Pharmacological Therapies to Enhance Motor Recovery and Walking After Stroke

Emerging Strategies

Wieslaw Oczkowski

Disclosures

Expert Rev Neurother. 2013;13(8):903-909. 

In This Article

How Does the Brain Recover After Stroke?

Like any other organ or tissue in the human body, the brain is primed to heal and has mechanisms of healing. However, given the complex organization of the brain, and the life-associated learned abilities, simple scar formation and union of tissues cannot easily compensate for lost function and abilities.

Animal studies and observational studies in humans would suggest that recovery of function after stroke is an active process that responds to external influences such as repetitive training. This active experience-based recovery after stroke has been termed neural plasticity – the ability of the brain to change in response to internal or external influences.

Neural plasticity is a complex concept that can be considered at the biological or behavioral level. At the biological level, there is initial recovery of injured brain tissue, engagement of new uninjured areas and training of other brain areas to perform new functions. At the behavioral level, there is recovery of function to a pre-injury functioning and recovery of limitations of activities to a pre-injury ability.[8] At the biological level, spontaneous recovery of brain tissue occurs as the area of ischemia heals. Furthermore, remote areas of the brain compromised by diaschisis (hypometabolism, neurovascular uncoupling and aberrant neurotransmission) return to function and existing neural pathways change, and new neuronal connections develop.[9]

There is clearly interplay of biological and behavioral factors. In rats, after an induced middle cerebral artery stroke, reaching 'therapy' enhances forelimb recovery when introduced within 5 or 14 days but not 30 days after stroke.[10] However, intense 'therapy' started within 24 h of stroke in rats was associated with an increase in infarct volume.[11] The timing and intensity of an intervention may be crucial.

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