Training and exercise to drive poststroke recovery

Abstract

To make practical recommendations regarding therapeutic strategies for the rehabilitation of patients with hemiparetic stroke, it is important to have a general understanding of the fundamental mechanisms underlying the neuroplasticity that is induced by skills training and by exercise programs designed to increase muscle strength and cardiovascular fitness. Recent clinical trials have provided insights into methods that promote adaptations within the nervous system that correlate with improved walking and upper extremity function, and that can be instigated at any time after stroke onset. Data obtained to date indicate that patients who have mild to moderate levels of impairment and disability can benefit from interventions that depend on repetitive task-oriented practice at the intensity and duration necessary to reach a plateau in a reacquired skill. Studies are underway to lessen the consequences of more-severe motor deficits by drawing on medications that augment plasticity, biological interventions that promote neural repair, and strategies that employ electrical stimulation and robotics.

Figure 1

Functional MRI studies performed before and after locomotor training in a 12-year-old who had undergone hemispherectomy. The left side of each panel shows the right hemispherectomy, which was performed to treat epilepsy 4 years before this study. The patient, who had left hemiparesis and impaired gait, received 2 weeks (~20 h) of therapy using BWSTT and over-ground training. The scan was performed while the subject dorsiflexed his left or right ankle 10 times over 30 s, rested for 30 s, and repeated this block design sequence a total of four times. The arrow points to the primary sensorimotor cortical sulcus. (A) Before training, a small region of activation representing the paretic left ankle (red) and a larger region representing the nonparetic ankle (yellow) seemed to partially overlap (orange) within the sulcus and precentral gyrus of the leg representation in M1/S1, but this was a small activation compared with healthy controls. A more-diffuse SMA activation was also seen extending into the premotor area. (B) When the scan was repeated a day after the subject completed training, the movements of both ankles had an enlarged and overlapping representation more within the typical M1/S1 region, consistent with the subject’s improvement in motor skills for walking and ability to kick a soccer ball. Abbreviations: BWSTT, body-weight-supported treadmill training; M1/S1, primary sensorimotor cortex; SMA, supplementary motor area.