Deafness
Conditions
Keywords
cochlear implant
Brief summary
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.
Detailed description
Cochlear implants are surgically placed in the inner ears of people with severe to profound hearing loss. Although these devices are generally successful, outcomes differ a great deal from one person to the next. Many people who use cochlear implants continue to struggle with understanding speech when there is background noise and with appreciating music. More research is needed to understand why results vary so much among cochlear implant users. The main goal of this study is to better understand the underlying condition of the inner ear and how it relates to how well people hear with their cochlear implant. The researchers will use this knowledge to test new ways of programming the devices. A cochlear implant has multiple electrodes, and each one stimulates a different region of the hearing nerve. In some people, certain regions of the nerve are healthier than others. By estimating where the nerve is weaker or stronger, the researchers hope to program the device in a way that takes advantage of the healthier areas. The study has one main aim with two parts: The first part compares how well participants understand speech in noise using their usual everyday program versus an experimental program. In the experimental program, the electrical signal is narrowed and focused for electrodes that are farther from healthy nerve regions, and electrodes near poorly functioning nerve regions may be turned off. These adjustments are guided by a model of nerve health developed in earlier research. The second part looks at whether performance improves after participants spend four weeks getting used to the experimental program. The researchers expect that programming based on each person's individual nerve health will improve their ability to understand speech in noise, and that this improvement will be greater after they have had time to adjust to the new program. This work is expected to provide a better understanding of how long a person needs to adapt when their programming strategy changes. The findings could be applied fairly quickly in clinical settings to improve speech understanding for both adults and children who use cochlear implants.
Interventions
DEVICEEveryday Clinical Listening Program (Control)
The 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.
DEVICEENI-Based Experimental Program 1
An 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.
DEVICEENI-Based Experimental Program 2
A 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.
Sponsors
Massachusetts Eye and Ear Infirmary
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* 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. * Bilateral hearing loss
Exclusion criteria
* 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 * Have unmanageable facial nerve stimulation or pain as a result of their implant * Does not tolerate implant well * Unable to carry out the study protocol or tasks required in the study * Poor vision such that the subject cannot adequately perform the study tasks on the computer screen
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Sentence Recognition in Noise (Everyday Program vs. Experimental Programs), In-Lab | Across a minimum of two in-lab sessions (each up to 3.5 hours) | 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 | Across a minimum of two in-lab sessions (each up to 3.5 hours) | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Sentence Recognition in Noise After 4 Weeks of Acclimatization (Crossover) | Baseline and after 4 weeks of take-home use for each program, within a 12-week crossover trial | 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) | Baseline and after 4 weeks of take-home use for each program, within a 12-week crossover trial | 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. |
Contacts
CONTACTJulie Arenberg, PhD, CCC-A
PRINCIPAL_INVESTIGATORJulie Arenberg, PhD, CCC-A
Massachusetts Eye and Ear
Outcome results
None listed