Recording sensory nerve action potential using different electrode types.

INTRODUCTION/AIMS: Switching between different types of electrodes during motor and sensory nerve conduction studies adds time to a study. We investigated the use of disposable disc electrodes (DDE) used for motor nerve conduction studies to record the antidromic sensory nerve action potential (SNAP) in median, ulnar and radial sensory nerve conduction studies.

METHODS

The SNAP was recorded using four different electrode types: reusable ring, reusable bar, disposable ring, and DDE in a random rotating order. Studies were performed in healthy subjects. Other than being an adult with no history of neuromuscular disease, there were no exclusion criteria.

RESULTS

We studied 20 subjects (11 females, 9 males; age 41.1 ± 15.7 y). The SNAP waveforms recorded by all four electrode types were similar. There was no statistically significant difference in the onset latency, peak latency (PL), negative peak amplitude (NPA), peak to peak amplitude, or conduction velocity. In individual nerve recordings, the absolute PL difference between reusable ring electrodes (our current standard) and DDE was less than 0.2 ms in 58 of 60 (97%) nerves. The mean absolute NPA difference was 3.1 μV (standard deviation = 2.85 μV). Recordings with NPA difference >5 μV also had high NPA and/or had large artifacts.

DISCUSSION: DDE may be used for performing motor and sensory nerve conduction studies. This can reduce the time required for electrodiagnostic testing.