Clinical trial NCT05558514: Place-based Cochlear Implant Mapping
Official title: Performance Comparisons With Default Versus Place-based Maps
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Hearing Loss, Sensorineural
Cochlear Implants
Keywords: cochlear implant
pitch map
hearing loss
cochlear implant programming
place-pitch mismatch
Lead sponsor: Western University, Canada
Sponsor class: OTHER
Collaborators: name: Academic Medical Organization of Southwestern Ontario
name: University of North Carolina
name: London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
First posted: 2022-09-28
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Participants will be randomized into either the intervention group or the control group. In the intervention group, cochlear implants will be programmed according to a custom, place-based pitch map. In the control group, cochlear implants will be programmed according to the standard of care, generalized pitch map.

Participants will undergo repeated audiological and music and speech perception testing at baseline, initial activation (\~ 6 months post-operative), 1-month, 3-months, 6-months, 7-months, and 1-year post-activation. Each participant will listen to their assigned map during the first 6 months of cochlear implant use. After 6 months, participants will listen to the alternative map for 1 additional month. After the 7th month, participants will have the opportunity to choose their preferred map. Final assessment will take place at 1-year post-implantation. Performance will be compared between the groups and as a function of frequency-to-place mismatch.
Primary purpose: TREATMENT

Brief summary: The current standard of care approach for programming cochlear implants uses a generalized pitch-map for all patients. This approach fails to account for individualized inner ear anatomy. As a result, many cochlear implant recipients experience place-pitch mismatch. We have recently developed an automated mathematical tool to produce patient-specific, customized cochlear implant pitch-maps (Helpard et al., 2021). In this study, cochlear implant recipients will be randomized to receive either the clinical default pitch-map (the control group) or a place-based pitch-map (the intervention group).

Assessments will be conducted at multiple time-intervals to account for patient acclimation and plasticity to both the generalized and individualized pitch-maps. Audiological assessments will be tuned to identify patients' ability to discern pitch scaling and variation in sounds, as well as to understand complexities in speech such as mood and tone. Audiological testing will be conducted in collaboration with the National Centre for Audiology (London, ON) to ensure that the most accurate and relevant metrics are applied.

Detailed description: The cochlea is a spiral-shaped organ of hearing within the inner ear where acoustic vibrations are decomposed into different frequencies to create electrical signals that transmit audio information to the brain. The basilar membrane (BM), which is an internal soft tissue component of the cochlea, mechanically filters different frequencies at different distances along the helical shape. This separation is what allows us to discern different pitches in sound. Due to individual anatomical differences, each person naturally has their own unique pitch-map, or tonotopic map, that maps nerves at specific locations along the basilar membrane to perceived frequencies in the brain.

When the cochlea is not functioning properly, cochlear implantation is a successful treatment to restore the sense of sound. A cochlear implant (CI) is a neural-prosthetic device that consists of an external portion that sits behind the ear and a surgically implanted array of electrodes inserted along the cochlea. After surgery, implants are programmed using a process called pitch mapping, whereby each implanted electrode is assigned a specific stimulation frequency. A CI must span the entire length of the cochlea and stimulate with the correct pitch-map (meaning the correct nerves and locations are stimulated with the correct frequencies) to produce full and accurate hearing. When a generalized pitch-mapping approach is used, each electrode within a CI array will stimulate with a pre-specified frequency, independent of a patient's individual tonotopy or postoperative electrode location. Generalized pitch-mapping can result in a place-pitch mismatch of over one octave. This mismatch inhibits the pitch perception required for complex hearing tasks, such as music appreciation or speech recognition. Neural plasticity can allow auditory perception to adapt over time to reduce the effect of cochlear implant pitch-map errors, however this requires long periods of acclimation, is dependent on recipient age and environment, and can only overcome certain sized pitch-map errors. Customization of CI pitch-maps can reduce rehabilitation time and the need for implant acclimation.

