Cervical paraspinal electromyography: normal values in 100 control subjects.

The normal electromyographic values and the significance of spontaneous activity, when examining the cervical paraspinal muscles, has been studied rarely, and there are very few studies concerning this issue.To obtain muscle unit potential (MUP) reference values for cervical paraspinal muscles, we examined 100 volunteers. Spontaneous activity and the analysis of 20 MUPs in every individual were checked by the automated MUP analysis program.In those individuals ages 20 to 40 years, no spontaneous activity was observed, and in the ones ages 40 to 60 years and 60 years or older, fibrillations and/or positive sharp waves were seen in 8% and 92%, respectively. MUP values were found to be close to those of upper limb muscles. Age has no significant effect on MUP values, except for mean amplitude that was increased in individuals ages 60 to 80 years.Our findings suggest that fibrillations and positive sharp waves do not have much electrodiagnostic value in the study of cervical paraspinal muscles of middle-aged and elderly subjects, when it is an isolated finding, and there is a need for an extended electromyographic examination, including other muscles, to exclude radiculopathy. Automated MUP analysis is easily performed, and our results may serve as reference values.