Neuropsychiatric symptom profile differs based on pathology in patients with clinically diagnosed behavioral variant frontotemporal dementia

Targeting shared pathways in tauopathies and age-related macular degeneration: implications for novel therapies

The intricate parallels in structure and function between the human retina and the central nervous system designate the retina as a prospective avenue for understanding brain-related processes. This review extensively explores the shared physiopathological mechanisms connecting age-related macular degeneration (AMD) and proteinopathies, with a specific focus on tauopathies. The pivotal involvement of oxidative stress and cellular senescence emerges as key drivers of pathogenesis in both conditions. Uncovering these shared elements not only has the potential to enhance our understanding of intricate neurodegenerative diseases but also sets the stage for pioneering therapeutic approaches in AMD.

Apathy-like behaviour in tau mouse models of Alzheimer's disease and frontotemporal dementia

Apathy is the most common behavioural and psychological symptom in Alzheimer's disease (AD) and other neurodegenerative diseases including frontotemporal dementia (FTD) and Parkinson's disease (PD). In patients, apathy can include symptoms of loss of motivation, initiative, and interest, listlessness, and indifference, flattening of emotions, absence of drive and passion. Researchers have later refined this to a reduction in goal direct behaviours. In animals, specific symptoms of apathy-like behaviour have been modelled including goal directed or nest-building behaviour which are seen as indicative of proxies for motivation and daily activities. In the present study a nest-building protocol was established using four different inbred mouse strains (CD1, BALB/c, C57Bl/6J, C3H) before assessing AD and FTD tau transgenic mice of Line 1 (L1) and Line 66 (L66) in this paradigm. Female mice aged 5 - 6 months were assessed in the home cage over a period of 7 days with nest-building behaviour scored by three independent experimenters at intervals of 1-, 2- and 7-days post nestlet introduction. Inbred mouse strains displayed different levels of nesting behaviour. BALB/c mice were more proficient than CD1 and C3H mice, while all strains displayed similar nest-building behaviour by day 7. In the tau mouse models, L66 presented with impaired nesting compared to wild-type on days 1 and 2 (not day 7), whereas L1 performed like wild-type on all days. Anhedonia measured in a sucrose preference test was only observed in L66. Anhedonia and low nesting scores in L66 mice are indicative of apathy-like phenotypes. Differences evident between the L1 and L66 tau transgenic mouse models are likely due to the different human tau species expressed in these mice.

Psychosis in Neurodegenerative Dementias: A Systematic Comparative Review

Background

Psychosis, characterized by delusions and/or hallucinations, is frequently observed during the progression of Alzheimer's disease (AD) and other neurodegenerative dementias (ND) (i.e., dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD)) and cause diagnostic and management difficulties.

Objective

This review aims at presenting a concise and up-to-date overview of psychotic symptoms that occur in patients with ND with a comparative approach.

Methods

A systematic review was conducted following the PRISMA guidelines. 98 original studies investigating psychosis phenotypes in neurodegenerative dementias were identified (40 cohort studies, 57 case reports).

Results

Psychosis is a frequently observed phenomenon during the course of ND, with reported prevalence ranging from 22.5% to 54.1% in AD, 55.9% to 73.9% in DLB, and 18% to 42% in FTD. Throughout all stages of these diseases, noticeable patterns emerge depending on their underlying causes. Misidentification delusions (16.6-78.3%) and visual hallucinations (50-69.6%) are frequently observed in DLB, while paranoid ideas and somatic preoccupations seem to be particularly common in AD and FTD, (respectively 9.1-60.3% and 3.10-41.5%). Limited data were found regarding psychosis in the early stages of these disorders.

Conclusions

Literature data suggest that different ND are associated with noticeable variations in psychotic phenotypes, reflecting disease-specific tendencies. Further studies focusing on the early stages of these disorders are necessary to enhance our understanding of early psychotic manifestations associated with ND and help in differential diagnosis issues.

Glaucoma as a Tauopathy-Is It the Missing Piece in the Glaucoma Puzzle?

Glaucoma is a chronic neurodegenerative disorder affecting the visual system which can result in vision loss and blindness. The pathogenetic mechanisms underlying glaucomatous optic neuropathy are ultimately enigmatic, prompting ongoing investigations into its potential shared pathogenesis with other neurodegenerative neurological disorders. Tauopathies represent a subclass of neurodegenerative diseases characterized by the abnormal deposition of tau protein within the brain and consequent microtubule destabilization. The extended spectrum of tauopathies includes conditions such as frontotemporal dementias, progressive supranuclear palsy, chronic traumatic encephalopathy, and Alzheimer's disease. Notably, recent decades have witnessed emerging documentation of tau inclusion among glaucoma patients, providing substantiation that this ocular disease may similarly manifest features of tauopathies. These studies found that: (i) aggregated tau inclusions are present in the somatodendritic compartment of RGCs in glaucoma patients; (ii) the etiology of the disease may affect tau splicing, phosphorylation, oligomerization, and subcellular localization; and (iii) short interfering RNA against tau, administered intraocularly, significantly decreased retinal tau accumulation and enhanced RGC somas and axon survival, demonstrating a crucial role for tau modifications in ocular hypertension-induced neuronal injury. Here, we examine the most recent evidence surrounding the interplay between tau protein dysregulation and glaucomatous neurodegeneration. We explore the novel perspective of glaucoma as a tau-associated disorder and open avenues for cross-disciplinary collaboration and new treatment strategies.

Mild behavioral impairment is associated with progression to Alzheimer's disease: A clinicopathological study

INTRODUCTION

Mild behavioral impairment (MBI) is characterized by later-life emergence of neuropsychiatric symptoms. Investigating its relationship with progression to Alzheimer's disease (AD) would provide insight on its importance as a predictor of AD.

