Vestibular-evoked myogenic potentials – the literature review of the method based on results of recordings in infants with impaired inner ear function
Olaf Zagólski, Dariusz Jurkiewicz
CaseRepClinPractRev 2005; 6:80-84
Vestibular-evoked myogenic potentials (VEMPs) occurring in sternocleidomastoid muscles after intense acoustic stimulation are a polysynaptic response of otolith-vestibular nerve origin. The reflex originates in the saccule, the afferent pathways is the inferior vestibular nerve, and the efferent pathways the vestibulospinal tract. VEMPs are most effectively evoked by short tone bursts and consist of positive and negative successive waves (pI-nII). So far results of recording VEMPs in infants have not been reported. The aim of this paper is to present the review of the literature concerning VEMPs, describe their characteristics in infants and determine if they correlate with auditory brainstem responses (ABR) and caloric test measures. ABR, VEMPs and caloric tests were performed in 10 healthy infants and 10 subjects with sensorineural hearing loss, aged 3 months. Normal VEMPs and caloric nystagmus were elicited in all healthy individuals and in 13 ears with impaired hearing. Mean latency values were pI=7.1, nII=12.2 ms. No response to caloric stimulation was observed in 7 ears. VEMPs were normal in the patient with sensorineural hearing loss and no response to caloric stimulation. In another individual with delayed caloric nystagmus, pI-nII latencies were prolonged. No VEMPs were recorded in the remaining ears with vestibular dysfunction. Latencies of VEMPs are shorter in infants than in adults. VEMP latencies do not correlate with ABR latencies but in the majority of infants they correlate with caloric test measures. VEMP recording could provide important information about the otolith reflex pathways in infants.
Keywords: inner ear, saccule, vestibular system, vestibular-evoked myogenic potentials, VEMPs