FIGURE 7.

(A) For decades auditory researchers have used objective measures of cochlear nerve, hair cell and mechanical function in the CAP, CM, and basilar membrane vibration to comprehensively investigate the cellular basis of hearing and associated disorders. (B) Analogous tools have recently been developed and characterized from the utricle, in the VsEP, UM and macular vibration to differentially assess peripheral vestibular function, in vivo. Reproduced (adapted) from Assessment of utricular nerve, hair cell and mechanical function, in vivo. Pg. 10. Doctoral Thesis. The University of Sydney. Christopher Pastras. 2018. With permission from Copyright owner Christopher Pastras. (C) Low-frequency (4.8 Hz) biased cochlear microphonic (CM) waveforms recorded from scala media of the basal turn in response to a 500 Hz, 90 dB SPL probe stimulus after injection of 0.5 μL Healon gel, used to mimic endolymphatic hydrops in the cochlear apex. (D) Lissajous figures show the same CM waveforms (heavy lines) plotted against a sinusoidal input, displaced to best fit the transducer curve (thinner line). The open circle indicates the displacement, which corresponds to the operating point at that point on the bias cycle. Reproduced from Salt et al. (2009) Copyright Elsevier (Hearing Research). (E) 220Hz Utricular microphonic (UM) waveforms during a 10 Hz hydrodynamic bias of the utricular macula. (F) UMs plotted on a Boltzmann Lissajous curve representing MET channel gating, using the approximated macular displacement, which includes an estimate of the operating point with displacement (gray circles). Reproduced from Pastras et al. (2020) Copyright Springer (Journal of the Association for Research in Otolaryngology).