Background and purpose: Nearly 4 decades of investigation into the plasticity of the nervous system suggest that both timing and dose could matter. This article provides a synopsis of our lectures at the IV STEP meeting, which presented a perspective of current data on the issues of timing and dose for adult stroke and spinal cord injury motor rehabilitation.
Summary of key points: For stroke, the prevailing evidence suggests that greater amounts of therapy do not result in better outcomes for upper extremity interventions, regardless of timing. Whether or not greater amounts of therapy result in better outcomes for lower extremity and mobility interventions needs to be explicitly tested. For spinal cord injury, there is a complex interaction of timing postinjury, task-specificity, and the microenvironment of the spinal cord. Inflammation appears to be a key determinant of whether or not an intervention will be beneficial or maladaptive, and specific retraining of eccentric control during gait may be necessary.
Recommendations for clinical practice: To move beyond the limitations of our current interventions and to effectively reach nonresponders, greater precision in task-specific interventions that are well-timed to the cellular environment may hold the key. Neurorehabilitation that ameliorates persistent deficits, attains greater recovery, and reclaims nonresponders will decrease institutionalization, improve quality of life, and prevent multiple secondary complications common after stroke and spinal cord injury.