Validation of the UPDRS section IV for detection of motor fluctuations in Parkinson's disease

Abstract

Introduction: The UPDRS-IV represents the most common screening tool to assess motor fluctuations in patients with PD despite the lack of a clinimetric validation.

Objectives: We evaluated sensitivity and specificity of UPDRS-IV using a 12-h waking-day motor assessment as the gold standard.

Methods: We consecutively enrolled PD patients who underwent a 12-h waking-day motor assessment in the study. Patients were clinically evaluated every 2 h for 12 h using the UPDRS-III. Motor scores were reported as a line graph and six blinded raters classified patients as having or not having motor fluctuations. The UPDRS-IV was used in order to assess the presence of predictable and unpredictable motor fluctuations according to items 36-38.

Results: Sixty two PD patients were enrolled in the study. According to the raters' evaluations, 39 (62.9%) were classified as having motor fluctuations, while according to the UPDRS-IV 47 (75.8%) presented a motor fluctuation giving a sensitivity of 87.2% (95%CI 72.6-95.7) and a specificity of 43.5% (95%CI 23.2-65.5).

Conclusion: Our study results confirm the high level of sensitivity with a lower level of specificity of UPDRS-IV to screen motor fluctuations in PD patients.

Keywords: Motor fluctuations; Sensitivity and specificity; UPDRS.