A noninvasive technique to assess completeness of spinal cord lesions in humans.

The effect of scalp stimulation delivered through electrodes overlying the motor cortex was evaluated in five healthy subjects and six patients with traumatic spinal cord injury. The latency to the onset of the electromyographic response was measured in the biceps brachii and abductor pollicis brevis muscles. In all the patients, latencies to the muscle (biceps brachii) whose innervation originated above the lesion were in the normal range; whereas, latencies to the muscle (abductor pollicis brevis) whose innervation originated below the lesion were prolonged.

Visually displayed EMG feedback: single case studies of hemiplegic upper extremity rehabilitation.

The efficacy of visually displayed EMG feedback in treating hemiplegic upper limb motor disorders was investigated in 5 patients (0.5-4 years poststroke). A single case experimental method "multiple-baseline across target behaviors" was used to compare performance during the feedback phase to that occurring in the monitored baseline phase.

Sensory nerve action potentials of the medial and lateral plantar nerve.

A simple, reliable method of recording sensory nerve action potentials (SNAP) from the medial and lateral plantar nerves was established using 30 healthy adults as subjects. Potentials were recorded with surface electrodes both antidromically and orthodromically. The mean latency and amplitude of the SNAP of the medial plantar nerve using antidromic stimulation were 2.

Electrical stimulation effect on denervated skeletal myofibers in rats: a light and electron microscopic study.

The purpose of the present study was to determine morphologically the effect of electrical stimulation on denervated rat extensor digitorum longus (EDL) muscle. Fifteen adult male rats were divided in to 3 groups: control, denervated-nonstimulated, and denervated-stimulated. Electrical stimulation treatment (1 hr/day for 24 days) began 4 days postsurgery.

Sensory conduction study of distal radial nerve.

The technique of recording superficial radial sensory nerve action potential (SNAP) from the thumb was compared with that of recording from the 1st web space. The spread of stimulus to the median nerve in the forearm when stimulating the radial sensory nerve with relatively high intensity was also investigated. Recording the radial SNAP from the 1st web space produces a larger amplitude response with a sharper takeoff point compared with that of recording from the thumb.

Experimental myotonia induced in denervated muscles by 2,4-D.

Rats were denervated in one hind limb and injected with 2,4-dichlorophenoxyacetic acid (2,4-D). Isotonic tetanic contractions of the muscles treated with 2,4-D after more than 10 days of denervation revealed prolonged relaxation times similar to those of the intact side and characteristic of clinical myotonia. No myotonic discharges were observed in the muscles denervated for more than 10 days and treated with 2,4-D.

Computer analysis in clinical electromyography.

Electromyographic findings are traditionally evaluated in terms of the duration, amplitude and shape of the myoelectric potentials as well as the pattern of discharge. Unfortunately, the evaluation is frequently dependent on the examiner's subjective observations with the result that mild, early cases or variations in the typical symptoms of the disease may be missed. To overcome these deficiencies, various approaches employing either analog or digital computer techniques have been explored.

Mercury poisoning in a dentist.

We examined a dentist with chronic elemental mercury poisoning electrophysiologically. Motor conduction in the upper and lower limbs was normal. Sensory nerve action potentials in the ulnar and median nerves were normal, but could not be elicited in the superfical peroneal nerves.

The effect of angiography on the electrophysiological state of the spinal cord. A study in control and traumatized cats.

The tonic vibration reflex (TVR) and evoked cerebral potential (ECP) were used to evaluate the effects of aortic injections of Renografin- 76, saline, and a mixture of sodium and sucrose on the spinal cord in 7 control cats and 12 which were recovering from trauma. Results showed that Renografin-76 produced different toxic effects in control and traumatized spinal cords as measured by the TVR. The disappearance of either ECP or TVR following the Renografin injection in 4 cases exemplifies the enhanced risk of injecting angiographic materials into traumatized spinal cords during recovery.

Electromyographic studies in a case of foramen magnum meningioma.

Atrophy of muscles innervated by the lower cervical cord is a well-known feature in patients with foramen magnum tumours. Electromyographic evidence of denervation in the atrophic muscles is presented. The significance and possible mechanisms are reviewed and discussed.