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Stroke victims can experience motor dysfunction from a stroke. This study by Dr. Mindy Levin looks at 2 variables to help succeed in the reacquisition of movement
30-66% of stroke victims continue to experience arm motor dysfunction for more than six months. Various approaches have been attempted with enhanced outcomes being dependent on 2 variables: training intensity and task specificity. Research suggests that repetitive motor activity brings skill reacquisition but the type of activity is also important. Knowledge of Results (KR — terminal goal-related movement outcomes) and Knowledge of Performance (KP — goal-related performance feedback) along with timing and frequency is what is primarily used or studied. The hypothesis studied was the effects of repetitive movement according to different feedback in which 20% received terminal feedback vs. faded concurrent knowledge performance feedback. Leven suggests that motor improvement would be related to cognitive abilities and would affect training.
This was a double-blind study of 37 participants who met the criteria of having a single stroke within 3 to 24 months and did not incur any occipital, cerebellar, or brain stem lesions during the stroke nor did they have any multiple strokes, perceptual deficiencies, or shoulder subluxations. Of the 37, 2 were not able to do the follow-up. Each person was randomly assigned to one of three groups:
Tests were used to assess arm and motor impairment along with Neuropsychological exams across 5 cognitive domains (verbal, visuospatial memory, attention, mental flexibility, and planning/problem-solving abilities) with a mean score calculated for each test. MRI exams to be recorded and classified according to the involvement of the cortical, subcortical involvement, or both.
Study participants were asked to perform 25 pointing movements with the impaired arm from an initial target located next to them at hip level and to sagittally locate the second target the was located and adjusted to should height and placed just beyond arm’s reach in front of them and such that no tactile sensation feedback could be provided (no touching the targets). Subjects were asked to point to the 2nd target as precisely and as quickly as possible in a single movement and maintain the arm position until hearing a tone. Subjects were allowed to practice 5 times before doing 25 repetitions of 2 to 4 seconds each. There was a 10-second rest between tests or up to 2 minutes if requested. Movement times, precision, segmentation, and variability of velocity were recorded and analyzed.
Compared to healthy patients, patients with hemiparesis made slower, less precise, and more segmented or variable movements with no initial difference between age, chronicity, or clinical scores. Arm movement and unilateral function improved in all groups with no difference among the groups. The KP group (group 2) improved with movement time and segmentation but not with spasticity. Group 1 KR people improved with precision, movement time and variability improved much greater than the control group. Group 1 was also less segmented and more consistent. There was an increase in precision that correlated to the increase in speed also. By contrast, Group 2 and the control group both increased in speed of movement but not in precision.
If done, appropriate intervention helps with the chronic hemiparesis of stroke. This study showed that motor improvement depended on the type of feedback. Participants who received feedback on precision of movement outcome only improved in that movement as opposed to feedback about movement performance improved outcomes across a spectrum of areas. All improvements persisted after a month of the study but those that received KR made more precise and faster movements and though their gains in speed were less than the other groups. KP test subjects were able to improve with speed at the expense of precision. The results also suggest that successful motor intervention may involve varying degrees of cognitive processes and the demands of the processes. These must be taken into the approach when selecting a protocol.
