The Modified Frontal Behavioral Inventory (FBI-mod) for Patients with Frontotemporal Lobar Degeneration, Alzheimer’s Disease, and Mild Cognitive Impairment

A systematic review of cognitive and behavioral tools to differentiate behavioral variant frontotemporal dementia from other conditions

The behavioral variant of frontotemporal dementia (bvFTD) is thought to be the commonest clinical presentation of frontotemporal lobar degeneration and is predominantly characterized by changes in behavior. In patients lacking unequivocal biomarker evidence of frontotemporal neurodegeneration, the clinical diagnosis of bvFTD is often unstable. In response, we conducted a systematic review and critical appraisal of cognitive and behavioral tools that have sought to differentiate bvFTD from other conditions. A systematic literature review of PubMed, Scopus, and Web of Science was conducted on December 31, 2023 for cognitive and behavioral tools that differentiated bvFTD from other cohorts. Ninety-six studies were included. The quality appraisal of almost all studies was low and introduced a high risk of bias. The few studies that were of high quality had a prospective study design and recruited patients suspected (but not yet confirmed) to have bvFTD. These studies reported that behavioral tools (e.g., the Frontal Behavioral Inventory) and social cognition tests (e.g., the Ekman's Faces Test) had good test performance in differentiating bvFTD from a broad range of psychiatric and neurological conditions. Importantly, the review highlighted the extreme paucity of studies that have evaluated methods where, in Bayesian terms, there is genuine clinical uncertainty regarding a diagnosis of bvFTD. Most studies used healthy controls of typical Alzheimer's disease as comparators-groups that often have negligible pretest probability of bvFTD. In response, we propose a study design checklist for studies seeking to develop diagnostic algorithms in bvFTD research.

Neuropsychological Profiles, Etiologies, and Medical Comorbidities in Early-Onset Dementia and Cognitive Impairment: A Memory Outpatient Clinic Cohort Study

Background

Although early-onset dementia (EOD) is associated with diagnostic challenges that differ from those of related to late-onset dementia, only limited studies have addressed the neuropsychological and health characteristics or specified the diagnoses underlying early-onset cognitive impairment in a real-world clinical setting.

Objective

To investigate the neuropsychological profiles, etiologies, and comorbidities of an unselected cohort of memory clinic patients (≤65 years at symptom onset).

Methods

The patients' (n = 210) diagnoses were determined based on comprehensive diagnostic workup. Medical comorbidities and neuropsychological profiles were compared between clinically relevant patient groups, namely early-onset dementia (n = 55), mild cognitive impairment due to vascular or suspected neurodegenerative (MCI-n, n = 35) or non-neurodegenerative (MCI-o, n = 106) etiologies, and subjective cognitive decline (n = 14).

Results

The most prevalent diagnoses were Alzheimer's disease (AD, 14%) and depression (11%). Multiple prior medical conditions were common (67%); however, EOD patients had fewer other diagnoses (p = 0.008) than MCI-o patients. Compared to other groups, EOD patients had more severe deficits (p < 0.001) on immediate and delayed memory, processing speed, symptom awareness, and global cognition. AD patients had weaker memory retention ability but less behavioral symptoms than frontotemporal dementia (FTD) patients (p≤0.05). Depression was associated with better immediate memory, symptom awareness, and global cognition than AD and FTD (p < 0.05).

Conclusions

EOD is associated with more severe and widespread neuropsychological deficits but fewer prior medical diagnoses than nondegenerative etiologies of cognitive impairment. AD and depression are common etiologies and the neuropsychological profiles are partly overlapping; however, memory, symptom awareness and global cognitive impairment measures may help in the differential diagnosis.

