Trigeminal somatosensory evoked potentials in assessment of craniofacial pain: Preliminary results

Abstract

Background Craniofacial pain syndromes include various kinds of primary and secondary headaches, most of which are related to trigeminal system such as trigeminal neuralgia, trigeminal neuropathy, cluster headache or other trigeminal autonomic cephalalgia. Blink reflex, masseter inhibitory reflex, jaw jerk and trigeminal laser-evoked potentials are known to be more reliable in neurophysiological testing of trigeminal system and electrophysiologic testing of trigeminal reflexes accurately distinguishes symptomatic and classic trigeminal neuropathy. Here, we aimed to evaluate the reliability and stability of trigeminal nerve somatosensory evoked potentials (TSEP) in less frequently encountered craniofacial pain syndromes. Patients and method TSEP and blink reflex (BR) were recorded in 10 patients with craniofacial pain during the active disease period and in 25 healthy individuals. The latencies of N2, P2 and N3 waves as well as amplitudes of N2/P1 and N2/P2 were measured. Results We could not obtain TSEP in three patients (30%) whereas it was elicited in all healthy subjects ( p = 0.01). All of the patients without TSEP response had idiopathic etiology and only one of them also lacked BR responses. Latencies appeared to be longer in patients with craniofacial pain compared to healthy subjects. However, BR responses were symmetrical and within normal ranges. Conclusion Keeping in mind the low number of participants included, we think that TSEP is able to be obtained in a stable manner in healthy subjects and it may be more capable to reflect changes in pain conditions compared to BR.