Sensory nerve conduction: effect of ultrasound.

Bilateral antidromic sensory conduction measurements of the lateral cutaneous branch of the radial nerves of 5 men were performed at intervals before and for 15 minutes following ultrasonic application over a segment of the nerve. The ultrasound was applied over the area of the radial nerve for 5 minutes at a frequency of 1 MHz, continuous wave and using 1.5 watts/sq cm dosage. Nerve bed temperature was continuously recorded during the study via a subcutaneous needle thermistor probe. Eighty measurements were made of temperature latency, amplitude and duration of the nerve action potentials. Amplitude and duration of the nerve action potentials did not change following sonation. Latency and temperature values changed significantly following the application of ultrasound. The latencies decreased, indicating increased speed of conduction, as the subcutaneous temperatures increased. The ultrasound dosage used in this study increased the speed of nerve conduction.