Apraxia testing to distinguish early Alzheimer's disease from psychiatric causes of cognitive impairment

Objective: Mood- and stress-related disorders commonly cause attentional and memory impairments in middle-aged individuals. In memory testing, these impairments can be mistakenly interpreted as symptoms of dementia; thus, more reliable diagnostic approaches are needed. The present work defines the discriminant accuracy of the Dementia Apraxia Test (DATE) between psychiatric conditions and early-onset Alzheimer's disease (AD) on its own and in combination with memory tests. Method: The consecutive sample included 50-70-year-old patients referred to dementia investigations for recent cognitive and/or affective symptoms. The DATE was administered and scored as a blinded measurement, and a receiver operating curve analysis was used to define the optimal diagnostic cut-off score. Results: A total of 24 patients were diagnosed with probable AD (mean age 61 ± 4) and 23 with a psychiatric condition (mean age 57 ± 4). The AD patients showed remarkable limb apraxia, but the psychiatric patients mainly performed at a healthy level on the DATE. The test showed a total discriminant accuracy of 87% for a total sum cut-off of 47 (sensitivity 79% and specificity 96%). The limb subscale alone reached an accuracy of 91% for a cut-off of 20 (sensitivity 83% and specificity 100%). All memory tests were diagnostically less accurate, while the combination of the limb praxis subscale and a verbal episodic memory test suggested a correct diagnosis in all but one patient. Conclusions: Apraxia testing may improve the accuracy of differentiation between AD and psychiatric aetiologies. Its potential in severe and chronic psychiatric conditions should be examined in the future.

Diagnóstico da demência frontotemporal: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia

RESUMO A “demência frontotemporal” (DFT) é uma síndrome clínica, cujo denominador comum é o acometimento focal dos lobos frontais e/ou temporais. A DFT tem três fenótipos clínicos distintos: a variante comportamental e dois subtipos linguísticos, a saber, a afasia progressiva primária não-fluente/agramática (APP-NF/A) e a afasia progressiva primária semântica (APP-S). A DFT é a segunda causa mais comum de demência em indivíduos com idade inferior a 65 anos, após a doença de Alzheimer. O presente artigo apresenta recomendações para diagnóstico da DFT no cenário brasileiro, considerando os três níveis de complexidade do sistema de saúde: atenção primária à saúde e níveis secundários. São propostos protocolos de investigação diagnóstica abrangendo testagem cognitiva, avaliação comportamental, avaliação fonoaudiológica, exames laboratoriais e de neuroimagem.

Diagnosis of frontotemporal dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

ABSTRACT “Frontotemporal dementia” (FTD) is a clinical syndrome characterized by the focal involvement of the frontal and/or temporal lobes. FTD has three clinical phenotypes: the behavioral variant and two linguistic subtypes, namely, non-fluent/agrammatic primary progressive aphasia (PPA-NF/A) and semantic PPA (PPA-S). FTD is the second most common cause of dementia in individuals under the age of 65 years. This article presents recommendations for the diagnosis of FTD in the Brazilian scenario, considering the three levels of complexity of the health system: primary health care, secondary and tertiary levels. Diagnostic guidelines are proposed, including cognitive testing, behavioral and language assessments, laboratory tests, and neuroimaging.

Early Identification of Different Behavioral Phenotypes in the Behavioral Variant of Frontotemporal Dementia with the Aid of the Mini-Frontal Behavioral Inventory (mini-FBI)

Background: The Frontal Behavioral Inventory (FBI) is a questionnaire designed to quantify behavioral changes in frontotemporal dementia (FTD). Literature showed heterogeneous FBI profiles in FTD versus Alzheimer’s disease (AD) with variable occurrence of positive and negative symptoms. Objective: In this study, we constructed a short FBI version (i.e., mini-FBI) with the aim to provide clinicians with a short tool for the identification of early behavioral changes in behavioral variant of FTD (bvFTD), also facilitating the differential diagnosis with AD. Methods: 40 bvFTD and 33 AD patients were enrolled. FBI items were selected based on internal consistency and exploratory factor analysis. Convergent validity of mini-FBI was also assessed. A behavioral index (i.e., B-index) representing the balance between positive and negative mini-FBI symptoms was computed in order to analyze its distribution in bvFTD through a cluster analysis and to compare performance among patient groups. Results: The final version of the mini-FBI included 12 items, showing a significant convergent validity with the Neuropsychiatric Inventory scores (rp = 0.61, p < 0.001). Cluster analysis split patients in four clusters. bvFTD were included in three different clusters characterized by prevalent positive symptoms, both positive and negative symptoms, or prevalent negative behavioral alterations, similar to a subset of AD patients. A fourth cluster included only AD patients showing no positive symptoms. Conclusion: The mini-FBI is a valuable easily administrable questionnaire able to early identify symptoms effectively contributing to the bvFTD behavioral syndrome, aiding clinician in diagnosis and management.