METHODS

Cognitively normal participants (N = 11,372) from the National Alzheimer's Coordinating Center were stratified by MBI status, using the Neuropsychiatric Inventory-Questionnaire. We investigated whether MBI and its domains were predictors of progression to clinically-diagnosed AD. MBI as a predictor of progression to neuropathology-confirmed AD was also investigated in those with neuropathological data.

RESULTS

Six percent (N = 671) of participants progressed to AD. MBI (N = 2765) was a significant predictor of progression to clinically-diagnosed (hazard ratio [HR] = 1.75) and neuropathology-confirmed AD (HR = 1.59). MBI domains were also associated with clinically-diagnosed AD, with psychosis having the greatest effect (HR = 6.49).

DISCUSSION

These findings support the biological underpinnings of MBI, emphasizing the importance of later life behavioral changes in dementia detection and prognostication.

Neuropsychological and Neuroanatomical Features of Patients with Behavioral/Dysexecutive Variant Alzheimer’s disease (AD): A Comparison to Behavioral Variant Frontotemporal Dementia and Amnestic AD Groups

Background: An understudied variant of Alzheimer’s disease (AD), the behavioral/dysexecutive variant of AD (bvAD), is associated with progressive personality, behavior, and/or executive dysfunction and frontal atrophy. Objective: This study characterizes the neuropsychological and neuroanatomical features associated with bvAD by comparing it to behavioral variant frontotemporal dementia (bvFTD), amnestic AD (aAD), and subjects with normal cognition. Methods: Subjects included 16 bvAD, 67 bvFTD, and 18 aAD patients, and 26 healthy controls. Neuropsychological assessment and MRI data were compared between these groups. Results: Compared to bvFTD, bvAD showed more significant visuospatial impairments (Rey Figure copy and recall), more irritability (Neuropsychological Inventory), and equivalent verbal memory (Philadelphia Verbal Learning Test). Compared to aAD, bvAD indicated more executive dysfunction (F-letter fluency) and better visuospatial performance. Neuroimaging analysis found that bvAD showed cortical thinning relative to bvFTD posteriorly in left temporal-occipital regions; bvFTD had cortical thinning relative to bvAD in left inferior frontal cortex. bvAD had cortical thinning relative to aAD in prefrontal and anterior temporal regions. All patient groups had lower volumes than controls in both anterior and posterior hippocampus. However, bvAD patients had higher average volume than aAD patients in posterior hippocampus and higher volume than bvFTD patients in anterior hippocampus after adjustment for age and intracranial volume. Conclusion: Findings demonstrated that underlying pathology mediates disease presentation in bvAD and bvFTD.

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.

Tauopathies: new perspectives and challenges

BACKGROUND

Tauopathies are a class of neurodegenerative disorders characterized by neuronal and/or glial tau-positive inclusions.

MAIN BODY

Clinically, tauopathies can present with a range of phenotypes that include cognitive/behavioral-disorders, movement disorders, language disorders and non-specific amnestic symptoms in advanced age. Pathologically, tauopathies can be classified based on the predominant tau isoforms that are present in the inclusion bodies (i.e., 3R, 4R or equal 3R:4R ratio). Imaging, cerebrospinal fluid (CSF) and blood-based tau biomarkers have the potential to be used as a routine diagnostic strategy and in the evaluation of patients with tauopathies. As tauopathies are strongly linked neuropathologically and genetically to tau protein abnormalities, there is a growing interest in pursuing of tau-directed therapeutics for the disorders. Here we synthesize emerging lessons on tauopathies from clinical, pathological, genetic, and experimental studies toward a unified concept of these disorders that may accelerate the therapeutics.

CONCLUSIONS

Since tauopathies are still untreatable diseases, efforts have been made to depict clinical and pathological characteristics, identify biomarkers, elucidate underlying pathogenesis to achieve early diagnosis and develop disease-modifying therapies.

Examining the presence and nature of delusions in Alzheimer's disease and frontotemporal dementia syndromes

OBJECTIVES

Abnormal beliefs and delusions have been reported in some people with dementia, however, the prevalence of delusions, and their neurocognitive basis has been underexplored. This study aimed to examine the presence, severity, content and neural correlates of delusions in a large, well-characterised cohort of dementia patients using a transdiagnostic, cross-sectional approach.

METHODS

Four-hundred and eighty-seven people with dementia were recruited: 102 Alzheimer's disease, 136 behavioural-variant frontotemporal dementia, 154 primary progressive aphasia, 29 motor neurone disease, 46 corticobasal syndrome, 20 progressive supranuclear palsy. All patients underwent neuropsychological assessment and brain magnetic resonance imaging, and the Neuropsychiatric Inventory was conducted with an informant, by an experienced clinician.

RESULTS

In our cohort, 48/487 patients (10.8%) had delusions. A diagnosis of behavioural-variant frontotemporal dementia (18.4%) and Alzheimer's disease (11.8%) were associated with increased risk of delusions. A positive gene mutation was observed in 11/27 people with delusions. Individuals with frequent delusions performed worse on the Addenbrooke's Cognitive Examination (p = 0.035), particularly on the orientation/attention (p = 0.022) and memory (p = 0.013) subtests. Voxel-based morphometry analyses found that increased delusional psychopathology was associated with reduced integrity of the right middle frontal gyrus, right planum temporale and left anterior temporal pole.

CONCLUSION

Our results demonstrate that delusions are relatively common in dementia and uncover a unique cognitive and neural profile associated with the manifestation of delusions. Clinically, delusions may lead to delayed or misdiagnosis. Our results shed light on how to identify individuals at risk of neuropsychiatric features of dementia, a crucial first step to enable targeted symptom management.

Apathy in UK Care Home Residents with Dementia: Longitudinal Course and Determinants

BACKGROUND

Apathy in dementia is common and associated with worse disease outcomes.

OBJECTIVE

To describe the longitudinal course of apathy in dementia and identify associated sociodemographic and disease-related factors.

