Improving interaural time difference sensitivity using short interpulse intervals with vowel-like stimuli in bilateral cochlear implants

2017 ◽  
Vol 141 (5) ◽  
pp. 3973-3974 ◽  
Author(s):  
Sridhar Srinivasan ◽  
Bernhard Laback ◽  
Piotr Majdak
Keyword(s):  
Cochlear Implants ◽  
Interaural Time Difference ◽  
Time Difference ◽  
Bilateral Cochlear Implants

scholarly journals Neural ITD coding with bilateral cochlear implants: effect of binaurally coherent jitter

2012 ◽  
Vol 108 (3) ◽  
pp. 714-728 ◽  
Author(s):  
Kenneth E. Hancock ◽  
Yoojin Chung ◽  
Bertrand Delgutte
Keyword(s):  
Pulse Rate ◽  
Interaural Time Difference ◽  
Time Difference ◽  
High Rate ◽  
Neural Responses ◽  
Neural Basis ◽  
Pulse Trains ◽  
Bilateral Cochlear Implants ◽  
Periodic Pulse ◽  
High Pulse

Poor sensitivity to the interaural time difference (ITD) constrains the ability of human bilateral cochlear implant users to listen in everyday noisy acoustic environments. ITD sensitivity to periodic pulse trains degrades sharply with increasing pulse rate but can be restored at high pulse rates by jittering the interpulse intervals in a binaurally coherent manner (Laback and Majdak. Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates. Proc Natl Acad Sci USA 105: 814–817, 2008). We investigated the neural basis of the jitter effect by recording from single inferior colliculus (IC) neurons in bilaterally implanted, anesthetized cats. Neural responses to trains of biphasic pulses were measured as a function of pulse rate, jitter, and ITD. An effect of jitter on neural responses was most prominent for pulse rates above 300 pulses/s. High-rate periodic trains evoked only an onset response in most IC neurons, but introducing jitter increased ongoing firing rates in about half of these neurons. Neurons that had sustained responses to jittered high-rate pulse trains showed ITD tuning comparable with that produced by low-rate periodic pulse trains. Thus, jitter appears to improve neural ITD sensitivity by restoring sustained firing in many IC neurons. The effect of jitter on IC responses is qualitatively consistent with human psychophysics. Action potentials tended to occur reproducibly at sparse, preferred times across repeated presentations of high-rate jittered pulse trains. Spike triggered averaging of responses to jittered pulse trains revealed that firing was triggered by very short interpulse intervals. This suggests it may be possible to restore ITD sensitivity to periodic carriers by simply inserting short interpulse intervals at select times.

scholarly journals Microsecond Interaural Time Difference Discrimination Restored by Cochlear Implants After Neonatal Deafness

2018 ◽  
Author(s):  
Nicole Rosskothen-Kuhl ◽  
Alexa N Buck ◽  
Kongyan Li ◽  
Jan W H Schnupp
Keyword(s):  
Cochlear Implants ◽  
Critical Period ◽  
Interaural Time Difference ◽  
Spatial Hearing ◽  
Time Difference ◽  
Interaural Time Differences ◽  
Behavioral Thresholds ◽  
Essentially Normal ◽  
High Degree ◽  
Prelingually Deaf

AbstractCochlear implants (CIs) can restore a high degree of functional hearing in deaf patients however spatial hearing remains poor, with many early deaf CI users reported to have no measurable sensitivity to interaural time differences (ITDs) at all. Deprivation of binaural experience during an early critical period is often blamed for this shortcoming. However, we show that neonatally deafened rats provided with precisely synchronized CI stimulation in adulthood can be trained to localize ITDs with essentially normal behavioral thresholds near 50 μs. Furthermore, neonatally deaf rats show high physiological sensitivity to ITDs immediately after binaural implantation in adulthood. The fact that our neonatally deaf CI rats achieved very good behavioral ITD thresholds while prelingually deaf human CI patients usually fail to develop a useful sensitivity to ITD raises urgent questions about whether shortcomings in technology or treatment may be behind the usually poor binaural outcomes for current binaural CI patients.

scholarly journals Microsecond interaural time difference discrimination restored by cochlear implants after neonatal deafness

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Nicole Rosskothen-Kuhl ◽  
Alexa N Buck ◽  
Kongyan Li ◽  
Jan W H Schnupp
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implants ◽  
Early Development ◽  
Critical Period ◽  
Interaural Time Difference ◽  
Spatial Hearing ◽  
Time Difference ◽  
Interaural Time Differences ◽  
Behavioral Thresholds ◽  
Essentially Normal

Spatial hearing in cochlear implant (CI) patients remains a major challenge with many early deaf users reported to have no measurable sensitivity to interaural time differences (ITDs). Deprivation of binaural experience during an early critical period is often hypothesized to be the cause of this shortcoming. However, we show that neonatally deafened (ND) rats provided with precisely synchronized CI stimulation in adulthood can be trained to lateralize ITDs with essentially normal behavioral thresholds near 50 μs. Furthermore, comparable ND rats show high physiological sensitivity to ITDs immediately after binaural implantation in adulthood. Our result that ND CI rats achieved very good behavioral ITD thresholds while prelingually deaf human CI patients often fail to develop a useful sensitivity to ITD raises urgent questions concerning the possibility that shortcomings in technology or treatment, rather than missing input during early development, may be behind the usually poor binaural outcomes for current CI patients.

Bilateral Cochlear Implants

ASHA Leader ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 14-17 ◽  
Author(s):  
Ruth Litovsky
Keyword(s):  
Cochlear Implants ◽  
Bilateral Cochlear Implants
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