The Frontotemporal Dementia versus Primary Psychiatric Disorder (FTD versus PPD) Checklist: A Bedside Clinical Tool to Identify Behavioral Variant FTD in Patients with Late-Onset Behavioral Changes

Article type: Research Article

Authors: Ducharme, Simon^{a; b; *} | Pearl-Dowler, Leora^a | Gossink, Flora^{c; d} | McCarthy, Jillian^b | Lai, Jimmy^b | Dickerson, Bradford C.^e | Chertkow, Howard^f | Rapin, Lucile^b | Vijverberg, Everard^{c; d} | Krudop, Welmoed^{c; d} | Dols, Annemieke^{c; d} | Pijnenburg, Yolande^d

Affiliations: [a] Department of Psychiatry, McGill University Health Centre, Montreal, QC, Canada | [b] McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada | [c] Department of Old Age Psychiatry, GGZinGeest/Amsterdam University Medical Centre, Amsterdam, The Netherlands | [d] Department of Neurology, Alzheimer Center Amsterdam, Amsterdam Neuroscience Campus, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands | [e] Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA | [f] Department of Neurology, Jewish General Hospital, McGill University, Montreal, QC, Canada

Correspondence: [*] Correspondence to: Simon Ducharme, MD, MSc, FRCP(C), Montreal Neurological Institute, McConnell Brain Imaging Centre, 3801 University Street, Montreal, QC, H3A 2B4, Canada. Tel.: +1 514 398 1911; Fax: +1 514 398 3745; E-mail: simon.ducharme@mcgill.ca.

Abstract: Background: Differentiating early behavioral variant frontotemporal dementia (bvFTD) and primary psychiatric disorders (PPD) is complex and biomarkers have limited accuracy, leading to inaccurate diagnoses. Objectives: Develop a simple bedside clinical tool to differentiate bvFTD from PPD. Methods: A checklist of clinical features differentiating bvFTD from PPD was developed based on literature and clinical experience. The checklist was filled prospectively for 29 consecutive patients (Montreal Neurological Hospital) with late-onset (≥ age 40) behavioral changes suggestive of bvFTD. The checklist was subsequently retrospectively completed on the baseline visit (N = 137) of the Late-Onset Frontal Lobe study (Amsterdam). In both cohorts, patients were followed 2 years to establish a final best clinical diagnosis, categorizing patients into Probable FTD (N = 46), Possible FTD (N = 8), Other Cognitive Disorder (N = 36), Other Neurological Disorder (N = 10), or PPD (N = 66). Results: All items distinguished the two groups except “duration more than 5 years”, which was removed to create a final 17-item version. Mean checklist scores were significantly different across all groups (Oneway ANOVA F(4,161) = 27.462, p < 0.001). The PPD group had lower scores than all other dementia categories, with the largest difference between Probable FTD ( X¯ = 12.04) and PPD ( X¯ = 7.48). A score ≥11 was found to be strongly indicative of bvFTD (specificity 93.9%, sensitivity 71.1%, PPV 89.2%). Scores ≤8 were strongly indicative of a PPD (specificity 91.3%, sensitivity 77.3%, PPV 92.7%). Patient with scores of 9–10 are considered indeterminate. Conclusions: Although further prospective validation is required, the “FTD vs PPD Checklist” could provide a simple tool to improve diagnostic accuracy, particularly in non-specialized settings.

Keywords: Behavioral variant frontotemporal dementia, diagnosis, frontotemporal dementia, psychiatric disorders, scale

DOI: 10.3233/JAD-180839

Journal: Journal of Alzheimer's Disease, vol. 67, no. 1, pp. 113-124, 2019