Comparison of Design Fluency Test Results among Patients with Parkinson’s Disease, Frontotemporal Dementia, and the Control Group

Design Fluency Test (DFT) is a nonverbal frame‑free, nonstructured assessment of executive function (EF). Since previous studies evaluating EF in Parkinson’s disease (PD) have mainly used verbal assessments for EF, this study aims to evaluate the pattern of executive domains in PD using DFT and to compare it with behavioral variant frontotemporal dementia (FTD) as a prototype for executive dysfunction and also with normal controls (NCs).

Twenty‑eight patients with PD, 27 with FTD, and 27 NCs were included in the study in Ayatollah Kashani Neuropsychiatry Clinic affiliated to Isfahan University of Medical Sciences from September 2019 to February 2020. All participants were assessed via semi‑structured neuropsychiatric interview, questionnaire for demographic profile (age, handedness, gender, education, and marital status), duration of illness, comorbid medical condition, comorbid psychiatric illnesses and medications, DFT, Short Parkinson’s Evaluation Scale, Frontal Assessment Battery, Judgment of Line Orientation, and Neuropsychiatry Unit Cognitive Assessment Tool.

Fixed condition novelty score was significantly different between FTD and PD (P < 0.001), FTD and control (P < 0.001), and also between PD and control (P = 0.001). When free and fixed condition novelty scores were considered to predict diagnostic attribution, multinomial logistic regression revealed that odds ratio for free condition novelty score was 0.705 (P = 0.005, 95% confidence interval [CI] = 0.553–0.899) and 0.494 (P = 0.001, 95% CI = 0.328–0.744) in PD and FTD, respectively. The odds ratio for fixed condition novelty score was 0.772 (P = 0.011, 95% CI = 0.632–0.942) and 0.449 (P = 0.00, 95% CI = 0.292–0.691).

DFT subscores can be helpful in diagnosis and differentiation between FTD and PD.