Electrodiagnostic study of trigeminal nerve

APPLICATION of electrodiagnostic studies to the cranial nerves has been limited largely to measurement of conduction in the distal facial nerve and to examination of the facial musculatiire. We have recently reported on an easily applied method for elicitation of reflex contraction of the orbicularis oculi muscle by electric;il stimulation of the supraorbital nerve.' The orbicularis oculi reflex2 may be affected by lesions of the trigeminal nerve (afferent path) ,R,4 the facial nerve (efferent path) , l a 5 or the pons (central connection) .G We have demonstrated the usefulness of this test in evaluation of lesions of the facial nerve1 and in localization of disease to the pons.6 This report will relate our experience with changes in the orbicularis oculi reflex and the masseter stretch reflex7 in lesions of the fifth cranial nerve. Our studies were first applied to patieiits with cIassical tic douloureux and then to patients suffering from compressing lesions i , f the ifth nerve. The studies are of special intrrest in this latter group since symptoms may reqemble those of tic douloureux and since i1.0 ohjt ctive test for dysfunction of the trigenii:ial nerve has been available until now.