Analysis of semicircular canal function as evaluated by video Head Impulse Test in patients with vestibular schwannoma

Audiovestibular Findings in Patients with Concurrent Superior Canal Dehiscence and Vestibular Schwannoma

“…This latter finding has been replied in intraoperative studies confirming that VS mainly originates from the IVN (41). On the other hand, VEMPs data did not reflect this selective impairment, as both patients with PSC hypofunction exhibited either normal or enhanced cVEMPs rather than absent/hypoactive potentials as expected in IVN lesions (1,8,13,39,40). It might be here hypothesized that a concurrent slight damage of the afferents running through the IVN because of the VS might have only minimally mitigated the SCD-related hyperactivity of saccular function, providing interesting insights concerning the different vulnerability of vestibular sensors to insults in the case of reduced intralabyrinthine impedance due a concurrent TMW lesion (33,42,43).…”

“…A different sensitivity for tumor compression or invasion between afferents encoding sustained stimuli (impaired) and fibers reacting to transient impulses (preserved) has been hypothesized. Nevertheless, it should be also kept in mind how the prediction of the vestibular nerve involvement not always overlaps the intraoperative findings, and several factors other than the mere nerve origin of the tumor should be always considered when interpreting instrumental data in VS (1,2,4,8,9,13). Moreover, it should be considered that the patient with ILVS presented with MD-like symptoms and an extremely impaired vestibular function, consistent with clinical, instrumental and imaging data correlating such lesions with atypical MD clinical pictures (45)(46)(47).…”

“…A complete audiovestibular assessment plays a pivotal role in the differential among inner ear diseases. The complementarity of the instrumental examinations and imaging for a correct diagnosis is increasingly understood (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). This is even more true considering the possible coexistence of multiple disease affecting the same inner ear.…”

“…VS should always be suspected in patients with asymmetric sensorineural hearing loss (SNHL), dizziness, and tinnitus, despite symptoms severity is not related with the tumor size (15,16). Despite vertigo and unsteadiness are rarer than auditory symptoms (15)(16)(17), signs of vestibular impairment are often detected in VS (1,2,4,6,8,9,12,13,18). Although the diagnosis of VS requires a brain MRI (19), an extensive instrumental work-up including pure-tone and speech-audiometry, auditory brainstem responses, video-oculography (VOG), bithermal caloric test (BCT), video-head impulse test (vHIT), and vestibular-evoked myogenic potentials (VEMPs) recording can help physicians to address the diagnosis (1,2,4,6,8,9,12,13,(15)(16)(17)(18).…”

Sensibilidade e especificidade do video head impulse test no diagnóstico do recrutamento vestibular pós-calórico

“…O achado típico nas lesões do órgão vestibular periférico é o baixo ganho com presença de sacadas corretivas. Está presente na neurite vestibular (Yang et al, 2018), nos grandes Schawannomas vestibulares (Fujiwara et al, 2020), algumas vezes na vertigem postural paroxística benigna (Castellucci et al, 2020) e nas otites (Tozar et al, 2020). Ocorre em decorrência da assimetria de tônus entre os núcleos vestibulares ocasionada pela falta da informação periférica.…”