Regional cortical thinning predicts worsening apathy and hallucinations across the Alzheimer disease spectrum

Limited awareness of hallucinations in patients with Alzheimer's disease

INTRODUCTION

We investigated the degree of cognitive insight in patients with Alzheimer's Disease (AD) regarding their hallucinations, aiming to elucidate the subjective experiences and perceptions associated with this phenomenon.

METHODS

Using a cross-sectional design, we invited both AD patients (n = 31) and their informants to evaluate the occurrence of hallucinations. Degree of cognitive insight was based upon the discrepancy between the patients' and informants' evaluations.

RESULTS

Analysis demonstrated that AD patients rated the occurrence of hallucinations lower than their informants, indicating that patients tended to underestimate the frequency of their hallucinations. The discrepancy between the ratings of patients and informants was negatively correlated with cognitive functioning, suggesting that a greater discrepancy (indicating poorer insight) was associated with lower cognitive functioning in patients.

DISCUSSION

Our findings highlight the deficits in insight into hallucinations among AD patients, specifically indicating that AD patients have limited awareness of their own hallucinations. Furthermore, our findings support the idea that deficits in insight into hallucinations are associated with the progression of AD.

Longitudinal associations of apathy and regional tau in mild cognitive impairment and dementia: Findings from the Alzheimer's Disease Neuroimaging Initiative

Introduction

It is important to study apathy in Alzheimer's disease (AD) to better understand its underlying neurobiology and develop effective interventions. In the current study, we sought to examine the relationships between longitudinal apathy and regional tau burden in cognitively impaired older adults from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.

Methods

Three hundred and nineteen ADNI participants with mild cognitive impairment (MCI) or AD dementia underwent flortaucipir (FTP) tau positron emission tomography (PET) imaging and clinical assessment with the Neuropsychiatric Inventory (NPI) annually. Longitudinal NPI Apathy (NPI-A) scores were examined in relation to baseline tau PET signal in three a priori selected regions implicated in AD and AD-related apathy (supramarginal gyrus, entorhinal cortex [EC] and rostral anterior cingulate cortex [rACC]). Secondary models were adjusted for global cognition (Mini-Mental State Examination score) and cortical amyloid (florbetapir PET).

Results

Higher baseline supramarginal gyrus and EC tau burden were each significantly associated with greater NPI-A over time, while rACC tau was associated with higher NPI-A but did not predict its trajectory over time. These results were retained for supramarginal and EC tau after adjusting models for global cognition and cortical amyloid.

Discussion

Our findings suggest that baseline in vivo tau burden in parietal and temporal brain regions affected in AD, and less so in a medial frontal region involved in motivational control, is associated with increasing apathy over time in older adults with MCI and AD dementia. Future work studying emergent apathy in relation to not only core AD pathology but also circuit level dysfunction may provide additional insight into the neurobiology of apathy in AD and opportunities for intervention.

Highlights

Tau (Flortaucipir PET) in regions implicated in AD was associated with increasing apathy over timeCortical amyloid was also found to be a robust predictor of the trajectory of apathyEvidence of synergy between regional tau and amyloid in overall higher levels of apathy.

Neuropsychiatric Manifestations in Alzheimer's Disease Patients: Genetics and Treatment Options

BACKGROUND

Alzheimer's disease (AD) is characterized by neuropsychiatric symptoms (NPS), which cause great misery to those with dementia and those who care for them and may lead to early institutionalization.

OBJECTIVE

The present systematic review aims to discuss the various aspects of Alzheimer's, including treatment options.

METHODS

The databases Embase, PubMed, and Web of Science were searched to collect data.

RESULTS

Incipient cognitive deterioration is commonly accompanied by these early warning signals of neurocognitive diseases. The neurobiology of NPSs in Alzheimer's disease, as well as particular symptoms, including psychosis, agitation, apathy, sadness, and sleep disorders, will be examined in this review. For NPSs in Alzheimer's disease, clinical trial designs, as well as regulatory issues, were also addressed. A fresh wave of research, however, is helping to push the discipline ahead. For medication development and repurposing, we highlight the most recent results in genetics, neuroimaging, and neurobiology. Even though identifying and treating psychosis in adults with dementia is still a challenging endeavor, new options are coming up that give the field fresh focus and hope. Conclsuion: It can be concluded from the complete literature survey that Alzheimer's-related psychosis as well as other symptoms that are not psychotic, have made significant progress in the last decade. These milestones in the development of safer, more effective treatments have been achieved as a consequence of great focus on non-pharmacological interventions like DICE or WHELD; the investigation into ways to improve existing drugs like aripiprazole, risperidone, amisulpride, and Escitalopram for safer precision-based treatment; and the development of a clinical trial program for pimavanserin.

Depression and Agitation Factors Are Related to Regional Brain Atrophy and Faster Longitudinal Cognitive Decline in Mild Cognitive Impairment

BACKGROUND

Neuropsychiatric symptoms (NPS) are a common aspect of Alzheimer's disease (AD). Multiple studies have investigated its brain correlates, but it still remains unclear how they relate with brain atrophy in mild cognitive impairment (MCI).

OBJECTIVE

Our objective was to investigate brain volume in MCI patients as a function of NPS.

METHODS

We measured grey matter volume, neuropsychological status and NPS (Neuropsychiatric Inventory, NPI), in a sample of 81 MCI patients (43 females). Participants were divided in groups depending on presence (NPS+) or absence (NPS-) of NPS and on type of NPS.

RESULTS

We found lower volume of left temporal pole in patients with depression compared to NPS- (p = 0.012), and in patients with agitation compared to NPS- in the right middle occipital gyrus (p = 0.003). We also found a significant correlation between volume of left temporal pole and MMSE (r (78)  = 0.232, p = 0.019). Finally, NPS+ presented lower cross-sectional cognitive level than NPS- (t (79)  = 1.79, p = 0.038), and faster cognitive decline (t (48)  = -1.74, p = 0.044).

CONCLUSIONS

Our results support the colocalization of structural damage as a possible mechanism underlying the relationship between MCI and depression and provide novel evidence regarding agitation. Moreover, our longitudinal evidence highlights the relevance of an adequate identification of NPS in MCI patients to identify those at risk of faster cognitive decline.

Neurobiological correlation between phosphorylated tau and mood symptoms in memory clinic patients

BACKGROUND

Alzheimer's disease (AD) dementia and mild cognitive impairment are characterised by impaired cognition accompanied by neuropsychiatric symptoms (NPS) relating to mood, including depression, anxiety, and apathy. However, the utility of AD biomarkers for predicting mood symptoms of NPS remains controversial. Herein, we analyzed the relationship between phosphorylated tau (p-tau) and depression, anxiety, and apathy of NPS. We also examined the influence of genetic factors such as apolipoprotein E (APOE) ε4 on these relationships.

METHODS

We conducted a cross-sectional survey in older patients (n = 122) with normal cognition (n = 12), mild cognitive impairment (n = 46), and AD (n = 64) strictly diagnosed by the board of psychiatrists and neurologists of Hokkaido University. NPS of the patients were assessed using the Neuropsychiatric Inventory Questionnaire (NPI). All patients also received a lumbar puncture to obtain cerebral spinal fluid for assessment of p-tau. The inverse probability weighting method was used to adjust for demographic differences between the p-tau present group and the p-tau absent group.

RESULTS

There was an association between p-tau accumulation and decreased incidence of depression and apathy. APOE ε4 non-carriers also showed a trend toward a negative association between p-tau and depression, which was not evident in APOE ε4 carriers.

CONCLUSIONS

We provide new evidence for a negative correlation between p-tau and depression and apathy of NPS, which may be influenced by APOE ε4. Future longitudinal studies are required to confirm the utility of p-tau for predicting the course of mood symptoms in patients with cognitive decline.

Association between CSF biomarkers of Alzheimer's disease and neuropsychiatric symptoms: Mayo Clinic Study of Aging

INTRODUCTION

We examined the association between cerebrospinal fluid (CSF)-derived biomarkers of Alzheimer's disease and neuropsychiatric symptoms (NPS) in older non-demented adults.

