The effect of superior-canal opening on middle-ear input admittance and air-conducted stapes velocity in chinchilla

Abstract

The recent discovery of superior semicircular canal (SC) dehiscence syndrome as a clinical entity affecting both the auditory and vestibular systems has led to the investigation of the impact of a SC opening on the mechanics of hearing. It is hypothesized that the hole in the SC acts as a "third window" in the inner ear which shunts sound-induced stapes volume velocity away from the cochlea through the opening in the SC. To test the hypothesis and to understand the third window mechanisms the middle-ear input admittance and sound-induced stapes velocity were measured in chinchilla before and after surgically introducing a SC opening and after patching the opening. The extent to which patching returned the system to the presurgical state is used as a control criterion. In eight chinchilla ears a statistically significant, reversible increase in low-frequency middle-ear input admittance magnitude occurred as a result of opening the SC. In six ears a statistically significant reversible increase in stapes velocity was observed. Both of these changes are consistent with the hole creating a shunt pathway that increases the cochlear input admittance.

Stapes Vibration in the Chinchilla Middle Ear: Relation to Behavioral and Auditory-Nerve Thresholds

“…Ravicz and Rosowski (2013b) recently reviewed the literature of chinchilla stapes-velocity transfer functions and found them to be generally similar Songer and Rosowski 2006;Slama et al 2010;Koka et al 2010; Ravicz and Rosowski 2013b). All but two of the then available stapes-velocity transfer functions were limited to frequencies G20 kHz (see Fig.…”

Estimating Cochlear Frequency Selectivity with Stimulus-frequency Otoacoustic Emissions in Chinchillas

“…interference of SFOAE components with short and long latencies), although it may also in part be related to a small dip in the magnitude of the middle ear gain function at~2.5 kHz observed in open bulla preparations (e.g. Songer and Rosowski 2006;Ravicz and Rosowski 2013). Noteworthy, the short-latency component has been also present even at the highest probe frequencies, although smaller in magnitude than the long-latency ones (Shera et al 2008).…”

Morphological Study of Auditory Ossicles in the Mouse

“…Analogical descriptions of the ear structures of animals, found in veterinary anatomy textbooks, are scare, schematic and do not go beyond a rough enumeration of the structures, often with no data on topography and variability. Previous researches established the morphology of these ossicles in rodents and some laboratory animals (Kurtul et aZ., 2003;Songer and Rosowski, 2006;Gratton et al, 2008;Ravicz et al, 2008).…”