DPOAE level mapping for detecting noise-induced cochlear damage from short-duration music exposures

Abstract

Distortion product otoacoustic emission (DPOAE) level mapping provides a comprehensive picture of cochlear responses over a range of DP frequencies and f2/f1 ratios. We hypothesized that individuals exposed to high-level sound would show changes detectable by DPOAE mapping, but not apparent on a standard DP-gram. Thirteen normal hearing subjects were studied before and after attending music concerts. Pure-tone audiometry (500-8,000 Hz), DP-grams (0.3-10 kHz) at 1.22 ratio, and DPOAE level maps were collected prior to, as soon as possible after, and the day after the concerts. All maps covered the range of 2,000-6,000 Hz in DP frequency and from 1.3 to -1.3 in ratio using equi-level primary tone stimuli. Changes in the pure-tone audiogram were significant (P ≤ 0.01) immediately after the concert at 1,000 Hz, 4,000 Hz, and 6,000 Hz. The DP-gram showed significant differences only at f2 = 4,066 (P = 0.01) and f2 = 4,348 (P = 0.04). The postconcert changes were readily apparent both visually and statistically (P ≤ 0.01) on the mean DP level maps, and remained statistically significantly different from baseline the day after noise exposure although no significant changes from baseline were seen on the DP-gram or audiogram the day after exposure. Although both the DP-gram and audiogram showed recovery by the next day, the average DPOAE level maps remained significantly different from baseline. The mapping data showed changes in the cochlea that were not detected from the DP-gram obtained at a single ratio. DPOAE level mapping provides comprehensive information on subtle cochlear responses, which may offer advantages for studying and tracking noise-induced hearing loss (NIHL).

Lifetime leisure music exposure associated with increased frequency of tinnitus

“…However, a much more common source of noise exposure is that produced by listening to music as a leisure activity. Most reports of the potentially damaging effects on hearing of listening to music focus on hearing loss ( Buckey et al., 2015 , Halevi-Katz et al., 2015 , Helleman and Dreschler, 2015 , Opperman et al., 2006 ) but, as shown for the military, tinnitus may cause equal or greater life-limiting disability ( Elgoyhen et al., 2015 , Langguth et al., 2013 , McCormack et al., 2015 , Wunderlich et al., 2015 ). Epidemiological studies of tinnitus have generally not characterized in detail the source of noise exposure, for example grouping all forms of leisure exposure into a single yes/no question ( Shargorodsky et al., 2010 ).…”

Using tablet-based technology to deliver time-efficient ototoxicity monitoring

“…This technique measures DPOAEs at multiple f2 frequencies and f2/f1 frequency ratios, providing an overall picture or map of outer hair cell responses throughout the cochlea. Preliminary data using DPOAE L/P mapping before and after loud music exposures showed cochlear changes that were not detected from the DP-gram obtained at a single frequency ratio (Buckey et al 2015). The use of DPOAE mapping for ototoxicity monitoring is currently being assessed by Geisel School of Medicine at Dartmouth and Creare LLC with support from the Office of Naval Research.…”