disease

BACKGROUND/AIMS

The most devastating features of Alz-heimer's disease (AD) are often the behavioral and psychological symptoms in dementia (BPSD). There is controversy as to whether subcortical lesions contribute to BPSD. The aim of this study was to examine the relationship between BPSD and subcortical lesions (white-matter lesions and lacunes) in AD.

METHODS

CT or MRI from 259 patients with mild-to-moderate AD were assessed with the Age-Related White Matter Changes scale. Linear measures of global and temporal atrophy and Mini-Mental State Examination scores were used to adjust for AD pathology and disease severity in logistic regression models with the BPSD items delusions, hallucinations, agitation, depression, anxiety, apathy and irritability.

RESULTS

Lacunes in the left basal ganglia were associated with delusions (OR 2.57, 95% CI 1.21-5.48) and hallucinations (OR 3.33, 95% CI 1.38-8.01) and lacunes in the right basal ganglia were associated with depression (OR 2.13, 95% CI 1.01-4.51).

CONCLUSION

Lacunes in the basal ganglia resulted in a 2- to 3-fold increased risk of delusions, hallucinations and depression, when adjusting for cognition and atrophy. This suggests that basal ganglia lesions can contribute to BPSD in patients with AD, independently of the AD process.

Different associations of periventricular and deep white matter lesions with cognition, neuropsychiatric symptoms, and daily activities in dementia

We investigated the associations of periventricular white matter hyperintensities (PWMHs) and deep white matter hyperintensities (DWMHs) with cognition, activities of daily living (ADLs), and neuropsychiatric symptoms in dementia. This was a hospital-based MRI300 study. We recruited patients newly diagnosed with mild-to-moderate dementia caused either by Alzheimer's disease or subcortical ischemic vascular dementia from 13 dementia clinics at university or general hospitals in South Korea. We enrolled 289 patients aged over 50 from August 2007 to March 2008. We compared cognition, ADLs, and neuropsychiatric symptoms among 3 groups according to the severities of PWMHs and DWMHs, respectively, by adjusting for age, vascular risk factors, and level of other WMHs. A higher severity of PWMHs was related to lower cognitive function and severer neuropsychiatric symptoms, whereas basic ADLs were associated with DWMH. Both PWMHs and DWMHs exhibited different associations with cognition, neuropsychiatric symptoms, and daily activities.

Neuropsychiatric correlates of white matter hyperintensities in Alzheimer's disease

OBJECTIVE

To investigate the association of behavioral and psychological symptoms of dementia (BPSD) in Alzheimer's disease (AD) and magnetic resonance imaging (MRI) measures of brain atrophy and white matter hyperintensities (WMH).

METHODS

Thirty-seven patients with probable AD received the Neuropsychiatric Inventory (NPI), the Mini Mental Status Exam (MMSE), and an MRI scan as part of their initial evaluation at the Outpatient Memory Diagnostic Clinic at McLean Hospital. MRI-based volumetric measurements of whole brain atrophy, hippocampal volumes, and WMH were obtained. Analysis of covariance models, using age as a covariate and the presence of specific BPSD as independent variables, were used to test for differences in whole brain volumes, hippocampal volumes and WMH volumes.

RESULTS

Increased WMH were associated with symptoms of anxiety, aberrant motor behavior, and night time disturbance, while symptoms of disinhibition were linked to lower WMH volume. No associations were found for whole brain or hippocampal volumes and BPSD.

CONCLUSIONS

These findings suggest that white matter changes are associated with the presence of BPSD in AD.

Brazilian caregiver version of the Apathy Scale

No Brazilian version of a specific scale for evaluating apathy in dementia is available.

[Neuropsychiatric symptoms in mild cognitive impairment and Alzheimer's disease]

INTRODUCTION

To describe the neuropsychiatric symptoms (NPS) in elderly patients with either mild cognitive impairment (MCI) or Alzheimer's disease (AD) and their relevance in the differential diagnosis between the two entities.

MATERIAL AND METHODS

A total of 179 subjects, aged more than 64 years old, with either MCI (n=90) or AD (n=89) and Global Deterioration Scale stage 4-5 were studied. NPS were assessed using the Neuropsychiatric Inventory scale. We identified the prevalence of the symptoms in each group and determined the risk conferred by each symptom to the differential diagnosis between the two entities.

