Impact-Tardive Dyskinesia (Impact-TD) Scale: A Clinical Tool to Assess the Impact of Tardive Dyskinesia

Tardive dyskinesia (TD) is a movement disorder that can negatively affect health-related quality of life. However, the impact of TD is not necessarily dependent solely on the objective severity of TD movements. There is currently no easy-to-use, standardized, clinician-rated assessment of the impact of TD on functioning. The aim of this consensus panel was to develop a scale (Impact-TD scale) to assess the impact of TD on patients' daily functioning in practice settings.

Nine health care professionals with expertise in TD and clinical scale development met to discuss how TD negatively impacts the functional activities of patients.

This panel comprised 7 individuals from a previous panel that developed recommendations on the importance of optimally assessing the functional impact of TD. The previous panel published a narrative literature review that summarized the existing approaches to assess the impact of TD in clinical research and practice.

A modified Delphi process was used to assess agreement on the format and content of the Impact-TD scale. The panel discussed key features of the Impact-TD scale (ie, simplicity, usability, assessment of frequency of impact versus interference/distress). The scale aimed to describe specific consequences of TD symptoms with which patients may have difficulty.

Consensus was reached on a list of consequences of TD symptoms that have a functional impact and were categorized in 4 functional domains: social, psychological/psychiatric, physical, and vocational/educational/recreational. The Impact-TD scale offers an easy-to-use clinical scale to measure the functional impact of TD in practice settings.