Dynamic Variability of Isometric Action Tremor in Precision Pinching

Table 1

Means and standard deviations of tremor variables stratified by total tremor power level.

Grouping level^a	𝑛^b	Frequency difference (Hz)^c	Power difference^c,d	Concordance phase
PD background	194	0.019 (0.162)	0 (3)	145 (11)
PD minimal	90	−0.018 (0.247)	−1 (6)	126 (19)
PD intermediate	86	0.072 (0.278)	38 (122)	104 (34)
PD substantial	26	−0.087 (0.127)	2289 (3090)	92 (34)
OA background	354	0.044 (0.092)	0 (1)	154 (17)
OA minimal	41	0.034 (0.334)	0 (1)	154 (17)
OA intermediate	3	0.233 (0.273)	36 (42)	107 (31)
OA substantial	0	—	—	—

PD: Parkinson’s disease participants.
OA: older well adults.
^aBased on total tremor power (sum of thumb and index finger) in mN²/sampling.
0–50: background; 50–100: minimal; 100–1000: intermediate; 1000+: substantial.
^bTotal number of application and release task segments in the power grouping.
^cDifferences represent index finger values subtracted from thumb values within trials.
^dPower difference units in mN²/sampling.