Table 2.
Activity | Sensor Feature and Unit | MDS‐UPDRS Item(s) | Test‐Retest Reliability of Sensor Feature | Controls vs. All PD | PD Participants: Relationship Between Active Test Feature and MDS‐UPDRS Item(s) Score | Controls vs. PD Subgroup Rated as Having No Symptoms (MDS‐UPDRS score = “0”) at Respective Site Visit | |||
---|---|---|---|---|---|---|---|---|---|
Active tests | ICC | t Value | P Value | t Value | P Value | t Value | P Value | ||
Sustained phonation | MFCC2 | 2.1 | 0.82 | −4.48 | <0.001 | –0.36 | n.s | −3.29 | <0.001 |
Rest tremor | Skewness | 3.18 | 0.90 | 7.6 | <0.001 | 2.17 | 0.033 | 5.5 | <0.001 |
Postural tremor | Power (m2/s3) | 2.10 | 0.97 | 4.42 | <0.001 | 2.61 | 0.011 | 0.83 | n.s. |
Finger tapping | Tap variability | 2.5 | 0.64 | 8.46 | <0.001 | 2.18 | 0.028 | 6.95 | <0.001 |
Balance | Mean velocity (m/s) | 3.13 | 0.80 | 8.29 | <0.001 | 2.38 | 0.027 | 5.16 | 0.005 |
Gait | Turn speed (degree/s) | PIGD | 0.88 | −9.31 | <0.001 | −2.45 | 0.022 | −8.25 | <0.001 |
Passive monitoring | ICC | Mann‐Whitney U | P Value | t Value | P Value | Mann‐Whitney U | P Value | ||
Walking | Turn speed (degree/s) | Average PIGD | n/a | 1,392 | <0.001 | −3.01 | 0.005 | 229 | 0.018 |
Sit‐to‐stand transitions | Sit‐to‐stand transitions (#/hour) | Average PIGD | n/a | 1,087 | 0.005 | −1.48 | n.s. | 250 | n.s. |
Walking vs. not walking | Activity ratio (%) | Average PIGD | n/a | 1,392 | <0.001 | −2.02 | 0.055 | 321 | 0.003 |
Values for the active tests are t values from linear mixed‐effects models that quantify the relationship between given MDS‐UPDRS item(s) and the selected features and take repeated tests over time of the same subjects into account. Values for the passive monitoring activities are U values from the Mann‐Whitney U test.
MFCC2, mel‐frequency cepstral coefficient 2; n/a, not applicable; n.s., not significant; STS, sit‐to‐stand/stand‐to‐sit transitions.