Neurophysiological Effect of Low Level Laser Therapy on Ulnar Nerve

Abstract

Low level laser therapy is widely used in managing pain and inflammation in musculoskeletal ailments. Its effect on Peripheral nervous system and its function is not yet clearly studied. Objective: To analyze the neurophysiological effect of Low level laser irradiation on ulnar nerve MATERIALS AND METHODS: Sixty healthy subjects with age group between 20-30 years of both genders were recruited in this experimental study design.. The procedure was clearly explained to the subjects and informed consent was obtained. They were assigned randomly to either Ga. As.Laser group or Sham laser group. All the subject’s were positioned in supine lying with the irradiated dominant hand kept at 135 degrees of flexion. Ground electrode was placed over the thenar eminence. The subject's skin (electrode placement area) was degreased for proper transmission of laser. Nerve conduction velocity was recorded Antidromically. A 904nm diode laser was used to irradiate the skin overlying the ulnar nerve behind the medial epicondyle of the humerus for 20 secs. The laser was set to deliver continuous energy at 4.0 J/cm².Antidromically action potential, peak to peak amplitude, onset latency, nerve conduction velocity was recorded before and after irradiation of the ulnar nerve. RESULT: The study revealed that there was a significant difference in onset Latency (P=0.0021) but there was no significant difference in Nerve conduction velocity (P=0.2738) and PPA (P=1.0000) between laser group and sham laser group. CONCLUSIONS: Low level laser irradiation of skin overlying the ulnar nerve resulted in a significant increase in latency in this study. This increase in latency corresponds to a decrease in sensory nerve conduction velocity and could help explain the alleged pain relieving effects of low level laser irradiation.