Active Elbow Research Articles

Surgical treatment for absent single-hand grip and elbow extension in quadriplegia. Principles and preliminary experience

A classification of quadriplegic patients based on available sensory receptors (ocular only or both ocular and hand sensibility) and motor function in each upper extremity greatly facilitates the planning and evaluation of surgical treatment. In forty hands of thirty-three patients with post-traumatic quadriplegia and cord lesions higher than those usually thought to be benefited by reconstructive surgery, three or more procedures were performed at one or more sittings to create an active wrist extensor and a thumb flexor grip, a function easier to provide and much more useful to these patients than tripod pinch. In these forty hands no function was lost and in all but two function was improved significantly if not greatly. A useful level of active elbow extension was restored in fifteen of sixteen extremities in quadriplegics by transfer of the posterior half of the deltoid to the triceps aponeurosis, lengthening the deltoid with free grafts from the toe extensors. Each upper extremity of quadriplegic patients of the type under consideration is a highly individualized problem. Successful treatment requires strict attention to every detail of preoperative evaluation, surgical treatment, and postoperative care.

Operant conditioning of specific patterns of neural and muscular activity.

In awake monkeys we recorded activity of single "motor" cortex cells, four contralateral arm muscles, and elbow position, while operantly reinforcing several patterns of motor activity. With the monkey's arm held semiprone in a cast hinged at the elbow, we reinforced active elbow movements and tested cell responses to passive elbow movements. With the cast immobilized we reinforced isometric contraction of each of the four muscles in isolation, and bursts of cortical cell activity with and without simultaneous suppression of muscle activity. Correlations between a precentral cell and specific arm muscles consistently appeared under several behavioral conditions, but could be dissociated by reinforcing cell activity and muscle suppression.