No evidence for enhanced processing of speech that is low-pass filtered near the edge frequency of cochlear dead regions in children

Abstract

Objectives: Cochlear dead regions (DRs) are regions in the cochlea where the inner hair cells and/or neurons are not functioning. Adults with extensive high-frequency DRs have enhanced abilities in processing sounds with frequencies just below the edge frequency, f_edge, of the DR. It was assessed whether the same is true for children.

Design: Performance was compared for children aged 8 to 13 years with: DRs (group DR), hearing impairment but without DRs (group NODR), and normal hearing (group NH). Seven ears in each group were tested. Each ear in the DR group was matched in age and low-frequency hearing with an ear in the NODR group, and in age with an ear in the NH group, giving seven “triplets”. Within each triplet, the percent correct identification of vowel-consonant-vowel stimuli was measured using stimuli that were low-pass filtered at f_edge and 0.67f_edge, based on the ear with a DR. For the hearing-impaired ears, stimuli were given frequency-selective amplification as prescribed by DSL 4.1.

Results: No significant differences in performance were found between groups for either low-pass cut-off frequency.

Conclusion: Unlike adults, the children with DRs did not show enhanced discrimination of speech stimuli with frequencies below f_edge.

Keywords:

• Cochlear dead regions
• speech perception
• neuroplasticity
• low-pass filtered speech

Acknowledgements

The study was supported by the NIHR Manchester Biomedical Research Centre.

Disclosure statement

No potential conflict of interest was reported by the authors.