The effects of noise upon human hearing sensitivity from 8000 to 20 000 Hz.
High-frequency (8 to 20 kHz) hearing sensitivity was compared in thirty-six, 20 to 29-year-old military veterans with histories of steady-state or impulsive noise exposure. Threshold shifts were prominent for the steady-state noise subjects from 13 to 20 kHz. Mean thresholds from 8 through 12 kHz were maximally 20 dB poorer than a sample of young adult normals. Audiometric configurations for this group were generally smooth and symmetrical above 8000 Hz. For the impulsive noise group, substantial shifts in sensitivity were seen from 2 to 20 kHz and the high-frequency audiometric configurations were often jagged and/or asymmetrical. The variability of subjects in this group was greater than that seen in the steady-state noise exposed sample. Several case studies are presented to illustrate these characteristics. Measurement of auditory sensitivity from 8 to 20 kHz extends the mapping of basal cochlear function, providing information which often is not predictable from conventional audiometric measurement. This additional information provides for more comprehensive inter- and intra-subject comparison of the degree and extent of threshold changes present.
D000328:Adult; D001301:Audiometry, Pure-Tone / Q000379:methods; D001309:Auditory Threshold; D034381:Hearing Loss / Q000503:physiopathology*; D006316:Hearing Loss, High-Frequency / Q000503:physiopathology*; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D006801:Humans; D009622:Noise / Q000009:adverse effects; D013997:Time Factors