PERCEPTION OF PITCH CHANGES IN HEARING-IMPAIRED ADULTS WITH AIDED AND UNAIDED HEARING LOSS

Abstract

Background: Pitch relates to the low frequency temporal content of sound, which mainly depends on phase coding at the level of the auditory nerve. In this study, we aim to assess the detectibility of pitch changes in different populations of hearing- impaired subjects suffering from sensorineural hearing loss in order to identify possible poor temporal coding. Material and Methods: A number of tests - part of the A§E (ASSE or Auditory Speech Sounds Evaluation) psychoacoustic test suite - were used to assess the perception of pitch changes in adults with a hearing loss (a) in the high frequencies with or without classical hearing aids, (b) in the low frequencies, and (c) in a group of cochlear implant users. All test stimuli were controlled for their fundamental frequency (FO), which either remained stable during the stimulus presentation or which, simulating intonation, glided from FO to FO+A. Isolated synthetic complexes were used as well as pseudo-words or pseudo- sentences mimicking linguistically relevant contexts. The subjects were asked to distinguish these sounds in either identification or discrimination tasks. Results: Hearing-impaired subjects, and particularly those with low-frequency hearing loss, performed significantly worse in comparison to hearing adults on all tests. The use of a hearing aid did not yield significant improvements. The cochlear implant users experienced great difficulty in performing the tests. Conclusion: The intonation tests of A§E2009 are a useful diagnostic tool to distinguish hearing-impaired subjects based on their capacity to process low-frequency information. The tests may be of particular use in the evaluation of the impact of auditory rehabilitation, hearing aids, or electro-acoustic stimulation. (English) [ABSTRACT FROM AUTHOR]