Hemiparesis

About: Hemiparesis is a research topic. Over the lifetime, 3492 publications have been published within this topic receiving 103566 citations. The topic is also known as: unilateral paresis & hemiplegia.

Recovery of motor function after stroke.

Abstract: The natural history of recovery of motor function after stroke is described using data from a 1-year community-based study in Auckland, New Zealand. Of 680 patients, 88% presented with a hemiparesis; the proportion of survivors with a persisting deficit declined to 71% at 1 month and 62% at 6 months after the onset of the stroke. At onset, there were equal proportions of people with mild, moderate, and severe motor deficits, but the majority (76%) of those who survived 6 months had either no or only a mild deficit. Recovery of motor function was associated with the stroke severity but not with age or sex; patients with a mild motor deficit at onset were 10 times more likely to recover their motor function than those with a severe stroke. Our results confirm the reasonably optimistic outcome for survivors of stroke and further suggest that recovery of motor function is confined to patients whose motor deficit at onset is either mild or moderate.

Motor learning: its relevance to stroke recovery and neurorehabilitation.

Abstract: Purpose of reviewMuch of neurorehabilitation rests on the assumption that patients can improve with practice. This review will focus on arm movements and address the following questions: (i) What is motor learning? (ii) Do patients with hemiparesis have a learning deficit? (iii) Is recovery after in

Neural correlates of motor recovery after stroke: a longitudinal fMRI study.

Abstract: Recovery of motor function after stroke may occur over weeks or months and is often attributed to cerebral reorganization. We have investigated the longitudinal relationship between recovery after stroke and task-related brain activation during a motor task as measured using functional MRI (fMRI). Eight first-ever stroke patients presenting with hemiparesis resulting from cerebral infarction sparing the primary motor cortex, and four control subjects were recruited. Subjects were scanned on a number of occasions whilst performing an isometric dynamic visually paced hand grip task. Recovery in the patient group was assessed using a battery of outcome measures at each time point. Task-related brain activations decreased over sessions as a function of recovery in a number of primary and non-primary motor regions in all patients, but no session effects were seen in the controls. Furthermore, consistent decreases across sessions correlating with recovery were seen across the whole patient group independent of rate of recovery or initial severity, in primary motor cortex, premotor and prefrontal cortex, supplementary motor areas, cingulate sulcus, temporal lobe, striate cortex, cerebellum, thalamus and basal ganglia. Although recovery-related increases were seen in different brain regions in four patients, there were no consistent effects across the group. These results further our understanding of the recovery process by demonstrating for the first time a clear temporal relationship between recovery and task-related activation of the motor system after stroke.

Compensatory strategies for reaching in stroke.

Abstract: A major prerequisite for successful rehabilitation therapy after stroke is the understanding of the mechanisms underlying motor deficits common to these patients. Studies have shown that in stroke patients multijoint pointing movements are characterized by decreased movement speed and increased movement variability, by increased movement segmentation and by spatial and temporal incoordination between adjacent arm joints with respect to healthy subjects. We studied how the damaged nervous system recovers or compensates for deficits in reaching, and correlated reaching deficits with the level of functional impairment. Nine right-hemiparetic subjects and nine healthy subjects participated. All subjects were right-hand dominant. Data from the affected arm of hemiparetic subjects were compared with those from the arm in healthy subjects. Seated subjects made 40 pointing movements with the right arm in a single session. Movements were made from an initial target, for which the arm was positioned alongside the trunk. Then the subject lifted the arm and pointed to the final target, located in front of the subject in the contralateral workspace. Kinematic data from the arm and trunk were recorded with a three-dimensional analysis system. Arm movements in stroke subjects were longer, more segmented, more variable and had larger movement errors. Elbow-shoulder coordination was disrupted and the range of active joint motion was decreased significantly compared with healthy subjects. Some aspects of motor performance (duration, segmentation, accuracy and coordination) were significantly correlated with the level of motor impairment. Despite the fact that stroke subjects encountered all these deficits, even subjects with the most severe motor impairment were able to transport the end-point to the target. All but one subject involved the trunk to accomplish this motor task. In others words, they recruited new degrees of freedom typically not used by healthy subjects. The use of compensatory strategies may be related to the degree of motor impairment: severely to moderately impaired subjects recruited new degrees of freedom to compensate for motor deficits while mildly impaired subjects tended to employ healthy movement patterns. We discuss the possibility that there is a critical level of recovery at which patients switch from a strategy employing new degrees of freedom to one in which motor recovery is produced by improving the management of degrees of freedom characteristic of healthy performance. Our data also suggest that stroke subjects may be able to exploit effectively the redundancy of the motor system.