Binaural frequency discrimination was studied in musically trained normal subjects. The frequency chosen was that of a spontaneous oto-acoustic emission (SOAE) in one ear. The other ear was free from SOAEs in the test frequency range. Subjective frequency sensation was found to drift away from the frequency of the peak of the emission: Frequencies lower than that of the emission were perceived as being lower than they actually were; frequencies higher than that of the emission were felt to be higher than they actually were (test range, emission frequency +/- 30 Hz).
A test procedure based on the patient's understanding of acoustic material is presented. The score obtained in this test showed a highly significant correlation with the postoperative score evaluated by independent examiners 4 weeks after stimulator adjustment.
Binaural beats have been investigated in normal volunteers using high-stable synthesizers. There are considerable differences between the subjective rhythm heard and the difference of the two frequencies, indicating that this dissimilarity must be caused centrally.
In a follow-up study of 22 ears made after a mean interval of 68 months, spontaneous oto-acoustic emissions (SOAEs) showed marked changes. At follow-up visits, fewer SOAEs were recorded than at the first examination. As the set-up employed at follow-ups was much more sensitive, this observation gains even more weight, because--given identical cochlear structures--a greater number of SOAEs ought to have been recorded. In analogy to age-related high-frequency hearing loss, SOAEs recorded at the follow-up examination were found at lower frequencies. This was associated with yet another phenomenon: Precise frequency data (derived from a 4,000 line spectrum) available for 13 SOAEs (7 subjects) from the first examination showed that SOAE frequencies had dropped slightly in all subjects. In 5 of them the frequency drop was significant (p less than 1/1000 in each case).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.