Ultra-audiometric hearing among the “profoundly deaf.”

Abstract

We recently reported an unusual audiometric configuration in a woman misdiagnosed as having “an hysterical hearing loss” in which she detected 12 000 Hz signals at 45 dB SPL. In a series of tests, we uncovered a sizeable percentage of deaf people who have better hearing above than below 8000 Hz. Virtually all these people have unusually good speech considering the amount of loss in the so-called speech frequencies. We will present speech samples with audiograms and postulate the following: (1) Zero dB HL for 12 kHz is approximately 25 dB SPL; (2) an audiometric configuration such as demonstrated by these patients permits (a) a modicum of sensitivity to transients in the field (but not from frequency limited hearing aids); (b) time-code perception for broadband signals, and (3) may give-the patient considerable access to temporal monitoring of speech especially with sibilants and plosives. At present we have no idea of the etiology of these hearing losses; a companion paper will describe a translating hearing aid we built for two patients and discuss some of our experiences with the aids. [Supported by NIH, DRF, and The Kresge Foundation.]