THE EFFECTS OF LOW POWER LASER ON ELECTROPHYSIOLOGICAL PARAMETERS OF SURAL NERVE IN NORMAL SUBJECTS: A COMPARISON BETWEEN 670 AND 780 nm WAVELENGTHS

Abstract- There is just one study about the effects of 830 nm low power laser (LPL) on conduction velocity of sural nerve in human. Considering the fact that the sural nerve is a pure sensory nerve, therefore, for determining the effect of LPL on electrophysiological parameters of the nerve in human, this study was carried out as a base for further basic and clinical researches. Thirty eight normal volunteer men participated (20–35 yr.) in this study. LPL (670 and 780 nm) was applied on left and right sural nerves. Electrophysiological parameters such as Onset Latency (OL), Peak Latency (PL), Negative Peak Amplitude (NPA), Peak to Peak Amplitude (PPA) and Duration were measured before and after the application of various doses (0.5, 1.5 and 2.5 J/cm) of LPL. This study showed that both wavelengths of LPL increase the latencies and therefore reduce the nerve conduction velocity (NCV). In addition, LPL application decreased the nerve amplitudes. Among the various intensities, the application of 2.5 J/cm was the most effective (P< 0.001). On the other hand, 670 nm wavelength and 2.5 J/cm had the greatest effects on OL in comparison with 780 nm (P< 0.04). However, there was no significant difference between the effects of 670 and 780 nm on the other electrophysiological parameters of sural nerve