RESULTS

Sixty-seven patients with MCI (74.4%) and 82 with AD (92.1%) showed at least one NPS (p<0.01), the most prevalent being depression and apathy in both groups. The mean number of NPS was 2.1 in MCI and 3.2 in AD. NPS were more frequent in patients with more white matter ischemic lesions (WMIL) (p<0.05). The presence of at least one NPS increased the risk of being diagnosed with AD rather than MCI (odds ratio [OR] 3.6: 95% confidence interval [CI] 1.4-5.7; p<0.01) adjusted by age, sex, Mini-Mental State Examination and WMIL. The NPS independently associated with a diagnosis of AD were delusions (OR 4.9; 95% CI 1.3-18.6; p<0.05), apathy (OR 2.5; 95% CI 1.3-4.7 p<0.01), disinhibition (OR 3.1; 95% CI 1.5-6.4; p<0.01) and aberrant motor behavior (OR 6.3; 95% CI 1.7-23.4; p<0.01).

CONCLUSIONS

NPS are frequent in elderly individuals with MCI and mild-moderate AD and may help to differentiate between these two entities.

Neurobiology of apathy in Alzheimer's disease

Apathy is considered the most frequent neuropsychiatric disturbance in dementia and its outcome is generally deleterious. Apathy can be related to a dysfunction of the anatomical-system that supports the generation of voluntary actions, namely the prefrontal cortex and/or the prefrontal-subcortical circuits. In Alzheimer's disease, pathological and neuroimaging data indicate that apathy is likely due to a dysfunction of the medial prefrontal cortex. Accordingly, in this review article, we propose a pathophysiological model to explain apathetic behavior in Alzheimer's disease, combining data from neuroimaging, neuropathology and experimental research on the role of orbito-frontal cortex, anterior cingulate cortex, basal ganglia and dopamine in decision-making neurobiology.

Impact of cerebrovascular pathology on behavioural and neuropsychiatric symptoms in patients with Alzheimer's dementia: findings from a retrospective, naturalistic study

AIM

Cerebrovascular disease (CVD) has been associated with depression and a host of neuropsychiatric conditions including dementia. This study assessed the relationship between cerebrovascular findings reported on MRI brain scans and neuropsychiatric symptoms (NPS) and behavioural problems in patients with Alzheimer's disease (AD).

METHODS

Medical notes were retrospectively reviewed in patients undergoing brain MRI following referral for cognitive impairment to a memory clinic between January 2004 and June 2008. Patients with AD were graded into four categories of CVD severity based on neuroradiology reports and assessed for behavioural and NPS and activities of daily living using Neuropsychiatric Inventory (NPI), Geriatric Depression Scale (GDS) and Bristol Activities of Daily Living (BADL). Frontal lobe symptoms and parkinsonian features were also evaluated.

RESULTS

Of the initial 232 patients who underwent MRI 72% were diagnosed with AD. 89% of AD patients had CVD findings reported on MRI. Moderate-to-severe CVD was present in 47% of patients. None of the AD patients satisfied a diagnosis of vascular dementia. There was no significant relationship observed between level of MRI CVD findings and scores on NPI (p = 0.57), GDS (p = 0.26) and BADL (p = 0.46). The level of CVD severity did not appear to influence frontal lobe and parkinsonian assessments (p = 0.60).

CONCLUSION

The contribution of CVD to the pathogenesis of various NPS is still debated. Our study, based on patients diagnosed with AD in a memory clinic setting, suggests that there is no relationship between the extent of CVD pathology and neuropsychiatric and behavioural measures in AD patients. Further prospective quantitative studies are needed to assess the role of CVD, if any, in neuropsychiatric and behavioural symptoms in AD. It is possible that the relatively small pathological contribution of CVD to the development of these symptoms is obscured by the effect of the wider neurodegeneration encountered in AD.

Leukoaraiosis and pulse-wave encephalopathy: observations with phase-contrast MRI in mild cognitive impairment

PURPOSE

To test the pathogenic hypothesis of a breakdown in the vital buffering of the arterial pulsations behind leukoaraiosis (LA) in mild cognitive impairment (MCI).

METHODS

Seventy-one elderly patients with MCI underwent a combined structural and dynamic MR examination (3D T1-weighted and fast-FLAIR T2-weighted sequences, phase contrast sequences). Arterial indices of pulsatility (IP) and composite indicators of the amplitude transfer function between cerebrospinal fluid and cerebral venous flow (Icsf/veins) were used to assess the large artery stiffness and the intracranial compliance respectively. Cerebral total arterial blood flow (tCBF), superficial and deep venous flow rates were also measured. Intracranial dynamic parameters and potential confounders including age, gender and vascular risk factors were compared between two groups respectively with and without significant LA.

