Portable objective assessment of upper extremity motor function in Parkinson's disease

Introduction Objective, portable measures of motor function for out-of-office assessments are needed in Parkinson's Disease (PD). This study had 3 objectives. First, to examine change in objective motor measurements in PD (as assessed with the Objective PD Measurement (OPDM) system). Second, to correlate objective measures with clinical features and putative PD cerebrospinal fluid (CSF) and dopaminergic imaging biomarkers. Third, to assess participant compliance with and perceptions of serial in-home motor assessments. Methods De novo PD subjects participating in this pilot study of the Parkinson Progression Markers Initiative (PPMI) completed OPDM assessments at home weekly for 3 months and in the clinic at baseline and 3-, 6-, and 12-months. Tasks included (i)digitography (ii)a repetitive hand tapping task and (iii)timed pegboard task. A global objective motor score (OMS) was derived from the latter three. MDS-UPDRS-III score was obtained at each time point, and CSF and dopamine transporter (DAT) SPECT at baseline. Results 27 participants, mean age 62.6 years, 19 male were included. A mean of 10.5 in-home assessments were completed. There was no significant change in in-home OMS over 12 weeks (p = 0.48). There was strong correlation between mean baseline OMS and MDS-UPDRS-III scores (spearman's rho = 0.60, p=<0.0001). Baseline OMS predicted 6-month MDS-UPDRS-III (β = 0.80, p = 0.0002) but not change in MDS-UPDRS-III score, DAT SPECT, or putative CSF biomarkers. Conclusions This study suggests that administration of in-home motor tasks as part of a large multi-center study is feasible and scores derived from these assessments may serve as surrogates of in-person clinician-assessed motor score.