The correlation between hair and eye colour on contralateral suppression of otoacoustic emissions

Abstract

Noise-induced hearing loss (NIHL) is becoming increasingly prevalent amongst young adults leading to a whole series of social and public health problems. Genetics and environmental factors frequently influence individual’s susceptibility to hearing loss. It is postulated that melanin in the inner ear is related to individual’s susceptibility to NIHL. General pigmentation in turn, it is suspected to be related to the amount of pigmentation in the inner ear. The amount of melanin in the inner ear is said to modulate the endocochlear potential and provide an otoprotective effect. The current study aimed to determine the relationship between the contralateral suppression of otoacoustic emissions (CSOAE) in individuals with different hair and eye colour, and temporary emission shift (TES) after short-term noise exposure. Method: The hearing sensitivity of young adults were determined by using pure tone audiometry followed by CSOAE’s and distortion product otoacoustic emissions (DPOAE) before listening to music for one hour individually. Pure tone audiometry and DPOAE’s were repeated after short-term music exposure to determine the amount of TES and temporary threshold shift (TTS). Twenty-five normal-hearing adults, ranging from 18 to 28 years (Mean age: 21.64, SD: 1.80) were recruited for the current study. A quasi-experimental repeated within subject’s measurement design was used to compare the CSOAE in subjects with different hair and eyes colour with TES after noise exposure for one hour. Results: No statistically significant difference was measured between the participants with brown eyes and brown hair, and the participants blue eyes and blond hair, efferent suppression as measured by CSOAE’s. The blue eyes with blond hair had a temporary threshold shift (TTS) at 4000 Hz as well as a TES in at 2000 Hz after short-term noise exposure. Conclusion: CSOAE’s were therefore unable to predict which group of individuals were more susceptible to NIHL after short-term noise exposure.