Robot-Aided Stroke Stimulation
Abstract & Commentary
Source: Volpe BT, et al. A novel approach to stroke rehabilitation: Robot-aided sensorimotor stimulation. Neurology 2000;54:1938-1944.
Volpe and colleagues applied a scientifically developed robotic device that passively manipulated the rostral portion of the shoulder and connected elbow of patients recovering from moderate to severe stroke-induced hemiplegia. Of 56 such patients, all receiving standard physiotherapy, 30 were randomly selected for robotic treatment and 26 served as controls. All patients started the program within two weeks following the paralytic onset. By chance, the 26 controls tended to have larger strokes and slightly greater degrees of paralysis. The robotic shoulder device was applied for one hour per day, five days a week at least five consecutive weeks in duration. Standard physical therapy was carried throughout for all patients. All patients could understand the procedure and respond to the mechanized therapy. Functional outcomes at onset and outcomes of completed robotic therapy were measured by motor assessment consisting of a Motor Status score, a Motor Power score, and Functional Independence Measurement. Clinical outcome was evaluated on all patients by a blinded, experienced physical therapist. Robotic therapy significantly increased power and coordination between shoulders and elbows, as well as total at functional activity of the whole arm-shoulder areas. Hand and wrist functions, however, failed to improve with the treatment. The relative duration of permanent improvement in the robot group vs. the controls has not yet been reported, nor has the present recovery of the improved member been described as accomplishing everyday needs.
Commentary
This report reflects several years’ efforts in prosthetic engineering aimed at finding ways to apply extracorporeal, interactive machines that would improve paralytic arm use following partial or severe stroke. The robotic instrument described here improved both shoulder strength and shoulder-elbow coordinated activity in poststroke patients. The lack of manual function, however, represents a considerable limitation to functional recovery. The results of this study differ greatly from the semipermanent success of "constraint induced movements (CIM)" reported by Miltner et al (Stroke 1999;30:586-592) and abstracted in the June Neurology Alert (6:82). The CIM report described remarkable recoveries of chronic hand-wrist dysfunction when applied two years after severe arm strokes. In that report, constraints were placed on the patients’ normal hands and arms for an estimated 90% of wakeful time every day for two weeks. After that, the heretofore dysfunctional member returned to a relatively high level of skillful activity, which, when reviewed, continued for at least many months. Several questions appear. What is the durability of the robot-activating, applied increase in strength? How much more strength could be induced by longer daily robot exercises, and could peripheral stimulation to the hand evoke transynaptic, presently silent cerebral sensory-motor circuits to induce manual activity? Finally, was the overcoming of hemiparalytic manual function in the CIM program only a reflection of functional disuse rather than a reflection of cerebral plasticity? Answers to these questions will not come easily, but they amplify the increasing contributions of neuroscientific methods to the previously empirical discipline of neurological rehabilitation. —fred plum
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