Distortion Product Otoacoustic Emission Components in Neonates & Children

Otoacoustic emissions evoked using two closely related tones f1 and f2 are referred to as distortion product otoacoustic emissions (DPOAE). Based on the taxonomy of Shera & Guinan (1999), DPOAE recorded in the ear canal represent a mixture of two types of emissions – linear reflection and nonlinear distortion – which correspond to cochlear activity at the characteristic place for 2f1-f2 and the overlap region between f2 and f1, respectively. Studies have shown that reflection and distortion emissions are differently affected by development, aging, and noise exposure (Abdala & Dhar, 2012; Poling et al, 2022). Here we investigated DPOAE in early childhood (0-12 years) to fully characterize the component behavior for f2 frequencies up to 12 kHz (f2/f1 = 1.22; L1/L2 = 55/40 dB FPL). Data were collected across five age groups: newborns (n = 22), 6 months (n = 10), 3 – 5 years (n = 11), 6 – 8 years (n = 28) , and 9 – 12 years (n = 30). Linear mixed effects analysis showed that the youngest two age groups had larger DPOAE component levels than the oldest three age groups, suggesting a change in cochlear and/or middle ear processing very early in childhood.

References:
1. Shera, C. A., & Guinan Jr, J. J. (1999). Evoked otoacoustic emissions arise by two fundamentally different mechanisms: a taxonomy for mammalian OAEs. The Journal of the Acoustical Society of America, 105(2), 782-798.
2. Abdala, C., & Dhar, S. (2012). Maturation and aging of the human cochlea: a view through the DPOAE looking glass. Journal of the Association for Research in Otolaryngology, 13, 403-421.
3. Poling, G. L., Siegel, J. H., Lee, J., & Dhar, S. (2022). The influence of self-reported noise exposure on 2ƒ1-ƒ2 distortion product otoacoustic emission level, fine structure, and components in a normal-hearing population. The Journal of the Acoustical Society of America, 151(4), 2391-2402.