Inter-Rater Reliability of Motor Unit Number Estimation Method

Abstract

Background: Motor unit number estimation (MUNE), is a method developed to determine the number of motor axons to the best possible quantity. Objective: In this study, we aimed to test the reliability of the method by comparing the results of 3 different investigators. Material and Methods: The healthy volunteers with neither peripheral nerve disease nar any systemid metabolic disease with normal neurological examination included in the study. All had normal median and ulnar nerve conduction velocities. One hundred and ten subjects (58 males, 52 females) at a mean age of 38.9 ± 6.6 years were evaluated in 3 age groups. There were 36 volunteers in 15-30 age range, 44 in 31-45 age range and 30 in ?46 age range. Manuel incremental method was performed for MUNE. lnvestigator A completed 2 series of studies and recordings with a stimulation of 0.1 msn in all subjects. lnvestigator B repeated these studies in 45 subjects and investigator C in 24 subjects who were not examined by the investigator B. Results: Three investigators obtained approximately the same MUNE scores (p=0.250). This finding suggests that results of this method are reproducible. Sex did not have an effect on the scores (p=0.28). Peripheral nevre fibers detected by MUNE showed a relative decrease with aging, however this was not statistically significant. Conclusion: These findings suggest that MUNE studies can be used in clinical trials when performed by experienced investigators ..