Persistent Diagnostic Disagreement Among Individuals With Functional Movement Disorders

OBJECTIVE: Diagnostic agreement influences treatment outcomes, but studies on persistent diagnostic disagreement (PDD) in functional movement disorder (FMD) are lacking. The authors propose a definition for PDD and identified associated factors in a clinical cohort of patients with FMD. METHODS: The authors retrospectively reviewed clinical data of 158 FMD patients seen in an integrated movement disorders program from July 2019 to December 2021. Patients self-reported diagnostic agreement before an initial assessment (as disagree, unsure, or agree). PDD status was determined by a specialist assessment on the basis of observable behaviors. Exploratory logistic regression and a least absolute shrinkage and selection operator (LASSO) model were used to examine associations of demographic and clinical features with PDD. Alignment between referring clinician impressions and patient self-reports was also evaluated. RESULTS: Of 158 patients, 116 had complete data for both baseline self-reports and specialist PDD determination. Forty-seven patients (41%) were classified as having PDD. PDD was observed for 52% (N=15 of 29) of those who self-reported disagreement, 71% (N=17 of 24) who self-reported ambivalence, and 24% (N=15 of 63) who self-reported agreement. Variables associated with PDD included low agency, cluster B traits, lower readiness to change, inability to notice symptom variability, and lower self-reported agreement; only low agency was retained in the LASSO analysis. Among 78 patients with complete data including referring physician impressions, concordance with patient self-reported disagreement was low (weighted κ=0.21, p