The Psychiatric Misdiagnosis of Behavioral Variant Frontotemporal Dementia in a Colombian Sample

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.

A Case of Posterior Cortical Atrophy Presenting with Mood and Psychotic Symptoms

Posterior cortical atrophy (PCA) is a rare neurodegenerative disorder characterized by predominant visual deficits due to its atrophy of the occipital lobes. Patients typically have preserved cognitive function during the early stages, making diagnosis more difficult when compared to other neurocognitive disorders. In this case, the patient presented predominantly with mood symptoms, delusions, and visual hallucinations. The disease course began 5 years ago with anxiety and insomnia. It developed into depressive symptoms including two suicide attempts (SAs), paranoia, and hallucinations. The diagnosis was eventually reached utilizing a thorough clinical exam, neuropsychological testing, MRI, positron emission tomography (PET), and dopamine transporter (DAT) scans. We conclude that mood or psychotic symptoms that emerge, escalate, or change dramatically at later ages merit further workup to evaluate for underlying neurodegenerative disorders.

The Media Coverage of Bruce Willis Reveals Unfamiliarity With Frontotemporal Degeneration

In 2022, Bruce Willis' family released a statement saying that he had been diagnosed with aphasia (an acquired language impairment) and would no longer be acting. Ten months later, the Willis family released another statement indicating that he received a more specific diagnosis of frontotemporal degeneration (FTD). This resulted in an explosion of media coverage, as prominent news outlets scrambled to produce stories describing FTD to a public largely unfamiliar with the disease. The quality of these stories varied widely, and in many cases the relationship between aphasia and FTD was misrepresented, as were basic descriptions and facts about FTD. FTD refers to a class of protein-misfolding diseases that are a common cause of aphasias due to neurodegeneration, or primary progressive aphasias (PPA). Rather than describing how FTD was discovered to be the underlying source of Mr. Willis' aphasia, many reports described his aphasia as "progressing into" FTD, implying they are two different disorders. Furthermore, these reports used the terminology of frontotemporal "dementia" rather than "degeneration", a term that invokes many stereotypes in the public imagination and may have contributed to misrepresentations in coverage. Instead of focusing on the language symptoms of PPA, reports often emphasized the personality and behavioral changes more closely associated with other variants of FTD. The substance of various facts, such as how common FTD is and how it can be treated, varied widely across reports. In sum, the media coverage of Mr. Willis' diagnosis reveals the extent to which the media and general public are uninformed about FTD and PPA. The remedy for this problem is to promote greater awareness of FTD, in both the public and the medical provider class. The Willis family's disclosure was a courageous act that helped bring much-needed attention to this disease.

Diagnostic Instability Over Time in the Late-Onset Frontal Lobe Syndrome: When Can We Say it's FTD?

OBJECTIVES

Distinguishing sporadic behavioral variant of frontotemporal dementia (bvFTD) from late-onset primary psychiatric disorders (PPD) remains challenging with the lack of robust biomarkers. An early bvFTD misdiagnosis in PPD cases and vice-versa is common. Little is known about diagnostic (in)stability over longer period of time. We investigated diagnostic instability in a neuropsychiatric cohort up to 8 years after baseline visit and identified which clinical hallmarks contribute to diagnostic instability.

DESIGN

Diagnoses of participants of the late-onset frontal lobe (LOF) study were collected from the baseline visit (T0) and the 2-year follow-up visit (T2). Clinical outcomes were retrieved 5-8 years after baseline visit (Tfinal). Endpoint diagnoses were categorized into bvFTD, PPD and other neurological disorders (OND). We calculated the total amount of participants that switched diagnosis between T0-T2 and T2-Tfinal. Clinical records of participants that switched diagnosis were assessed.

RESULTS

Of the 137 patients that were included in the study, the final diagnoses at Tfinal were bvFTD 24.1% (n = 33), PPD 39.4% (n = 54), OND 33.6% (n = 46) and unknown 2.9% (n = 4). Between T0 and T2, a total of 29 (21.2%) patients switched diagnosis. Between T2 and Tfinal, 8 (5.8%) patients switched diagnosis. Prolonged follow-up identified few cases with diagnostic instability. Major contributors to diagnostic instability where a nonconverting diagnosis of possible bvFTD and a probable bvFTD diagnosis based on informant-based history and an abnormal FDG-PET scan whilst having a normal MRI.

