Speech Recognition Performance Differences Between Precurved and Straight Electrode Arrays From a Single Manufacturer

Investigating the Minimal Clinically Important Difference for AzBio and CNC Speech Recognition Scores

OBJECTIVE

To assess the minimal clinically important difference (MCID) values for cochlear implant-related speech recognition scores, which have not been previously reported.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

PATIENTS

Eight hundred sixty-three adult patients who underwent cochlear implantation between 2009 and 2022.

MAIN OUTCOME MEASURES

MCID values for consonant-nucleus-consonant (CNC) word scores and AzBio sentences in quiet and noise scores using distribution-based methods (half-standard deviation, standard error of measurement, Cohen's d, and minimum detectable change).

RESULTS

In this cohort, the mean preoperative CNC word score was 13.9% (SD, 15.6). The mean preoperative AzBio sentences in quiet score was 19.1% (SD, 22.1), and the mean preoperative AzBio sentences in noise score was 13.0% (SD, 12.0). The average MCID values of several distribution-based methods for CNC, AzBio in quiet, and AzBio in noise were 7.4%, 9.0%, and 4.9%, respectively. Anchor-based approaches with the Speech, Spatial, and Qualities of hearing patient-reported measure did not have strong classification accuracy across CNC or AzBio in quiet and noise scores (ROC areas under-the-curve ≤0.69), highlighting weak associations between improvements in speech recognition scores and subjective hearing-related abilities.

CONCLUSIONS

Our estimation of MCID values for CNC and AzBio in quiet and noise allows for enhanced patient counseling and clinical interpretation of past, current, and future research studies assessing cochlear implant outcomes.

Cochlear Implant Electrode Array Design and Speech Understanding

OBJECTIVE

Cochlear implant electrode arrays are categorized based on their design as lateral wall (LW) and perimodiolar (PM) electrode arrays. The objective of this study was to investigate the effect of LW versus PM designs on postoperative speech perception across multiple manufacturers and over long follow-up durations.

DESIGN

Retrospective cohort study.

SETTING

Single academic medical center.

PARTICIPANTS

A total of 478 adult cochlear implant recipients, implanted between the years 1992 and 2017.

INTERVENTIONSS

PM versus LW cochlear implants.

MAIN OUTCOMES AND MEASURES

Postoperative Consonant-Nucleus-Consonant Word (CNC-w) and Hearing in Noise Test (HINT) scores between 6 months and 5 years.

RESULTS

Across 478 patients, approximately one-third received LW (n = 176, 36.8%), whereas 302 patients received a PM array (63.2%). The PM group had higher CNC-w scores from 6 months to 2 years (52 [interquartile range, 38-68] versus 48 [31-62], p = 0.036) and from 2 to 5 years (58 [43-72] versus 48 [33-66], p < 0.001). Multivariable analysis of patient-averaged scores indicated that the PM group had greater improvement from preoperative scores at all time points after the initial 6 months for both CNC-w ( β = 4.4 [95% confidence interval, 0.6-8.3], p = 0.023) and HINT testing ( β = 4.5 [95% confidence interval, 0.3-8.7], p = 0.038).

CONCLUSIONS

This study indicates that PM electrode arrays are associated with small increases in postoperative speech perception scores, relative to LW arrays, when assessed across manufacturers, over long time durations, and using multiple outcome instruments. These findings may help guide surgeon selection and patient counseling of cochlear implant arrays.

Comparison of Speech Recognition and Hearing Preservation Outcomes Between the Mid-Scala and Lateral Wall Electrode Arrays

OBJECTIVE

To assess speech recognition and hearing preservation (HP) outcomes with the Advanced Bionics Mid-Scala and SlimJ electrodes.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

PATIENTS

A total of 237 adult patients implanted between 2013 and 2020 (Mid-Scala, n = 136; SlimJ, n = 101).

MAIN OUTCOME MEASURES

Consonant-nucleus-consonant (CNC) and AzBio (Arizona Biomedical) scores at 6 and 12 months; postoperative HP, defined as low-frequency pure-tone average ≤ 80 dB HL; scalar position.

RESULTS

Mean CNC scores did not significantly differ between Mid-Scala and SlimJ recipients at 6 (45.8% versus 46.0%, p = 0.962) and 12 (51.9% versus 48.8%, p = 0.363) months. Similarly, mean AzBio in quiet scores were equivalent for both groups at 6 (55.1% versus 59.2%, p = 0.334) and 12 (60.6% versus 62.3%, p = 0.684) months. HP rates were significantly higher with the SlimJ (48.4%) than the Mid-Scala (30.8%; p = 0.033). Scalar translocations were 34.8 and 16.1% for the Mid-Scala and SlimJ groups, respectively ( p = 0.019). Ears with postoperative HP had significantly fewer scalar translocations (16.7% versus 37.2%, p = 0.048), and postoperative HP was associated with higher AzBio in noise scores at the most recent follow-up interval (38.7% versus 25.1%, p = 0.042). CNC, AzBio in quiet and noise, low-frequency pure-tone average shifts, and PTA at 6 and 12 months were not significantly different between patients with scala tympani insertions of the SlimJ versus the Mid-Scala ( p > 0.05).

CONCLUSIONS

Compared with the Mid-Scala, the lateral wall electrode has superior HP rates and fewer scalar translocations, whereas speech recognition scores are equivalent between both electrode arrays. These findings can help providers with electrode selection and patient counseling.

A Multicenter Comparison of 1-yr Functional Outcomes and Programming Differences Between the Advanced Bionics Mid-Scala and SlimJ Electrode Arrays

OBJECTIVE

To determine if there is a difference in hearing outcomes or stimulation levels between Advanced Bionics straight and precurved arrays.