Network analysis of impulse dyscontrol in mild cognitive impairment and subjective cognitive decline

OBJECTIVES

To investigate conditional dependence relationships of impulse dyscontrol symptoms in mild cognitive impairment (MCI) and subjective cognitive decline (SCD).

DESIGN

A prospective, observational study.

PARTICIPANTS

Two hundred and thirty-five patients with MCI (n = 159) or SCD (n = 76) from the Prospective Study for Persons with Memory Symptoms dataset.

MEASUREMENTS

Items of the Mild Behavioral Impairment Checklist impulse dyscontrol subscale.

RESULTS

Stubbornness/rigidity, agitation/aggressiveness, and argumentativeness were frequent and the most central symptoms in the network. Impulsivity, the fourth most central symptom in the network, served as the bridge between these common symptoms and less central and rare symptoms.

CONCLUSIONS

Impulse dyscontrol in at-risk states for dementia is characterized by closely connected symptoms of irritability, agitation, and rigidity. Compulsions and difficulties in regulating rewarding behaviors are relatively isolated symptoms.

The Frontal Behavioral Battery: A Measure of Frontal Lobe Symptoms in Brain Aging and Neurodegenerative Disease

BACKGROUND

Approximately 90%of persons living with dementia experience behavioral symptoms, including frontal lobe features involving motivation, planning, social behavior, language, personality, mood, swallowing, and gait.

OBJECTIVE

We conducted a two-stage study with a development sample (n = 586) and validation sample (n = 274) to evaluate a brief informant-rated measure of non-cognitive features of frontal lobe dysfunction: the Frontal Behavioral Battery (FBB).

METHODS

In the development sample, internal consistency, principal factor analysis, and correlations between the FBB and outcomes were evaluated. In the validation sample, we examined (a) FBB scores by diagnosis, (b) known-group validity by demographics, subjective complaints, and dementia staging, and (c) correlation between FBB and MRI volumes. Receiver operator characteristic curves assessed the ability of the FBB to discriminate individuals with frontal lobe features due to a neurodegenerative disease.

RESULTS

The FBB characterized 11 distinct frontal lobe features. Individuals with dementia with Lewy bodies and frontotemporal degeneration had the greatest number of frontal lobe features. Premorbid personality traits of extroversion, agreeableness, and openness were associated with fewer frontal lobe behavioral symptoms, while subjective cognitive complaints were associated with greater symptoms. The FBB provided very good discrimination between individuals with and without cognitive impairment (diagnostic odds ratio: 13.1) and between individuals with and without prominent frontal lobe symptoms (diagnostic odds ratio: 84.8).

CONCLUSION

The FBB may serve as an effective and efficient method to assess the presence of non-cognitive symptoms associated with frontal lobe dysfunction, but in a brief fashion that could facilitate its use in clinical care and research.

Recommendations to distinguish behavioural variant frontotemporal dementia from psychiatric disorders

