An acoustic analysis and auditory performance evaluation of pediatric hearing aid fittings

This study evaluated auditory performance of 40 five-year-old children with normal hearing when presented with a representation of the acoustic signal that would be available to a child with hearing loss fitted with hearing aids according to currently utilized clinical methods. Evaluation was conducted at three levels of auditory skills: detection, discrimination, and identification. The intensity effect of four different degrees of hearing loss (mild, moderate, severe, and profound) was simulated. The effects of distance (three feet and 10 feet source-listener distances) were examined. ^ Results showed: (1) a significant decrease in performance at all levels of auditory skills when subjects listened to experimental stimuli that had been recorded through a hearing aid (and presented at a normal conversational level) as compared to listening to stimuli that had not been processed through a hearing aid, (2) a significant decrease in performance at all levels of auditory skills when subjects listened to the amplified stimuli at sensation levels representing the amplified hearing losses as compared to a normal conversational level, (3) a significant decrease in performance at all levels of auditory skills as the source listener distance increased from three feet to 10 feet, and (4) a significant decrease in performance at all levels of auditory skills as degree of simulated hearing loss increased (sensation level decreased). ^ In the conditions where stimuli represented a close source-listener distance and were presented at sensation levels representing the amplified hearing losses, subjects listening to the mild- and moderate-hearing loss simulations generally performed at similar and better levels than the severe- and profound-hearing loss groups. When distance was added to these listening conditions, the subjects listening to the mild-hearing loss simulation performed better than all three of the other groups. ^ Results suggest a need for greater access to the speech signal for children with severe and profound hearing loss who are fitted with hearing aids according to currently utilized clinical methods. This increase may be accomplished, to a certain extent, through improvements in hearing aid technology (i.e., frequency response flexibility, increased bandwidth) and/or increases in gain and output levels.