Disposable Concentric Needle Electromyography Electrodes Artifact Discharge Mimicking Positive Sharp Waves

Abstract

Objectives: To determine a new artifact discharge produced from the disposable concentric needle (DCN) electromyography (EMG) electrodes. Methods: We have recorded the activity obtained after the first insertion of 41 DCN (37 mm) and 36 DCN (50 mm) in several muscles during the rest. The number of the patients was 77 (26 male, 51 female). Results: We observed an artifact discharge (AD) resembling positive sharp waves (PSWs) in 31 patients of 77 insertions. The AD occurred with 18 of 41 insertions of DCN 37 mm and 13 of DCN 50 mm. The artifact resolved when the needle has been moved in the muscle or in the adipose subcutaneous tissue. Conclusion: This AD should be recognized when using DCN electrodes to avoid confusion with PSWs. Recognizing these artifacts during needle EMG is important to avoid false positive results.