METHODS

Prospective cohort study of UK care home residents with dementia. At baseline, 4, 8, 12, and 16 months, care home staff rated apathy using the Neuropsychiatric Inventory (clinically-significant apathy if≥4), dementia severity, and provided other sociodemographic information about each participant. We examined the prevalence and persistence of apathy and, in mixed linear models, its association with time, age, sex, dementia severity, antipsychotic use, and baseline apathy and other neuropsychiatric symptoms.

RESULTS

Of 1,419 included participants (mean age 85 years (SD 8.5)), 30% had mild dementia, 33% moderate, and 37% severe. The point prevalence of clinically-significant apathy was 21.4% (n = 304) and the 16-month period prevalence was 47.3% (n = 671). Of participants with follow-up data, 45 (3.8%) were always clinically-significantly apathetic, 3 (0.3%) were always sub-clinically apathetic, and 420 (36.2%) were never apathetic until death or end of follow-up. In adjusted models, apathy increased over time and was associated with having more severe dementia, worse baseline apathy and other neuropsychiatric symptoms.

CONCLUSION

It is important for clinicians to know that most people with dementia are not apathetic, though it is common. Most of those with significant symptoms of apathy improve without specific treatments, although some also relapse, meaning that intervention may not be needed. Future research should seek to target those people with persistent severe apathy and test treatments in this group.

Research Criteria for the Behavioral Variant of Alzheimer Disease: A Systematic Review and Meta-analysis

Importance

The behavioral variant of Alzheimer disease (bvAD) is characterized by early and predominant behavioral deficits caused by AD pathology. This AD phenotype is insufficiently understood and lacks standardized clinical criteria, limiting reliability and reproducibility of diagnosis and scientific reporting.

Objective

To perform a systematic review and meta-analysis of the bvAD literature and use the outcomes to propose research criteria for this syndrome.

Data Sources

A systematic literature search in PubMed/MEDLINE and Web of Science databases (from inception through April 7, 2021) was performed in duplicate.

Study Selection

Studies reporting on behavioral, neuropsychological, or neuroimaging features in bvAD and, when available, providing comparisons with typical amnestic-predominant AD (tAD) or behavioral variant frontotemporal dementia (bvFTD).

Data Extraction and Synthesis

This analysis involved random-effects meta-analyses on group-level study results of clinical data and systematic review of the neuroimaging literature. The study was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

Main Outcomes and Measures

Behavioral symptoms (neuropsychiatric symptoms and bvFTD core clinical criteria), cognitive function (global cognition, episodic memory, and executive functioning), and neuroimaging features (structural magnetic resonance imaging, [18F]fluorodeoxyglucose-positron emission tomography, perfusion single-photon emission computed tomography, amyloid positron emission tomography, and tau positron emission tomography).

Results

The search led to the assessment of 83 studies, including 13 suitable for meta-analysis. Data were collected for 591 patients with bvAD. There was moderate to substantial heterogeneity and moderate risk of bias across studies. Cases with bvAD showed more severe behavioral symptoms than tAD (standardized mean difference [SMD], 1.16 [95% CI, 0.74-1.59]; P < .001) and a trend toward less severe behavioral symptoms compared with bvFTD (SMD, -0.22 [95% CI, -0.47 to 0.04]; P = .10). Meta-analyses of cognitive data indicated worse executive performance in bvAD vs tAD (SMD, -1.03 [95% CI, -1.74 to -0.32]; P = .008) but not compared with bvFTD (SMD, -0.61 [95% CI, -1.75 to 0.53]; P = .29). Cases with bvAD showed a nonsignificant difference of worse memory performance compared with bvFTD (SMD, -1.31 [95% CI, -2.75 to 0.14]; P = .08) but did not differ from tAD (SMD, 0.43 [95% CI, -0.46 to 1.33]; P = .34). The neuroimaging literature revealed 2 distinct bvAD neuroimaging phenotypes: an AD-like pattern with relative frontal sparing and a relatively more bvFTD-like pattern characterized by additional anterior involvement, with the AD-like pattern being more prevalent.

Conclusions and Relevance

These data indicate that bvAD is clinically most similar to bvFTD, while it shares most pathophysiological features with tAD. Based on these insights, we propose research criteria for bvAD aimed at improving the consistency and reliability of future research and aiding the clinical assessment of this AD phenotype.

Cognitive and behavioural inhibition deficits in neurodegenerative dementias

Disinhibition, mainly caused by damage in frontotemporal brain regions, is one of the major causes of caregiver distress in neurodegenerative dementias. Behavioural inhibition deficits are usually described as a loss of social conduct and impulsivity, whereas cognitive inhibition deficits refer to impairments in the suppression of prepotent verbal responses and resistance to distractor interference. In this review, we aim to discuss inhibition deficits in neurodegenerative dementias through behavioural, cognitive, neuroanatomical and neurophysiological exploration. We also discuss impulsivity and compulsivity behaviours as related to disinhibition. We will therefore describe different tests available to assess both behavioural and cognitive disinhibition and summarise different manifestations of disinhibition across several neurodegenerative diseases (behavioural variant of frontotemporal dementia, Alzheimer's disease, Parkinson's disease, progressive supranuclear palsy, Huntington's disease). Finally, we will present the latest findings about structural, metabolic, functional, neurophysiological and also neuropathological correlates of inhibition impairments. We will briefly conclude by mentioning some of the latest pharmacological and non pharmacological treatment options available for disinhibition. Within this framework, we aim to highlight i) the current interests and limits of tests and questionnaires available to assess behavioural and cognitive inhibition in clinical practice and in clinical research; ii) the interpretation of impulsivity and compulsivity within the spectrum of inhibition deficits; and iii) the brain regions and networks involved in such behaviours.

Psychotic symptoms in frontotemporal dementia with right frontotemporal atrophy

Frontotemporal dementia (FTD) often mimics a primary psychiatric disorder. A subset of patients with FTD presents with psychotic symptoms either during the course of illness and less often prior to the onset of cognitive decline. This leads to delay in diagnosis and inappropriate exposure to high dose antipsychotic medication. Among the predictors for psychotic symptoms, the involvement of specific anatomical regions such as right frontotemporal lobe has been reported in few studies. We report a case of FTD presenting as late-onset psychosis with right frontotemporal atrophy.