METHODS

We included 784 persons (699 cognitively unimpaired, 85 with mild cognitive impairment) aged ≥ 50 years who underwent CSF amyloid beta (Aβ42), hyperphosphorylated tau 181 (p-tau), and total tau (t-tau) as well as NPS assessment using Beck Depression and Anxiety Inventories (BDI-II, BAI), and Neuropsychiatric Inventory Questionnaire (NPI-Q).

RESULTS

Lower CSF Aβ42, and higher t-tau/Aβ42 and p-tau/Aβ42 ratios were associated with BDI-II and BAI total scores, clinical depression (BDI-II ≥ 13), and clinical anxiety (BAI ≥ 10), as well as NPI-Q-assessed anxiety, apathy, and nighttime behavior.

DISCUSSION

CSF Aβ42, t-tau/Aβ42, and p-tau/Aβ42 ratios were associated with NPS in community-dwelling individuals free of dementia. If confirmed by a longitudinal cohort study, the findings have clinical relevance of taking into account the NPS status of individuals with abnormal CSF biomarkers.

An Update on Apathy in Alzheimer's Disease

Apathy is a complex multi-dimensional syndrome that affects up to 70% of individuals with Alzheimer's disease (AD). Whilst many frameworks to define apathy in AD exist, most include loss of motivation or goal-directed behaviour as the central feature. Apathy is associated with significant impact on persons living with AD and their caregivers and is also associated with accelerated cognitive decline across the AD spectrum. Neuroimaging studies have highlighted a key role of fronto-striatial circuitry including the anterior cingulate cortex (ACC), orbito-frontal cortex (OFC) and associated subcortical structures. Importantly, the presence and severity of apathy strongly correlates with AD stage and neuropathological biomarkers of amyloid and tau pathology. Following from neurochemistry studies demonstrating a central role of biogenic amine neurotransmission in apathy syndrome in AD, recent clinical trial data suggest that apathy symptoms may improve following treatment with agents such as methylphenidate-which may have an important role alongside emerging non-pharmacological treatment strategies. Here, we review the diagnostic criteria, rating scales, prevalence, and risk factors for apathy in AD. The underlying neurobiology, neuropsychology and associated neuroimaging findings are reviewed in detail. Finally, we discuss current treatment approaches and strategies aimed at targeting apathy syndrome in AD, highlighting areas for future research and clinical trials in patient cohorts.

Plasma-derived biomarkers of Alzheimer's disease and neuropsychiatric symptoms: A community-based study

INTRODUCTION

We examined associations between plasma-derived biomarkers of Alzheimer's disease (AD) and neuropsychiatric symptoms (NPS) in community-dwelling older adults.

METHODS

Cross-sectional study involving 1005 persons ≥50 years of age (mean 74 years, 564 male, 118 cognitively impaired), who completed plasma-derived biomarker (amyloid beta 42 [Aβ42]/Aβ40, phosphorylated tau 181 [p-tau181], p-tau217, total tau [t-tau], neurofilament light [NfL]), and NPS assessment.

RESULTS

P-tau181 (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.41-3.00, p < 0.001), p-tau217 (OR 1.70, 95% CI 1.10-2.61, p = 0.016), and t-tau (OR 1.44, 95% CI 1.08-1.92, p = 0.012) were associated with appetite change. We also found that p-tau181 and p-tau217 were associated with increased symptoms of agitation (OR 1.93, 95% CI 1.20-3.11, p = 0.007 and OR 2.04, 95% CI 1.21-3.42, p = 0.007, respectively), and disinhibition (OR 2.39, 95% CI 1.45-3.93, p = 0.001 and OR 2.30, 95% CI 1.33-3.98, p = 0.003, respectively). Aβ42/Aβ40 and NfL were not associated with NPS.

CONCLUSION

Higher plasma-derived p-tau181 and p-tau217 levels are associated with increased symptoms of appetite change, agitation, and disinhibition. These findings may support the validity of plasma tau biomarkers for predicting behavioral symptoms that often accompany cognitive impairment.

HIGHLIGHTS

We studied 1005 community-dwelling persons aged ≥ 50 yearsHigher plasma tau levels are associated with increased neuropsychiatric symptomsAβ42/Aβ40 and NfL are not associated with neuropsychiatric symptomsClinicians should treat neuropsychiatric symptoms in persons with high plasma-derived tau.

White matter hyperintensities and smaller cortical thickness are associated with neuropsychiatric symptoms in neurodegenerative and cerebrovascular diseases

BACKGROUND

Neuropsychiatric symptoms (NPS) are a core feature of most neurodegenerative and cerebrovascular diseases. White matter hyperintensities and brain atrophy have been implicated in NPS. We aimed to investigate the relative contribution of white matter hyperintensities and cortical thickness to NPS in participants across neurodegenerative and cerebrovascular diseases.

METHODS

Five hundred thirteen participants with one of these conditions, i.e. Alzheimer's Disease/Mild Cognitive Impairment, Amyotrophic Lateral Sclerosis, Frontotemporal Dementia, Parkinson's Disease, or Cerebrovascular Disease, were included in the study. NPS were assessed using the Neuropsychiatric Inventory - Questionnaire and grouped into hyperactivity, psychotic, affective, and apathy subsyndromes. White matter hyperintensities were quantified using a semi-automatic segmentation technique and FreeSurfer cortical thickness was used to measure regional grey matter loss.

RESULTS

Although NPS were frequent across the five disease groups, participants with frontotemporal dementia had the highest frequency of hyperactivity, apathy, and affective subsyndromes compared to other groups, whilst psychotic subsyndrome was high in both frontotemporal dementia and Parkinson's disease. Results from univariate and multivariate results showed that various predictors were associated with neuropsychiatric subsyndromes, especially cortical thickness in the inferior frontal, cingulate, and insula regions, sex(female), global cognition, and basal ganglia-thalamus white matter hyperintensities.

CONCLUSIONS

In participants with neurodegenerative and cerebrovascular diseases, our results suggest that smaller cortical thickness and white matter hyperintensity burden in several cortical-subcortical structures may contribute to the development of NPS. Further studies investigating the mechanisms that determine the progression of NPS in various neurodegenerative and cerebrovascular diseases are needed.

Effects of risk factors on longitudinal changes in brain structure and function in the progression of AD

INTRODUCTION

Past research on Alzheimer's disease (AD) has focused on biomarkers, cognition, and neuroimaging as primary predictors of its progression, albeit additional ones have recently gained attention. When turning to the prediction of the progression from one stage to another, one could benefit from the joint assessment of imaging-based biomarkers and risk/protective factors.

METHODS

We included 86 studies that fulfilled our inclusion criteria.

RESULTS

Our review summarizes and discusses the results of 30 years of longitudinal research on brain changes assessed with neuroimaging and the risk/protective factors and their effect on AD progression. We group results into four sections: genetic, demographic, cognitive and cardiovascular, and lifestyle factors.

DISCUSSION

Given the complex nature of AD, including risk factors could prove invaluable for a better understanding of AD progression. Some of these risk factors are modifiable and could be targeted by potential future treatments.

Decreased miR-451a in cerebrospinal fluid, a marker for both cognitive impairment and depressive symptoms in Alzheimer's disease

Background: Alzheimer's disease (AD) patients are often accompanied by depressive symptoms, but its underlying mechanism remains unclear. The present study aimed to explore the potential role of microRNAs in the comorbidity of AD and depression. Methods: The miRNAs associated with AD and depression were screened from databases and literature and then confirmed in the cerebrospinal fluid (CSF) of AD patients and different ages of transgenic APP/PS1 mice. AAV9-miR-451a-GFP was injected into the medial prefrontal cortex (mPFC) of APP/PS1 mice at seven months, and four weeks later, a series of behavioral and pathological analyses were performed. Results: AD patients had low CSF levels of miR-451a, which was positively correlated with the cognitive assessment score, but negatively with their depression scale. In the mPFC of APP/PS1 transgenic mice, the miR-451a levels also decreased significantly in the neurons and microglia. Specific virus vector-induced overexpression of miR-451a in the mPFC of APP/PS1 mice ameliorated AD-related behavior deficits and pathologies, including long-term memory defects, depression-like phenotype, β-amyloid load, and neuroinflammation. Mechanistically, miR-451a decreased the expression of neuronal β-secretase 1 of neurons through inhibiting Toll-like receptor 4/Inhibitor of kappa B Kinase β/ Nuclear factor kappa-B signaling pathway and microglial activation by inhibiting activation of NOD-like receptor protein 3, respectively. Conclusion: This finding highlighted miR-451a as a potential target for diagnosing and treating AD, especially for those with coexisting symptoms of depression.

