The influence of disappearing and reappearing spontaneous otoacoustic emissions on one subject's threshold microstructure

• Published in: Hearing research Vol. 115; no. 1; pp. 197 - 205
• Main Authors: Smurzynski, Jacek, Probst, Rudolf
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1998; Elsevier
• Subjects: Acoustic Stimulation; Adult; Auditory Threshold - physiology; Biological and medical sciences; Cochlea - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Female; Fundamental and applied biological sciences. Psychology; Hearing threshold; Humans; Otoacoustic Emissions, Spontaneous; Psychoacoustics; Spontaneous otoacoustic emission; Temporal integration; Vertebrates: nervous system and sense organs; Temporal integration; Spontaneous otoacoustic emission; Hearing threshold; Human; Hearing; Acoustic stimulus; Otoacoustic emission; Perception threshold; Cochlea; Masking; Neural integration; Inner ear; Organ of hearing; Adaptation
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(97)00193-7

The effects of a consistently disappearing and reappearing spontaneous otoacoustic emission (SOAE) at around 2280 Hz on microstructure for pure tones of varying durations in a 33 year-old woman with normal hearing was studied. The SOAE began to appear after 10–15 min in a quiet test room and increased in level by up to 22 dB over a 30–40-min period. The SOAE was measured every 12 to 15 min. Between measurements, the subject performed a signal detection task for pure tones with total durations varying from 20 to 320 ms. The signal frequencies were within a ±30-Hz range relative to the SOAE frequency. For signal durations of 40–320 ms, there was a local dip at the target SOAE frequency when it was either not detectable or its level was lower than −14 dB SPL. Subjective threshold levels were as much as 12 dB better than those obtained when the SOAE was −6 dB SPL or greater. The results suggest that a region of the cochlea with high sensitivity and instability can be put into self-oscillation producing an SOAE, possibly by a change of efferent activity. Hearing threshold is affected possibly due to adaptation or masking.