Frontotemporal Dementia: Correlations Between Psychiatric Symptoms and Pathology

OBJECTIVE

The pathology of frontotemporal dementia, termed frontotemporal lobar degeneration (FTLD), is characterized by distinct molecular classes of aggregated proteins, the most common being TAR DNA-binding protein-43 (TDP-43), tau, and fused in sarcoma (FUS). With a few exceptions, it is currently not possible to predict the underlying pathology based on the clinical syndrome. In this study, we set out to investigate the relationship between pathological and clinical presentation at single symptom level, including neuropsychiatric features.

METHODS

The presence or absence of symptoms from the current clinical guidelines, together with neuropsychiatric features, such as hallucinations and delusions, were scored and compared across pathological groups in a cohort of 150 brain donors.

RESULTS

Our cohort consisted of 68.6% FTLD donors (35.3% TDP-43, 28% tau, and 5.3% FUS) and 31.3% non-FTLD donors with a clinical diagnosis of frontotemporal dementia and a different pathological substrate, such as Alzheimer's disease (23%). The presence of hyperorality points to FTLD rather than non-FTLD pathology (p < 0.001). Within the FTLD group, hallucinations in the initial years of the disease were related to TDP-43 pathology (p = 0.02), including but not limited to chromosome 9 open reading frame 72 (C9orf72) repeat expansion carriers. The presence of perseverative or compulsive behavior was more common in the TDP-B and TDP-C histotypes (p = 0.002).

INTERPRETATION

Our findings indicate that neuropsychiatric features are common in FTLD and form an important indicator of underlying pathology. In order to allow better inclusion of patients in targeted molecular trials, the routine evaluation of patients with frontotemporal dementia should include the presence and nature of neuropsychiatric symptoms. ANN NEUROL 2020;87:950-961.

The Neuropsychiatric Inventory: Development and Applications

REASONS FOR THE STUDY

The Neuropsychiatric Inventory (NPI) has been used for studies of neuropsychiatric symptoms in neurodegenerative disorders for the past 25 years. This article reviews the history of the development and application of the NPI.

MAIN FINDINGS

The NPI consists of 10 (or 12) items that are assayed with questions, subquestions, and ratings of frequency and severity. The NPI has been shown to be valid and reliable. The NPI has been translated into approximately 40 languages; it has 4 of versions designed for different clinical applications. The NPI studies show contrasting profiles of behavioral symptoms in different neurologic disorders. The NPI has been used in approximately 350 clinical trials. In economic studies, the NPI captures the cost of behavioral symptoms in dementias.

PRINCIPLE CONCLUSIONS

The NPI is a useful instrument for capturing behavioral changes in Alzheimer disease and other neurodegenerative disorders.

An Autopsy Case of Preclinical/Early Clinical Pick Disease

Here, we report a 74-year-old woman with a long history of schizophrenia but no clinical manifestation of dementia. Cause of death after autopsy was atherosclerotic heart disease. Although neuropathological investigation showed no significant brain atrophy, superficial microvacuolation with neuronal loss was restrictedly detected in the right anterior cingulate gyrus by microscopic examination. Pick bodies (PBs) positive for Bodian and Bielshowsky staining and 3-repeat-tau were detected in frontal and temporal lobes and limbic regions. Prevalence of PBs was most frequent in the right anterior cingulate gyrus and lateral base, followed by other neocortical regions of the frontal lobe, amygdala, and granular layer of the hippocampus. Although the number of glial inclusions was low, ramified astrocytes and various forms of astrocytes with AT8-positive inclusions were also found. Thus, the case may reflect preclinical or very early clinical Pick disease. Distribution of PBs does not necessarily have to be consistent with previously reported preclinical/early clinical Pick disease. These results show that tau pathology in the earlier stage of Pick disease may be heterogeneous, and the anterior cingulate gyrus may be initially affected in Pick disease. Neuropathological examination, including immunohistochemistry without case selection, is useful in identifying clinical and pathological manifestations of Pick disease.

Apathy and Disinhibition Related to Neuropathology in Amnestic Versus Behavioral Dementias

OBJECTIVES

Investigating the frequency of apathy and disinhibition in patients clinically diagnosed with dementia of the Alzheimer type (DAT) or behavioral variant frontotemporal dementia (bvFTD) with neuropathology of either Alzheimer disease (AD) or frontotemporal lobar degeneration (FTLD).

METHODS

Retrospective data from 887 cases were analyzed, and the frequencies of apathy and disinhibition were compared at baseline and longitudinally in 4 groups: DAT/AD, DAT/FTLD, bvFTD/FTLD, and bvFTD/AD.

RESULTS

Apathy alone was more common in AD (33%) than FTLD (25%), and the combination of apathy and disinhibition was more common in FTLD (43%) than AD (14%; P < .0001). Over time, apathy became more frequent in AD with increasing dementia severity (33%-41%; P < .006).

CONCLUSIONS

Alzheimer disease neuropathology had the closest association with the neuropsychiatric symptom of apathy, while FTLD was most associated with the combination of apathy and disinhibition. Over time, the frequency of those with apathy increased in both AD and FTLD neuropathology.

