Clinical assessments necessarily provide only a snapshot of PD patients’ clinical status, which notoriously fluctuates. Remote and frequent symptom monitoring with digital devices promises to improve the assessment of motor symptom progression in PD.  

A smartphone app with 10 active tests (cognition, tremor, bradykinesia, rigidity/postural stability) and continuous passive monitoring is currently deployed in a Phase II Prasinezumab study (PASADENA) in recently diagnosed PD patients (n=113  at data-cutoff). Sensor features were extracted from each active test and during passive monitoring and aggregated over two-week periods centered at baseline clinical visits. Intra-class correlation coefficients and Spearman correlations quantified test-retest reliability and validity compared to clinical gold standard MDS-UPDRS item/subscale scores, respectively.

Average adherence was high with 82% of all possible active tests performed during the two study weeks around baseline. Test-retest reliabilities of active tests ranged from 0.66-0.98, median 0.91. All active tests except digit symbol (r=-0.15, p=0.29) demonstrated excellent clinical validity via significant correlations with MDS-UPDRS scores ranging from r=-0.23 (p=0.02; finger tapping right hand) to r=0.63 (p<0.001; rest tremor left hand). Average turn speed during daily life shows low but significant correlations with MDS-UPDRS Part III (r=-0.24, p=0.02) and a bradykinesia composite score (r=-0.35, p<0.001).