Perioperative quantification of MDS-UPDRS-III tremor measurements in patients with Parkinson’s disease using accelerometry
摘要
Tremor in patients with Parkinson’s disease (PD) is usually evaluated using the Movement Disorder Society Unified PD Rating Scale (MDS-UPDRS). Limitations of the MDS-UPDRS include subjectivity and rater-dependency, which may be overcome by accelerometry. This study focused on relating the MDS-UPDRS hand tremor scores to an objective scoring method with 3D-accelerometry. An accelerometric algorithm to measure and classify tremor of the hands according to MDS-UPDRS criteria is proposed. Sixty-four PD patients and 64 healthy controls (matched on sex and age) were included. Two raters assessed MDS-UPDRS tremor-criteria, while accelerometry was performed at the index finger. Measurements were executed in an off-medication state, after a washout period of at least 12 h. The 3D-acceleration data included amplitude and area-under-the-curve of power in the 4–7 Hz range. Agreement between MDS-UPDRS and accelerometric scores was analyzed with Cohen’s kappa coefficient (κ). The trends between tremor amplitude and MDS-UPDRS score were consistent with the logarithmic relationship reported in previous studies. Overall, the accelerometric scores showed a substantial agreement (> 80.2%, κ ≥ 0.732) with the tremor amplitude according to MDS-UPDRS ratings. Accelerometric constancy of rest tremor (CRT) measures correlated less with MDS-UPDRS scores (R2 < 0.469, p < 0.001) than the other tasks. Accelerometric test–retest reliability was good to excellent (ICC ≥ 0.789, p < 0.001). MDS-UPDRS tremor tests can be reliably translated to objective accelerometric measurements. However, discrepancies were found between accelerometric CRT-measures and MDS-UPDRS ratings. Accelerometry could complement visual evaluations of tremor, aiming to reduce rater-variability of MDS-UPDRS measurements and allow for more objective monitoring of tremor in the clinical setting.