Progress in clinical neurosciences: stroke recovery and rehabilitation.

Background: Recent literature has provided new insights into the role of rehabilitation in neurological recovery post-stroke. The present review combines results of animal and clinical research to provide a summary of published information regarding the mechanisms of neural recovery and impact of rehabilitation.

Methods: Plasticity of the uninjured and post-stroke brain is examined to provide a background for the examination of brain reorganization and recovery following stroke.

Driving evaluation practices of clinicians working in the United States and Canada.

Objective: To determine off-road and on-road driving evaluation practices of clinicians in the United States and Canada who assess individuals with disabilities for fitness to drive.

Participants: Participants were 114 clinician attendees at the 2003 annual Association of Driver Educators for the Disabled with driving assessment experience ranging from 1 month to 25 years.

Measures: Information was elicited regarding the clinician, clientele, referral practices, and off-road and on-road driving evaluation practices and retraining practices using a self-administered questionnaire.

The role of task-specific training in rehabilitation therapies.

Task-oriented therapy is important. It makes intuitive sense that the best way to relearn a given task is to train specifically for that task. In animals, functional reorganization is greater for tasks that are meaningful to the animal.

The role of timing and intensity of rehabilitation therapies.

In both animal and clinical studies, motor rehabilitation and training increase cortical representation and improve recovery, whereas lack of training decreases cortical representation for particular motor functions. In animals, delays in providing rehabilitation reduce the impact of therapy with a worsening in motor outcomes and a corresponding reduction in cortical reorganization. In clinical studies, there is an association between earlier admission to rehabilitation and better outcomes that correlates with animal work both in terms of functional gains from chronic stroke deficits and cortical reorganization.

Training and stimulation in post stroke recovery brain reorganization.

In both animal and clinical studies, training or rehabilitation increases cortical representation with subsequent functional recovery, whereas a lack of rehabilitation or training decreases cortical representation and delays recovery. Animals exposed to enriched environments post stroke have improved functional outcomes compared with animals exposed to nonenriched environments. In humans, stroke units may be the closest approximation there is to an enriched environment.

Intrinsic factors influencing post stroke brain reorganization.

Reorganization of the brain, specifically the motor cortex surrounding the stroke, accounts for much of the observed neurological recovery following stroke. Not surprisingly, size of the stroke lesion has the greatest impact on neurological recovery in both animal and clinical research studies. Spontaneous recovery of lost function is possible after a cortical lesion, particularly if the lesion is small.

Plasticity and reorganization of the brain post stroke.

Reorganization of the cortex post stroke is dependent not only on the lesion site but also on remote brain areas that have structural connections with the area damaged by the stroke. Motor recovery is largely dependent on the intact cortex adjacent to the infarct, which points out the importance of preserving the penumbral areas. There appears to be a priority setting with contralateral and ipsilateral motor pathways, with ipsilateral (unaffected hemisphere) pathways only becoming prominent after more severe strokes where functional contralateral (affected hemisphere) pathways are unable to recover.

Plasticity and reorganization of the uninjured brain.

Brain capacity is dependent not so much on the number of neurons but on the number of synaptic connections with functional connections that develop over a lifetime of genetic programming and life experiences. In the uninjured human brain, cortical reorganization that occurs in response to learning and experience is referred to as brain plasticity. Motor learning and complex environments result in a greater number of synapses and an increase in dendritic branching, whereas repetitive movements alone, in the absence of motor learning, do not.