title: Changes in motor unit action potential parameters in monopolar recordings related to filter settings of the EMG amplifier.
abstract: We studied the effect of different electromyographic amplifier settings on various parameters of motor unit potentials (MUPs) as recorded by the monopolar needle. Of the four filter settings used--2Hz-10kHz, 20Hz-10kHz, 20Hz-2kHz and 500Hz-10kHz--2Hz-10kHz yielded longest duration recordings. Reductions of all parameters of the MUP except for phases and turns were demonstrated with the 500Hz-10kHz filter. No significant differences were noted between recordings obtained with 20Hz-10kHz and 20Hz-2kHz filters. Frequencies below 500Hz were more significant in determining the various parameters of the MUP than were those above 2kHz. Most suitable filter settings for recording MUPs were 2Hz-10kHz and 20Hz-10kHz. Measurements of MUPs were shown to be specific for a given filter setting.
mesh_terms: D000200:Action Potentials; D000328:Adult; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D004594:Electrophysiology; D006801:Humans; D007866:Leg / Q000294:innervation; D008297:Male; D009045:Motor Endplate / Q000502:physiology; D009339:Needles; D009469:Neuromuscular Junction / Q000502:physiology*