Objective The goal of the present study was to investigate the clinical utility of measurements of ear-canal reflectance (ECR) in a population of patients with conductive hearing loss in the presence of an intact, healthy tympanic membrane (TM) and an aerated middle ear. We also sought to compare the diagnostic accuracy of umbo velocity (VU) measurements and measurements of ECR in the same group of patients. Design This prospective study comprised 31 adult patients with conductive hearing loss, of which 14 had surgically-confirmed stapes fixation due to otosclerosis, 6 had surgically-confirmed ossicular discontinuity, and 11 had CT- and VEMP-confirmed superior semicircular canal dehiscence (SCD). Measurements on all 31 ears included pure-tone audiometry for 0.25 – 8 kHz, ECR for 0.2 – 6 kHz using the Mimosa Acoustics HearID system, and VU for 0.3 – 6 kHz using the HLV-1000 laser Doppler vibrometer (Polytec Inc). We analyzed power reflectance |ECR|2 as well as the absorbance level = 10×log10(1−|ECR|2). All measurements were made prior to any surgical intervention. The VU and ECR data were plotted against normative data obtained in a companion study of 58 strictly defined normal ears (Rosowski et al. 2011). Results Small increases in |ECR|2 at low-to-mid frequencies (400–1000 Hz) were observed in cases with stapes fixation, while narrow-band decreases were seen for both SCD and ossicular discontinuity. The SCD and ossicular discontinuity differed in that the SCD had smaller decreases at mid-frequency (~1000 Hz), while ossicular discontinuity had larger decreases at lower frequencies (500–800 Hz). SCD tended to have less air-bone gap at high frequencies (1–4 kHz) compared to stapes fixation and ossicular discontinuity. The |ECR|2 measurements, in conjunction with audiometry, could successfully separate 28 of the 31 cases into the three pathologies. By comparison, VU measurements, in conjunction with audiometry, could successfully separate various pathologies in 29 of 31 cases. Conclusions The combination of |ECR|2 with audiometry showed clinical utility in the differential diagnosis of conductive hearing loss in the presence of an intact TM and an aerated middle ear, and appears to be of similar sensitivity and specificity to measurements of VU plus audiometry. Additional research is needed to expand upon these promising preliminary results.

Objective Hearing loss is a common symptom in patients with cochleovestibular schwannoma (VS). Clinical and histological observations have suggested that the hearing loss may be caused by both retrocochlear and cochlear mechanisms. Our goal was to perform a detailed assessment of cochlear pathology in patients with VS. Study Design Retrospective analysis of temporal bone histopathology. Setting Multi-center study. Material Temporal bones from 32 patients with unilateral, sporadic VS within the internal auditory canal. Main Outcome Measures Sections through the cochleae on the VS side and opposite (control) ear were evaluated for loss of inner and outer hair cells, atrophy of the stria vascularis, loss of cochlear neurons, and for presence of endolymphatic hydrops and precipitate within endolymph or perilymph. Observed pathologies were correlated to nerve of origin, VS volume, and distance of VS from the cochlea. Hearing thresholds were also assessed. Results VS caused significantly more inner and outer hair cell loss, cochlear neuronal loss, precipitate in endolymph and perilymph, and decreased pure tone average, when compared to the opposite ear. Tumor size, distance from the cochlea, and nerve of origin did not correlate with structural changes in the cochlea or the hearing threshold. Conclusions There is significant degeneration of cochlear structures in ears with VS. Cochlear dysfunction may be an important contributor to the hearing loss caused by VS, and can explain certain clinically observed phenomena in patients with VS.

dle ear effusion, led to a decrease in intracochlear ECoG signal amplitudes. This was not attributable to changes of cochlear function. All persistent reductions in ECoG response magnitude after normalization of the tympanogram occurred during the first week following implantation. Thresholds of ECoG signals were at or below hearing thresholds in all cases. Conclusion: Gross intracochlear trauma during surgery appears to be rare. In the early postoperative phase the ability to assess cochlear status by ECoG recordings was limited due to the regular occurrence of middle ear effusion. Still, intracochlear ECoG along with tympanogram recordings suggests that any changes of low-frequency cochlear function occur mainly during the first week after cochlear implantation. ECoG seems to be a promising tool to objectively assess changes in cochlear function in cochlear implant recipients and may allow further insight into the mechanisms underlying the loss of residual hearing.