Background and Purpose-Many stroke survivors have minimal to moderate neurological deficits but are physically deconditioned and have a high prevalence of cardiovascular problems; all of these are potentially modifiable with exercise. The purposes of this randomized, controlled pilot study were (1) to develop a home-based balance, strength, and endurance program; (2) to evaluate the ability to recruit and retain stroke subjects; and (3) to assess the effects of the interventions used. Methods-Twenty minimally and moderately impaired stroke patients who had completed inpatient rehabilitation and who were 30 to 90 days after stroke onset were randomized to a control group or to an experimental group that received a therapist-supervised,

Insight into the functional neural substrates associated with the control of goal-directed purposive movements can be obtained through the study of the performance of individuals with brain damage. The control of rapid reciprocal aiming was investigated by comparing ipsilateral limb performance of subjects with unilateral brain damage to that of controls performing with the same limb. Thirty right-hand-dominant individuals, ten with right hemisphere stroke, ten with left hemisphere stroke, and ten age-matched controls performed unconstrained alternating tapping movements under three conditions of task complexity. The path of the stylus was recorded by video using two-dimensional kinematic techniques. Key kinematic features of the vertical and horizontal components of the trajectories were analyzed using both quantitative and qualitative methods. All subjects with brain damage showed prolonged movement times; however, the locus of the slowing depended on lesion side. Specifically, subjects with left stroke showed deficits in the open-loop component of the movement across all three conditions of task complexity, and a prolonged reversal phase surrounding target impact, particularly in the most complex condition. In contrast, subjects with right stroke showed deficits in the closed-loop phase of the movement prior to target impact, particularly in the most complex condition when visual information was necessary for accuracy. Together, these results suggest that for the control of rapid goal-directed aiming movements, the left hemisphere is dominant for task-relevant aspects of processing associated with the ballistic component and the timing or triggering of sequential movements. In contrast, the right hemisphere is dominant for processing associated with rapid, on-line visual information even when target location is known and direction is certain.

Differences in the kinematics and pattern of relative regional cerebral blood flow (rCBF) during goal-directed arm aiming were investigated with the use of a Fitts continuous aiming paradigm with three difficulty conditions (index of difficulty, ID) and two aiming types (transport vs. targeting) in six healthy right-handed young participants with the use of video-based movement trajectory analysis and positron emission tomography. Movement time and kinematic characteristics were analyzed together with the magnitude of cerebral blood flow to identify areas of brain activity proportionate to task and movement variables. Significant differences in rCBF between task conditions were determined by analysis of variance with planned comparisons of means with the use of group mean weighted linear contrasts. Data were first analyzed for the group. Then individual subject differences for the movement versus no movement and task difficulty comparisons were related to each individual subjects' anatomy by magnetic resonance imaging. Significant differences in rCBF during reciprocal aiming compared with no-movement conditions were found in a mosaic of well-known cortical and subcortical areas associated with the planning and execution of goal-directed movements. These included cortical areas in the left sensorimotor, dorsal premotor, and ventral premotor cortices, caudal supplementary motor area (SMA) proper, and parietal cortex, and subcortical areas in the left putamen, globus pallidus, red nucleus, thalamus, and anterior cerebellum. As aiming task difficulty (ID) increased, rCBF increased in areas associated with the planning of more complex movements requiring greater visuomotor processing. These included bilateral occipital, left inferior parietal, and left dorsal cingulate cortices--caudal SMA proper and right dorsal premotor area. These same areas showed significant increases or decreases, respectively, when contrast means were compared with the use of movement time or relative acceleration time, respectively, as the weighting factor. Analysis of individual subject differences revealed a correspondence between the spatial extent of rCBF changes as a function of task ID and the individuals' movement times. As task ID decreased, significant increases in rCBF were evident in the right anterior cerebellum, left middle occipital gyrus, and right ventral premotor area. Functionally, these areas are associated with aiming conditions in which the motor execution demands are high (i.e., coordination of rapid reversals) and precise trajectory planning is minimal. These same areas showed significant increases or decreases, respectively, when contrast means were compared with the use of movement time or relative acceleration time, respectively, as the weighting factor. A functional dissociation resulted from the weighted linear contrasts between larger (limb transport) or smaller (endpoint targeting) type amplitude/target width aiming conditions. Areas with significantly greater rCBF for targeting were the left motor cortex, left in...

The guidance hypothesis (Schmidt, 1991) predicts that the guiding properties of augmented feedback are beneficial for motor learning when used to reduce error, but detrimental when relied upon. Therefore, a heavily guiding form of feedback might be detrimental for learning. In addition, the guidance hypothesis predicts that practice with a high relative frequency of augmented feedback would be detrimental for learning. An experiment is described that crossed two forms of feedback with two levels of relative frequency. Subjects practiced movements to a target with either physical guidance or knowledge of results, and with either a high or faded relative frequency. The high frequency physical guidance condition resulted in the poorest retention, and both high frequency feedback conditions resulted in the least accuracy in transfer. These results provide support for the guidance hypothesis and suggest consideration of the combined effects on learning of the type and relative frequency of augmented feedback and acquisition-test conditions.

Background. Disparate results have been reported on the implicit learning ability of adults with stroke. Objective. This study aimed to elucidate the relationships between stroke severity and the task employed to test implicit motor learning. Methods. Twenty-eight patients with chronic stroke were divided according to stroke severity using the Orpington prognostic score into those with mild (n = 16, score < 3.2) or moderate stroke (n = 12, score 3.2-5.0). Seventeen healthy individuals served as matched controls (HC). All participants practiced 2 implicit learning tasks, the Serial Reaction Time (SRT) and Serial Hand Movement (SHM). Results. A group-bytask-by-block interaction (P = .000) demonstrated differences across the experimental factors. Post hoc analyses revealed differences between groups and tasks. Greater change in the speed of responding was exhibited for the SHM than the SRT task by the HC and mild groups; however, the moderate group did not demonstrate a between-task difference. Conclusion. Both stroke severity and motor task influenced the magnitude of implicit learning across acquisition, which suggests for the first time that different tasks may yield disparate implicit learning outcomes in the same population. Additionally, the impact of stroke severity may be important when assessing residual implicit motor learning capability. The combination of these 2 factors helps explain previously reported contradictory findings and may inform future studies.