Does low‐Intensity helium‐Neon laser irradiation alter sensory nerve active potentials or distal latencies?

Abstract

The effect of 1 mW helium neon continuous-wave (0.633 microns) laser irradiation on superficial radical sensory and median sensory nerve function was examined in a double-blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low-energy lasers of this power and wavelength alter nerve function.

Effects of low intensity infrared laser irradiation upon conduction in the human median nerve in vivo

“…In contrast, Snyder-Mackler & Bork (1988) found significant lasermediated latency increases in the same nerve following percutaneous irradiation using a 1 mW He-Ne continuous wave laser (632 8 nm; 19 mJ/cm2). Nevertheless, Basford, Daube, Hallman, Millard & Moyer (1990), in attempting to replicate this study under carefully controlled conditions, using both the human superficial radial and median nerves with an apparently equivalent irradiation protocol, found no such latency shifts in either nerve. The precise reasons for these contradictory findings are not clear, although incomplete specification of the irradiation parameters used in the first two studies limits informed consideration and precise replication.…”

“…During attendance, all subjects (n = 51; forty females and eleven males; 19-28 years old) received a briefing on the procedure and purpose of the experiment, and were asked to sign a simple consent form. Subjects were screened for peripheral neuropathy or neuromuscular disorders according to routine clinical standards (Guarantors of Brain, 1986;Basford et al 1990). It was not found necessary to exclude any subjects on the basis of such screening.…”

Pain reduction by infrared light-emitting diode irradiation: a pilot study on experimentally induced delayed-onset muscle soreness in humans

“…In general, this research was performed on the superficial radial nerve [10][11][12][13], described by Shin J Oh [14] as an uncommon nerve conduction technique, or on the mixed median nerve [8,9,13,[15][16][17]. Following the method of Cambier et al [18], the authors of this study decided to investigate the effect of the light source used on the conduction characteristics of the sural nerve.…”

“…A second major difference between the trials, and therefore also hindering an appropriate comparison between the results, is the wide range of used light sources: HeNe lasers [12,13,16] and GaAlAs lasers [8-10, 17, 18] or a monochromatic infrared multisource treatment unit [15].…”

Effect of low-level laser therapy (LLLT) on viscoelasticity of the contracted knee joint: Comparison with whirlpool treatment in rats

“…Although high-energy laser therapy for surgical cutting and hemostasis is well known, the effect of low-energy laser, which usually means <100 mW power intensity and is regarded as showing a nonthermal effect, still remains surrounded by skepticism and controversies over investigated results [1]. Low-Level Laser Therapy (LLLT) has recently been studied for modulating various processes in biological systems [2][3][4], e.g., tissue healing, mainly cutaneous wound [5,6], pain control and nerve function [7][8][9], and arthritis and other lesions [10][11][12][13].…”