Q10 and Tip Frequencies in Individuals with Normal-Hearing Sensitivity and Sensorineural Hearing Loss

Abstract

Context: Cochlear plays a major role in providing fine-tuned frequency resolution of the sounds that were perceived. However, in the impaired auditory systems, this frequency resolution is affected, which indirectly leads to distortion in the perception of the sounds. However, the sharpness of tuning of a filter can be obtained from Q10 values and the shift in the tip frequencies of the psychophysical tuning curve can provide an estimate for the frequency resolution of the cochlea. Aim: This study aimed to estimate and compare the Q10 values and tip frequency between individuals with normal hearing and hearing loss. Subjects and Methods: A total of 92 ears were included for the study which was divided into two groups based on the hearing sensitivity. The psychophysical turning curves were obtained for 500 Hz, 1 kHz, 2 kHz, 4 kHz, and 6 kHz. The data on Q10 and the tip frequencies were statistically analyzed. Results: The results reveal that individuals with hearing loss have lesser Q10 values compared to individuals with normal hearing and this increased with increase in the test frequencies. Comparing the shift in the tip frequency between the two groups of individuals, the shift was toward the lower frequency which indicates it is an involvement of the outer hair cells. However, this study was limited only to those with mild flat sensory neural hearing loss. Conclusion: It could be concluded that Q10 and tip frequency measurement would be a valid measure for frequency resolution of the cochlea.