Hypobaric pressure exposure effects on cochlear frequency selectivity in fluctuating, low-frequency hearing loss

Abstract

Aim: To study the effects of hypobaric pressure chamber exposure on cochlear frequency selectivity in subjects with monaural fluctuating low-frequency hearing loss, such as Ménière's disease.Methods: We used a hypobaric pressure chamber to create relative underpressure in the ear canal to impose positive pressure gradients to the inner ear. Psychophysical tuning curves (PTC), transiently evoked otoacoustic emissions (TEOAE) and speech recognition scores in noise was measured in 10 subjects with fluctuating low-frequency hearing loss before and after pressure exposure.Results: After the exposure, overall pure tone average showed no improvement, but individual results showed improved SPEECH RECOGNITION SCORES in noise (six subjects), increased TEOAE strength (three subjects) and increased steepness for PTCs (two subjects).Deteriorations were also seen, mainly in PTCs. No association could be established between the different tests and measured parameters could not predict subjective improvement. Conclusion:The results suggest variable effects of hypobaric pressure exposure on inner ear physiology.