Intention tremor and deficits of sensory feedback control in multiple sclerosis: a pilot study

Table 2 Experimental tasks and analysis

Task	Input	Parameter measured		Analysis method
Spiral tracing	Line tracing	f _t , M _t	Tremor frequency and magnitude	Power spectrum analysis
Task 1	Low frequency visual perturbation	T_v	Visual response delay	Cross correlation of subject response with input
Task 1	Low frequency visual perturbation	T_v^*	Predictive response delay	Cross correlation of subject response with input
Task 2	Low-frequency torque perturbation	T_p	Proprioceptive response delay	Cross correlation of subject response with input
Task 2	Low-frequency torque perturbation	T_p^*	Predictive proprioceptive response delay	Cross correlation of subject response with input
Task 3	Fixed levels of isometric torque	α	Multiplicative motor noise	Linear fit of variance vs. average torque
Task 4	High-frequency visual perturbation	J, B, K	Inertia, viscosity, stiffness of arm	Bootstrapped model fit to the subject’s measured frequency response function (FRF)
		J^, B^, K^*	Predictive inertia, viscosity, stiffness of arm
		K_v, K_p, K_v^, K_p^, K_d, K_pr, K_i	Sensory and Controller gains
Task 5	Visual offset	RMSE	Movement error	Kinematic analysis

ISSN: 1743-0003