Interaural time difference sensitivity under binaural cochlear implant stimulation persists at high pulse rates up to 900 pps.

Spatial hearing remains one of the major challenges for bilateral cochlear implant (biCI) users, and early deaf patients in particular are often completely insensitive to interaural time differences (ITDs) delivered through biCIs. One popular hypothesis is that this may be due to a lack of early binaural experience. However, we have recently shown that neonatally deafened rats fitted with biCIs in adulthood quickly learn to discriminate ITDs as well as their normal hearing litter mates, and perform an order of magnitude better than human biCI users.

Characterizing subcutaneous cortical auditory evoked potentials in mice.

Auditory Brainstem Responses (ABRs) are a reliably robust measure of auditory thresholds in the mammalian hearing system and can be used to determine deficits in the auditory periphery. However, because these measures are limited to the lower stages of the auditory pathway, they are insensitive to changes or deficits that occur in the thalamic and cortical regions. Cortical Auditory Evoked Potentials (CAEPs), as longer latency responses, capture information from these regions.

Sensitivity to interaural time differences in the inferior colliculus of cochlear implanted rats with or without hearing experience.

For deaf patients cochlear implants (CIs) can restore substantial amounts of functional hearing. However, binaural hearing, and in particular, the perception of interaural time differences (ITDs) with current CIs has been found to be notoriously poor, especially in the event of early hearing loss. One popular hypothesis for these deficits posits that a lack of early binaural experience may be a principal cause of poor ITD perception in pre-lingually deaf CI patients.

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

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.

Time-compression thresholds for Mandarin sentences in normal-hearing and cochlear implant listeners.

Faster speech may facilitate more efficient communication, but if speech is too fast it becomes unintelligible. The maximum speeds at which Mandarin words were intelligible in a sentence context were quantified for normal hearing (NH) and cochlear implant (CI) listeners by measuring time-compression thresholds (TCTs) in an adaptive staircase procedure. In Experiment 1, both original and CI-vocoded time-compressed speech from the MSP (Mandarin speech perception) and MHINT (Mandarin hearing in noise test) corpora was presented to 10 NH subjects over headphones.