[The record of sensitive nerve action potentials. Interelectrode distance in healthy children]

Studies in adults show that with a 3 or 4 cm distance between active and reference electrodes, maximum amplitude and latency values of sensitive nerve action potentials are obtained. The purpose of this study was to identify, in healthy children, the interelectrode distances at which the amplitude and peak latency do not differ significantly from those obtained with the intereletrode distance at which the maximum values are obtained.

Four reference electrodes were placed at 1, 2, 3 and 4 cm distance from the active electrode. The electrode signal was recorded simultaneously with a physical jumper between the four channels. A sample of 66 median nerves was analyzed in children aged 5 to 9 years. Amplitude and latency maximum values were obtained with an interelectrode distance of 4 cm. Values obtained with 4 cm were compared against those obtained with 1, 2 and 3 cm interelectrode distances.

Amplitude values did not show significant difference with 3 and 4 cm interelectrode distances (p = 0.216). With regard to latency, the values did not indicate significant difference with the 4 and 3 cm interelectrode distances (p = 0.266).

The amplitude increase resulting from interelectrode distance augmentation is not influenced by the peripheral nerve growth process in children. The optimal distance for the record of the nerve potential actions was similar to that seen in adults.