Comparison of hearing thresholds obtained by different methods of assessment [subjective and objective] in normal and different forms of hearing loss

ABSTRACT

This study was designed to compare hearing threshold obtained by different methods of assessment, both subjective and objective, in 60 ears of normal hearing sensitivity and 120 ears with different types, degrees [up to moderately severe] and configuration of hearing loss. Auditory Brainstem Response [ABR] has been found to correlate well with behavioral threshold with certain limits. It cannot differentiate sharply between normal and mild hearing loss with specific configurations such as low frequency and notched hearing loss. Transient Evoked Otoacoustic Emissions [TEOAEs,] response was present when hearing threshold was equal to or better than 45dBHL. So, it cannot differentiate between ears with normal hearing from those with mild hearing loss, so presence of TEOAEs does not always reflect normal hearing sensitivity. Distortion product Otoacoustic Emissions [DPOAEs,] showed that, the response was present when hearing sensitivity was better than 55-60dB. But could not be recorded with hearing threshold greater than 60 dBHL. it is preferable to use a battery of ABR, TEOAEs and immittancemetry to determine hearing threshold in young children and difficult to test subjects to solve overlap between normal hearing and mild degree of hearing loss