Impairments in arm control in subjects with left and right hemisphere stroke

Our purpose was to identify impairments in movement control for subjects with left and right brain lesions using a kinematic analysis of the trajectory of a stylus during an upper limb tapping task. We hypothesized that subjects with left cerebrovascular accident (LCVA) would have bilateral deficits in programming while subjects with right cerebrovascular accident (RCVA) would only have deficits in the limb contralateral to the lesion.

Data were collected from 11 subjects with LCVA, 11 with RCVA, and 22 non-disabled subjects who were age and gender-matched to subjects with left or RCVA. Subjects were videotaped performing a Fitts tapping task on a single 3-inch target with each hand. The stylus movement was digitized at 60 Hz and data were calculated for each tap cycle and averaged across each 10-s trial. We examined differences in the kinematic variables of cycle frequency, amplitude, symmetry in up and down velocity, symmetry in timing of up and down velocity, and temporal phases of acceleration and deceleration for up and down directions of the tap cycle. Multivariate analyses were performed on four dependent kinematic variables, and univariate ANOVAs were conducted for the differences in phases between stroke and non-disabled limbs.

Subject with LCVA showed lower frequencies, and asymmetrical velocity and timing ratio in both 'uninvolved' and 'involved' limbs compared to non-disabled subjects. Subjects with RCVA showed similar impairments for the 'involved' limb only.

Left hemisphere lesions create bilateral impairments in programming movement reversals. Right hemisphere lesions produced deficits only for the limb contralateral to the lesion. Strategies used by the subjects with LCVA may be-related to the need for subjects to use feedback to perform this rapid continuous sequencing task. Suggestions for rehabilitation are presented.