. 2018 May 16;8:7663. doi: 10.1038/s41598-018-25999-0

Table 2.

Results of correlation analysis between the most frequently selected features and UPDRS Part III single-item scores of interest/total score.

Selected Feature	UPDRS Part III Single Items							Total UPDRS Part III Score
Selected Feature	Finger Tapping (RH)	Finger Tapping (LH)	Rigidity UE (RH)	Rigidity UE (LH)	Action Tremor (RH)	Action Tremor (LH)	BK/HK	Total UPDRS Part III Score
HT $\bar{μ i}$	0.60^†	0.33^†	0.69^†	0.30^†	0.39^†	0.05^n.s.	0.50^†	0.53^†
HT $\bar{σ i}$	0.64^†	0.49^†	0.71^†	0.47^†	0.42^†	0.16^n.s.	0.63^†	0.62^†
NFT $\bar{S_{i}}$	−0.48^†	−0.46^†	−0.51^†	−0.45^†	−0.35^†	−0.11^n.s	−0.58^†	−0.51^†
NP $\bar{μ i}$	−0.60^†	−0.56^†	−0.55^†	−0.52^†	−0.40^†	−0.31^†	−0.62^†	−0.62^†

Values of Spearman’s correlation coefficient r_s are presented after correlating the most frequently selected features (HT $\bar{μ i}$ , HT $\bar{σ i}$ , NFT $\bar{S i}$ , NP $\bar{μ i}$ ) (see also Table 1) with UPDRS Part III single-item scores of relevant PD motor symptoms, i.e., rigidity of upper extremities, action tremor, and bradykinesia (finger tapping and body bradykinesia-hypokinesia), as well as with the total UPDRS Part III score, across all subjects (both early PD patients and controls). All healthy controls were assigned a value of zero for each UPDRS Part III item. As the latter renders each UPDRS item variable skewed, Spearman’s rank correlation was employed for this analysis. BK/HK: Bradykinesia/Hypokinesia; RH: Right Hand; LH: Left Hand; UE: Upper Extremity; ^†p < 0.001; n.s.: p > 0.05.