A review on shared clinical and molecular mechanisms between bipolar disorder and frontotemporal dementia

Mental disorders are highly prevalent and important causes of medical burden worldwide. Co-occurrence of neurological and psychiatric symptoms are observed among mental disorders, representing a challenge for their differential diagnosis. Psychiatrists and neurologists have faced challenges in diagnosing old adults presenting behavioral changes. This is the case for early frontotemporal dementia (FTD) and bipolar disorder. In its initial stages, FTD is characterized by behavioral or language disturbances in the absence of cognitive symptoms. Consequently, patients with the behavioral subtype of FTD (bv-FTD) can be initially misdiagnosed as having a psychiatric disorder, typically major depression disorder (MDD) or bipolar disorder (BD). Bipolar disorder is associated with a higher risk of dementia in older adults and with cognitive impairment, with a subset of patients presents a neuroprogressive pattern during the disease course. No mendelian mutations were identified in BD, whereas three major genetic causes of FTD have been identified. Clinical similarities between BD and bv-FTD raise the question whether common molecular pathways might explain shared clinical symptoms. Here, we reviewed existing data on clinical and molecular similarities between BD and FTD to propose biological pathways that can be further investigated as common or specific markers of BD and FTD.

Clinical features of the behavioural variant of frontotemporal dementia that are useful for predicting underlying pathological subtypes of frontotemporal lobar degeneration

BACKGROUND

The behavioural variant of frontotemporal dementia (bvFTD) is the most common phenotype of frontotemporal lobar degeneration (FTLD). FTLD is divided into three main pathological subtypes: tau-positive FTLD (FTLD-tau), FTLD-TAR DNA-binding protein (TDP), and FTLD-Fused in sarcoma (FUS). At present, it is difficult to predict the underlying pathological subtypes of sporadic bvFTD before a patient's death.

METHODS

We retrospectively investigated the clinical features of 34 Japanese patients with sporadic bvFTD, with or without motor neuron disease (MND), who had been pathologically diagnosed with FTLD. We examined whether, and how, the clinical features differed among Pick's disease, FTLD-TDP, and FTLD-FUS patients.

RESULTS

Six of the 34 patients developed MND during the course of bvFTD. These six bvFTD-MND patients were all pathologically diagnosed with FTLD-TDP. The other 28 patients were composed of 12 FTLD-tau patients including 11 Pick's disease patients, 8 FTLD-TDP patients, and 8 FTLD-FUS patients. A comparison of the clinical features of the three pathological subtypes of the 33 patients demonstrated that the age at onset was significantly younger in FTLD-FUS patients than in Pick's disease or FTLD-TDP patients. Furthermore, while hyperorality and dietary changes in the early stage of the disease were present in approximately 40% of Pick's disease and FTLD-FUS patients, they were absent in FTLD-TDP patients.

CONCLUSION

The comorbidity of MND, a younger age at onset, and hyperorality and dietary changes in the early stage may be useful clinical features for predicting underlying pathological subtypes of sporadic bvFTD. The results of our study should be confirmed by prospective studies employing a larger number of cases.

Semantic Memory in HIV-associated Neurocognitive Disorders: An Evaluation of the "Cortical" Versus "Subcortical" Hypothesis

OBJECTIVE

HIV-associated neurocognitive disorders (HAND) have historically been characterized as a subcortical condition that does not affect semantic memory; however, recent evidence suggests that the cortical regions that support semantic memory may be affected in HIV.

METHOD

The current study examined the effects of HAND on semantic memory in 85 HIV+ individuals with HAND, 193 HIV+ individuals without HAND, and 181 HIV- individuals who completed the Boston Naming Test (BNT) and the Famous Faces subtest of the Kauffman Adolescent and Adult Intelligence Test (KAIT-FF).

RESULTS

Linear regressions revealed a significant adverse effect of HAND on total scores on the BNT and the KAIT-FF (all ps < .01). Analyses of BNT errors showed that individuals with HAND committed more semantically related errors as compared to the other two study groups (all ps < .05). However, there were no group differences in rates of visually based errors, which are more commonly observed in traditional subcortical diseases (all ps > .10).

CONCLUSIONS

Results indicate that HAND may impose adverse effects on individuals' object naming and identification abilities suggestive of mild semantic deficits that parallel traditional cortical diseases such as Alzheimer's disease.

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.

[Emotional, affective and behavioral disorders in a behavioral variant of frontotemporal dementia]

AIM

To determine the prevalence and severity of non-cognitive nervous and psychiatric disorders (NNPD) in a behavioral variant of frontotemporal dementia.

MATERIAL AND METHODS

Twenty-nine patients with BVFTD, aged from 41 to 73 years (mean 60.7±8.1 years), were studied. All patients underwent neurological and neuropsychological examinations. NNPD were assessed using the Neuropsychiatric Inventory (J. Cummings et al). Twenty-seven patients underwent brain MRI with T1, T2 and FLAIR sequences.

RESULTS

The most clinically significant symptoms of NNPD were apathy, behavioral disinhibition, eating disorders, abnormal motor activity and euphoria. Irritability, sleep disorders and excitement were less frequent. Anxiety and depression were identified in 13.8 and 20.7% of the patients, respectively. The severity of NNPD can increase and their spectrum can be qualitatively changed with the disease progression that indicates the spread of the neurodegenerative process.

CONCLUSION

Patients with BVFTD had all NNPD with the exception of delusion and hallucinations. The character and degree of severity of some emotional, affective and behavioral disorders are associated with the predominant localization of the pathological process in frontal and temporal brain regions.

