Cochlear implants are devices placed in the inner ear through surgery to help people with severe to profound hearing loss. While these devices work well overall, results vary widely from person to person. Many people with cochlear implants still have trouble understanding speech in noisy places and enjoying music.
This study looks at whether customizing the way a cochlear implant is programmed, based on the health of the hearing nerve in different areas of the ear, can help people understand speech better in noisy settings. The researchers will adjust or turn off certain electrodes in areas where the nerve appears weaker, then test whether this improves hearing compared to each person's everyday program. They will also examine whether giving people time to get used to the new program leads to better results.
Age 18 - 80 years old
Native speakers of American English or Multilingual
Wears a cochlear implant manufactured by Advanced Bionics (Clarion Hi-Focus I or newer)
At least 6 months of listening experience with their cochlear implant, but could be recruited and consented prior.
Inability to provide informed consent
Lost their hearing prior to the age of language acquisition (3-4 years) but did not receive a cochlear implant until adulthood
Do not have age-appropriate speech perception testing from clinical visits or do not use their implant for oral communication
Have neurological disease
Single group
Everyday Clinical Listening Program (Control)
DeviceThe participant's standard clinical cochlear implant sound-processing program, as currently fit for everyday use. This serves as the within-subjects control condition and remains available as a backup throughout the take-home trial.
ENI-Based Experimental Program 1
DeviceAn experimental cochlear implant sound-processing strategy that applies focused electrical fields for electrodes distant from regions of healthy neural tissue and/or deactivates channels near regions of poor neural density or integrity, as inferred from a previously developed electrode-neuron interface model. Tested acutely in the lab and during one 4-week take-home interval.
ENI-Based Experimental Program 2
DeviceA second experimental cochlear implant sound-processing strategy applying focused electrical fields and/or channel deactivation based on electrode-neuron interface estimates, configured differently from Experimental Program 1. Tested acutely in the lab and during one 4-week take-home interval.
Change in Sentence Recognition in Noise (Everyday Program vs. Experimental Programs), In-Lab
Sentence recognition in background noise will be measured using the American Matrix Test (AMT), an adaptive, closed-set speech-in-noise test consisting of 4 blocks of 20 sentences each (5 words per sentence). The adaptive procedure yields a speech reception threshold expressed in dB SNR, the signal-to-noise ratio at which the participant correctly identifies 50 percent of words, with lower (more negative) values indicating better performance. Scores obtained with the participant's everyday clinical listening program (control) will be compared to scores obtained with two experimental sound-processing strategies that apply focused electrical fields for distant electrodes and/or deactivate channels near regions of poor neural density or integrity, as inferred from a previously developed electrode-neuron interface model.
Change in Vowel Identification (Everyday Program vs. Experimental Programs), In-Lab
Medial vowel identification will be measured using a closed-set vowel discrimination task in quiet and at a +10 dB signal-to-noise ratio in four-talker babble noise. Performance is scored as percent correct, with higher values indicating better performance. Scores obtained with the participant's everyday clinical program (control) will be compared to scores obtained with the two experimental sound-processing strategies.
Change in Sentence Recognition in Noise After 4 Weeks of Acclimatization (Crossover)
Using a randomized crossover design, sentence recognition in noise (American Matrix Test) will be assessed before and after 4 weeks of at-home listening for the control program and each experimental program. The adaptive procedure yields a speech reception threshold in dB SNR, with lower (more negative) values indicating better performance. Participants complete 4 weeks of baseline testing with their clinical program followed by 4 weeks with each of the two experimental strategies. The outcome is the change in score across time points and programs, evaluating the effect of acclimatization.
Change in Vowel Identification After 4 Weeks of Acclimatization (Crossover)
Using the randomized crossover design, medial vowel identification will be assessed before and after 4 weeks of at-home listening for the control and experimental programs. Performance is scored as percent correct, with higher values indicating better performance. The outcome evaluates the effect of acclimatization on performance.
Subjective Sound Quality Ratings
Participants rate the sound quality of the listening programs using a custom Sound Quality Questionnaire administered at baseline and at weekly intervals throughout the take-home trial. Results are reported as scores on the questionnaire's rating scale.
Electrically Evoked Compound Action Potential (ECAP)
The Electrically Evoked Compound Action Potential (ECAP) will be recorded via telemetry to measure the auditory nerve's response to electrical stimulation delivered through the cochlear implant. Response amplitude is reported in microvolts. This measure helps characterize the electrode-neuron interface used to inform the experimental programming strategies.
Electrical Field Imaging (EFI)
Electrical Field Imaging (EFI) will be recorded via telemetry to measure the distribution of electrical current within the cochlea where the implant electrodes are located. Recorded voltages are reported in volts. This measure helps characterize the electrode-neuron interface used to inform the experimental programming strategies.
Psychophysical Detection Threshold
Detection threshold, defined as the softest level at which the participant can detect a stimulus, will be measured across multiple electrode configurations including monopolar and novel focused stimulation modes. Thresholds are reported in clinical units (CU) as used for clinical device programming.
Click on the lead sponsor to view all of their trials.