Apathy in Alzheimer's disease: A neurocircuitry based perspective

In addition to memory deficits and other cognitive disturbances, patients with Alzheimer's disease (AD) experience neuropsychiatric symptoms, notably apathy, which is a state of impaired motivation observed by deficits in goal directed behavior. Apathy is a multifaceted neuropsychiatric condition and appears to be a prognostic indicator, correlating with the progression of AD. Strikingly, recent studies point out that the neurodegenerative pathology of AD may drive apathy independent of cognitive decline. These studies also highlight that neuropsychiatric symptoms, in particular apathy, might manifest early in AD. Here, we review the current understanding of the neurobiological underpinnings of apathy as a neuropsychiatric symptom of AD. Specifically, we highlight the neural circuits and brain regions recognized to be correlated with the apathetic symptomatology. We also discuss the current evidence that supports the notion that apathy and cognitive deficits may develop as independent but concurrent phenomena driven by AD pathology, suggesting its efficacy as an additional outcome measure in Alzheimer's disease clinical trials. The current and prospective therapeutic interventions for apathy in AD from a neurocircuitry based perspective are also reviewed.

Neuropsychiatric Symptoms of Alzheimer's Disease: An Anatomic-Genetic Framework for Treatment Development

BACKGROUND

Despite the burden on patients and caregivers, there are no approved therapies for the neuropsychiatric symptoms of Alzheimer's disease (NPS-AD). This is likely due to an incomplete understanding of the underlying mechanisms.

OBJECTIVE

To review the neurobiological mechanisms of NPS-AD, including depression, psychosis, and agitation.

METHODS

Understanding that genetic encoding gives rise to the function of neural circuits specific to behavior, we review the genetics and neuroimaging literature to better understand the biological underpinnings of depression, psychosis, and agitation.

RESULTS

We found that mechanisms involving monoaminergic biosynthesis and function are likely key elements of NPS-AD and while current treatment approaches are in line with this, the lack of effectiveness may be due to contributions from additional mechanisms including neurodegenerative, vascular, inflammatory, and immunologic pathways.

CONCLUSION

Within an anatomic-genetic framework, development of novel effective biological targets may engage targets within these pathways but will require a better understanding of the heterogeneity in NPS-AD.

The neural signatures of psychoses in Alzheimer's disease: a neuroimaging genetics approach

Psychoses in Alzheimer's disease (AD) are associated with worse prognosis. Genetic vulnerability for schizophrenia (SCZ) may drive AD-related psychoses, yet its impact on brain constituents is still unknown. This study aimed to investigate the association between polygenic risk scores (PRSs) for SCZ and psychotic experiences (PE) and grey matter (GM) volume in patients with AD with (AD-PS) and without (AD-NP) psychosis. Clinical, genetic and T1-weighted MRI data for 800 participants were extracted from the ADNI database: 203 healthy controls, 121 AD-PS and 476 AD-NP. PRSs were calculated using a Bayesian approach and analysed at ten p-value thresholds. Standard voxel-based morphometry was used to process MRI data. Logistic regression models including both PRSs for SCZ and PE, and an AD-PRS were used to predict psychosis in AD. Associations between PRSs and GM volume were investigated in the whole sample and the three groups independently. Only the AD-PRS predicted psychosis in AD. Inconsistent associations between the SCZ-PRS and PE-PRS and GM volumes were found across groups. The SCZ-PRS was negatively associated with medio-temporal/subcortical volumes and positively with medial/orbitofrontal volumes in the AD-PS group. Only medio-temporal areas were more atrophic in the AD-PS group, while there was no significant correlation between psychosis severity and GM volume. Although not associated with psychoses, the SCZ-PRS was correlated with smaller medio-temporal and larger orbitofrontal volumes in AD-PS. Similar alterations have also been observed in SCZ patients. This finding suggest a possible disconnection between these regions associated with psychoses in more advanced AD.

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.

Lipid Peroxidation as a Marker of Apathy and Executive Dysfunction in Patients at Risk for Vascular Cognitive Impairment

Background: The co-occurrence of apathy and executive dysfunction, a correlate of vascular cognitive impairment (VCI), is highly prevalent, yet facilitating factors are largely unknown. Objective: This study investigates the relationship between lipid peroxidation, apathy, and executive dysfunction in patients at risk for VCI. Methods: In participants with coronary artery disease, who are at a high risk of VCI, apathy (Apathy Evaluation Scale), and executive function (composite z-score based on age and education population norms from trails making test B, animal naming, and phonemic fluency tests) were assessed. Serum concentrations of an early (lipid hydroperoxide (LPH)) and late (8-isoprostane (8-ISO)) lipid peroxidation marker, were measured and the 8-ISO/LPH ratio was calculated. Results: Participants (n = 206, age±SD = 63.0±7.5, 80% men, total years of education = 15.9±3.4, AES score = 28.3±8.8, executive function = 0±1) demonstrated significantly different 8-ISO/LPH ratios between groups (F(3, 202) = 10.915, p <  0.001) with increasing levels in the following order: no apathy or executive dysfunction, only executive dysfunction (executive function composite score≤–1), only apathy (AES≥28), and both apathy and executive dysfunction. A model adjusting for demographics showed that lipid peroxidation was associated with both apathy (B(SE) = 4.63 (0.954), t = 4.852, p <  0.001) and executive function (B(SE) = –0.19 (0.079), t = –2.377, p = 0.018). However, when controlling for both demographics and vascular risk factors, lipid peroxidation was associated with only apathy (B(SE) = 3.11 (0.987), t = 3.149, p = 0.002). Conclusion: The results highlight a potentially important involvement of lipid peroxidation in the co-occurrence of apathy and executive dysfunction in those at risk for VCI.

A Multimodal Neuroimaging and Neuropsychological Study of Visual Hallucinations in Alzheimer’s Disease

Background: Hallucinations in Alzheimer’s disease (AD) have been linked to more severe cognitive and functional decline. However, research on visual hallucinations (VH), the most common type of hallucinations in AD, is limited. Objective: To investigate the cognitive and cerebral macrostructural and metabolic features associated with VH in AD. Methods: Twenty-four AD patients with VH, 24 with no VH (NVH), and 24 cognitively normal (CN) matched controls were selected from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. Differences in regional gray matter (GM) volumes and cognitive performance were investigated with whole brain voxel-based morphometry analyses of MRI structural brain scans, and analyses of neuropsychological tests. Glucose metabolic changes were explored in a subsample of patients who had FDG-PET scans available. Results: More severe visuoconstructive and attentional deficits were found in AD VH compared with NVH. GM atrophy and hypometabolism were detected in occipital and temporal areas in VH patients in comparison with CN. On the other hand, NVH patients had atrophy and hypometabolism mainly in temporal areas. No differences in GM volume and glucose metabolism were found in the direct comparison between AD VH and NVH. Conclusion: In addition to the pattern of brain abnormalities typical of AD, occipital alterations were observed in patients with VH compared with CN. More severe visuoconstructive and attentional deficits were found in AD VH when directly compared with NVH, and might contribute to the emergence of VH in AD.

Risk factors for apathy in Alzheimer's disease: A systematic review of longitudinal evidence

BACKGROUND

Apathy is frequent and persistent in Alzheimer's disease (AD), associated with poor prognosis and carer distress; yet our knowledge of risk factors remains limited.

AIMS

To identify risk factors associated with apathy incidence and progression in AD over time.

METHODS

We systematically reviewed evidence based on longitudinal studies assessing risk factors for apathy in AD up to June 2021. Two authors independently assessed article eligibility and rated quality.

