P51-F Quantitative electromyography: Normative data in paraspinal muscles

Abstract

Objectives Paraspinal muscle may be affected in neuromuscular disorders, and EMG may be crucial in the diagnosis. The aim of the study was to develop normative data at different spinal segments. Methods Sixty-five healthy subjects (49% men, 51% women) aged 21–82 years were studied. In each subject, 16–92 motor unit potentials (MUPs) were recorded bilaterally at C7, Th10 and L5 segments using concentric needle electrodes. At each segment, average MUP amplitudes, durations, incidence of polyphasic potentials, and the amplitude at maximal voluntary contraction (MVC) were measured. The incidence of spontaneous activity was examined. Results There was no relationship between the EMG parameters and age. The mean MUP duration and amplitude, and the amplitude at MVC increased caudally (ANOVA, P Conclusions In contrast to limb-muscles EMG parameters were unrelated to the age of the subject. The gradient of EMG parameters caudally from C7 suggesting larger motor units at more caudal segments. The proportion of polyphasic potentials may be due to the organization of muscle fibers. The incidence of fibrillation activity was similar to limb muscles. Significance The study describes normative data for EMG of paraspinal muscles according to the examined spinal segment. These data may be useful in quantitative EMG examination of paraspinal muscle in neuromuscular disease.