Comparison of Sensory Nerve Action Potential Parameters Using Different Recording Electrodes

ABSTRACT

OBJECTIVE: To investigate the influence of five different recording electrodes on the various parameters of sensory nerve action potentials (SNAPs). METHOD: Median sensory nerve conduction study was performed in 50 normal subjects using different five types of recording electrodes-disc electrode, ring electrode, bar electrode and two kinds of felt-tip bar electrodes (type 1 and 2). The interelectrode distances between active and reference electrodes were set at 4 cm for the disc and ring electrodes. The bar electrode, felt-tip electrodes type 1 and 2 were fixed at interelectrode distances of 3 cm, 3.7 cm and 2.3 cm, respectively. Onset and peak latency, onset to peak amplitude, peak to peak amplitude and duration of negative spike of SNAPs were measured. These parameters were compared using ANOVA test. RESULTS: Onset and peak latencies of SNAPs recorded from five different electrodes were not different (p>0.05). Onset to peak and peak to peak amplitudes of SNAPs recorded from felt-tip type 2 electrode were significantly reduced compared to other electrodes (p<0.05). Onset to peak amplitude of SNAPs was also reduced when the ring electrode was used (p<0.05). The negative spike durations of SNAPs recorded from felt-tip type 2 and bar electrodes were shorter than other electrodes recording (p<0.05). CONCLUSION: Onset and peak latencies of SNAPs were not affected by the types of electrodes used. Shortening of interelectrode distance may be a main cause of reduction of peak to peak amplitude and negative spike duration of SNAPs.