Clinicopathological correlations in behavioural variant frontotemporal dementia

Accurately predicting the underlying neuropathological diagnosis in patients with behavioural variant frontotemporal dementia (bvFTD) poses a daunting challenge for clinicians but will be critical for the success of disease-modifying therapies. We sought to improve pathological prediction by exploring clinicopathological correlations in a large bvFTD cohort. Among 438 patients in whom bvFTD was either the top or an alternative possible clinical diagnosis, 117 had available autopsy data, including 98 with a primary pathological diagnosis of frontotemporal lobar degeneration (FTLD), 15 with Alzheimer's disease, and four with amyotrophic lateral sclerosis who lacked neurodegenerative disease-related pathology outside of the motor system. Patients with FTLD were distributed between FTLD-tau (34 patients: 10 corticobasal degeneration, nine progressive supranuclear palsy, eight Pick's disease, three frontotemporal dementia with parkinsonism associated with chromosome 17, three unclassifiable tauopathy, and one argyrophilic grain disease); FTLD-TDP (55 patients: nine type A including one with motor neuron disease, 27 type B including 21 with motor neuron disease, eight type C with right temporal lobe presentations, and 11 unclassifiable including eight with motor neuron disease), FTLD-FUS (eight patients), and one patient with FTLD-ubiquitin proteasome system positive inclusions (FTLD-UPS) that stained negatively for tau, TDP-43, and FUS. Alzheimer's disease was uncommon (6%) among patients whose only top diagnosis during follow-up was bvFTD. Seventy-nine per cent of FTLD-tau, 86% of FTLD-TDP, and 88% of FTLD-FUS met at least 'possible' bvFTD diagnostic criteria at first presentation. The frequency of the six core bvFTD diagnostic features was similar in FTLD-tau and FTLD-TDP, suggesting that these features alone cannot be used to separate patients by major molecular class. Voxel-based morphometry revealed that nearly all pathological subgroups and even individual patients share atrophy in anterior cingulate, frontoinsula, striatum, and amygdala, indicating that degeneration of these regions is intimately linked to the behavioural syndrome produced by these diverse aetiologies. In addition to these unifying features, symptom profiles also differed among pathological subtypes, suggesting distinct anatomical vulnerabilities and informing a clinician's prediction of pathological diagnosis. Data-driven classification into one of the 10 most common pathological diagnoses was most accurate (up to 60.2%) when using a combination of known predictive factors (genetic mutations, motor features, or striking atrophy patterns) and the results of a discriminant function analysis that incorporated clinical, neuroimaging, and neuropsychological data.

Determinants of behavioral and psychological symptoms of dementia: A scoping review of the evidence

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) are prevalent in people with neurodegenerative diseases.

PURPOSE

In this scoping review the Kales, Gitlin and Lykestos framework is used to answer the question: What high quality evidence exists for the patient, caregiver and environmental determinants of five specific BPSD: aggression, agitation, apathy, depression and psychosis?

METHOD

An a priori review protocol was developed; 692 of 6013 articles retrieved in the search were deemed eligible for review. Gough's Weight of Evidence Framework and the Cochrane Collaboration's tool for assessing risk of bias were used. The findings from 56 high quality/low bias articles are summarized.

DISCUSSION

Each symptom had its own set of determinants, but many were common across several symptoms: neurodegeneration, type of dementia, severity of cognitive impairments, and declining functional abilities, and to a lesser extent, caregiver burden and communication.

CONCLUSION

Research and policy implications are relevant to the National Plan to Address Alzheimer's Disease.

Diagnosing the frontal variant of Alzheimer's disease: a clinician's yellow brick road

Background

Disruption of the frontal lobes and its associated networks are a common consequence of neurodegenerative disorders. Given the wide range of cognitive, behavioral and motor processes in which the frontal lobes are involved, there can be a great variety of manifestations depending on the pathology distribution. The most common are the behavioral variant of frontotemporal dementia (bvFTD) and the frontal variant of Alzheimer’s disease (fvAD), which are particularly challenging to disentangle. Recognizing fvAD from bvFTD-related pathologies is a diagnostic challenge and a critical need in the management and counseling of these patients.

Case presentation

Here we present three pathology-proven cases of Alzheimer’s disease initially misdiagnosed as bvFTD and discuss the distinctive or less overlapping historical, examination, and laboratory findings of fvAD and bvFTD, deriving analogies for mnemonic endurance from the Wizard of Oz worldview.

Conclusion

The Yellow Brick Road to diagnosing these disorders may be served by the metaphor of fvAD as the irritable, paranoid, and tremulous Scarecrow and bvFTD the heartless, ritualistic, and rigid Tin Man. An Oz-inspired creative license may help the clinician recognize the differential disease progression, caregiver burden, and treatment response of fvAD compared with bvFTD.

Electronic supplementary material

The online version of this article (doi:10.1186/s40734-017-0052-4) contains supplementary material, which is available to authorized users.

Executive Dysfunction and Behavioral Symptoms Are Associated with Deficits in Instrumental Activities of Daily Living in Frontotemporal Dementia

BACKGROUND

Deficits in instrumental activities of daily living (ADLs) may be more prominent in behavioral variant frontotemporal dementia (bvFTD) than in nonfluent/agrammatic variant primary progressive aphasia (nfvPPA) or semantic variant primary progressive aphasia (svPPA). It is uncertain whether frontotemporal dementia (FTD) subgroups exhibit different patterns and/or predictors of functional impairment.

METHODS

We examined data from participants diagnosed with bvFTD (n = 607), svPPA (n = 132), and nfvPPA (n = 155) who were included in the National Alzheimer's Coordinating Center (NACC) Uniform Data Set (UDS) and assessed with the Functional Activities Questionnaire (FAQ). Stepwise multiple linear regression analyses were performed to identify associations between FAQ scores and cognitive/behavioral deficits using the NACC UDS neuropsychological testing battery and the Neuropsychiatric Inventory Questionnaire.

RESULTS

FAQ scores were higher in bvFTD than svPPA or nfvPPA. Functional deficits across FTD subtypes differed in severity, but not pattern, and were driven by executive dysfunction and behavioral symptoms.

CONCLUSION

Executive dysfunction and behavioral symptoms underlie instrumental ADL deficits in FTD, which are most prominent in bvFTD.

