Harmonic coherent demodulation for improving sound coding in cochlear implants

The paper presents a promising application of the coherent demodulation technique to improving hearing with cochlear implants. It has been a challenge to encode temporal fine structure (TFS) in cochlear implants for better speech and music perception. We propose a pitch-synchronized coherent demodulation strategy—Harmonic Single Sideband Encoder (HSSE)—to efficiently encode TFS cues. A dynamic carrier estimation approach based on harmonic detection was chosen to enhance temporal pitch coding in cochlear implants. Acoustic analysis results showed that the HSSE strategy preserves temporal fine structure cues including fundamental frequency (F0) information as well. The coding of temporal fine structure cues in cochlear implants could be potentially improved with the F0-synchronized coherent demodulation.

[1]  R. Plomp,et al.  Effect of temporal envelope smearing on speech reception. , 1994, The Journal of the Acoustical Society of America.

[2]  Fan-Gang Zeng,et al.  Encoding frequency Modulation to improve cochlear implant performance in noise , 2005, IEEE Transactions on Biomedical Engineering.

[3]  Les E. Atlas,et al.  Coherent envelope detection for modulation filtering of speech , 2005, Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005..

[4]  Brian C J Moore,et al.  Speech perception problems of the hearing impaired reflect inability to use temporal fine structure , 2006, Proceedings of the National Academy of Sciences.

[5]  Les E. Atlas,et al.  Time-Frequency Coherent Modulation Filtering of Nonstationary Signals , 2009, IEEE Transactions on Signal Processing.

[6]  Rahul Sarpeshkar,et al.  A Low-Power Asynchronous Interleaved Sampling Algorithm for Cochlear Implants That Encodes Envelope and Phase Information , 2007, IEEE Transactions on Biomedical Engineering.

[7]  Philipos C Loizou,et al.  Speech processing in vocoder-centric cochlear implants. , 2006, Advances in oto-rhino-laryngology.

[8]  Fan-Gang Zeng,et al.  Temporal pitch in electric hearing , 2002, Hearing Research.

[9]  J. T Rubinstein,et al.  Pseudospontaneous activity: stochastic independence of auditory nerve fibers with electrical stimulation , 1999, Hearing Research.

[10]  Hideki Kawahara,et al.  YIN, a fundamental frequency estimator for speech and music. , 2002, The Journal of the Acoustical Society of America.

[11]  Les E. Atlas,et al.  Single sideband encoder for music coding in cochlear implants , 2008, 2008 IEEE International Conference on Acoustics, Speech and Signal Processing.

[12]  B. Moore.  The Role of Temporal Fine Structure Processing in Pitch Perception, Masking, and Speech Perception for Normal-Hearing and Hearing-Impaired People , 2008, Journal of the Association for Research in Otolaryngology.

[13]  Bertrand Delgutte,et al.  Phase-locking of auditory-nerve discharges to sinusoidal electric stimulation of the cochlea , 1992, Hearing Research.