Perioperative quantification of clinical bradykinesia measurements in patients with Parkinson's disease using...

The gold standard for assessing bradykinesia in Parkinson's disease (PD) is the Movement Disorder Society Unified PD Rating Scale (MDS-UPDRS), although it is inherently subjective and relies on experienced raters. Therefore, we translated MDS-UPDRS upper limb bradykinesia assessments into an objective scoring method with 3D-accelerometry.

In this study, 44 PD-patients and 44 healthy controls (sex and age matched) were included. Two raters assessed MDS-UPDRS criteria for bradykinesia, while accelerometric measurements were conducted at the index fingers. Measurements were performed in an off-medication state. The 3D-acceleration data produced quantitative measures, like frequency and amplitude of hand movement. The algorithm for calculating accelerometric scores was based on MDS-UPDRS criteria with thresholds from healthy controls. Agreement between MDS-UPDRS bradykinesia scores and accelerometric scores was estimated with Cohen's kappa-coefficient (κ).

The accelerometric scores showed moderate agreement (κ ≥ 0.548) with MDS-UPDRS ratings. The inter-rater agreement between the two MDS-UPDRS raters was moderate for all tests (κ ≥ 0.595). Accelerometric test-retest reliability was good to excellent (ICC ≥ 0.764, p < 0.001).

This study introduces an accelerometric algorithm to classify upper extremity bradykinesia according to MDS-UPDRS criteria, yielding high test-retest reliability.

Given its consistency, this method could reduce MDS-UPDRS rater-dependency and improve objective monitoring of upper limb bradykinesia.