RESULTS

13,280 articles were screened, of which 13 met inclusion criteria. Studies had a mean follow-up of 2.7 years reporting on a total of 2012 participants. Most findings were based on single studies of moderate quality evidence. Risk factors increasing apathy onset were: being a carrier of the T allele of the PRND gene polymorphism, and having high levels of the IL-6 and TNFα cytokines at baseline. Risk factors for apathy worsening were: reduced inferior-temporal cortical thickness, taking antidepressants, being an ApoE ε4 carrier, living longer with AD, lower cognitive test scores, higher baseline apathy, premorbid personality traits (lower agreeableness, higher neuroticism), and higher midlife motivational abilities.

CONCLUSIONS

Although results are limited by the small number of studies, this review identified specific genetic, neurobiological, AD specific, and dispositional factors that may increase risk of apathy onset and worsening in AD.

A transdiagnostic review of neuroimaging studies of apathy and disinhibition in dementia

Apathy and disinhibition are common and highly distressing neuropsychiatric symptoms associated with negative outcomes in persons with dementia. This paper is a critical review of functional and structural neuroimaging studies of these symptoms transdiagnostically in dementia of the Alzheimer type, which is characterized by prominent amnesia early in the disease course, and behavioural variant frontotemporal dementia, characterized by early social-comportmental deficits. We describe the prevalence and clinical correlates of these symptoms and describe methodological issues, including difficulties with symptom definition and different measurement instruments. We highlight the heterogeneity of findings, noting however, a striking similarity of the set of brain regions implicated across clinical diagnoses and symptoms. These regions involve several key nodes of the salience network, and we describe the functions and anatomical connectivity of these brain areas, as well as present a new theoretical account of disinhibition in dementia. Future avenues for research are discussed, including the importance of transdiagnostic studies, measuring subdomains of apathy and disinhibition, and examining different units of analysis for deepening our understanding of the networks and mechanisms underlying these extremely distressing symptoms.

Psychosis in Alzheimer disease - mechanisms, genetics and therapeutic opportunities

Psychosis is a common and distressing symptom in people with Alzheimer disease, and few safe and effective treatments are available. However, new approaches to symptom assessment and treatment are beginning to drive the field forward. New nosological perspectives have been provided by incorporating the emergence of psychotic symptoms in older adults - even in advance of dementia - into epidemiological and neurobiological frameworks as well as into diagnostic and research criteria such as the International Psychogeriatric Association criteria for psychosis in neurocognitive disorders, the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) research criteria for psychosis in neurodegenerative disease, and the ISTAART criteria for mild behavioural impairment. Here, we highlight the latest findings in genomics, neuroimaging and neurobiology that are informing approaches to drug discovery and repurposing. Current pharmacological and non-pharmacological treatment options are discussed, with a focus on safety and precision medicine. We also explore trial data for pimavanserin, a novel agent that shows promise for the treatment of psychosis in people with dementia, and discuss existing agents that might be useful but need further exploration such as escitalopram, lithium, cholinesterase inhibitors and vitamin D. Although the assessment and management of psychosis in people with dementia remain challenging, new opportunities are providing direction and hope to the field.

Differences of apathy perfusion correlates between Alzheimer's disease and frontotemporal dementia. A 99mTc-HMPAO SPECT study with automated Brodmann areas analysis

OBJECTIVES

To explore differences of apathy perfusion correlates between Alzheimer's disease (AD) and Frontotemporal dementia (FTD) using perfusion SPECT.

METHODS

We studied 75 FTD and 66 AD patients. We evaluated apathy using Neuropsychiatric Inventory (NPI). We compared perfusion of BAs on left (L) and right (R) hemisphere in AD and FTD.

RESULTS

Apathy in AD was significantly and negatively correlated with dorsolateral prefrontal cortex bilaterally, right anterior prefrontal cortex, inferior frontal cortex bilaterally, especially on the right, orbital part of inferior frontal gyrus bilaterally, left dorsal anterior cingulate cortex, right primary and secondary visual cortex, and with bilateral anterior and dorsolateral prefrontal cortex, inferior frontal cortex and orbital part of inferior frontal gyrus, bilaterally, bilateral anterior -ventral and dorsal- cingulate cortex, left posterior ventral cingulate cortex, right inferior, middle and anterior temporal gyri, entorhinal and parahippocampal cortex in FTD.

CONCLUSIONS

Significant overlapping of apathy perfusion correlates between AD and FTD is seen in frontal areas and anterior cingulate. Right occipital cortex is also involved in AD, while right temporal cortex and left posterior cingulate are involved in FTD. Nuclear imaging could be a useful biomarker for revealing apathy underlying mechanisms, resulting in directed treatments.KEYPOINTSUnderlying neural networks and clinical manifestation of apathy may differ between AD and FTD.Apathy in AD is correlated with hypoperfusion in bilateral frontal areas, more prominent on the right, left anterior cingulate and right occipital cortex.Apathy in FTD is correlated with hypoperfusion in bilateral frontal areas, bilateral anterior cingulate, left posterior cingulate and right temporal cortex.Brain perfusion SPECT with automated BAs analysis and comparison with normal healthy subjects may provide significant information for apathy mechanisms in neurodegenerative disorders, affecting patients' treatment.

Apathy as a Treatment Target in Alzheimer's Disease: Implications for Clinical Trials

Apathy is one of the most prevalent, stable and persistent neuropsychiatric symptom across the neurocognitive disorders spectrum. Recent advances in understanding of phenomenology, neurobiology and intervention trials highlight apathy as an important target for clinical intervention. We conducted a comprehensive review and critical evaluation of recent advances to determine the evidence-based suggestions for future trial designs. This review focused on 4 key areas: 1) pre-dementia states; 2) assessment; 3) mechanisms/biomarkers and 4) treatment/intervention efficacy. Considerable progress has been made in understanding apathy as a treatment target and appreciating pharmacological and non-pharmacological apathy treatment interventions. Areas requiring greater investigation include: diagnostic procedures, symptom measurement, understanding the biological mechanisms/biomarkers of apathy, and a well-formed approach to the development of treatment strategies. A better understanding of the subdomains and biological mechanisms of apathy will advance apathy as a treatment target for clinical trials.

Hallucinations and Covid-19: Increased Occurrence of Hallucinations in Patients with Alzheimer's Disease During Lockdown

We investigated the effects of lockdown, as implemented by retirement homes to cope with the spread of Covid-19, on hallucinatory experiences in patients with Alzheimer's disease (AD). The study included 47 patients with AD living in retirement homes and who were already experiencing hallucinations prior to the lockdown. We invited caregivers to rate hallucinatory experiences in these patients during the lockdown, and compared this rating with that provided by the same caregivers prior to the lockdown. Results demonstrated increased hallucinatory experiences in patients with AD during the lockdown, compared with before the lockdown. The decrease in social and physical activities during the lockdown, and especially, the physical separation of residents from family members, might have led to decreased sensory stimulation and increased loneliness, and consequently, to the hallucinatory experiences in patients with AD living in retirement homes during the lockdown. While the restrictive measures were necessary to cope with the spread of Covid-19, these measures have increased hallucinations in patients with AD living in retirement homes, at least in those who were already experiencing hallucinations prior to the lockdown.

Prefrontal Aβ pathology influencing the pathway from apathy to cognitive decline in non-dementia elderly

The purpose of this study is to investigate the complex connection between apathy and cognitive decline that remains unclear. A total of 1057 non-dementia elderly from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database received up to 13 years of follow-up and were divided into an apathy negative (-) group of 943 participants and an apathy positive (+) group of 114 participants through the Neuropsychiatric Inventory (NPI)-apathy subitem. Cerebrospinal fluid (CSF) AD biomarkers and amyloid β (Aβ) PET were measured, and their longitudinal changes were assessed using linear mixed-effects models. Risk factors for cognitive decline and apathy conversion were explored through the Cox proportional hazards model. Mediation effects of Aβ pathology on cognition were investigated using the causal mediation analysis. Apathy syndrome was associated with faster impairment of cognition and elevation of the Aβ burden. The effects of apathy on cognitive function and life quality were mediated by Aβ pathology, including CSF Aβ₄₂/total tau ratio, and Aβ deposition in the prefrontal regions. Apathy syndrome was the risk factor for cognitive deterioration; meanwhile, frontal Aβ burden was the risk factor for apathy conversion. Apathy syndrome is an early manifestation of cognitive decline and there are bidirectional roles between apathy syndrome and Aβ pathology. Prefrontal Aβ pathology influenced the pathway from apathy to cognitive decline.

