title: The role of first formant information in simulated electro-acoustic hearing.
abstract: Cochlear implant (CI) recipients with residual hearing show improved performance with the addition of low-frequency acoustic stimulation (electro-acoustic stimulation, EAS). The present study sought to determine whether a synthesized first formant (F1) signal provided benefit to speech recognition in simulated EAS hearing and to compare such benefit with that from other low-frequency signals. A further aim was to determine if F1 amplitude or frequency was more important in determining benefit and if F1 benefit varied with formant bandwidth. In two experiments, sentence recordings from a male speaker were processed via a simulation of a partial insertion CI, and presented to normal hearing listeners in combination with various low-frequency signals, including a tone tracking fundamental frequency (F0), low-pass filtered speech, and signals based on F1 estimation. A simulated EAS benefit was found with F1 signals, and was similar to the benefit from F0 or low-pass filtered speech. The benefit did not differ significantly with the narrowing or widening of the F1 bandwidth. The benefit from low-frequency envelope signals was significantly less than the benefit from any low-frequency signal containing fine frequency information. Results indicate that F1 provides a benefit in simulated EAS hearing but low frequency envelope information is less important than low frequency fine structure in determining such benefit.
authors.affiliation: Hearing and Balance Centre, Institute of Sound and Vibration Research, University of Southampton, Highfield, Southampton SO16 7ES, United Kingdom. cav@isvr.soton.ac.uk
authors.forename: Carl
authors.initials: C
authors.lastname: Verschuur
authors.forename: Conor
authors.initials: C
authors.lastname: Boland
authors.forename: Emily
authors.initials: E
authors.lastname: Frost
authors.forename: Jack
authors.initials: J
authors.lastname: Constable
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention; D001309:Auditory Threshold; D003054:Cochlear Implants; D003131:Combined Modality Therapy; D003463:Cues; D003638:Deafness / Q000523:psychology / Q000534:rehabilitation*; D005260:Female; D006310:Hearing Aids; D006801:Humans; D008297:Male; D010470:Perceptual Masking; D010700:Phonetics; D013018:Sound Spectrography; D013061:Speech Acoustics; D013069:Speech Reception Threshold Test; D055815:Young Adult