PREVALENCE OF 6 KHZ “NOTCH” IN POPULATIONS OF ADOLESCENTS AND YOUNG ADULTS

Le Prell CG (1), Guire K (2), Hall JW (1), Holmes AE (1).

(1) University of Florida; (2) University of Michigan, USA.

The classic evidence for noise-induced hearing loss (NIHL) in industrial workers is a “notched” audiogram, with discrete hearing loss largely confined to 4 kHz test frequencies.  In contrast, a number of studies suggest that musicians largely experience hearing loss at 6 kHz.  Such data suggest the effects of industrial noise may differ from those of exposure to loud music. We screened various adolescent and young adult populations, including juvenile residents housed at a detention facility, incoming college students, and adolescents participating in the NHANES study.  We detected a discrete 6 kHz hearing loss consistent with NIHL in a subset of the members of each of these adolescent and young adult multiple populations.  More recently, we have been screening college students at the University of Florida for normal hearing.  To date we have screened 45 students who use digital music players.  A general elevation in threshold sensitivity, as well as a notched hearing loss at 6 kHz, was detected in 12 students (27%).  Taken together, these data indicate that certain adolescent and young adult populations may experience NIHL at a higher rate than that reported for the age-matched general population and the primary effect may be at a higher frequency (6kHz) than the traditional industrial-noise-induced 4 kHz notch.  The potential that factors such as gender and/or ear canal resonance may contribute to a 6 kHz notched audiogram will be discussed.  The prevalence of NIHL in younger populations, and the potential that digital music player use may contribute to an increased incidence of NIHL, is of significant interest but remains a controversial topic. 

Funded by NIH/NIDCD U01 DC008423.

E-mail: colleeng@phhp.ufl.edu