Finger Tapping Clinimetric Score Prediction in Parkinson's Disease Using Low-Cost Accelerometers
Figure 8
Typical features for an SMD consensus score of 3. Plot (a) gives the movement frequencies (circles). Plot (b) gives the percentages of movement time for maximum opening acceleration. Plot (c) gives the maximum closing accelerations. Plot (d) gives the maximum opening accelerations. Plot (e) gives the opening angles. Plot (f) gives the level of hypometria (circles) and the possible presence of initiation hesitations (triangles). For each plot except (f), the mean is in dotted line, the linear regression among points is in continuous line, and the limits for the detection of hesitations are in dashed lines (plots (a) and (b) only). The PD patient performed the FT task at a slower frequency, but there was no sign of decrementing or augmenting frequency. Maximum closing acceleration strongly decreases over samples, as for the maximum opening acceleration, which reflects a decrementing performance of the FT movement. Compared to the healthy volunteer, the mean values are lower, suggesting more difficulties in performing the movement. The mean opening angle is quite lower and decrements over time, reflected by a Dangle feature value of 2. So, the patient managed to keep a constant frequency but performed smaller and smaller movements. The patient does not present signs of hypometria. Three hesitations but no halts are detected. According to the analysis of the movement frequencies, the 3rd movement is abnormally fast, reflecting a jerky movement, the 8th movement is too slow, reflecting a hesitation while closing the fingers (lower value of percentage time for maximum opening acceleration), and the 4th movement is detected as an opening hesitation because the maximum opening acceleration occurs too late in the movement. On the frequency plot, this last movement is among the slowest.
