Brief Summary

This study examines how cochlear implant users understand and comprehend speech in realistic communication situations. Through six experiments measuring listening effort via pupillometry and discourse comprehension, we will investigate how linguistic context, cognitive demands, and processing time affect speech understanding in CI users, and in normal-hearing controls) to identify factors underlying communication resilience versus vulnerability and develop improved, ecologically valid assessment and rehabilitation strategies.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

460

participants targeted

Target at P75+ for not_applicable

Timeline

45mo left

Started Jan 2025

Longer than P75 for not_applicable

Geographic Reach

1 country

2 active sites

Status

recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

5 years study duration

Study Progress27%

Jan 2025Jan 2030

Study Start

First participant enrolled

January 2, 2025

Completed

11 months until next milestone

First Submitted

Initial submission to the registry

December 9, 2025

Completed

3 days until next milestone

First Posted

Study publicly available on registry

December 12, 2025

Completed

4.1 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

January 2, 2030

Expected

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

January 2, 2030

Last Updated

December 12, 2025

Status Verified

December 1, 2025

Enrollment Period

5 years

First QC Date

December 9, 2025

Last Update Submit

December 9, 2025

Conditions

Cochlear Implant Users

Keywords

CICochlear implant

Outcome Measures

Primary Outcomes (12)