[Reconciliating neurology and psychiatry: The prototypical case of frontotemporal dementia]

Frontotemporal degeneration (FTD) in its behavioral variant (bvFTD) is probably one of the conditions that best illustrates the links between psychiatry and neurology. It is indeed admitted that between a third and half of patients with this condition, especially in early-onset forms, receive an initial diagnosis of psychiatric disorder (depression, schizophrenia, bipolar disorder) and are then referred to a psychiatric ward. BvFTD can thus be considered a neurological disorder with a psychiatric presentation. Among psychiatric symptoms reported in this disease, psychotic symptoms (hallucinations, delusions, especially of persecution), which have long been underestimated in bvFTD and are not part of the current diagnostic criteria, are present in about 20% of cases and may be inaugural. They are particularly common in the genetic forms related to a mutation in the C9orf72 gene (up to 50%), and to a lesser extent in the GRN gene (up to 25%). C9orf72 gene mutation is often associated with a family history of dementia or motor neuron disease but also of psychiatric disorders. It has also been described in sporadic presentation forms. Sometimes, the moderate degree of brain atrophy on MRI described in patients carrying this mutation may complicate the differential diagnosis with late-onset psychiatric diseases. In the present article, we underline the importance of considering that psychiatric - especially psychotic - symptoms are not rare in bvFTD, which should lead to a revision of the diagnostic criteria of this disease by taking greater account of this fact. We also propose a diagnostic chart, based on concerted evaluation by neurologists and psychiatrists for cases of atypical psychiatric symptoms (late-onset or pharmacoresistant troubles) leading to consider the possibility of a neurological disorder, in order to shed a new light on these difficult clinical situations. In the field of research, bvFTD may constitute a model to explore the neural basis of certain psychiatric disorders, and a possible molecular link between bvFTD and psychoses, which could eventually lead to new therapeutic approaches, has been recently suggested. Thus, bvFTD illustrates how the links between neurology and psychiatry are close and tend to evolve with the progress of scientific knowledge. It is necessary to strengthen collaboration between the two disciplines both to improve the care - diagnosis and management of these patients - and to promote the emergence of innovative clinical research.

Using the Disease State Fingerprint Tool for Differential Diagnosis of Frontotemporal Dementia and Alzheimer's Disease

BACKGROUND

Disease State Index (DSI) and its visualization, Disease State Fingerprint (DSF), form a computer-assisted clinical decision making tool that combines patient data and compares them with cases with known outcomes.

AIMS

To investigate the ability of the DSI to diagnose frontotemporal dementia (FTD) and Alzheimer's disease (AD).

METHODS

The study cohort consisted of 38 patients with FTD, 57 with AD and 22 controls. Autopsy verification of FTD with TDP-43 positive pathology was available for 14 and AD pathology for 12 cases. We utilized data from neuropsychological tests, volumetric magnetic resonance imaging, single-photon emission tomography, cerebrospinal fluid biomarkers and the APOE genotype. The DSI classification results were calculated with a combination of leave-one-out cross-validation and bootstrapping. A DSF visualization of a FTD patient is presented as an example.

RESULTS

The DSI distinguishes controls from FTD (area under the receiver-operator curve, AUC = 0.99) and AD (AUC = 1.00) very well and achieves a good differential diagnosis between AD and FTD (AUC = 0.89). In subsamples of autopsy-confirmed cases (AUC = 0.97) and clinically diagnosed cases (AUC = 0.94), differential diagnosis of AD and FTD performs very well.

CONCLUSIONS

DSI is a promising computer-assisted biomarker approach for aiding in the diagnostic process of dementing diseases. Here, DSI separates controls from dementia and differentiates between AD and FTD.

The behavioral variant of frontotemporal dementia: An analysis of the literature and a case report

The aim of this case report is to underline the importance of possible legal consequences of the behavioral variant of frontotemporal dementia (bvFTD). This disease is associated with antisocial behavior, impulse control disorder and cognitive and personality impairment, which are often the earliest manifestations of the bvFTD. One of the antisocial behaviors possibly associated with this neurodegenerative disease is pathological stealing. This case report is about a 50-year-old Italian man who had a regular life until 2010. In 2010 and 2011, some critical events occurred: he lost his job, his father-in-law, to whom he was particularly close, died, and his wife had a serious illness. He began to show symptoms of depression, a significant weight loss, apathy, poor self-care, and lack of interest in the activities of his family. He became disengaged from his prior activities, emotionally detached from his family and developed compulsive hoarding. Moreover, he had uninhibited behaviors, a memory retrieval deficit, executive dysfunctions and impulsive behaviors. In January 2012, the subject began stealing objects, particularly components of computer, without premeditation or concern for resulting legal actions. He was then diagnosed affected by bvFTD. He was charged with theft and attempted theft and the Court asked for a psychiatric evaluation, in order to analyze the effect of the neurodegenerative disease on his behavior. To answer to the Court, the Authors analyzed his history of life and made a mental examination. The subject was considered mentally insane at the time of his crimes. This is an example of the practical application in judicial cases of the latest knowledge and evidence in the literature about the frontotemporal dementia, a disease associated with antisocial behaviors that could create tensions with the criminal law. The focus of the paper is to explain how the behavioral symptoms of bvFTD can have legal implications and how to deal with legal aspects of the behaviors induced by a neuro-psychiatric condition, such as bvFTD.

Psychotic symptoms in frontotemporal dementia

Although psychotic features have long been recognized in association with frontotemporal dementia (FTD), recent genetic discoveries enabling further subtyping of FTD have revealed that psychotic symptoms are frequent in some forms of FTD. Hallucinations and delusions can even precede onset of other cognitive or behavioural symptoms in patients with FTD. In this review, we explore the frequency and types of psychotic symptoms reported in patients with FTD, as well as in other neuropsychiatric disorders, to aid practitioners' consideration of these features in the diagnosis of FTD and related disorders.

Memory Test Performance on Analogous Verbal and Nonverbal Memory Tests in Patients with Frontotemporal Dementia and Alzheimer's Disease

BACKGROUND

Patients with frontotemporal dementia (FTD) typically have initial deficits in language or changes in personality, while the defining characteristic of Alzheimer's disease (AD) is memory impairment. Neuropsychological findings in the two diseases tend to differ, but can be confounded by verbal impairment in FTD impacting performance on memory tests in these patients.

METHODS

Twenty-seven patients with FTD and 102 patients with AD underwent a neuropsychological assessment before diagnosis. By utilizing analogous versions of a verbal and nonverbal memory test, we demonstrated differences in these two modalities between AD and FTD.