Affective symptoms and regional cerebral tau burden in early-stage Alzheimer's disease

OBJECTIVE

Neuropsychiatric symptoms (NPS) are often present in individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia. NPS are associated with structural and functional changes in the brain such as atrophy, regional hypometabolism, and hypoperfusion, considered proxies of neurodegeneration. Our objective was to evaluate the association between NPS and regional cerebral tau burden, a more direct representation of neurodegeneration, in cognitively normal (CN), MCI, and AD dementia individuals.

METHODS

Cross-sectional NPS were assessed using the Neuropsychiatric Inventory (NPI) in 410 CN, 199 MCI, and 61 AD dementia participants who underwent flortaucipir tau positron emission tomography as part of the AD Neuroimaging Initiative (ADNI). Total NPI score and two factors of NPS (affective and hyperactive) were used in analyses. Linear regression models with backward elimination were employed with NPI as dependent variable and regional tau or tau-amyloid interaction as predictor of interest. Covariates included education, age, sex, Rey Auditory Verbal Learning Test Total Learning, and Trail Making Test B.

RESULTS

There were significant associations (p < 0.05) between the NPI variables (total score, Affective factor) and entorhinal and precuneus tau across all participants. These associations were also significant for the tau-amyloid interaction. These effects were significant in cognitively symptomatic participants (MCI and AD dementia), but not in CN participants.

CONCLUSIONS

Increased tau burden in the entorhinal and precuneus cortices was modestly associated with greater NPS in MCI and AD dementia. Further evaluation of NPS and their effect on early-stage AD could aid in finding new interventions and slowing disease progression.

Brain mechanisms underlying neuropsychiatric symptoms in Alzheimer's disease: a systematic review of symptom-general and -specific lesion patterns

Neuropsychiatric symptoms (NPSs) are common in patients with Alzheimer's disease (AD) and are associated with accelerated cognitive impairment and earlier deaths. This review aims to explore the neural pathogenesis of NPSs in AD and its association with the progression of AD. We first provide a literature overview on the onset times of NPSs. Different NPSs occur in different disease stages of AD, but most symptoms appear in the preclinical AD or mild cognitive impairment stage and develop progressively. Next, we describe symptom-general and -specific patterns of brain lesions. Generally, the anterior cingulate cortex is a commonly damaged region across all symptoms, and the prefrontal cortex, especially the orbitofrontal cortex, is also a critical region associated with most NPSs. In contrast, the anterior cingulate-subcortical circuit is specifically related to apathy in AD, the frontal-limbic circuit is related to depression, and the amygdala circuit is related to anxiety. Finally, we elucidate the associations between the NPSs and AD by combining the onset time with the neural basis of NPSs.

Structural Brain Differences Between Cognitively Impaired Patients With and Without Apathy

OBJECTIVE

Since apathy increases in prevalence with severity of dementia pathology, we sought to distinguish concomitant neurodegenerative processes from brain differences associated with apathy in persons with mild cognitive impairment (MCI) and Alzheimer's Disease (AD). We examined relative structural brain differences between case-control matched cognitively impaired patients with and without apathy.

DESIGN

Cross-sectional case-control study.

SETTING

Fifty-eight clinical sites in phase 2 of the AD Neuroimaging Initiative across the United States and Canada.

PARTICIPANTS

The ≥ 55 years of age with MCI or AD dementia and no major neurological disorders aside from suspected incipient AD dementia. Participants with apathy (n=69) were age-, sex-, apolipoprotein E ε4 allele carrier status-, Mini-Mental State Exam score-, and MCI or AD dementia diagnosis-matched to participants without apathy (n=149).

INTERVENTIONS

The 3-tesla T1-weighted MRI scan and neurocognitive assessments. Using the Neuropsychiatric Inventory apathy domain scores, participants were dichotomized into a with-apathy group (score ≥ 1) and a without-apathy group (score = 0).

MEASUREMENTS

Cortical thicknesses from 24 a priori regions of interest involved in frontostriatal circuits and frontotemporal association areas.

RESULTS

False-discovery rate adjusted within-group comparisons between participants with apathy and participants without apathy showed thinner right medial orbitofrontal (mOFC; meandifference(MD)±standarderrorofMD(SE)=-0.0879±0.0257mm; standardizedMD(d)=-0.4456) and left rostral anterior cingulate (rACC; MD±SE=-0.0905±0.0325mm; d=-0.3574) cortices and thicker left middle temporal cortices (MTC; MD±SE=0.0688±0.0239mm; d=0.3311) in those with apathy.

CONCLUSION

Atrophy of the right mOFC and left rACC and sparing of atrophy in the left MTC are associated with apathy in cognitively impaired persons.

Hallucinations and Delusions Signal Alzheimer's Associated Cognitive Dysfunction More Strongly Compared to Other Neuropsychiatric Symptoms

OBJECTIVES

Neuropsychiatric symptoms (NPS) are common among individuals with dementia of the Alzheimer's type (DAT). We sought to characterize which NPS more purely relate to cognitive dysfunction in DAT, relative to other NPS.

METHOD

Demographic, neurocognitive, neuroimaging, and NPS data were mined from the Alzheimer's Disease Neuroimaging Initiative database (n = 906). Using factor analysis, we analyzed the degree to which individual NPS were associated with DAT-associated cognitive dysfunction. We also employed item response theory to graphically depict the ability of individual NPS to index DAT-associated cognitive dysfunction across a continuum ranging from cognitively normal to mild DAT.

RESULTS

Psychotic symptoms (hallucinations and delusions) were more strongly related to the continuum of DAT-associated cognitive dysfunction than other NPS, with the strength of the relationship peaking at high levels of disease severity. Psychotic symptoms also negatively correlated with brain volume and did not relate to the presence of vision problems. Aberrant motor behavior and apathy had relatively smaller associations with DAT-associated cognitive dysfunction, while other NPS showed minimal associations.

DISCUSSION

Psychotic symptoms most strongly indexed DAT-associated cognitive dysfunction, whereas other NPS, such as depression and anxiety, were not as precisely related to the DAT-associated cognitive dysfunction.

Pervasively Thinner Neocortex as a Transdiagnostic Feature of General Psychopathology

OBJECTIVE

Neuroimaging research has revealed that structural brain alterations are common across broad diagnostic families of disorders rather than specific to a single psychiatric disorder. Such overlap in the structural brain correlates of mental disorders mirrors already well-documented phenotypic comorbidity of psychiatric symptoms and diagnoses, which can be indexed by a general psychopathology or p factor. The authors hypothesized that if general psychopathology drives the convergence of structural alterations common across disorders, then 1) there should be few associations unique to any one diagnostic family of disorders, and 2) associations with the p factor should overlap with those for the broader diagnostic families.

METHODS

Analyses were conducted on structural MRI and psychopathology data collected from 861 members of the population-representative Dunedin Multidisciplinary Health and Development Study at age 45.

RESULTS

Study members with high scores across three broad diagnostic families of disorders (externalizing, internalizing, thought disorder) exhibited highly overlapping patterns of reduced global and widely distributed parcel-wise neocortical thickness. Study members with high p factor scores exhibited patterns of reduced global and parcel-wise neocortical thickness nearly identical to those associated with the three broad diagnostic families.

CONCLUSIONS

A pattern of pervasively reduced neocortical thickness appears to be common across all forms of mental disorders and may represent a transdiagnostic feature of general psychopathology. As has been documented with regard to symptoms and diagnoses, the underlying brain structural correlates of mental disorders may not exhibit specificity, and the continued pursuit of such specific correlates may limit progress toward more effective strategies for etiological understanding, prevention, and intervention.