RESULTS

The only dynamic changes on multivariate analyse were an IP increase, a lowering of deep venous outflow and Icsf/veins in patients with LA. There was a significant interaction between IP and Icsf/veins in the logistic regression: as compared with patients with low IP (suggestive of high large artery compliance) and high Icsf/veins (suggestive of high intracranial compliance), the adjusted odds ratios for the presence of LA were 9 (95% CI 1-64, P=0.02) in cases of both high IP and Icsf/veins, 10 (95% CI 1-64, P=0.02) in cases of both high IP and low Icsf/veins and 19 (95% CI 3-127, P=0.002) in cases of both low IP and Icsf/veins.

CONCLUSION

LA may reflect an arteriosclerotic and/or resistive pulse wave encephalopathy in MCI.

Cerebral white matter: neuroanatomy, clinical neurology, and neurobehavioral correlates

Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord. Lesions of association fibers prevent communication between cortical areas engaged in different domains of behavior. Lesions of subcortical structures or projection/striatal fibers disrupt the contribution of subcortical nodes to behavior. Disconnection syndromes thus result from lesions of the cerebral cortex, subcortical structures, and WM tracts that link the nodes that make up the distributed circuits. The nature and the severity of the clinical manifestations of WM lesions are determined, in large part, by the location of the pathology: discrete neurological and neuropsychiatric symptoms result from focal WM lesions, whereas cognitive impairment across multiple domains--WM dementia--occurs in the setting of diffuse WM disease. We present a detailed review of the conditions affecting WM that produce these neurobehavioral syndromes, and consider the pathophysiology, clinical effects, and broad significance of the effects of aging and vascular compromise on cerebral WM, in an attempt to help further the understanding, diagnosis, and treatment of these disorders.

Vascular factors and risk for neuropsychiatric symptoms in Alzheimer's disease: the Cache County Study

OBJECTIVE

To examine, in an exploratory analysis, the association between vascular conditions and the occurrence of neuropsychiatric symptoms (NPS) in a population-based sample of incident Alzheimer's disease (AD).

METHODS

The sample consisted of 254 participants, identified through two waves of assessment. NPS were assessed using the Neuropsychiatric Inventory. Prior to the onset of AD, data regarding a history of stroke, hypertension, hyperlipidemia, heart attack or coronary artery bypass graft (CABG), and diabetes were recorded. Logistic regression procedures were used to examine the relationship of each vascular condition to individual neuropsychiatric symptoms. Covariates considered were age, gender, education, APOE genotype, dementia severity, and overall health status.

RESULTS

One or more NPS were observed in 51% of participants. Depression was most common (25.8%), followed by apathy (18.6%), and irritability (17.7%). Least common were elation (0.8%), hallucinations (5.6%), and disinhibition (6.0%). Stroke prior to the onset of AD was associated with increased risk of delusions (OR = 4.76, p = 0.02), depression (OR = 3.87, p = 0.03), and apathy (OR = 4.48, p = 0.02). Hypertension was associated with increased risk of delusions (OR = 2.34, p = 0.02), anxiety (OR = 4.10, p = 0.002), and agitation/aggression (OR = 2.82, p = 0.01). No associations were observed between NPS and diabetes, hyperlipidemia, heart attack or CABG, or overall health.

CONCLUSIONS

Results suggest that a history of stroke and hypertension increase the risk of specific NPS in patients with AD. These conditions may disrupt neural circuitry in brain areas involved in NPS. Findings may provide an avenue for reduction in occurrence of NPS through the treatment or prevention of vascular risk conditions.

White matter changes in dementia: does radiology matter?

White matter changes are frequently seen on MRI in elderly patients. The significance of these changes is still debated. The origin of white matter changes is heterogeneous but the majority are due to arteriosclerosis in brain vessels. The clinical consequence of the presence of white matter changes in relation to dementia is still unclear. Lately, however, many studies have found a relation between the presence and the degree of white matter changes and cognitive dysfunction. This is most obvious in vascular dementia, but has also been suggested to be of importance in Alzheimer's disease. In this review we discuss the background of these changes and the clinical consequences of them in relation to cognitive disorders.

