Sensitivity to Interaural Time Differences with Combined Cochlear Implant and Acoustic Stimulation

The interaural time difference (ITD) is an important cue to localize sound sources. Sensitivity to ITD was measured in eight users of a cochlear implant (CI) in the one ear and a hearing aid (HA) in the other severely impaired ear. The stimulus consisted of an electric pulse train of 100 pps and an acoustic filtered click train. Just-noticeable differences (JNDs) in ITD were measured using a lateralization paradigm. Four subjects exhibited median JNDs in ITD of 156, 341, 254, and 91 μs; the other subjects could not lateralize the stimuli consistently. Only the subjects who could lateralize had average acoustic hearing thresholds at 1,000 and 2,000 Hz better than 100-dB SPL. The electric signal had to be delayed by 1.5 ms to achieve synchronous stimulation at the auditory nerves.

[1]  W. Baumgartner,et al.  Effects of interaural time differences in fine structure and envelope on lateral discrimination in electric hearing. , 2006, The Journal of the Acoustical Society of America.

[2]  R. Tyler,et al.  Speech perception, localization, and lateralization with bilateral cochlear implants. , 2003, The Journal of the Acoustical Society of America.

[3]  H. Dillon,et al.  Binaural-Bimodal Fitting or Bilateral Implantation for Managing Severe to Profound Deafness: A Review , 2007, Trends in amplification.

[4]  R. V. Hoesel,et al.  Sensitivity to binaural timing in bilateral cochlear implant users. , 2007 .

[5]  Bernhard Laback,et al.  Sensitivity to Interaural Level and Envelope Time Differences of Two Bilateral Cochlear Implant Listeners Using Clinical Sound Processors , 2004, Ear and hearing.

[6]  G. Nikiforidis,et al.  Reduced Variance in the latency and Amplitude of the Fifth Wave of Auditory Brain Stem Response after Normalization for Head Size , 1993, Ear and hearing.

[7]  Paul J. Abbas,et al.  Binaural interactions of electrically and acoustically evoked responses recorded from the inferior colliculus of guinea pigs , 2007, International journal of audiology.

[8]  R. V. Hoesel.  Exploring the benefits of bilateral cochlear implants. , 2004 .

[9]  P. Abbas,et al.  Electrically evoked auditory brainstem response: Growth of response with current level , 1991, Hearing Research.

[10]  M. Kompis,et al.  Minimum Audible Angle, Just Noticeable Interaural Differences and Speech Intelligibility with Bilateral Cochlear Implants Using Clinical Speech Processors , 2005, Audiology and Neurotology.

[11]  A. Beiter,et al.  Electrically evoked auditory brain stem responses (EABR) and middle latency responses (EMLR) obtained from patients with the nucleus multichannel cochlear implant. , 1990, Ear and hearing.

[12]  G. Henning.  Detectability of interaural delay in high-frequency complex waveforms. , 1974, The Journal of the Acoustical Society of America.

[13]  B. Moore.  An Introduction to the Psychology of Hearing , 1977 .

[14]  D. M. Green,et al.  Lateralization of filtered clicks. , 1971, The Journal of the Acoustical Society of America.

[15]  Leslie R Bernstein,et al.  Enhancing sensitivity to interaural delays at high frequencies by using "transposed stimuli". , 2002, The Journal of the Acoustical Society of America.

[16]  H Steven Colburn,et al.  Binaural sensitivity as a function of interaural electrode position with a bilateral cochlear implant user. , 2003, The Journal of the Acoustical Society of America.

[17]  Felix Wichmann,et al.  The psychometric function: II. Bootstrap-based confidence intervals and sampling , 2001, Perception & psychophysics.

[18]  D T Lawson,et al.  Bilateral cochlear implants controlled by a single speech processor. , 1998, The American journal of otology.

[19]  Jan Wouters,et al.  Sensitivity to Interaural Level Difference and Loudness Growth with Bilateral Bimodal Stimulation , 2007, Audiology and Neurotology.

[20]  Piotr Majdak,et al.  Lateralization discrimination of interaural time delays in four-pulse sequences in electric and acoustic hearing. , 2007, The Journal of the Acoustical Society of America.

[21]  Jan Wouters,et al.  APEX 3: a multi-purpose test platform for auditory psychophysical experiments , 2008, Journal of Neuroscience Methods.

[22]  M Don,et al.  Analysis of the click-evoked brainstem potentials in man unsing high-pass noise masking. , 1978, The Journal of the Acoustical Society of America.

[23]  C. Trahiotis,et al.  Lateralization of low-frequency, complex waveforms: the use of envelope-based temporal disparities. , 1985, The Journal of the Acoustical Society of America.

[24]  Joseph W. Hall,et al.  Neural and Behavioral Sensitivity to Interaural Time Differences Using Amplitude Modulated Tones with Mismatched Carrier Frequencies , 2007, Journal of the Association for Research in Otolaryngology.

[25]  R Domnitz.  The interaural time jnd as a simultaneous function of interaural time and interaural amplitude. , 1973, The Journal of the Acoustical Society of America.

[26]  Ervin R. Hafter,et al.  Discrimination of interaural delays in complex waveforms: Spectral effects , 1981 .

[27]  J. Zwislocki,et al.  Just Noticeable Differences in Dichotic Phase , 1956 .

[28]  E. Hafter,et al.  Binaural interaction in low-frequency stimuli: the inability to trade time and intensity completely. , 1972, The Journal of the Acoustical Society of America.

[29]  R. V. van Hoesel,et al.  Sensitivity to binaural timing in bilateral cochlear implant users. , 2007, The Journal of the Acoustical Society of America.

[30]  W A Yost,et al.  Discriminations of interaural phase differences. , 1974, The Journal of the Acoustical Society of America.