Behavior of evoked otoacoustic emission under low-frequency tone exposure: Objective study of the bounce phenomenon in humans

• Published in: Hearing research Vol. 222; no. 1; pp. 62 - 69
• Main Authors: Kevanishvili, Zurab, Hofmann, Gert, Burdzgla, Irina, Pietsch, Markus, Gamgebeli, Zurab, Yarin, Yury, Tushishvili, Michael, Zahnert, Thomas
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2006; Elsevier
• Subjects: Acoustic Stimulation - methods; Acquisition dependence; Adult; Auditory Threshold; Biological and medical sciences; Bounce phenomenon; Ear - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; EOAE effects; Exposure intensity dependence; Female; Fundamental and applied biological sciences. Psychology; Hearing - physiology; Humans; Ipsilateral vs. contralateral effects; Male; Medical sciences; Non tumoral diseases; Otoacoustic Emissions, Spontaneous; Otorhinolaryngology. Stomatology; Vertebrates: nervous system and sense organs; Exposure intensity dependence; Acquisition dependence; Ipsilateral vs. contralateral effects; EOAE; N; p; SD; TTS; EOAE effects; min; dB SPL; cont; Bounce phenomenon; Human; Alteration; Click; Evoked otoacoustic emission; Low frequency; Recovery; Inner ear; Organ of hearing; Ipsilateral; Nonlinearity; Biological receptor
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/j.heares.2006.05.014

The bounce phenomenon has been investigated in humans, evaluating alterations of click evoked otoacoustic emission (EOAE) after presentation of 250-Hz frequency loud tones during 3 min. EOAE changes were manifested in initial augmentation followed by reduction, peaking at 1 and 3 min of post-exposure time, respectively. Recoveries took 5–7 min afterwards. Under linear and nonlinear EOAE acquisition modes both manifestations of bounce appeared similar. At lower exposure intensities, 65–75 dB SPL, augmentations prevailed over reductions. At higher intensities, 80–95 dB SPL, augmentations and reductions were of similar magnitudes. At highest intensity, 100 dB SPL, an obvious EOAE drop has hardly been preceded by any augmentation. Based upon these data, the bounce is considered to be a compound of two opposite events, appearance of each being dependent upon the exposure level. Subjects with high bounce indices in one ear displayed comparable indices in other ear too. Low bounce magnitudes were accordingly typical for particular subjects irrespective of the ears tested. EOAE alterations were observed under ipsilateral, but not contralateral exposures of tones. It has been concluded therefore that the bounce involves peripheral receptor rather than central neural mechanisms. No EOAE shifts were seen under application of clicks without any low-frequency exposure tones. Correspondingly, the bounce is judged to reflect inner-ear processes triggered by low-frequency tones, but not by regular presentations of test-stimuli.