Patient-specific pitch maps are produced by accurately determining each patient's cochlear duct length (CDL), or more specifically BM length, from diagnostic images. Previous methods to determine CDL have traditionally contained uncertainties at the start- and end-point of the BM, largely due to visualization limitations in the imaging modality used. Measuring an inaccurate BM length may cause an erroneous shift in all tonotopic frequencies. Using an enhanced imaging technique, our team has recently developed an algorithm to automatically and accurately estimate CDL, segment the BM, and determine CI electrode locations from individual patient computed-tomography (CT) scans to produce customized CI pitch-maps, called placed-based mapping (Helpard et al., 2021).

The primary objective of this study is to evaluate whether a place-based map improves hearing outcomes for cochlear implant recipients. We will compare the auditory abilities, speech recognition and spatial hearing (speech recognition in spatially separated noise, and sound source localization) for subjects randomized to listen exclusively with a default map versus our novel place-based map. We hypothesize that the majority of CI recipients will experience a faster rate of speech recognition and spatial hearing growth when their cochlear implant is mapped to match the electric stimulation with the tonotopic place frequency (i.e., using the place-based map).

Eligibility criteria: Inclusion Criteria:

* Adults (18 years of age or older) with moderate-to-profound sensorineural hearing loss bilaterally or single-sided deafness (SSD)
* Approved by the Cochlear Implant Program at London Health Sciences Centre (LHSC) to undergo unilateral cochlear implantation
* Identify as a native English speaker (recorded speech recognition/perception materials are presented in English)
* Deny any cognitive issues
* Willing and able to participate in study procedures (e.g., unaided testing, speech recognition testing, spatial hearing testing)
* Willing and able to return for follow-up visits (same intervals as recommended clinically for routine follow-up)

Exclusion Criteria:

* Fail the Mini Mental State Examination based on their age and education level

Primary outcomes:
measure: Change in score on the word and vowel recognition test (Consonant-Nucleus-Consonant (CNC) words/ phonemes)
timeFrame: Baseline (pre-surgery), device activation (~ 1 month post-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation, 1 year post-activation.
Secondary outcomes:
measure: Change in score on the Aided Sentence (AzBio) Test
timeFrame: Baseline (pre-surgery), device activation (~ 1 month post-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation, 1 year post-activation.
measure: Change in score on the Speech, Spatial & Qualities of Hearing Scale (SSQ)
timeFrame: Baseline (pre-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation, 1 year post-activation.
measure: Change in score on self-reported sound quality
timeFrame: Baseline (pre-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation.
measure: Change in score on the Multi Stimulus test with Hidden Reference and Anchor (CI-MUSHRA) adapted for cochlear implants
timeFrame: Baseline (pre-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation.
measure: Change in score on self-reported sound localization
timeFrame: Baseline (pre-surgery), 1 month post-activation, 3 months post-activation, 6 months post-activation, 7 months post-activation.
Other outcomes:
Locations:
city: London
country: Canada
facility: Western University
state: Ontario
Study officials:
affiliation: Western University
name: Sumit K Agrawal, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Helpard L, Li H, Rohani SA, Zhu N, Rask-Andersen H, Agrawal S, Ladak HM. An Approach for Individualized Cochlear Frequency Mapping Determined From 3D Synchrotron Radiation Phase-Contrast Imaging. IEEE Trans Biomed Eng. 2021 Dec;68(12):3602-3611. doi: 10.1109/TBME.2021.3080116. Epub 2021 Nov 19.
citation: Nikan S, Van Osch K, Bartling M, Allen DG, Rohani SA, Connors B, Agrawal SK, Ladak HM. PWD-3DNet: A Deep Learning-Based Fully-Automated Segmentation of Multiple Structures on Temporal Bone CT Scans. IEEE Trans Image Process. 2021;30:739-753. doi: 10.1109/TIP.2020.3038363. Epub 2020 Dec 4.