Cerebral blood flow by using pulsed arterial spin-labeling in elderly subjects with white matter hyperintensities

BACKGROUND AND PURPOSE

On MR imaging, white matter hyperintensities (WMH) on T2-weighted images are generally considered as a surrogate marker of ischemic small vessel disease in elderly subjects. Pulsed arterial spin-labeling (PASL) is a noninvasive MR perfusion-weighted technique. We hypothesized that elderly subjects with diffuse confluent WMH should have lower cerebral blood flow (CBF) measurements than subjects with punctiform or beginning confluent WMH.

MATERIALS AND METHODS

MR images of 21 subjects (13 women; mean age, 76 years; SD, 5), stratified for the degree of WMH, from a single center within the multinational Leukoaraiosis and Disability (LADIS) study, were investigated. CBF images were obtained by means of quantitative imaging of perfusion by using a single-subtraction second version, with thin-section TI periodic saturation PASL. Values of cortical gray matter, subcortical (including white matter and deep gray matter), and global CBF were calculated. CBF measurements of subjects with diffuse confluent WMH (n = 7) were compared with those of subjects with punctiform or beginning confluent WMH (n = 14).

RESULTS

Subjects with diffuse confluent WMH were found to have approximately 20% lower mean global CBF (43.5 mL/100 mL/min; SD, 6.3) than subjects with punctiform or beginning confluent WMH (57.9 mL/100 mL/min; SD, 8.6; P < .01), as well as approximately 20% lower mean subcortical (P < .01) and cortical gray matter CBF (P < .05).

CONCLUSION

PASL revealed a significant reduction of CBF measurements in elderly subjects with diffuse confluent WMH.

Behavioural and psychological symptoms are not related to white matter hyperintensities and medial temporal lobe atrophy in Alzheimer's disease

BACKGROUND

The neuropathology of behavioural and psychological symptoms is much less understood than the neuropathology of cognitive impairment in AD. On MRI, medial temporal lobe atrophy (MTA) is presumed to reflect Alzheimer- type pathology. White matter hyperintensities (WMH) are considered markers of vascular pathology.

AIM

We investigated differences in prevalence of behavioural and psychological symptoms in AD according to the presence of MTA and WMH on MRI.

METHODS

Behavioural and psychological symptoms of 111 consecutive AD patients were assessed using the Neuropsychatric Inventory (NPI). Symptoms were considered present when the score was > or =1. On MRI, MTA was rated using the five-point Scheltens-scale and WMH using the four-point Fazekas-scale. Both MRI measures were dichotomised (MTA: absent 0/1, present 2-4; WMH absent 0/1, present 2/3).

RESULTS

Of the 111 AD patients, 60(55%) had MTA, and 32(29%) had WMH. The presence of MTA was associated with the presence of WMH (chi (2) = 11.8, p < 0.001). The prevalence of behavioural and psychological symptoms--defined as a NPI score of > or =1 on at least one symptom--was 74%.The median NPI score of the total study population was 6(0-41). There was no difference in prevalence according to MTA (p = 0.53) or WMH (p = 0.18). On inspection of individual NPI items, neither MTA, nor WMH was related to any of the symptoms.

CONCLUSIONS

There were no differences in prevalence of behavioural and psychological symptoms according to MTA or WMH, as rated on MRI. This suggests that the occurrence of those symptoms depends on other determinants, such as coping style or genetic make-up.

Physical activity and cognition in Alzheimer's disease: relationship to vascular risk factors, executive functions and gait

Epidemiological studies show a positive relationship between physical activity and cognition in patients with Alzheimer's disease (AD). A relatively small number of intervention studies have examined the effects of physical activity, such as walking, on cognition in AD patients. The results of these studies, reviewed here, include both positive and negative findings. The finding that physical activity does not improve cognition in all AD patients could be explained by two factors that have received little attention thus far: executive dysfunction and gait disturbances. These two factors are part of a cascade of events, initiated by cerebrovascular disease in AD. This cascade of events is addressed in detail. Finally, (non)pharmacological interventions to improve executive dysfunctions and gait disturbances in patients with AD are discussed.

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.