Mild behavioral impairment and its relation to tau pathology in preclinical Alzheimer's disease

Mild behavioral impairment (MBI) is suggested as risk marker for neurodegenerative diseases, such as Alzheimer's disease (AD). Recently, pathologic tau deposition in the brain has been shown closely related to clinical manifestations, such as cognitive deficits. Yet, associations between tau pathology and MBI have rarely been investigated. It is further debated if MBI precedes cognitive deficits in AD. Here, we explored potential mechanisms by which MBI is related to AD, this by studying associations between MBI and tau in preclinical AD. In all, 50 amyloid-β-positive cognitively unimpaired subjects (part of the BioFINDER-2 study) underwent MBI-checklist (MBI-C) to assess MBI, and the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) delayed word recall (ADAS-DR) to assess episodic memory. Early tau pathology was determined using tau-PET ([¹⁸F]RO948 retention in entorhinal cortex/hippocampus) and cerebrospinal fluid (CSF) P-tau₁₈₁. Regression models were used to test for associations. We found that higher tau-PET signal in the entorhinal cortex/hippocampus and CSF P-tau₁₈₁ levels were associated with higher MBI-C scores (β = 0.010, SE = 0.003, p = 0.003 and β = 1.263, SE = 0.446, p = 0.007, respectively). When MBI-C and ADAS-DR were entered together in the regression models, tau-PET (β = 0.009, p = 0.009) and CSF P-tau₁₈₁ (β = 0.408, p = 0.006) were predicted by MBI-C, but not ADAS-DR. We conclude that in preclinical AD, MBI is associated with tau independently from memory deficits. This denotes MBI as an important early clinical manifestation related to tau pathology in AD.

Widespread white matter aberration is associated with the severity of apathy in amnestic Mild Cognitive Impairment: Tract-based spatial statistics analysis

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In aMCI, apathy severity was associated with lower FA in widespread WM pathways.

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WM aberrations are related to apathy severity after controlling for depression.

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Disruptions related to apathy severity are not limited to frontal-subcortical area.

Apathy is recognized as a prevalent behavioral symptom of amnestic Mild Cognitive Impairment (aMCI). In aMCI, apathy is associated with an increased risk and increases the risk of progression to Alzheimer’s Disease (AD). Previous DTI study in aMCI showed that apathy has been associated with white matter alterations in the cingulum, middle and inferior longitudinal fasciculus, fornix, and uncinate fasciculus. However, the underlying white matter correlates associated with apathy in aMCI are still unclear. We investigated this relationship using whole-brain diffusion tensor imaging (DTI). Twenty-nine aMCI patients and 20 matched cognitively healthy controls were included. Apathy severity was assessed using the Apathy Evaluation Scale Clinician version. We applied the tract-based spatial statistics analyses to DTI parameters: fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity to investigate changes in white matter pathways associated with the severity of apathy. No significant difference was found in any of the DTI parameters between aMCI and the control group. In aMCI, higher severity of apathy was associated with lower FA in various white matter pathways including the left anterior part of inferior fronto-occipital fasciculus/uncinate fasciculus, genu and body of the corpus callosum, superior and anterior corona radiata, anterior thalamic radiation of both hemispheres and in the right superior longitudinal fasciculus/anterior segment of arcuate fasciculus (p < .05, TFCE-corrected) after controlling for age, gender and GDS non-apathy. A trend association was observed in the right posterior corona radiata and corticospinal tract/internal capsule, and bilateral forceps minor (p < .065, TFCE-corrected). In conclusion, in aMCI, severity of apathy is associated with aberrant white matter integrity in widely distributed pathways, within and between hemispheres.

Alzheimer's disease biomarkers as predictors of trajectories of depression and apathy in cognitively normal individuals, mild cognitive impairment, and Alzheimer's disease dementia

OBJECTIVES

To examine trajectories of depression and apathy over a 5-year follow-up period in (prodromal) Alzheimer's disease (AD), and to relate these trajectories to AD biomarkers.

METHODS

The trajectories of depression and apathy (measured with the Neuropsychiatric Inventory or its questionnaire) were separately modeled using growth mixture models for two cohorts (National Alzheimer's Coordinating Center, NACC, n = 22 760 and Alzheimer's Disease Neuroimaging Initiative, ADNI, n = 1 733). The trajectories in ADNI were associated with baseline CSF AD biomarkers (Aβ_42, t-tau, and p-tau) using bias-corrected multinomial logistic regression.

RESULTS

Multiple classes were identified, with the largest classes having no symptoms over time. Lower Aβ₄₂ and higher tau (ie, more AD pathology) was associated with increased probability of depression and apathy over time, compared to classes without symptoms. Lower Aβ₄₂ (but not tau) was associated with a steep increase of apathy, whereas higher tau (but not Aβ₄₂ ) was associated with a steep decrease of apathy.

DISCUSSION

The trajectories of depression and apathy in individuals on the AD spectrum are associated with AD biomarkers.

Apathy and risk of probable incident dementia among community-dwelling older adults

OBJECTIVE

To evaluate the association between baseline apathy and probable incident dementia in a population-based sample of community-dwelling older adults.

METHODS

We studied 2,018 white and black community-dwelling older adults from the Health, Aging, and Body Composition (Health ABC) study. We measured apathy at year 6 (our study baseline) with the modified Apathy Evaluation Scale and divided participants into tertiles based on low, moderate, or severe apathy symptoms. Incident dementia was ascertained over 9 years by dementia medication use, hospital records, or clinically relevant cognitive decline on global cognition. We examined the association between apathy and probable incident dementia using a Cox proportional hazards model adjusting for demographics, cardiovascular risk factors, APOE4 status, and depressed mood. We also evaluated the association between the apathy group and cognitive change (as measured by the modified Mini-Mental State Examination and Digit Symbol Substitution Test over 5 years) using linear mixed effects models.

RESULTS

Over 9 years of follow-up, 381 participants developed probable dementia. Severe apathy was associated with an increased risk of dementia compared to low apathy (25% vs 14%) in unadjusted (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.5-2.5) and adjusted models (HR 1.7, 95% CI 1.3-2.2). Greater apathy was associated with worse cognitive score at baseline, but not rate of change over time.

CONCLUSION

In a diverse cohort of community-dwelling adults, apathy was associated with increased risk of developing probable dementia. This study provides novel evidence for apathy as a prodrome of dementia.

Clinical features and brain structural changes in magnetic resonance imaging in Alzheimer's disease patients with apathy

BACKGROUND

Apathy is common in Alzheimer's disease (AD) patients. However, its relation with other clinical symptoms in AD and brain structural changes in magnetic resonance imaging is unclear.

RESULTS

Compared with AD with no apathy group, cognitive function and activities of daily living were significantly impaired and neuropsychiatric symptoms were obviously presented in AD with apathy group (P<0.05). The frequency of Apolipoprotein E genotypes was not significantly different (P>0.05). Correlation analyses and multiple linear analyses revealed that thickness of left temporal pole and volume of posterior corpus callosum were significantly and negatively correlated with Modified Apathy Estimation Scale score in AD patients (P<0.05).

CONCLUSIONS

Apathy with AD is positively correlated with cognitive impairment, neuropsychiatric symptoms and poor activities of daily living. Atrophy of left temporal pole and posterior corpus callosum presented by MRI is positively related with apathy of AD.

METHODS

In this study, 137 AD patients were recruited and divided into AD with apathy group and AD with no apathy group according to Modified Apathy Estimation Scale score. We evaluated patients' cognitive function, neuropsychiatric symptoms and activities of daily living, detected the frequency of Apolipoprotein E genotypes and measured cortical thickness and volume by magnetic resonance imaging (MRI).

The Relationship between Neuropsychiatric Symptoms and Default-Mode Network Connectivity in Alzheimer's Disease

OBJECTIVE

Neuropsychiatric symptoms of dementia are prevalent and extremely burdening for the patient and caregivers, but the underlying mechanism of these symptoms has not been investigated. This study aimed to investigate the relationship between neuropsychiatric symptoms and default-mode functional connectivity in Alzheimer's disease.

