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New Approaches to Stroke Recovery

　　 Daniel Hanley, MD,[8] of The Johns Hopkins Hospital in Baltimore, Maryland, discussed neuroplasticity and recovery after stroke. He specifically focused on task-oriented exercise and motor function following hemiparetic stroke. It has been thought that irreversible neuron damage occurs after stroke and that there is minimal chance of recovery. In view of recent trials and findings, this may no longer be the case.
　　In an interesting study by Caro and associates[9] presented in Stroke in 1999, stroke patients were followed for 12 weeks after the acute event. The disappointing fact was that almost 50% of these patients were either still in the hospital, in a nursing home, in a rehabilitation facility, or had died. Based on older studies, 12 weeks (3 months) has been considered the approximate limit up to which substantial improvement occurred. There has been substantial improvement in the acute and subacute (less than 3 months) management of stroke. Chronic stroke patients have not been studied so far as they are usually home or in a nursing home facility, and there is a plateau in their presumed chance of recovery.
　　Although there are studies in the literature reporting up to 80% improvement after mild stroke, 85% of patients report difficulty in gait 3 months after the stroke and more than 50% of patients describe an impaired 6 minutes walking endurance 12 months after stroke.
Dr. Hanley and his colleagues studied the endurance of 53 chronic stroke patients (mean, 2 years after stroke). What was surprising was that these patients were not exercised before. These patients had significant comorbidity, mainly hypertension (73%), diabetes, and coronary artery disease. They undertook a zero-incline treadmill tolerance test, and they were allowed to stay for 3 minutes at a speed higher than 0.3 miles per hour. What was found was that stroke patients used 66% of their maximum energy capacity (measured as VO2) when walking at a self-selected pace as opposed to 27% for controls. Their peak energy capacity was also lower than controls. A low-density CT scan of midthigh also showed that the affected limb was more heavily infiltrated with fat, probably as a result of underusage. These patients underwent regular treadmill intervention (1 hour sessions starting at 0.2 miles per hour [MPH], 3 sessions per week), and they were re-evaluated after 3 and 6 months. It should be noted that these were chronic stroke patients. The results were encouraging: in 6 months, a 33% reduction of the energy cost of walking was demonstrated. There was also a 39% increase in the peak ambulatory workload capacity; both results suggest increased endurance and reserves.
　　An innovative method called Bilateral Arm Training With Auditory Cue (BATRAC) was also tested. In this method, the patient is lying flat on a magnetic resonance imaging (MRI) table. The patient is given instructions to perform essentially rowing-like movements. At the same time, brain activity, as depicted by functional MRI, is followed. In healthy volunteers, the classic neurologic physiology was reproduced: the right side of the brain was activated when the left side of the body was moving and vice versa. Chronic stroke patients were then subjected to 60-minute BATRAC training sessions 3 times a week for 6 weeks. It was shown that the normal side of the brain was compensating for the injured tissue of the contralateral side. Additionally, transmagnetic stimulation of the healthy part of the brain resulted in muscle activation normally innervated by the diseased part of the brain. Of note, functional improvement after BATRAC was higher compared with standard physical therapy. Functional recovery was evaluated in terms of facilitation of everyday activities, mainly reaching and grasping. It is not clear how this occurs. It is hypothesized that the activation of the normal brain tissue is probably a result of brain compensation or induction.
　　Dr. Hanley concluded that there appears to be significant brain plasticity and recovery potential even after a significant time period poststroke, and that repetitive task-oriented interventions offer the best chance for improvement.