Diagnostic agreement in patients with psychogenic movement disorders.

BACKGROUND: The reliability and applicability of published diagnostic criteria for psychogenic movement disorders (PMDs) have never been examined. METHODS: Eight movement disorder and six general neurologists rated 14 patients diagnosed with PMD and 14 patients diagnosed with organic movement disorders. Raters provided a dichotomous judgment (i.e., psychogenic or organic) upon review of video-based movement phenomenology and a category of diagnostic certainty based on the Fahn-Williams and Shill-Gerber criteria after accessing standardized clinical information. We measured interobserver agreement on the diagnosis and clinical certainty judgment of PMD. RESULTS: In both groups of raters, agreements were "fair" on the video-based dichotomous judgment, but improved to "substantial" after access to standardized clinical information. "Slight" to "poor" agreement was reached for the "probable" and "possible" categories of diagnostic certainty corresponding to both diagnostic criteria. CONCLUSIONS: Diagnosis according to clinical available criteria for PMD yields poor diagnostic agreement