The Clinician's Tardive Inventory (CTI): A New Clinical Tool for Documenting and Rating Tardive Dyskinesia

Objective: Current clinician-rated tardive dyskinesia (TD) symptom scales have not addressed the expanding clinical signs and functional impact of TD. The study objective was to develop and test the reliability of a new integrated instrument. Methods: A movement disorder neurologist devised the outline of the rating scale. A Steering Committee (5 neurologists and 2 psychiatrists) provided revisions until consensus was reached. The Clinician's Tardive Inventory (CTI) assesses abnormal movements of the eye/eyelid/face, tongue/mouth, jaw, and limb/trunk; complex movements defined as complicated movements different from simple patterned movements or postures; and vocalizations. The CTI rates frequency of symptoms from 0 to 3 (ranging from absent to constant). Functional impairments, including activities of daily living (ADL), social impairment, symptom distress, and physical harm, are rated 0-3 (ranging from unawareness to severe impact). The CTI underwent interrater and test-retest reliability testing between February and June 2022 based on videos and accompanying vignettes, which were reviewed by 2 movement disorder specialists to determine adequacy. Four clinicians rated each video/vignette. Interrater agreement was analyzed via 2-way random-effects intraclass correlation (ICC), and test-retest agreement was assessed utilizing the Kendall tau-b. Results: Forty-five video/vignettes were assessed for interrater reliability and 16 for test-retest reliability. The most prevalent movements were those of the tongue and mouth (77.8%) and jaw (55.6%). ICCs for movement frequency for anatomic symptoms were as follows: anatomic symptom summary score 0.92, abnormal eye movement 0.89, abnormal tongue/mouth movement 0.91, abnormal jaw movement 0.89, abnormal limb movement 0.76, complex movement 0.87, and abnormal vocalization 0.77; ICCs for functional impairments were as follows: total impairment score 0.92, physical harm 0.82, social embarrassment 0.88, ADLs 0.83, and symptom bother 0.92; Retests were conducted a mean (SD) of 15 (3) days later with correlation coefficients ranging from 0.66 to 0.87. Conclusions: The CTI is a new integrated instrument with proven reliability in assessing TD signs and functional impacts. Future validation study is warranted.