METHODS

Neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory. Functional magnetic resonance imaging was conducted on seventy patients with Alzheimer's disease during rest. We conducted a seed-based functional connectivity analysis to identify anterior and posterior default-mode networks (DMN). Seeds were the medial prefrontal cortex (Montreal Neurological Institute 12, 51, 36; seed radius=3 mm) for the anterior DMN and the precuneus (Montreal Neurological Institute -6, -63, 27; seed radius=3 mm) for the posterior DMN We then correlated the scores on neuropsychiatric inventory syndromes (apathy, hyperactivity, affective, and psychosis syndrome) with maps of connectivity in the default-mode network.

RESULTS

There was a significant correlation between decreased connectivity in the medial prefrontal cortex of the anterior defaultmode network and hyperactivity (agitation, irritability, aberrant motor behavior, euphoria, and disinhibition) syndrome (p<0.05, family wise error cluster-level corrected).

CONCLUSION

Our study demonstrated that hyperactivity syndrome is related to hypoconnected default-mode network in Alzheimer's disease. This finding suggests that specific network alterations are associated with certain neuropsychiatric syndromes.

Regional Tau Correlates of Instrumental Activities of Daily Living and Apathy in Mild Cognitive Impairment and Alzheimer's Disease Dementia

BACKGROUND

Instrumental activities of daily living (IADL) impairment and apathy occur in early-stage Alzheimer's disease (AD) and are associated with regional atrophy and hypometabolism in vivo and greater tau burden at autopsy.

OBJECTIVE

To explore the association between IADL impairment, apathy, and in vivo regional tau in mild cognitive impairment (MCI) and AD dementia.

METHODS

Forty participants (24 MCI, 16 AD dementia) underwent assessments of IADL (Functional Activities Questionnaire, FAQ) and apathy (Apathy Evaluation Scale Informant report, AES-I). Regional tau was assessed using flortaucipir positron emission tomography (PET) and amyloid using Pittsburgh Compound B PET. Regions with unadjusted associations of p≤0.01 were entered into regression models assessing the relationship between tau and FAQ or AES-I, adjusting for age, sex, and cognition, with/without a tau by amyloid interaction.

RESULTS

Unadjusted IADL impairment but not apathy was associated with greater tau in multiple regions. After adjusting for covariates, for medial orbitofrontal and entorhinal cortex the interaction between tau and amyloid was associated with IADL impairment and for anterior cingulate it was not but independent associations with both tau and amyloid were retained. With whole brain analyses, similar results were seen for IADL, while for apathy tau in small clusters within the right anterior cingulate and dorsolateral prefrontal cortices were seen, which were more pronounced in individuals with greater amyloid.

CONCLUSIONS

This exploratory study suggests that IADL impairment in AD is associated with medial temporal and frontal tau, especially in individuals with elevated amyloid, while apathy may be associated with right frontal tau.

Empirical support for the vascular apathy hypothesis: A structured review

OBJECTIVES

A systematic review of the relationship between subclinical small vessel disease (SSVD) in the general population and apathy to examine the hypothesis that apathy has a vascular basis.

METHODS

We searched for studies on associations between apathy and SSVD, operationalized as white matter hyperintensities (WMH) or white matter diffusivity changes, lacunar infarcts, cerebral microbleeds, decreasing cortical thickness, and perivascular spaces, while also peripheral proxies for SSVD were considered, operationalized as ankle brachial pressure index (ABI), intima media thickness, arterial stiffness, cardio-femoral pulse wave velocity, hypertension, or cardiovascular disease. Only eligible retrospective and prospective observational studies conducted in the general population were included.

RESULTS

The 14 studies eligible for review examined the associations between apathy and hypertension (3), ABI (1), arterial stiffness (1), cardiovascular disease (2), WMH (3), white matter diffusivity (2), cerebral microbleeds (1), or cortical thickness (3). Arterial stiffness and white matter diffusivity were not related to apathy, while the associations with cortical thickness were contradictory. Cross-sectional studies in the general population did find evidence of apathy being associated with WMH, CM, cardiovascular disease, hypertension, and ABI, and cardiovascular disease was prospectively associated with apathy. The methodologies of the studies reviewed were too heterogeneous to perform meta-analyses.

CONCLUSIONS

Although more prospective evidence is needed and vascular depression needs to be controlled for, cardiovascular disease, hypertension, and ABI as proxies for SSVD, and WMH and cerebral microbleeds as direct measures of SSVD have been found to be associated with apathy in the general population, supporting the hypothesis of vascular apathy.

The Effects of Confinement on Neuropsychiatric Symptoms in Alzheimer's Disease During the COVID-19 Crisis

BACKGROUND

Neuropsychiatric symptoms, such as depression, anxiety, apathy, agitation, and hallucinations, are frequent in Alzheimer's disease (AD) and their prevalence tends to increase with external stressors.

OBJECTIVE

We offer the first investigation of the effects of confinement during the COVID-19 crisis on neuropsychiatric symptoms in patients with AD.

METHODS

We contacted caregivers of 38 patients with AD who were confined to their homes for nearly two months and asked them to report whether patients experienced any change in neuropsychiatric symptoms during, compared to before, the confinement and rate its severity and impact on themselves using the Neuropsychiatric Inventory-Questionnaire.

RESULTS

Among the 38 patients, only 10 demonstrated neuropsychiatric changes during the confinement. Cognitive function of these 10 patients, assessed with the Mini-Mental State Examination, was worse than that of patients who did not demonstrate neuropsychiatric changes. Interestingly, among the 10 patients with neuropsychiatric changes, the duration of confinement significantly correlated with the severity of symptoms as well as with their caregivers' distress.

DISCUSSION

The confinement seems to impact neuropsychiatric symptomatology in AD patients with low baseline cognitive function.

Behavioral and Psychiatric Symptoms of Dementia and Rate of Decline in Alzheimer's Disease

Alzheimer’s disease causes both cognitive and non-cognitive symptoms. There is increasing evidence that the presentation and course of Alzheimer’s disease is highly heterogenous. This heterogeneity presents challenges to patients, their families, and clinicians due to the difficulty in prognosticating future symptoms and functional impairment. Behavioral and psychiatric symptoms are emerging as a significant contributor to this clinical heterogeneity. These symptoms have been linked to multiple areas of neurodegeneration, which may suggest that they are representative of network-wide dysfunction in the brain. However, current diagnostic criteria for Alzheimer’s disease focus exclusively on the cognitive aspects of disease. Behavioral and psychiatric symptoms have been found in multiple studies to be related to disease severity and to contribute to disease progression over time. A better understanding of how behavioral and psychiatric symptoms relate to cognitive aspects of Alzheimer’s disease would help to refine the models of disease and hopefully lead to improved ability to develop therapeutic options for this devastating disease.

Affective symptoms and AT(N) biomarkers in mild cognitive impairment and Alzheimer's disease: A systematic literature review

INTRODUCTION

Alzheimer's disease (AD) biomarkers such as amyloid, p-tau and neuronal injury markers have been associated with affective symptoms in cognitively impaired individuals, but results are conflicting.

METHODS

CINAHL, Embase, PsycINFO and PubMed were searched for studies evaluating AD biomarkers with affective symptoms in mild cognitive impairment and AD dementia. Studies were classified according to AT(N) research criteria.

RESULT

Forty-five abstracts fulfilled eligibility criteria, including in total 8,293 patients (41 cross-sectional studies and 7 longitudinal studies). Depression and night-time behaviour disturbances were not related to AT(N) markers. Apathy was associated with A markers (PET, not CSF). Mixed findings were reported for the association between apathy and T(N) markers; anxiety and AT(N) markers; and between agitation and irritability and A markers. Agitation and irritability were not associated with T(N) markers.

DISCUSSION

Whereas some AD biomarkers showed to be associated with affective symptoms in AD, most evidence was inconsistent. This is likely due to differences in study design or heterogeneity in affective symptoms. Directions for future research are given.

Mild behavioral impairment is linked to worse cognition and brain atrophy in Parkinson disease

OBJECTIVE

To evaluate the associations of mild behavioral impairment (MBI) with cognitive deficits and patterns of gray matter changes in Parkinson disease (PD).