STUDY DESIGN

Retrospective chart review across three implant centers.

SETTING

Tertiary centers for cochlear and auditory brainstem implantation.

PATIENTS

One hundred fifteen pediatric and 205 adult cochlear implants (CIs) were reviewed. All patients were implanted under the National Institute for Health and Care Excellence 2009 guidelines with a HiRes Ultra SlimJ or Mid-Scala electrode array.

MAIN OUTCOME MEASURES

Hearing preservation after implantation, as well as CI-only listening scores for Bamford-Kowal-Bench sentences were compared 1 year after implantation. Stimulation levels for threshold and comfort levels were also compared 1 year after implantation.

RESULTS

Hearing preservation was significantly better with the SlimJ compared with the Mid-Scala electrode array. Bamford-Kowal-Bench outcomes were not significantly different between the two arrays in any listening condition. Stimulation levels were not different between arrays but did vary across electrode contacts. At least one electrode was deactivated in 33% of implants but was more common for the SlimJ device.

CONCLUSION

Modern straight and precurved arrays from Advanced Bionics did not differ in hearing performance or current requirements. Although hearing preservation was possible with both devices, the SlimJ array would still be the preferred electrode in cases where hearing preservation was a priority. Unfortunately, the SlimJ device was also prone to poor sound perception on basal electrodes. Further investigation is needed to determine if deactivated electrodes are associated with electrode position/migration, and if programming changes are needed to optimize the use of these high-frequency channels.

Incomplete Partition Type II Cochlear Malformations: Delineating the Three-Dimensional Structure from Digitized Human Histopathological Specimens

HYPOTHESIS

There are clinically relevant differences in scalae anatomy and spiral ganglion neuron (SGN) quantity between incomplete partition type II (IP-II) and normal cochleae.

BACKGROUND

IP-II is a commonly implanted cochlear malformation. Detailed knowledge of intracochlear three-dimensional (3D) morphology may assist with cochlear implant (CI) electrode selection/design and enable optimization of audiologic programming based on SGN maps.

METHODS

IP-II (n = 11) human temporal bone histological specimens were identified from the National Institute on Deafness and Other Communication Disorders National Temporal Bone Registry and digitized. The cochlear duct, scalae, and surgically relevant anatomy were reconstructed in 3D. A machine learning algorithm was applied to map the location and number of SGNs.

RESULTS

3D scalae morphology of the basal turn was normal. Scala tympani (ST) remained isolated for 540 degrees before fusing with scala vestibuli. Mean ST volume reduced below 1 mm 2 after the first 340 degrees. Scala media was a distinct endolymphatic compartment throughout; mean ± standard deviation cochlear duct length was 28 ± 3 mm. SGNs were reduced compared with age-matched norms (mean, 48%; range, 5-90%). In some cases, SGNs failed to ascend Rosenthal's canal, remaining in an abnormal basalward modiolar location. Two forms of IP-II were seen: type A and type B. A majority (98-100%) of SGNs were located in the basal modiolus in type B IP-II, compared with 76 to 85% in type A.

CONCLUSION

Hallmark features of IP-II cochleae include the following: 1) fusion of the ST and scala vestibuli at a mean of 540 degrees, 2) highly variable and overall reduced SGN quantity compared with normative controls, and 3) abnormal SGN distribution with cell bodies failing to ascend Rosenthal's canal.

Early Datalogging Predicts Cochlear Implant Performance: Building a Recommendation for Daily Device Usage

OBJECTIVE

To quantify the effect of datalogging on speech recognition scores and time to achievement for a "benchmark" level of performance within the first year, and to provide a data-driven recommendation for minimum daily cochlear implant (CI) device usage to better guide patient counseling and future outcomes.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

PATIENTS

Three hundred thirty-seven adult CI patients with data logging and speech recognition outcome data who were implanted between August 2015 and August 2020.

MAIN OUTCOME MEASURES

Processor datalogging, speech recognition scores, achievement of "benchmark speech recognition performance" defined as 80% of the median score for speech recognition outcomes at our institution.

RESULTS

The 1-month datalogging measure correlated positively with word and sentences scores at 1, 3, 6, and 12 months postactivation. Compared with age, sex, and preoperative performance, datalogging was the largest predictive factor of benchmark achievement on multivariate analysis. Each hour/day increase of device usage at 1 month resulted in a higher likelihood of achieving benchmark consonant-nucleus-consonant and AzBio scores within the first year (odds ratio = 1.21, p < 0.001) as well as earlier benchmark achievement. Receiver operating characteristic curve analysis identified the optimal data logging threshold at an average of 12 hours/day.

CONCLUSIONS

Early CI device usage, as measured by 1-month datalogging, predicts benchmark speech recognition achievement in adults. Datalogging is an important predictor of CI performance within the first year postimplantation. These data support the recommended daily CI processor utilization of at least 12 hours/day to achieve optimal speech recognition performance for most patients.

A new paradigm of hearing loss and preservation with cochlear implants: Learnings from fundamental studies and clinical research

In 2010 Cochlear initiated a coordinated preclinical research program to identify the factors and underlying mechanisms of acoustic hearing loss following cochlear implantation and device use. At its inception the program was structured around several major hypotheses implicated in the loss of acoustic hearing. The understanding of causes evolved over the course of the program, leading to an increased appreciation of the role of the biological response in post-implant hearing loss. A systematic approach was developed which mapped the cochlear implant journey along a timeline that considers all events in an individual's hearing history. By evaluating the available data in this context, rather than by discrete hypothesis testing, causative and associated factors may be more readily detected. This approach presents opportunities for more effective research management and may aid in identifying new prospects for intervention. Many of the outcomes of the research program apply beyond preservation of acoustic hearing to factors important to overall cochlear health and considerations for future therapies.