Frequency and phase effects on cervical vestibular evoked myogenic potentials (cVEMPs) to air-conducted sound

Abstract

Few previous studies of tuning using air-conducted (AC) stimuli and the cervical vestibular evoked myogenic potential (cVEMP) have compensated for the effects of middle ear (ME) attenuation. Zhang et al. (Exp Brain Res 213:111-116, 2011a) who did allow for ME effects were able to show a secondary peak around 100 Hz for the ocular VEMP (oVEMP). Recently, it has become clear that the otolith afferents responsible for the cVEMP and oVEMP differ and thus the nature of tuning may be more related to the reflex studied determining which otolith receptors are activated rather than the properties of the stimulus. We wished to reinvestigate the tuning for the cVEMP using AC stimuli, to establish whether the low-frequency peak is specific for the oVEMP or a consequence of the stimulus modality itself. In response to recent evidence using a 500 Hz AC stimulus that there was no effect of stimulus phase, we also investigated whether phase (condensation or rarefaction) had an effect at any frequency. We measured corrected cVEMP amplitudes and latencies in response to stimuli between 50 and 1200 Hz in 10 normal volunteers using an AC stimulus adjusted for ME attenuation. We confirmed earlier reports of the similarity of the tuning for both the cVEMP and oVEMP reflexes but found no separate 100 Hz peak for the cVEMP. AC stimulus phase did not affect either amplitude or latency. Both the tuning pattern and the phase effects contrast with those previously reported for bone-conducted (BC) stimuli. Unlike BC stimulation, which shows tuning consistent with an action on the otolith membrane, AC stimuli are likely to act through a different mechanism, most likely directly at the hair cell level.

Vestibular Evoked Myographic Correlation

“…Thus, the VEMCorr appears to be ideally suited for investigating frequency tuning. That topic was already investigated in several VEMP studies (e.g., Govender et al 2016;Todd et al 2000Todd et al , 2009Wei et al 2013;Welgampola and Colebatch 2001). However, the transient stimuli used in those studies naturally had a relatively broad frequency spectrum, at least at low frequencies, where the total duration of the stimulus sometimes corresponded to only a single cycle of a tone so that the window function used to limit the stimulus duration had a significant effect as well.…”

Current diagnostic procedures for diagnosing vertigo and dizziness

“…Govender et al assumed different mechanisms for stimulation of the otolith organs. Bone conduction stimuli should rather lead to stimulation of the otolith membrane while air conduction stimuli should lead to direct stimulation of acoustically sensitive vestibular hair cells [ 202 ].…”

Moderne Schwindeldiagnostik

“…B. Trommelfellperforation, offene Mastoidhöhle) vorhanden ist. Govender et al vermuten unterschiedliche Mechanismen bei der Stimulation der Otolithenorgane, wobei die Knochenleitungsreize eher zu einer Reizung der Otolithenmembran und die Luftleitungsstimulation eher zu einer direkten Reizung akustisch sensitiver vestibulärer Haarzellen führen soll [202].…”