The most common cochlear implant intervention provides an electrode array that stimulates less than half of the length of the cochlea, leaving the regions which represent lower frequencies in the normally functioning ear unstimulated. Providing stimulation over the entire cochlea has the potential to improve speech understanding, sound quality, as well as spectral and temporal representation. Increasing the length of the electrode array to cover a greater portion of the cochlea has many potential issues, including increased damage to the cochlea and probability of incomplete insertions. In this study, a new technique is being investigated that allows stimulation across the entire cochlear extent without increasing the length of the electrode array. The purpose of this study is to evaluate the benefit of the new technique on speech understanding outcomes. Additionally, the study will investigate the new configuration to explore how the auditory system encodes temporal and spectral information.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
40
An electrode typically placed under the temporalis muscle will be placed into the cochlear helicotrema instead.
Cochlear implant (CI) system where stimulation from one of the intracochear electrodes is grounded via one of two (or both) extra cochlear electrodes in the device.
NYU Langone Health
New York, New York, United States
Upper Limit of Rate Pitch Perception for Cochlear Implant Stimuli
The upper limit of rate pitch perception will be evaluated for Apex-monopolar (MP), 22-Apex, 22-MP, and 11-MP cochlear implant stimuli using a 3-up 1-down 2-interval forced-choice adaptive task. The task measures the highest modulation frequency perceived as a lower pitch compared to a rate 5 semitones higher. A series of 750-ms, 5000-pps pulse trains with 100% amplitude modulation will be presented at a loudness-balanced most-comfortable level. The upper limit will be estimated from the average modulation frequency of the last 6 reversals across 10 trials per stimulation site.
Time frame: Month 12
Mean pitch rank
Pitch-ranking will be done using a 2-interval forced-choice protocol in which the pitch of a newly selected stimulus is ranked relative to the stimulus in the middle of a pitch-rank order list. Depending on the ranked pitch direction, this stimulus is repositioned in the pitch-rank order list and ranked against a neighboring stimulus until the correct position in the list is determined. This process repeated until all stimuli are successfully pitch ranked. A complete set of pitch ranks are measured 10 times allowing for the calculation of a mean rank and 95% confidence interval for the rank of each interval.
Time frame: Month 12
Percentage of Consonant-Nucleus-Consonant (CNC) words correctly repeated
Speech perception will be assessed using CNC word lists, a common method for evaluating monosyllabic word recognition. The CNC Monosyllabic Word Test includes 10 lists of 50 words. The word test score range typically used is between 10% and 60% correct in the ear to be implanted, and equal to or better than that ear in the contralateral ear, but not better than 80% correct.
Time frame: Month 12
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