Gait in ageing and associated dementias; its relationship with cognition

The focus of this review is on the close relationship between gait and cognition in ageing and associated dementias. This close relationship is supported by epidemiological studies, clinical studies of older people with and without dementia that focused on the intensity of the physical activity, clinical studies with older persons without dementia examining a relationship between gait and specific cognitive processes, and human and animal experimental studies examining a neural basis for such a relationship. Despite these findings, most studies with patients with dementia focus exclusively on the relationship between cognition and dementia, with relatively few addressing the relationship between gait and dementia. However, subtle disturbances in gait can be observed in ageing and in (preclinical) subtypes of dementia that are not known for prominent motor disturbances, i.e. Mild Cognitive Impairment, Alzheimer's Disease, vascular Cognitive Impairment No Dementia, Subcortical Ischaemic Vascular Dementia, Frontotemporal Mild Cognitive Impairment, and Frontotemporal Dementia, supporting a close relationship between gait and cognition. The relationship between gait and cognition is weakened by the few available intervention studies that examine the effects of walking on cognition in patients with (preclinical) dementia. These studies report equivocal results, which will be discussed. Finally, suggestions for future research will be made.

Locus ceruleus degeneration is ubiquitous in Alzheimer's disease: Possible implications for diagnosis and treatment

Degeneration of the locus ceruleus (LC) and decreased cortical levels of norepinephrine are common findings in Alzheimer's disease (AD), but their significance is unknown. Because the noradrenergic system is accessible to pharmacological intervention, the role of LC degeneration and noradrenergic dysfunction in the pathogenesis and clinical manifestations of AD needs clarification. Hypothetically, loss of noradrenergic innervation could cause microvascular dysfunction and manifest as ischemia. The objectives of this study were to develop a scale for assessment of LC degeneration and to determine whether degeneration of the LC correlates quantitatively with either duration of clinical dementia, overall severity of AD pathology or with measures of ischemic non-focal white matter disease (WMD) in AD. This report is a pathological follow-up of a clinical longitudinal dementia study of 66 consecutive cases of AD without admixture of vascular dementia (VaD) from the Lund Longitudinal Dementia Study, neuropathologically diagnosed between 1990 and 1999. Ten cases of VaD were included for comparative purposes. No correlation between degree of LC degeneration and duration of dementia, AD or WMD severity was found. LC degeneration was significantly more severe in the AD group than in the VaD group. Even though LC degeneration was not associated with WMD or the severity of AD pathology in this AD material, we suggest that clinical studies on the consequences of noradrenergic dysfunction are warranted. Treatment augmenting noradrenergic signaling is available and safe. The marked difference in the level of LC degeneration between AD and VaD cases suggests that LC degeneration could be used as a diagnostic marker of AD.

Lack of initiative and interest in Alzheimer's disease: a single photon emission computed tomography study

Apathy is defined as a lack of motivation. The aim of this study was to investigate the relation between two major dimensions of apathy (lack of initiative and lack of interest) and brain perfusion. in patients with Alzheimer's disease (AD). Brain perfusion was measured by single photon emission tomography (SPECT). Thirty-one AD patients were included. Lack of initiative and interest were assessed with the Apathy Inventory. Nineteen AD subjects presented a lack of initiative and interest pathological score whereas 12 AD subjects did not. The lack of initiative and interest score correlated significantly with the right frontal and the right inferior temporal lobes. The AD patients with lack of initiative and interest showed a significantly lower perfusion in the right anterior cingulate than the AD patients without lack of initiative and interest. These results derive from rather small subgroups of patients but have the interest to dismantle the complementary aspects of emotion and motivation in apathy and suggest that the latter one is more related to cingulate area.

CT perfusion as a useful tool in the evaluation of leuko-araiosis

Background

Leuko-araiosis (LA) and dementia are common geriatric conditions but their pathogenesis and clinical significance are not completely understood. An evaluation of CT perfusion (CTP) in both these conditions can further enhance the understanding of these diseases.

Methods

Twenty-one patients with LA and 21 age-matched controls were studied with CTP and assessed for their cognitive function. The subjects were classified into four groups: Group 1, with LA (n = 21); Group 2, without LA (n = 21); Group 3, with dementia (n = 7); Group 4, without dementia (n = 11). The mean cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) values were compared between groups 1 and 2, while mean CBF values were compared between groups 3 and 4.

Results

Mean white matter CBF was considerably reduced in patients with LA in the frontal region by 42% (p = 0.000), basal ganglia by 37% (p = 0.000) and occipital region by 18% (p = 0.019). The mean white matter CBV was reduced in patients with LA in the frontal region by 36% (p = 0.000) and basal ganglia by 28% (p = 0.017). The mean white matter CBF was dramatically reduced in patients with dementia in the frontal region by 44% (p = 0.000), basal ganglia by 32% (p = 0.038) and occipital regions by 24% (p = 0.001).

