The trigeminal nerve is the largest cranial nerve and the understanding of the anatomy of this nerve lying in deep facial structures makes the electrodiagnostic testing difficult and gives little information about this nerve. The conventional
study
using most widely for trigeminal nerve examination is blink reflex, which estimate mainly the ophthalmic branch and unable to detect the pathology of majority of other trigeminal branches.
The purpose of this study was to investigate the other method for electrodiagnostic evaluation of trigeminal nerve or each branches; Infraorbital SEP, motor conduction study of mandibular nerve and Jaw reflex study. This paper ad undertaken to
obtain
the normative data in thirty healthy adults to provide valuable parameters for application of this methods.
@ES The results were as follows;
@EN 1) Somatosensory evoked potential from the scalp in response to infraorbital electrical stimulation were recorded as very early potentials(w1, w2, and w3) and four next components(p4, n5, p6, and n7).
2) The mean peak latencies of SEP were 1.47±0.07, 2.39±0.15, 3.47±0.18 msec in w1, w2, w3 and 4.36±0.17, 5.78±0.12, 6.84±0.13, 7.41±0.23 msec in p4, n5, p6 and n7. And there were no statistically significant differences of the parameters
between
the both sides.
3) The mean latencies and amplitudes of M-wave by direct mandibular nerve stimulation below zygomatic arch were measured 1.5±0.14 msec, 25.8±6.24 m V on masseter muscle recording, 2.3±0.22 msec, 6.21±2.45m V on anterior belly of digastric
muscle.
4) The jaw reflex study by mechanical chin tapping with ossiloscope triggering hammer recorded bilateral reflex waves on masseter muscles, which latency was 7.3±0.74 msec(range of 5.8~8.8 msec) and the greatest latency difference between the
sides was
0.34 msec as mean+3S.D..
On the basis of these findings, it is concluded that infraorbital SEP, M-wave study on masseter and digastric muscles and jaw reflex study are the useful electrodiagnostic method to find out the lesion of trigeminal nerve and its branches and to
estimate the neurologic condition.
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