Development and clinimetric assessment of a nurse-administered screening tool for movement disorders in psychosis

Abstract

Background: Movement disorders (MD) associated with exposure to antipsychotic drugs (AP). MD are common and stigmatising, but underdiagnosed. Methods: We developed a screening procedure for AP-MD for administration by mental health (MH) nurses. Item selection and content validity assessment were conducted by a panel of neurologists, psychiatrists and a MH nurse, who operationalised a 31-item screening procedure (ScanMove instrument). Inter-rater reliability was measured on ratings from ten MH nurses evaluating video-recordings of the procedure on 30 patients with psychosis. Criterion and concurrent validity were tested comparing the ScanMove instrument-based rating of thirteen MH nurses of 635 community patients from MH services to diagnostic judgement of a MD neurologist based on the ScanMove instrument and a reference procedure comprising a selection of commonly used rating scales. Results: Inter-reliability analysis showed no systematic difference between raters in their prediction of any AP-MD category. On criterion validity testing, the ScanMove instrument showed good sensitivity for parkinsonism (94%) and hyperkinesia (89%), but not for akathisia (38%), whereas specificity was low for parkinsonism and hyperkinesia, and moderate for akathisia. Mixed effect regression models showed low concurrent validity of quantitative scores obtained from the ScanMove instrument. Conclusions: The ScanMove instrument demonstrated good feasibility and inter-rater reliability, and acceptable sensitivity as MH nurse-administered screening tool for parkinsonism and hyperkinesia