Conclusion

The CTP showed reduced white matter CBF and CBV in patients with LA. This is consistent with chronic ischemia as the pathogenesis of LA. The CTP is also a potentially important technique in the diagnosis and management of dementia, because of its ability to reveal cerebral hypoperfusion.

Alzheimer's disease: role of size and location of white matter changes in determining cognitive deficits

This study investigated the contribution that white matter changes (WMCs) make to clinical and cognitive features in Alzheimer's disease (AD), independently of possible confounders such as cortical atrophy and the apolipoprotein E genotype as well as their relationship to vascular risk factors. We semiquantitatively assessed the degree and location of WMCs (global, periventricular and deep white matter), lacunes and global atrophy on brain MRI scans of 86 AD cases, extensively evaluated from a clinical and neuropsychological point of view. Multivariate logistic and linear regression analysis showed that age was the only significant predictor of all WMC measures and revealed a significant association of periventricular WMCs with performance on executive function tasks as well as of deep WMCs with history of mood depression. Our results underline the significance of WMC location over size in the occurrence of specific cognitive deficits in AD.

Clinical significance of subcortical vascular disease in patients with mild cognitive impairment

Patients with mild cognitive impairment (MCI) typically present with memory complaints. Some of these patients have subcortical vascular disease on computed tomography (CT) scan, namely white matter changes and lacunar infarcts, however it is not known whether these findings are associated with more pronounced cognitive deficits. In the present study we compare demographic, clinical and neuropsychological characteristics of MCI patients according to the presence or the absence of subcortical vascular disease. Forty consecutive patients with memory complaints, at least one neuropsychological memory test below 1 SD the normal for age and education, and maintained activities of daily living, were included. Patients with dementia, history of stroke or transient ischemic attack, or other brain disorders, were excluded. Twenty-five (62.5%) patients with MCI had no ischemic lesions on CT scan, and 15 (37.5%) were found to have subcortical vascular changes. MCI patients with subcortical vascular changes were older (77.1 +/- 6.8 vs. 70.8 +/- 7.5 years old), and more often males. The number of vascular risk factors, the frequency of neurological signs, the Hachinski score and the neuropsychological tests scores were not significantly different. The presence of subcortical vascular disease on CT scan is frequent in older patients with MCI, but does not appear to be associated with the severity of cognitive deficits.

White matter hyperintensities are significantly associated with cortical atrophy in Alzheimer's disease

BACKGROUND AND OBJECTIVE

Methodological variability in the assessment of white matter hyperintensities (WMH) in dementia may explain inconsistent reports of its prevalence and impact on cognition. We used a method of brain MRI segmentation for quantifying both tissue and WMH volumes in Alzheimer's disease (AD) and examined the association between WMH and structural and cognitive variables.

METHODS

A consecutive series of 81 patients meeting NINCDS-ADRDA criteria for probable AD was studied. Nineteen healthy volunteers of comparable age served as the control group. Patients had a complete neurological and neuropsychological evaluation, and a three dimensional MRI was obtained. Images were segmented into grey matter, white matter, and cerebrospinal fluid. WMH were edited on segmented images, and lobar assignments were based on Talairach coordinates.

RESULTS

Mild and moderate to severe AD patients had significantly more WMH than controls (p<0.05). WMH preferentially involved the frontal lobes (70%), were inversely correlated with grey matter cortical volume (R(2) = 0.23, p<0.001), and were significantly associated with vascular risk factors and with a worse performance on memory tasks.

CONCLUSION

Objective measurements of tissue volumes in AD demonstrated that WMH are significantly related to cortical atrophy and neuropsychological impairment.

[Loss of motivation and frontal dysfunction. Role of the white matter change]

