Reference values for jitter recorded by concentric needle electrodes in healthy controls: A multicenter study.

Introduction: The aim of this study was to create reference values for jitter measured with concentric needle electrodes. Methods: Operators worldwide contributed recordings from orbicularis oculi (OO), frontalis (FR), and extensor digitorum (ED) muscles in healthy controls. Criteria for acceptable signal quality were agreed upon in advance. Fifteen or 20 recordings of acceptable quality from each muscle were required for voluntary and electrical stimulation recordings, respectively. Results: Recordings from 59 to 92 subjects were obtained for each muscle and activation type. Outlier limits for mean consecutive difference and individual jitter data for voluntary acti- vation were: OO, 31 and 45 ms; FR, 28 and 38 ms; ED, 30 and 43 ms; and for electrical stimulation they were: OO, 27 and 36 ms; FR, 21 and 28 ms; ED, 24 and 35 ms. Conclusion: Reference jitter values from con- centric needle electrode recordings were developed from signals of defined quality while seeking to avoid creating supernormal values. Muscle Nerve 53: 351-362, 2016