Abstract
Low power laser was irradiated on pain spots of II healthy volunteers. Two pain spots were selected by pin prick methods on the inside of the forearm of each volunteer. Two other spots were also chosen as control, which were not pain spots. The spots were as follows: uncolored non-pain spots (C1) black colored non-pain spots (C3), uncolored pain spots (C2) and black colored pain spots (C4). The spots were randomly irradiated.
Irradiation on Cl elicited pressing sensations in two of eleven and the mean of visual analogue scale (VAS) were 0.18, on C2, stabbing pain sensations occurred (mean of VAS; 1.64), on C3, prickling pain sensations occurred (mean of VAS; 2.41), on C4, unbearable pain occurred (mean of VAS; 4.32).
The mean value of VAS for the irradiation of each spot was significantly getting greater in the following order of Cl, C2, C3, C4.
The cause of analgesic effect of low power laser may be the stimulation of some nociceptors of the skin.