Since the recognition of white matter changes on computed tomography, researches were done to investigate a possible relation with ageing and cognition. This study examined whether computed tomography evidence of cerebrovascular disease in the form of white matter changes was associated with decreased implicit performance of frontal tests and with a loss of motivation in a group of 10 elderly volunteers with a mild cognitive impairment and in a group of 29 demented patients; 39 old patients (28 females: 82.4 +/- 7.1; 10 males: 75.5 +/- 11.3) cared in a psycho-geriatric day care hospital were enrolled for this essay. Motivation was evaluated with a specific scale: EAD. Patients were tested during the same period with MMSE for cognition, Cornell's scale for depression, Marin's scale for apathy. There were also assessed with a battery of frontal tests: BREF test. A brain scan was used to determinate the presence of leukoaraïosis. Table 1 give a description of the population according to the pathology. Cognitive disorder, but also apathy and loss motivation, frontal evaluation significantly differ in the two studied groups. The presence of a leukoaraïosis is associated with older people, a weaker cognitive status, a more important apathy or loss of motivation, and weaker results with frontal evaluation (table 2). Similar results were obtained considering only the frontal lesions (table 3). Age related changes of the white matter observed on computed tomography were associated with a decreased cognitive status. Leukoaraïosis is associated with loss of motivation and related with a poor results on frontal assessment. Loss of motivation is associated with certain frontal dysfunctions and with brain abnormal scan anomalies.

The role of cerebrovascular disease in dementia

BACKGROUND

Improvements in health care over the last 50 years have lengthened average life expectancy significantly, resulting in considerable growth of the population over 65 years of age. With increased age, however, comes an increased risk for Alzheimer's disease (AD), and the prevalence of AD is predicted to reach epidemic proportions by the later half of the 21st century. The prevalence of cerebrovascular disease also increases with age, and recent evidence suggests that cerebrovascular risk factors such as hypertension and hypercholesterolemia also increase an individual's risk for AD, suggesting a potential interaction between these two very common disorders. The potential impact of cerebrovascular disease on general cognitive health is not yet well understood, but is now being actively explored and clarified.

REVIEW SUMMARY

Cerebrovascular disease may manifest itself in many ways, and this review begins by discussing the possible spectrum of brain injury associated with common cerebrovascular risk factors. The prominent role of brain imaging to detect clinically silent cerebrovascular disease is recognized and reviewed. The neuropsychological consequences of cerebrovascular disease across the cognitive spectrum is also reviewed, including potential mechanisms by which cerebrovascular disease may interact with AD to increase the expression or hasten the progression of dementia.

CONCLUSIONS

Cerebrovascular risk factors, common to the elderly, lead to pernicious brain injury and subtle cognitive impairment that most probably places the individual at greater lifetime risk for dementia. The cause of dementia among individuals with cerebrovascular disease, however, remains AD. Recognition of the potential role of cerebrovascular disease as an independent risk factor for AD offers the possibility of primary prevention through treatment of well-recognized risk factors and deserves further study. In the meantime, clinicians presented with an individual suffering from a slowly progressive dementia and findings of clinically silent cerebrovascular brain injury should recognize the potential role of cerebrovascular disease in the dementia process but not ignore the likely overwhelming effects of AD and treat appropriately.

Prognostic significance of white matter changes in a memory clinic population

Non-specific white matter changes (WMC) can be seen on neuroimaging of the brain in healthy elderly but are more common in dementia. WMC are correlated to specific cognitive deficits and might also contribute to global cognitive decline. The value of WMC as a predictor of cognitive impairment has been incompletely elucidated. We studied the prognostic significance of extensive WMC in a group of patients with memory disturbances, to evaluate if the presence of such changes predicts a poorer outcome. We retrospectively selected a group of 24 patients with prominent WMC on magnetic resonance imaging (MRI) and with different grades of memory impairment. We matched each patient, with regard to age, education, length of follow-up, initial score on the Mini Mental State Examination (MMSE) and initial diagnosis, to a patient without white matter pathology. The matched pairs were evaluated and the decrease in MMSE score after follow-up (range 2-4 years) was used as the outcome measure. Results showed no difference in the decrease in MMSE score at follow-up between patients with or without WMC. In conclusion, the presence of WMC in cognitively impaired patients had no effect on the progression rate of dementia, as measured by MMSE decline.

Cerebral white matter abnormalities and lifetime cognitive change: a 67-year follow-up of the Scottish Mental Survey of 1932

Cerebral white matter abnormalities relate to cognitive functioning in elders. We examine whether this association is (a) independent of mental ability in youth and (b) related to general and/or specific mental abilities. We retested 83 participants of the Scottish Mental Survey of 1932 on a battery of mental tests. Their brains were scanned by magnetic resonance imaging. Three independent ratings (Fazekas) were made of periventricular, and subcortical and deep white matter abnormalities. Structural equation models showed that, irrespective of brain location, white matter abnormalities contributed about 14% of cognitive function variance in old age. Some of this effect might be due to hypertension. This contribution is independent of mental function in early life and is associated with general cognitive ability.