Signal processing of quantitative continuous measurement of movements in the extremities

A protocol for a low-cost quantitative continuous measurement of movements in the extremities of people with Parkinson’s disease (PD) (McKay, et al., 2019) modified from the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) (Goetz, et al., 2008) was administered by trained raters certified in the MDS-UPDRS once to ten participants with PD and again a month later to ten people with PD and eight age- and sex-matched healthy controls (HCs) (Brasic, et al., 2020). Raters certified in the MDS-UPDRS administered and scored the protocol live in person while signals from accelerometers on the extremities were recorded. Signals from the five repetitive activities were processed to generate fast Fourier transforms (FFTs) and continuous wavelet transforms (CWTs) (Harrigan, et al., Data Brief, Mendeley, 2020),

Of the 40 raters recruited for the project, 38 obtained certification in the MDS-UPDRS and 32 completed the ratings of several sets of transforms of the repetitive movements.

The rating scale for live ratings (McKay, et al., 2019) was modified for the assessment of signals and FFTs and CWTs by visual observation. The instructions were presented to raters to consult for the rating of representations of signals and transforms. The laterality of the representations was not stated.Raters were asked to complete ratings independently at convenient times during the week.

Pilot Study

Raters were presented two sets of 40 quizzes containing five representations of the ratings of participants with PD with single sessions for scoring of (A) output signals and FFTs and (B) CWTs (Pilot Test and Retest). Each quiz contained the panels of the x, y, and z representations of the finger and wrist or the toe and ankle of the five repetitive tasks. Each panel to be scored included six images corresponding to the signals of the three dimensions of the two accelerometers on a single extremity.Raters were presented five sets of six images of the original signal and the fast Fourier transform (FFT) or the continuous wavelet transforms (CWTs). Raters were presented either five panels of output signals and FFTs or CWTs. Panels did not include output signals and FFTs and CWTs simultaneously. Raters were instructed to score (A) output signals and FFTs and (B) CWTs analogously to the clinical coding forms as indicated the the instructions in the data.

The raters also completed the output of the ten participants with PD and eight HCs who completed a two test session (CWT Test and Retest). Raters were presented two sets of 72 quizzes containing five representations for scoring of CWTs (Pilot Test and Retest). Each quiz contained the panels of averaged signals of the x, y, and z representations of the finger and wrist or the toe and ankle of the five repetitive tasks. Each panel to be scored included two images corresponding to the signals of the three dimensions of the two accelerometers on a single extremity.