[Impact of combined medial temporal atrophy and white matter lesions on the cognitive and emotional functions in Alzheimer's disease patients]

The neurobiology of apathy in depression and neurocognitive impairment in older adults: a review of epidemiological, clinical, neuropsychological and biological research

Apathy is a common condition that involves diminished initiative, diminished interest and diminished emotional expression or responsiveness. It is highly prevalent in the context of a variety of neuropsychiatric disorders and is related to poor health outcomes. Presence of apathy is associated with cognitive and functional decline in dementia. Despite its negative impact on health, there is no definitive treatment for apathy, a clinical reality that may be due in part to lack of knowledge about assessment, neuropsychological features and neurobiological underpinnings. Here, we review and synthesize evidence from clinical, epidemiological, neuropsychological, peripheral biomarker and neuroimaging research. Apathy is a common feature of depression and cognitive disorders and is associated with impairment in executive function. Neuropsychological and neuroimaging studies point to dysfunction of brain circuitry involving the prefrontal cortex, especially the dorsolateral prefrontal cortex circuit, the dorsomedial prefrontal cortex circuit, and the ventromedial prefrontal cortex circuit. However, inconsistent findings, particularly in neuroimaging may be due to heterogeneity of apathy symptoms (with a need to better elucidate subtypes), neuropsychiatric comorbidities, the severity of cognitive impairment and other factors. These factors need to be accounted for in future studies so that biomarker research can make progress. On the whole, the literature on apathy has identified likely neurocognitive, peripheral biomarker and neuroimaging targets for understanding apathy, but also points to the need to address methodological issues that will better inform future studies. In turn, as we learn more about the underpinning of apathy and its subtypes, subsequent research can focus on new neurally based interventions that will strengthen the clinical management of apathy in the context of its comorbidities.

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.

Amplitude of low-frequency fluctuations on Alzheimer's disease with depression: evidence from resting-state fMRI

Background

The prevalence of Alzheimer’s disease (AD) comorbid with depression is common. However, the mechanisms of AD with depression remain unclear.

Aims

To investigate the regional alterations of brain activity of AD with depression in resting-state functional magnetic resonance imaging (rs-fMRI).

Methods

154 patients with AD who met the inclusion criteria were recruited from the Zhejiang Provincial People’s Hospital from October 2014 to October 2016. According to whether the core symptoms of depression were present, patients were divided into two groups, 22 patients with AD with depression (AD-D) and 52 patients with AD without depression (AD-nD). The amplitude of low frequency fluctuations (ALFF) was compared between two groups by performing independent-samples t-test.

Results

Compared with the AD-D group, increased ALFF values in the bilateral superior frontal gyrus, left middle frontal gyrus and left inferior frontal gyrus were observed in the AD-nD group. The brain activity in the AD-nD group in the bilateral superior frontal gyrus, left middle frontal gyrus and the left inferior frontal gyrus was higher than the AD-D group.

Conclusions

Resting-state brain functional alterations may be closely bound up with the pathophysiologic features of patients with AD with depressive symptoms.

Influence of cerebral white matter hyperintensities on cognitive impairment in elderly medical patients

AIM

We investigated the characteristics of elderly medical patients with white matter hyperintensities on magnetic resonance imaging.

METHODS

A total of 213 patients (123 men and 90 women; mean age 74.8 years) reported their history of hypertension, diabetes, dyslipidemia, previous stroke, coronary heart disease and chronic kidney disease (CKD). All patients completed the Mini-Mental State Examination and Geriatric Depression Scale. White matter hyperintensities were evaluated for the periventricular region, basal ganglia (BGH), deep white matter and infratentorial region, and brain atrophy was calculated as bicaudate ratios.

RESULTS

Patients with cognitive impairment (Mini-Mental State Examination score < 24) were significantly older (P = 0.001), had periventricular region hyperintensities (P = 0.029) and BGH (P = 0.0015), and showed atrophy (P < 0.0001). Logistic regression showed that cognitive impairment was predicted by stroke (OR 2.5, 95% CI 0.033-0.894, P = 0.036) and atrophy (OR 8.43, 95% CI 5.71-37.0, P = 0.0109). Multiple regressions showed that BGH was associated with CKD (β = 0.213; P = 0.003), and infratentorial region was associated with stroke (β = 0.157; P =0.035) and CKD (β = 0.172; P = 0.016). Periventricular region was associated with age (β = 0.2; P = 0.011) and Geriatric Depression Scale (β = 0.151; P = 0.037), and deep white matter hyperintensities with age (β = 0.189; P = 0.016).

CONCLUSIONS

Although cognitive impairment in elderly medical patients is associated with stroke and brain atrophy, white matter hyperintensities, especially BGH and infratentorial region, are associated with cognitive decline in relation to CKD. Geriatr Gerontol Int 2017; 17: 1488-1493.

Regional Coherence Changes in Alzheimer's Disease Patients with Depressive Symptoms: A Resting-State Functional MRI Study

Alzheimer's disease (AD) is characterized by progressive cognitive decline along with neuropsychiatric symptoms including depression and psychosis. Depression is a common psychiatric disorder occurring in people across the lifespan. Accumulating evidence indicates that depression may be a prodrome and/or a "risk factor" for AD. However, whether AD and depression share a common pathophysiological pathway is still unclear. The aim of this study was to identify regional alterations in brain function associated with depressive symptoms in mild AD patients. Thirty-two mild AD patients were evaluated using the Neuropsychiatric Inventory and Hamilton Depression Rating Scale, and were divided into two groups: 15 AD patients with depressive symptoms (D-AD) and 17 non-depressed AD (nD-AD) patients. Using the approach of regional homogeneity (ReHo), we characterized resting-state regional brain activity in D-AD and nD-AD patients. Compared with nD-AD patients, D-AD patients showed decreased ReHo in the right precentral gyrus, right superior frontal gyrus, right middle frontal gyrus, and right inferior frontal cortex. Our findings show regional brain activity alterations in D-AD patients. Thus, D-AD pathogenesis may be attributed to abnormal neural activity in multiple brain regions.

Age-dependent cognitive and affective differences in Alzheimer's and Parkinson's diseases in relation to MRI findings

OBJECTIVE

To compare age-dependent changes in cognitive and affective functions related to white matter changes between patients with Alzheimer's disease (AD) and Parkinson's disease (PD).

METHODS

We retrospectively compared age-dependent cognitive and affective functions in 216 AD patients, 153 PD patients, and 103 healthy controls with cerebral white matter lesions (WMLs), periventricular hyperintensity (PVH), deep white matter hyperintensity (DWMH), micro-bleeds (MBs), and lacunar infarcts (LIs).

RESULTS

The average mini-mental state examination (MMSE) scores were 19.6±6.1 and 26.8±3.6 in AD and PD patients, respectively. Significant decreases were found in the MMSE score, Hasegawa's dementia scale-revised (HDS-R) score, frontal assessment battery score, and Abe's BPSD score (ABS) among the age-dependent AD subgroups and in the MMSE, HDS-R, Montreal cognitive assessment, geriatric depression scale, and ABS scores among the age-dependent PD subgroups; they were worse in AD patients. White matter changes were observed in >88% and >72% of patients with AD and PD, respectively. An age-dependent direct comparison of AD and PD showed significant differences in the PVH and DWMH grades, and numbers of MBs and LIs.

CONCLUSION

WML-related cognitive and affective functions worsen with age in AD and PD patients; however, the abnormalities were more frequent and stronger in AD patients.