This research focuses on tinnitus caused by internal tones of presumed cochlear origin. Although the physiological basis of tinnitus is generally unknown, a major breakthrough has shown that some cases of tinnitus are linked to spontaneous otoacoustic emissions (SOAEs), acoustic energies which can be detected when a sensitive miniature microphone is inserted into the ear canal. Estimates of the prevalence of SOAE-caused tinnitus indicate that this pathology may affect 1 million Americans. Studies of SOAE-caused tinnitus have necessarily been limited to cases in which SOAEs could be measured. Because the details of the spectral analyses affect the emergence of SOAEs, the first experiment here examines the effect of various techniques on the appearance of SOAEs in the ear canal. Because tinnitus is often environmentally caused, the second experiment documents a case in which SOAEs were not heritable but appeared due to extrinsic factors. In addition to spectral analyses techniques, the attenuation characteristics of the middle ear and the properties of the tympanic membrane play a role in the emergence of SOAEs. Accordingly, it seems possible that more internal tones are generated than are measured as SOAES in the ear canal. The psychophysical similarity of tinnitus associated with SOAEs and tinnitus not so associated may be indicative of cochlear tinnitus. Experiments 3-9 expand the psychophysical armamentaria linking tinnitus and SOAEs. Using the pilot data from Experiments 3-9, preliminary data from Experiments 10 and 11 demonstrate that tinnitus may be caused by idiotones, internal tones of cochlear origin which may exist even when SOAEs cannot be measured. Finally, Experiments 12-14 are aimed at exploring the prevalence of cochlear tinnitus and palliatives for it.
| Zhang, T; Penner, M J (1998) A new method for the automated detection of spontaneous otoacoustic emissions embedded in noisy data. Hear Res 117:107-13 |
| Penner, M J; Zhang, T (1997) Prevalence of spontaneous otoacoustic emissions in adults revisited. Hear Res 103:28-34 |
| Penner, M J (1996) The emergence and disappearance of one subject's spontaneous otoacoustic emissions. Ear Hear 17:116-9 |
