Use of Linear Frequency Transposition in Simulated Hearing Loss

Abstract

To demonstrate the usability of new acoustic cues provided by a commercial hearing aid using linear frequency transposition. The importance of auditory training in realizing the benefit was evaluated. Quasi-experimental study design. All subjects were tested both with conventional amplification and with linear frequency transposition before and after directed training. A total of nine normal hearing participants with simulated high frequency hearing loss at and above 1600 Hz participated in the study. All subjects were native English speakers ranging in age from 18 to 24 years. Identification of voiceless phonemes in CV, VC, and CVC context processed with and without linear frequency transposition was evaluated. Identification test was carried out four times. Between test trials, participants completed 15 minutes of self-paced training using transposed stimuli. Prior to any training, transposition did not improve phoneme identification scores. Training of 30 minutes improved the overall identification scores of the transposed stimuli over the nontransposed stimuli by 14.4%. The results demonstrated that frequency transposition produces acoustic cues that normal hearing listeners with a simulated hearing loss at and above 1600 Hz may be trained to utilize.