METHODS

Sixty patients with PD without dementia and 29 healthy controls underwent a cognitive neuropsychological evaluation and structural MRI scan. MBI was evaluated with the MBI Checklist (MBI-C), a rating scale designed to elicit emergent neuropsychiatric symptoms in accordance with MBI criteria. We divided the patients with PD into 2 groups: 1 group with high MBI-C scores (PD-MBI) and the other with low MBI-C scores (PD-noMBI).

RESULTS

Among 60 patients with PD, 20 were categorized as having PD-MBI (33.33%). In healthy controls, no participants met the MBI cut-point threshold. The PD-MBI group had significantly lower Montreal Cognitive Assessment and z scores in all 5 domains and the global score compared to healthy controls and those with PD-noMBI. In addition, all cognitive domains except language and global cognition negatively correlated with the MBI-C total score in all patients with PD. For cortical structures, the PD-MBI group revealed middle temporal cortex thinning and decreased volume compared with the PD-noMBI group, and decreased volume in this area negatively correlated with the MBI-C total score.

CONCLUSIONS

The impaired cognitive function over all domains and atrophy in the temporal area in the PD-MBI group are in line with posterior cortical circuit deficits in PD, which have been associated with a faster rate of progression to dementia. These initial results suggest that MBI might be an early and important marker for incident cognitive decline and dementia in patients with PD.

Association Between CSF Beta-Amyloid and Apathy in Early-Stage Alzheimer Disease

AIM

The apathetic syndrome is a common clinical feature in patients with Alzheimer diseases (AD), from preclinical phases to late stages of dementia, and it is strongly related to major disease outcomes. Unfortunately, no specific pharmacological treatments for apathy have been accomplished so far. Translational evidences have previously shown that a link between apathy and hallmarks of AD-related pathophysiology, that is, β-amyloid (Aβ) plaques and neurofibrillary tangles, exists. However, only few studies investigated the association between core biomarkers of AD and apathy scores, finding conflicting results.

METHODS

Thirty-seven patients were identified as having AD dementia according to National Institute on Aging-Alzheimer Association 2011 criteria. All participants underwent an extensive diagnostic workup including cerebrospinal fluid (CSF) assessment to measure the concentrations of Aβ₄₂, t-tau, and pTau_181. To follow, they were stratified as: apathy absence, apathy mild, and apathy severe according to the Neuro Psychiatric Inventory-apathy item scores. We investigated for potential associations between apathy scores and CSF biomarkers concentrations as well as for differences in terms of clinical and CSF biomarkers data across the 3 apathy groups.

RESULTS

The CSF Aβ₄₂ concentrations were negatively correlated with apathy scores. In addition, patients with severe apathy had significantly lower Aβ₄₂ levels compared to nonapathetic ones.

CONCLUSION

Based on our results, we encourage further studies to untangle the potential association between the complex pathophysiological dynamics of AD and apathy which may represent an innovative reliable clinical outcome measure to use in clinical trials, investigating treatments with either a symptomatic or a disease-modifying effect.

Apathy in Alzheimer's disease

Apathy is the most common neuropsychiatric symptom in patients with Alzheimer's disease (AD). The presence of apathy has been related to greater caregiver distress, decreased quality of life, and increased morbidity. Here we review the most recent studies on this neuropsychiatric syndrome, focusing on prevalence, impact on quality of life, behavioural and neuroimaging studies, and treatment options. The results of some investigations on the behavioural and neuroanatomical profile of apathy in AD point to a role of frontostriatal circuits, specifically involving the anterior cingulate cortex. However, small and heterogeneous samples, lack of control for disease severity, and non-specific apathy scales complicate interpretation of results. Future studies might benefit from studying multiple dimensions of apathy within conceptual frameworks which allow for a deconstruction of underlying mechanisms.

Lower Choline and Myo-Inositol in Temporo-Parietal Cortex Is Associated With Apathy in Amnestic MCI

Apathy is a common symptom in patients with amnestic mild cognitive impairment (aMCI) and is associated with an increased risk of progression to Alzheimer's disease (AD). The neural substrates underlying apathy in aMCI may involve multiple brain regions, including the anterior cingulate cortex and the temporo-parietal region. Here we investigated neurometabolites in brain regions that may underlie apathy in aMCI patients using proton magnetic resonance spectroscopy (¹H-MRS). Twenty-eight aMCI patients with varying degrees of apathy and 20 matched controls underwent ¹H-MRS. Spectra were acquired from single voxels in the posterior cingulate cortex (PCC), dorsal anterior cingulate cortex (DACC), right dorsolateral prefrontal cortex (DLPFC), and right temporo-parietal cortex (TPC). Apathy was measured with the Apathy Evaluation Scale (AES). Spearman partial correlations between metabolite concentrations in each region and severity of apathy were determined. Additionally, analyses of covariance (ANCOVA) were performed to determine whether metabolite changes differed between patients with or without clinically-diagnosed apathy. The degree of apathy was found to be negatively correlated with choline and myo-inositol (mI) in the TPC. Additional exploratory analyses suggested that N-acetylaspartate (NAA)/mI ratio was reduced in aMCI without clinical apathy but not in aMCI with clinical apathy. In the DACC, glutamate and glutamine (Glx) levels tended to be higher in the aMCI with apathy group compared to controls and reduced in association with depression scores. In conclusion, apathy in aMCI patients was associated with neurometabolite changes indicative of altered membranal integrity and glial function in the right TPC. Findings also indicated that in a clinically-diagnosed aMCI cohort, apathy symptoms may be suggestive of neural changes that are distinct from aMCI without apathy.

State of the Science: Apathy As a Model for Investigating Behavioral and Psychological Symptoms in Dementia

Apathy is one of the most common and pervasive of the behavioral and psychological symptoms of dementia (BPSDs). Apathy has profound consequences for morbidity, mortality, and caregiver burden. Treatment of apathy has been hindered because of poor understanding of the mechanisms underlying this heterogeneous syndrome. Research has demonstrated that apathy is associated with disruption of the frontal-striatal system in individuals with neurodegenerative disease. As with other BPSDs, these neural mechanisms alone do not completely account for the syndrome; individual, caregiver, and environmental factors also contribute to apathy. In this article, we modify a current conceptual model of the factors contributing to BPSDs to examine determinants of apathy. This integrative model provides a more complete and theoretically informed understanding of apathy, allowing for greater insight into potential targets for research, intervention, and care. We end by proposing an agenda for moving the science of BPSDs in general, and apathy in particular, forward.

Psychosis and Clinical Outcomes in Alzheimer Disease: A Longitudinal Study

OBJECTIVE

Psychotic symptoms are a common feature in Alzheimer disease (AD), occurring in approximately 40% of patients. These symptoms are associated with worse clinical outcomes. Comparatively little research, however, has distinguished delusions and hallucinations, which may have distinct clinical, neuropathological, and genetic correlates. To address this, the current study examined the clinical outcomes associated with delusions and hallucinations in AD.

DESIGN

Three-year observational study.

SETTING

Nine memory clinics in Australia.

PARTICIPANTS

A total of 445 patients with AD.

MEASUREMENTS

Measures of neuropsychiatric symptoms, dementia severity, cognition, function, caregiver burden, and medication use were completed annually for 3 years with additional assessments at 3 months and 6 months in the first year. Mortality data were obtained from state registries approximately 5 years after the study.

RESULTS

Of 445 patients, 102 (22.9%) developed only delusions, 39 (8.8%) developed only hallucinations, and 84 (18.9%) developed both symptoms. Delusions and hallucinations were both associated with greater dementia severity, poorer cognition and function, higher levels of other neuropsychiatric symptoms, and greater caregiver burden. The presence of both symptoms was associated with worse outcomes than only one of these symptoms. Delusions, both by themselves and in combination with hallucinations, predicted institutionalization. Antipsychotic medication use predicted mortality.

CONCLUSIONS

Delusions and hallucinations independently and in combination are associated with poor clinical outcomes. The findings highlight the challenges managing these patients, particularly given the high levels of caregiver burden associated with psychotic symptoms and the likely mortality arising from antipsychotic medication.