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The biophysical effects of ultrasound on median nerve distal latencies

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
David H. Perrin, Provost and Executive Vice Chancellor (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/

Abstract: Purpose: Previous studies have documented the lack of ultrasound's non-thermal effects on nerve conduction using frequencies of 1 MHz and 870 kHz. The analyses and conclusions were reached, despite only one study incorporating pulsed ultrasound. The purpose of this study was to determine the biophysical effects of continuous wave (CW) and pulsed wave (PW) ultrasound on median nerve motor and sensory latencies using common frequencies of 1.0 and 3.0 MHz. Subjects: Fifteen healthy subjects (8 males, 7 females, age = 23.5 + 4.44 yrs, height = 171.2 + 10.7 cm, weight = 67.5 + 7.9 kg) without a history of neurological or musculoskeletal injury to their non-dominant arm volunteered for testing. Methods and materials: Subjects were exposed in counterbalanced order to five ultrasound treatment conditions: ( 1) 1 MHz, 1.0 W/cm², 8 min., (2) 1 MHz, 1.0 W/cm², 50% PW, 8 min., (3) 3.0 MHz, 1.0 W/cm², CW, 8 min., (4) 3.0 MHz, 1.0 W/cm², 50% PW, 8 min., (5) placebo, 0.0 W/cm², 8 min. Dependent measures for motor and sensory latencies, and subcutaneous temperatures were taken pretreatment, at 2, 4 and 6 minutes during treatment, and immediately post-treatment. Separate two within repeated measures ANO VA were used for each dependent measure. Results: Analysis revealed significant interactions for motor latencies [F ( 16,224) = 52.77, p < .001 ] , sensory latencies [F ( 16,224) = 41.10, p < .001J, and subcutaneous temperatures [F ( 16,224) = 52.77, p < .001 ] . Tukey's HSD post hoc analyses confirmed that nerve latencies responded similarly to subcutaneous temperature changes during and after ultrasound treatment. Conclusions: Alterations in nerve latencies from ultrasound on healthy nerves appeared to be related to temperature changes induced by ultrasound's thermal effects, and not by non-thermal or mechanical effects.

Additional Information

Publication
Electromyography and Clinical Neurophysiology, 40:169-180
Language: English
Date: 2000
Keywords
Ultrasound, Nerve conduction