Participants were randomly assigned to either an intervention group ( n = @ ) , who received @ nm laser irradiation as @ Jpoint for @ s over ipsilateral three nerve roots in the cervical region corresponding to C@-C@ vertebrae , and @ nm laser irradiation as @ Jcm@ for @ min in a tangential scanning mode over the affected extremity ; or a control group ( n = @ ) , who underwent the same protocol and timing of laser probe application with the laser switched off .