DISCUSSION

Better differentiation between AD and FTD is found in a nonverbal memory test, possibly because it eliminates the confounding variable of language deficits found in patients with FTD. These results highlight the importance of nonverbal learning tests with multiple learning trials in diagnostic testing.

The frontotemporal dementias

Frontotemporal dementia (FTD) is a heterogeneous group of hereditary and sporadic neurodegenerative disorders affecting frontotemporal areas. FTD, a leading cause of young-onset dementia, is often initially mistaken for primary psychiatric disorders. Based on early and predominant symptoms, different clinical syndromes can be distinguished: the behavioral variant and 2 variants of progressive aphasia; semantic dementia and progressive nonfluent aphasia. Neuropathological classification is based on protein accumulation in the brain. Pathogenic mutations in different genes have been identified. Specific pharmacological treatment is the main research goal. Meanwhile the management must focus on early correct diagnosis, symptom alleviation, caregiver support and educational interventions.

Psychotic symptoms in frontotemporal dementia: a diagnostic dilemma?

BACKGROUND

Frontotemporal dementia (FTD) constitutes a spectrum of neurodegenerative disorders associated with degeneration of, predominantly, the frontal and temporal lobes. The clinical heterogeneity is evident, and early diagnosis is a challenge. The primary objectives were to characterize psychotic symptoms, initial clinical diagnoses and family history in neuropathologically verified FTD-patients and to analyze possible correlations with different neuropathological findings.

METHODS

The medical records of 97 consecutive patients with a neuropathological diagnosis of frontotemporal lobar degeneration (FTLD) were reevaluated. Psychotic symptoms (hallucinations, delusions, paranoid ideas), initial diagnosis and family history for psychiatric disorders were analyzed.

RESULTS

Psychotic symptoms were present in 31 patients (32%). There were no significant differences in age at onset, disease duration or gender between patients with and without psychotic symptoms. Paranoid ideas were seen in 20.6%, and hallucinations and delusions in 17.5% in equal measure. Apart from a strong correlation between psychotic symptoms and predominantly right-sided brain degeneration, the majority of patients (77.4%) were tau-negative. Only 14.4% of the patients were initially diagnosed as FTD, while other types of dementia were seen in 34%, other psychiatric disorders in 42%, and 9.2% with other cognitive/neurological disorders. The patients who were initially diagnosed with a psychiatric disorder were significantly younger than the patients with other initial clinical diagnoses. A positive heredity for dementia or other psychiatric disorder was seen in 42% and 26% of the patients respectively.

CONCLUSIONS

Psychotic symptoms, not covered by current diagnostic criteria, are common and may lead to clinical misdiagnosis in FTD.

Interactions between traumatic brain injury and frontotemporal degeneration

BACKGROUND/AIMS

Prior work in smaller cohorts suggests that traumatic brain injury (TBI) may be a risk factor for frontotemporal degeneration (FTD). We sought to confirm and extend these results using the National Alzheimer's Coordinating Center Uniform Data Set.

METHODS

We compared the TBI prevalence between FTD subjects and matched normal controls. Indices of cognitive, behavioral, functional, and global dementia severity were compared between FTD subjects with and without prior TBI.

RESULTS

Remote TBI with extended loss of consciousness (TBI-ext) was more common in individuals with FTD than in controls (OR: 1.67; 95% CI: 1.004-2.778). With TBI-ext, less functional and global impairment was seen in the behavioral variant of FTD, but more behavioral pathology was seen in the semantic variant.

CONCLUSION

TBI may increase the FTD risk and influence clinical symptomatology and severity in FTD subtypes.

A scale of socioemotional dysfunction in frontotemporal dementia

Early social dysfunction is a hallmark symptom of behavioral variant frontotemporal dementia (bvFTD); however, validated measures for assessing social deficits in dementia are needed. The purpose of the current study was to examine the utility of a novel informant-based measure of social impairment, the Socioemotional Dysfunction Scale (SDS) in early-onset dementia. Sixteen bvFTD and 18 early-onset Alzheimer's disease (EOAD) participants received standard clinical neuropsychological measures and neuroimaging. Caregiver informants were administered the SDS. Individuals with bvFTD exhibited greater social dysfunction on the SDS compared with the EOAD group; t(32) = 6.32, p < .001. The scale demonstrated preliminary evidence for discriminating these frequently misdiagnosed groups (area under the curve = 0.920, p = <.001) and internal consistency α = 0.977. The SDS demonstrated initial evidence as an effective measure for detecting abnormal social behavior and discriminating bvFTD from EOAD. Future validation is recommended in larger and more diverse patient groups.

Neuropsychiatric aspects of dementia

Dementia affects approximately 6.5% of people over the age of 65. Whilst cognitive impairment is central to the dementia concept, neuropsychiatric symptoms are invariably present at some stage of the illness. Neuropsychiatric symptoms result in a number of negative outcomes for the individual and their caregivers and are associated with higher rates of institutionalization and mortality. A number of factors have been associated with neuropsychiatric symptoms including neurobiological changes, dementia type, and illness severity and duration. Specific patient, caregiver and environmental factors are also important. Neuropsychiatric symptoms can be broadly divided into four clusters: psychotic symptoms, mood/affective symptoms, apathy, and agitation/aggression. Neuropsychiatric symptoms tend to persist over time although differing symptom profiles exist at various stages of the illness. Assessment should take into account the presenting symptoms together with an appreciation of the myriad of likely underlying causes for the symptoms. A structured assessment/rating tool can be helpful. Management should focus on non-pharmacological measures initially with pharmacological approaches reserved for more troubling symptoms. Pharmacological approaches should target specific symptoms although the evidence-base for pharmacological management is quite modest. Any medication trial should include an adequate appreciation of the risk-benefit profile in individual patients and discussion of these with both the individual and their caregiver.