The behavioural variant of frontotemporal dementia (bvFTD) is a frequent cause of early-onset dementia. The diagnosis of bvFTD remains challenging because of the limited accuracy of neuroimaging in the early disease stages and the absence of molecular biomarkers, and therefore relies predominantly on clinical assessment. BvFTD shows significant symptomatic overlap with non-degenerative primary psychiatric disorders including major depressive disorder, bipolar disorder, schizophrenia, obsessive-compulsive disorder, autism spectrum disorders and even personality disorders. To date, ∼50% of patients with bvFTD receive a prior psychiatric diagnosis, and average diagnostic delay is up to 5-6 years from symptom onset. It is also not uncommon for patients with primary psychiatric disorders to be wrongly diagnosed with bvFTD. The Neuropsychiatric International Consortium for Frontotemporal Dementia was recently established to determine the current best clinical practice and set up an international collaboration to share a common dataset for future research. The goal of the present paper was to review the existing literature on the diagnosis of bvFTD and its differential diagnosis with primary psychiatric disorders to provide consensus recommendations on the clinical assessment. A systematic literature search with a narrative review was performed to determine all bvFTD-related diagnostic evidence for the following topics: bvFTD history taking, psychiatric assessment, clinical scales, physical and neurological examination, bedside cognitive tests, neuropsychological assessment, social cognition, structural neuroimaging, functional neuroimaging, CSF and genetic testing. For each topic, responsible team members proposed a set of minimal requirements, optimal clinical recommendations, and tools requiring further research or those that should be developed. Recommendations were listed if they reached a ≥ 85% expert consensus based on an online survey among all consortium participants. New recommendations include performing at least one formal social cognition test in the standard neuropsychological battery for bvFTD. We emphasize the importance of 3D-T1 brain MRI with a standardized review protocol including validated visual atrophy rating scales, and to consider volumetric analyses if available. We clarify the role of 18F-fluorodeoxyglucose PET for the exclusion of bvFTD when normal, whereas non-specific regional metabolism abnormalities should not be over-interpreted in the case of a psychiatric differential diagnosis. We highlight the potential role of serum or CSF neurofilament light chain to differentiate bvFTD from primary psychiatric disorders. Finally, based on the increasing literature and clinical experience, the consortium determined that screening for C9orf72 mutation should be performed in all possible/probable bvFTD cases or suspected cases with strong psychiatric features.

The Association Between Distinct Frontal Brain Volumes and Behavioral Symptoms in Mild Cognitive Impairment, Alzheimer's Disease, and Frontotemporal Dementia

Our aim was to investigate the association between behavioral symptoms of agitation, disinhibition, irritability, elation, and aberrant motor behavior to frontal brain volumes in a cohort with various neurodegenerative diseases. A total of 121 patients with mild cognitive impairment (MCI, n = 58), Alzheimer's disease (AD, n = 45) and behavioral variant frontotemporal dementia (bvFTD, n = 18) were evaluated with a Neuropsychiatric Inventory (NPI). A T1-weighted MRI scan was acquired for each participant and quantified with a multi-atlas segmentation method. The volumetric MRI measures of the frontal lobes were associated with neuropsychiatric symptom scores with a linear model. In the regression model, we included CDR score and TMT B time as covariates to account for cognitive and executive functions. The brain volumes were corrected for age, gender and head size. The total behavioral symptom score of the five symptoms of interest was negatively associated with the volume of the subcallosal area (β = −0.32, p = 0.002). High disinhibition scores were associated with reduced volume in the gyrus rectus (β = −0.30, p = 0.002), medial frontal cortex (β = −0.30, p = 0.002), superior frontal gyrus (β = −0.28, p = 0.003), inferior frontal gyrus (β = −0.28, p = 0.005) and subcallosal area (β = −0.28, p = 0.005). Elation scores were associated with reduced volumes of the medial orbital gyrus (β = −0.30, p = 0.002) and inferior frontal gyrus (β = −0.28, p = 0.004). Aberrant motor behavior was associated with atrophy of frontal pole (β = −0.29, p = 0.005) and the subcallosal area (β = −0.39, p < 0.001). No significant associations with frontal brain volumes were found for agitation and irritability. We conclude that the subcallosal area may be common neuroanatomical area for behavioral symptoms in neurodegenerative diseases, and it appears to be independent of disease etiology.

Psychological and Cognitive Markers of Behavioral Variant Frontotemporal Dementia-A Clinical Neuropsychologist's View on Diagnostic Criteria and Beyond

Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.