Overlap in the diagnostic criteria of frontotemporal dementia syndromes with parkinsonism

BackgroundDifferentiating neurodegenerative diseases can be difficult in the clinical setting. This study examines the overlap of diagnostic criteria between frontotemporal dementia (FTD) syndromes with parkinsonism [e.g., corticobasal syndrome (CBS), progressive supranuclear palsy (PSP), behavioral variant frontotemporal dementia (bvFTD)] and Parkinson's disease (PD).ObjectiveTo explore the diagnostic overlap in patients with FTD syndromes with parkinsonism and PD.MethodsPatient records from 2751 individuals at a tertiary neurological care center were reviewed, resulting in 112 bvFTD, 38 PSP, and 15 CBS patients. Clinical features and diagnostic criteria fulfillment were assessed.ResultsSignificant overlap in diagnostic criteria fulfilment was found: 42 bvFTD and 22 PSP patients met possible CBS criteria, 6 bvFTD patients met possible PSP criteria, and 4 met criteria for all three conditions. Higher cerebrospinal fluid levels of phosphorylated tau and tau were observed in the bvFTD group compared to PSP (p = 0.009, p = 0.002). The Mini-Mental State Examination score also differed between bvFTD and PSP (p = 0.020), and between PSP and CBS (p = 0.047). Neuroimaging showed substantial heterogeneity.ConclusionsThe study reveals significant overlap in diagnostic criteria among FTD syndromes with parkinsonism, underscoring the need for more precise diagnostic criteria. Improved biomarkers could support differential diagnosis and enhance clinical trial design. Common cerebrospinal fluid biomarkers used in Alzheimer's disease diagnostics may provide additional support in the differential diagnosis.