Percent correct Consonant-Nucleus-Consonant (CNC) words across experiments 1-3
Participants' ability to recognize individual spoken words will be assessed using the Consonant-Nucleus-Consonant (CNC) word test. Outcome is based on the percent of key words correctly repeated. Higher score indicate better speech understanding.
End experiments 1-3 (up to 9 hours)
Percent correct AzBio sentences across experiments 1-3
The AzBio sentence test consists of 15 lists of 20 sentences each. AzBio sentences are spoken by different talkers in a conversational style with limited contextual cues that the listener can use to predict or 'fill in' unintelligible words. Outcome is based on the percent of AzBio sentences correctly repeated. Higher score indicate better speech understanding.
End experiments 1-3 (up to 9 hours)
Error rates for word identification tasks across experiments 1-3
End experiments 1-3 (up to 9 hours)
Percentage of propositions recalled from narrative passages
Subjects will hear 24 150- word passages, with one half of the passages being narrative (tell a story with a setting, theme, plot, etc.) and the other half being expository (e.g. instructions from a health care provider). After each passage the subject will be asked to recall as much of the passage content as possible. Higher score indicate better speech understanding.
End of experiment 4 (up to 3 hours)
Ratio of main idea recall to detail recall
Subjects will hear recorded narratives and will be asked to recall them as best as they can. The narratives will include main ideas (defined as propositions whose arguments are directly related to the overall meaning of the passage), mid-level propositions (those that take main propositions as their arguments), and details (propositions that take mid-level or other minor propositions as their arguments. Ratio of main idea recall to detail recall will be assessed.
End of experiment 4 (up to 3 hours)
Percentage of true/false statements identified
Subjects will hear sentences with syntactic forms known to be graded in comprehension difficulty: active-conjoined sentences (The author insulted the critic // and the critic hired a lawyer), subject-relative sentences (The author that insulted the critic // hired a lawyer), and object-relative sentences (The author that the critic insulted // hired a lawyer). The subject will hear an equal number of each sentence type, where half are presented with self-pacing, and half are presented without interruption. After each sentence the subject will be presented that they must indicate is true or false about the sentence they just heard.
End of experiment 6 (up to 3 hours)
Percent correct increase from unstructured word lists to anomalous sentences (syntactic gain)
Participants will hear 30 meaningful, eight-word sentences to begin. The words from this list of sentences will then be used to create the unstructured word lists and syntactic strings, such that each word would be heard equally as often across the three stimulus conditions. Therefore, each subject will hear a total of 30 meaningful sentences, 30 anomalous strings, and 30 unstructured lists, presented in a counter-balanced design. Recall accuracy for the three conditions will be compared.
End of experiment 1 (up to 3 hours)
Percent correct increase from anomalous sentences to meaningful sentences (semantic gain).
Participants will hear 30 meaningful, eight-word sentences to begin. The words from this list of sentences will then be used to create the unstructured word lists and syntactic strings, such that each word would be heard equally as often across the three stimulus conditions. Therefore, each subject will hear a total of 30 meaningful sentences, 30 anomalous strings, and 30 unstructured lists, presented in a counter-balanced design. Recall accuracy for the three conditions will be compared.
End of experiment 1 (up to 3 hours)
Number semantically-driven misrecognitions in lure conditions
Subjects will hear word pairs, with the second (target) word of the pair presented in multi-talker babble. There will be three conditions: Neutral prime (the first word is unrelated to the target word, e.g. Jaw-PASS), Semantic prime (the two words are semantic associates, e.g. Row - BOAT), and Semantic lure (the target word is a semantic associate of a similar word e.g. Row - GOAT, where GOAT is a lure for BOAT), thus putting the semantic context in conflict with successful perception. Number semantically-driven misrecognitions in lure conditions will be assessed.
End of experiment 2 (up to 3 hours)
Frequency of semantically-driven misrecognitions in lure conditions
Subjects will hear word pairs, with the second (target) word of the pair presented in multi-talker babble. There will be three conditions: Neutral prime (the first word is unrelated to the target word, e.g. Jaw-PASS), Semantic prime (the two words are semantic associates, e.g. Row - BOAT), and Semantic lure (the target word is a semantic associate of a similar word e.g. Row - GOAT, where GOAT is a lure for BOAT), thus putting the semantic context in conflict with successful perception. Frequency of semantically-driven misrecognitions in lure conditions will be assessed.
End of experiment 2 (up to 3 hours)
Difference in recall accuracy between single-sentence and two-sentence conditions
Subjects will undergo four test conditions (two will require remembering only one sentence and the other two will require remembering two sentences). For each condition there will be two combinations of semantic association between the first and second sentence (half will have high predictability, and the other half will have low predictability). Difference in recall accuracy between single-sentence and two-sentence conditions will be assessed.
End of experiment 3 (up to 3 hours)
Difference in comprehension improvement (percentage of proposition's correctly recalled) with self-paced vs. continuous presentation
Subjects will hear 24 150- word passages, with one half of the passages being narrative (tell a story with a setting, theme, plot, etc.) and the other half being expository (e.g. instructions from a health care provider). After each passage the subject will be asked to recall as much of the passage content as possible. Subjects will be presented with equal numbers of "self-paced" passages (stopping at major clauses and sentence boundaries, subject decides when to continue) and passages presented without interruption.
End of experiment 5 (up to 3 hours)

Study Arms (2)

Cochlear Implant Users

EXPERIMENTAL

Postlingually deaf adults (age 18-80) with at least one year of CI experience. Participants will complete behavioral speech perception and comprehension tasks with pupillometry measurement.

Behavioral: Experiment 1: Syntactic and Semantic ContextBehavioral: Experiment 2: False Hearing and Context OveruseBehavioral: Experiment 3: Two-Sentence ProblemBehavioral: Experiment 4: Cascading Effects on Discourse ComprehensionBehavioral: Experiment 5: Self-Paced Discourse ComprehensionBehavioral: Experiment 6: Clinical Application

Normal-Hearing Controls (Vocoder Simulation)

ACTIVE COMPARATOR

Normal-hearing adults (age 18-80) listening to degraded speech via 4- and 8-channel vocoders. Participants will complete the same behavioral tasks as CI users but with (or without) acoustically degraded speech simulation.

Interventions

Experiment 1: Syntactic and Semantic ContextBEHAVIORAL

* Recall of meaningful sentences, anomalous word strings, and unstructured word lists * Measurement of syntactic and semantic gain * Pupillometry during auditory and visual presentation