Background: The prevalence of levodopa-induced dyskinesia (LID) in Parkinson's disease (PD) varies among geographical regions. Cultural differences in patient-based perceptions of LID have not been studied.

Objective: We compared patient and clinician evaluations of LID severity across multiple cultures in patients with PD.

Methods: The data set included the Unified Dyskinesia Rating (UDysRS) scores from 16 language translation programs (3566 patients). We defined the Perception Severity Index (PSI) as the ratio between normalized patient-based subjective ratings (UDysRS Part 1B) and normalized clinician examination (Parts 3 and 4) scores (Part 1B/Parts 3 + 4) and compared the PSI across languages.

Results: The mean PSI for the Chinese language (2.16) was higher than those of all other languages, whereas the ratio for the Korean language (0.73) was lower than those for Japanese, German, Turkish, Greek, Polish, and Finnish languages (corrected P values <0.05).

Conclusions: Culture, as represented by language, affects the subjective perception of LID and needs to be considered in multinational clinical PD trials on dyskinesia. © 2023 International Parkinson and Movement Disorder Society.