In a recent study, researchers aimed to develop and evaluate the Tardive Dyskinesia Impact Scale (TDIS), a patient-reported outcome measure specifically designed to assess the impact of tardive dyskinesia (TD) on patients. While the Abnormal Involuntary Movement Scale (AIMS) is the gold standard for evaluating treatment efficacy in TD clinical trials, it lacks patient perspective and is cumbersome in clinical settings. The TDIS was created to address these shortcomings, focusing on providing a comprehensive assessment of the disease’s impact from the patient’s viewpoint. Using data from qualitative studies and phase 3 trials of a VMAT2 inhibitor for TD treatment (KINECT3 and KINECT4), the study explored the TDIS’s psychometric properties, including construct validity and responsiveness to change.

Qualitative feedback indicated that the TDIS effectively captures the key impacts of TD as reported by patients and caregivers and was interpreted as intended, aligning well with patients’ experiences. Quantitatively, the TDIS demonstrated evidence of two primary domains: physical and socioemotional, with a Comparative Fit Index greater than 0.9. It showed distinct advantages over the AIMS, capturing unique content with only a low to moderate correlation between the two scales (0.2-0.28). The study concluded that the TDIS is a relevant, easy-to-administer tool that can be used alongside the AIMS for a more comprehensive assessment of TD, allowing for effective longitudinal tracking of the TD burden, enhancing understanding and management of this condition.

Reference: Farber RH, Stull DE, Witherspoon B, et al. The Tardive Dyskinesia Impact Scale (TDIS), a novel patient-reported outcome measure in tardive dyskinesia: development and psychometric validation. J Patient Rep Outcomes. 2024;8(1):2. doi: 10.1186/s41687-023-00679-4.