CONCLUSION

Considering these lessons, a FTD diagnosis remains stable enough to conclude that 2 years is sufficient to say if a patient with late-life behavioral disorder has FTD.

Preclinical Interventions in Mouse Models of Frontotemporal Dementia Due to Progranulin Mutations

Heterozygous loss-of-function mutations in progranulin (GRN) cause frontotemporal dementia (FTD), a leading cause of early-onset dementia characterized clinically by behavioral, social, and language deficits. There are currently no FDA-approved therapeutics for FTD-GRN, but this has been an active area of investigation, and several approaches are now in clinical trials. Here, we review preclinical development of therapies for FTD-GRN with a focus on testing in mouse models. Since most FTD-GRN-associated mutations cause progranulin haploinsufficiency, these approaches focus on raising progranulin levels. We begin by considering the disorders associated with altered progranulin levels, and then review the basics of progranulin biology including its lysosomal, neurotrophic, and immunomodulatory functions. We discuss mouse models of progranulin insufficiency and how they have been used in preclinical studies on a variety of therapeutic approaches. These include approaches to raise progranulin expression from the normal allele or facilitate progranulin production by the mutant allele, as well as approaches to directly increase progranulin levels by delivery across the blood-brain barrier or by gene therapy. Several of these approaches have entered clinical trials, providing hope that new therapies for FTD-GRN may be the next frontier in the treatment of neurodegenerative disease.

Clinical Spectrum of Tauopathies

Tauopathies are both clinical and pathological heterogeneous disorders characterized by neuronal and/or glial accumulation of misfolded tau protein. It is now well understood that every pathologic tauopathy may present with various clinical phenotypes based on the primary site of involvement and the spread and distribution of the pathology in the nervous system making clinicopathological correlation more and more challenging. The clinical spectrum of tauopathies includes syndromes with a strong association with an underlying primary tauopathy, including Richardson syndrome (RS), corticobasal syndrome (CBS), non-fluent agrammatic primary progressive aphasia (nfaPPA)/apraxia of speech, pure akinesia with gait freezing (PAGF), and behavioral variant frontotemporal dementia (bvFTD), or weak association with an underlying primary tauopathy, including Parkinsonian syndrome, late-onset cerebellar ataxia, primary lateral sclerosis, semantic variant PPA (svPPA), and amnestic syndrome. Here, we discuss clinical syndromes associated with various primary tauopathies and their distinguishing clinical features and new biomarkers becoming available to improve in vivo diagnosis. Although the typical phenotypic clinical presentations lead us to suspect specific underlying pathologies, it is still challenging to differentiate pathology accurately based on clinical findings due to large phenotypic overlaps. Larger pathology-confirmed studies to validate the use of different biomarkers and prospective longitudinal cohorts evaluating detailed clinical, biofluid, and imaging protocols in subjects presenting with heterogenous phenotypes reflecting a variety of suspected underlying pathologies are fundamental for a better understanding of the clinicopathological correlations.

Major Depression and Onset of Frontotemporal Dementia

PURPOSE

Frontotemporal dementia (FTD) is still a clinical challenge with the highest rate of misdiagnosis and poor outcome. The pathogenetic relationship between depression and neurodegeneration remains unclear. This study evaluated depression prevalence before FTD diagnosis.

PATIENTS AND METHODS

The aim was to assess the prevalence and impact of depression on FTD diagnostic process. The clinical characteristics of 72 patients hospitalized in Department of Affective and Psychotic Disorders Medical University of Lodz between 2010 and 2020 with final diagnosis FTD were analyzed. The data referring to first psychiatric diagnosis, time from first psychopathological symptoms to clarification of FTD diagnosis were collected. The patients who did not undergo full neuropsychiatric verification were excluded from the analysis.

RESULTS

About 69% of patients had other concomitant diagnosis of mental disorders which was made prior to FTD diagnosis. Among this subsample, 71% revealed depression diagnosis with at least moderate severity. The patients whose first diagnosis was psychotic depression revealed the longest period from the appearance of the first psychopathological symptoms to the diagnosis of FTD in comparison to the subsample with other psychiatric diagnosis (p=0.034; mean 4.33±3.28 years vs mean 2.68±1.39 years).

CONCLUSION

The severe depressive symptoms in older age may reflect the development of neurodegeneration before full-blown frontotemporal dementia symptomatology. We hypothesized that psychotic depression is a predictor of FTD. Further investigations in this field are required.