Audiovestibular Characteristics of Small Cochleovestibular Schwannomas in Neurofibromatosis Type 2

Abstract

In our cohort, ABR, caloric response, cVEMP, and elevated intralabyrinthine protein correlated with tumor volume, but 4f-PTA did not. Abnormal ABR and 4f-PTA correlated with elevated intralabyrinthine protein. These findings may provide insight on the effect of small CVS on the inner ear and cochleovestibular nerves, which may aid in their optimal management.

Audiologic Natural History of Small Volume Cochleovestibular Schwannomas in Neurofibromatosis Type 2

“…Proposed mechanisms for hearing loss include compression of the blood supply to the cochlea, disruption of cochlear neuron axonal transport, or direct effects on the cochlea itself. 7 A significant correlation was seen between baseline IAC tumor volume and AHDR, however the association could also be generalized to overall tumor volume when accounting for hearing level at baseline and volume as categorical rather than continuous variables. Further, the rate of IAC tumor growth was consistent among all groups regardless of baseline IAC tumor volume size, hearing level or PF extension (23.1-34.4 mm 3 /year, p =0.77).…”

“…Further, size has been defined variably including the using single largest linear dimension (diameter) or by calculated volumes. 2,7,10,13 Consensus from the literature regarding small tumors is that they are associated with better PTA, SRT and ABR, 4 hearing preservation can be good (65%) when offered surgery, 13 and risk of developing significant hearing loss is less than 0.5 after 2 to 6 years. 3,11 Within our cohort of 111 treatment-naïve ears with tumors <1000 mm 3 , we observed heterogeneity in patient-tumor characteristics.…”

“…We have previously correlated audiovestibular characteristics of small volume, treatment-naïve tumors in NF2 with MRI findings in a cross-sectional manner. 7 In the current study, we look at pure tone thresholds and word recognition scores (WRS) and correlate audiometric changes in these measures with tumor volume on magnetic resonance imaging (MRI) in a longitudinal manner. We compare characteristics of ears with progressive hearing loss through the duration of follow-up to those with stable hearing.…”

Cervical and Ocular Vestibular-Evoked Myogenic Potentials in Patients With Intracochlear Schwannomas

“…Many studies reported reduced or absent VEMPs in patients with cochleovestibular schwannoma (i.e., vestibular schwannoma, see introduction) and reported a strong relationship with tumor size (57). Cervical VEMPs in 38 ears of Neurofibromatosis Type 2 patients with small cochleovestibular schwannomas were described by Holliday et al (58). Normal results were found in 71% and abnormal cVEMPs were found in 29% of the patients with a correlation between abnormal cVEMPs and tumor size.…”

Audiologic and Otologic Complications of Cryptococcal Meningoencephalitis in Non-HIV Previously Healthy Patients

“…Comprehensive audiology examinations included, whenever possible, tympanometry, middle ear reflex measures, audiometry, otoacoustic emissions, and neurodiagnostic auditory brainstem response (ABR) studies. ABRs were graded from 0 to 4 with respect to waveform morphology, peak/interpeak latencies and amplitude ratios 21 . Grades 1 and 2 were considered normal; grades 3 and 4 were considered abnormal and consistent with involvement of the auditory nervous system; grade 0 was assigned when peripheral hearing loss precluded interpretation of the ABR.…”