Reappraisal of Supraorbital Sensory Nerve Conduction Recordings: Orthodromic and Antidromic Techniques.

OBJECTIVE To establish a supraorbital nerve sensory conduction recording method and assess its usefulness. METHODS Thirty-one healthy subjects without a history of trauma or neurological disease were recruited. For the orthodromic procedure, the recording electrode was attached immediately superior to the supraorbital notch. The stimulation electrode was placed on points along the hairline which evoked the largest sensory nerve action potentials (SNAPs). The antidromic sensory response was recorded after switching the recording and stimulating electrodes. The measured parameters were onset latency, peak latency, and baseline to peak amplitude of the SNAPs. The electrophysiological parameters of the bilateral supraorbital nerves were compared. We also recruited two patients who had sensory deficits on one side of their foreheads because of laceration injuries. RESULTS The parameters of orthodromically recorded SNAPs were as follows: onset latency 1.21±0.22 ms (range, 0.9-1.6 ms), peak latency 1.54±0.23 ms (range, 1.2-2.2 ms), and baseline to peak amplitude 4.16±1.92 µV (range, 1.4-10 µV). Those of antidromically recorded SNAPs were onset latency 1.31±0.27 ms (range, 0.8-1.7 ms), peak latency 1.62±0.29 ms (range, 1.3-2.2 ms), and baseline to peak amplitude 4.00±1.89 µV (range, 1.5-9.0 µV). There was no statistical difference in onset latency, peak latency, or baseline to peak amplitude between the responses obtained using the orthodromic and antidromic methods, and the parameters also revealed no statistical difference between the supraorbital nerves on both sides. CONCLUSION We have successfully recorded supraorbital SNAPs. This conduction technique could be quite useful in evaluating patients with supraorbital nerve lesions.