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Highlights • Surgery-free VOR measurement that allows screen for genes and drugs affecting vestibular function has been enabled. • Daily-progression profile of the vestibular impairment caused by IDPN at different dose levels has been obtained. • Mice with homozygous mutations of Lhfpl5 and Cdh23 have been identified based on their reduced VOR-response levels. Abstract Vestibulo-ocular reflex (VOR) responding to acceleration stimuli is originated from the vestibular apparatuses and thus widely used as an in vivo indicator of the vestibular function. We have developed a vestibular function testing (VFT) system that allows to evaluate VOR response with improved efficiency. The previously required surgical procedure has been avoided by using a newly designed animal-immobility setup. The efficacy of our VFT system was demonstrated on the mice with vestibular abnormalities caused by either genetic mutations (Lhfpl5−/− or Cdh23−/−) or applied vestibulotoxicant (3,3′-iminodipropionitrile, IDPN). Daily longitudinal inspection of the VOR response in the IDPN-administered mice gives the first VOR-based daily-progression profile of the vestibular impairment. The capability of VOR in quantifying the severity of toxicant-induced vestibular deficits has been also demonstrated. The acquired VOR-measurement results were validated against the corresponding behavioral-test results. Further validation against immunofluorescence microscopy was applied to the VOR data obtained from the IDPN-administered mice. We conclude that the improved efficiency of our surgery-free VFT system, firstly, enables the characterization of VOR temporal dynamics and quantification of vestibular-impairment severity that may reveal useful information in toxicological and/or pharmaceutical studies; and, secondly, confers our system promising potential to serve as a high-throughput screener for identifying genes and drugs that affect vestibular function. [ABSTRACT FROM AUTHOR]

• The vestibular reflexes and evoked potentials are in vivo tools for objectively assessing the vestibular function. • The VOR is widely used due to its stereotypical input-output relationship and simple motion pattern of the ocular response. • The cVEMPs and oVEMPs are able to respectively assess the saccular and utricular functions. • The VEMPs evoked by the air-conducted sound can evaluate the unilateral vestibular function noninvasively. • Location-specific functional information can be obtained by analyzing the morphological features of the VsEP waveforms. The normal function of the vestibular system is crucial for the sense of balance. The techniques used to assess the vestibular function plays a vital role in the research of the vestibular system. In this article, we have systematically reviewed some popular methods employing vestibular reflexes and vestibular evoked potentials for assessing the vestibular function in rodent models. These vestibular reflexes and vestibular evoked potentials to effective stimuli have been used as nondestructive and objective functional measures. The main types of vestibular reflexes include the vestibulo-ocular reflex (VOR), vestibulocollic reflex (VCR), and vestibulo-sympathetic reflex (VSR). They are all capable of indicating the functions of the semicircular canals and otoliths. However, the VOR assessment is much more prevalently used because of the relatively stereotypical inputoutput relationship and simple motion pattern of the ocular response. In contrast, the complicated motion pattern and small gain of the VCR response, as well as the undesired component possibly contributed from the acceleration receptors outside the labyrinths in the VSR response, restrict the widespread applications of VCR and VSR in the assessment of the vestibular system. The vestibular evoked myogenic potentials (VEMPs) and vestibular sensory evoked potentials (VsEPs) are the two typical evoked potentials that have been also employed for evaluating the vestibular function. Through exploiting different types of the VEMPs, the saccular and utricular functions can be evaluated separately. The sound-induced VEMPs, moreover, are capable of noninvasively assessing the unilateral vestibular function. The VsEPs, via the morphology of their signal waveforms, enable the access to the location-specific information that indicates the functional statuses of different components within the vestibular neural pathway. [ABSTRACT FROM AUTHOR]