Science Spotlight: Considerations for a revised adult cochlear implant candidacy evaluation protocol

By David Kessler, Au.D., CCC-A, Elizabeth Perkins, MD, René Gifford, Ph.D., CCC-A and Alejandro Rivas, MD

An important part in improving equity and access to appropriate hearing healthcare is ensuring professionals have the right assessment tools.  Hear from the team who created the Spanish AzBio Sentence test to learn more about its creation and impact.

What was the motivation for creating the Spanish AzBio Sentence test?

The English version of the AzBio sentence test, first introduced in 2004¹, is now considered a staple in cochlear implant clinical care.² Audiologists in English speaking countries routinely use AzBio speech recognition testing to assess patients for cochlear implant candidacy and post-implant evaluation. Unlike other sentence tests that have come before (e.g., CID, CUNY, and HINT sentences), AzBio sentences more accurately represent conversational speech by including average conversational rates and multiple talkers which reduces the risk for reaching ceiling performance. With 33 unique lists of 20 sentences each, audiologists can track performance over time without repeating lists and risking patient learning effects.*

In the United States, Spanish is the second most widely spoken language with nearly 41 million people ages 5 years or older in the U.S. speaking Spanish in the home.³ Though there are multiple speech recognition measures that are available in Spanish (e.g., HINT corpus), until recently, we have been unable to use AzBio sentence testing with Spanish speaking individuals, leaving audiologists at a loss for how to assess a large segment of the patient population. Many of the Spanish sentence speech recognition tests that existed prior to the release of Spanish AzBio sentences were too easy for patients resulting in ceiling effects and an overestimation of a patient’s real-world speech recognition performance.

Additionally, no Spanish sentence test had been previously validated using listeners with hearing loss or cochlear implants. This made it difficult for audiologists to determine cochlear implant candidacy and track longitudinal postoperative performance for their Spanish speaking patients. Thus, the Spanish AzBio Sentence test was created to surmount these shortcomings with the goal of diversifying access to cochlear implantation and overcoming the language divide between English- and Spanish-speaking populations in rehabilitative audiology and otology.

How was the test created?

The Spanish AzBio test was created to closely resemble the English version of the test.⁴ Sentences were recorded by two male and two female Spanish speakers, resulting in 42 lists of 20 sentences each. A validation study using cochlear implant users showed that these lists have equivalent across-list difficulty, similar to that of the English version of the test, making it the first assessment tool available in Spanish that has been validated using listeners with hearing loss or cochlear implants. The 30 most equivalent lists were included in the final purchasable version of the test. Given that the development and validation for the Spanish AzBio corpus was identical to that completed for the original English corpus, the Spanish AzBio sentences should yield equivalent ranges of outcomes as observed for the English AzBio sentences.⁵

How can this test be used clinically?

The test can be used in the same ways that the English version is used! Clinicians may use Spanish AzBio sentences when completing aided testing to determine if a patient qualifies for a cochlear implant. Clinicians may also use it to track an individual’s performance over time and across a variety of test conditions without fear of repeating test lists. As stated above, the similarity in development and validation across the English and Spanish AzBio sentence tests will now afford across-language comparisons and cross-cultural collaborations for research and clinical assessments. This latter point is critical as it will now be possible to complete multi-country clinical trials and use the same measures without concern of list repetition, need for high-level noise to avoid ceiling effects, or use of a closed-set matrix test which occasionally presents word combinations that may not be lexically meaningful.

What advice do you have for non-Spanish speaking clinicians who want to use this test?

While any clinician can easily administer this test, it is recommended that the patient’s responses be interpreted by a Spanish speaking individual. Although a clinic may not have a Spanish speaking clinician, a professionally certified Spanish interpreter can be trained to aid a clinician in scoring the patient’s responses. This is most easily achieved with an in-person interpreter; however, a video or telephone interpreter could be used assuming a clear and stable connection. We acknowledge that although this is not a perfect system, it far exceeds our previous ability to assess Spanish speaking patients which was to either use non-validated measures or skip sentence speech recognition testing entirely.

The Spanish AzBio Sentences and test scoresheets can be accessed from Auditory Potential, LLC at https://www.auditorypotential.com/purchase.html.

For more Spanish resources, click here.

References:

1. Spahr, A. J., & Dorman, M. F. (2004). Performance of subjects fit with the Advanced Bionics CII and Nucleus 3G cochlear implant devices. Archives of Otolaryngology–Head & Neck Surgery, 130(5), 624-628.
2. Minimum Speech Test Battery (MSTB) for Adult Cochlear Implant Users 2011. https://www.auditorypotential.com/MSTBfiles/MSTBManual2011-06-20%20.pdf. Published June 2011.
3. U.S. Census Bureau (2019). Language Spoken at Home, American Community Survey 5-year estimates. Retrieved from https://data.census.gov/cedsci/table?q=spanish&tid=ACSST5Y2019.S1601.
4. Rivas, A., Perkins, E., Rivas, A., Rincon, L. A., Litvak, L., Spahr, T., … & Gifford, R. (2021). Development and Validation of the Spanish AzBio Sentence Corpus. Otology & Neurotology, 42(1), 154-158.
5. Spahr, A. J., Dorman, M. F., Litvak, L. M., Van Wie, S., Gifford, R. H., Loizou, P. C., … & Cook, S. (2012). Development and validation of the AzBio sentence lists. Ear and hearing, 33(1), 112.

* The number of available lists varies depending on test version. A free version of the test is available with fewer test lists. 

About the authors:

David Kessler, Au.D., CCC-A is a clinical audiologist at Vanderbilt University Medical Center. Dr. Kessler specializes in adult cochlear implant and hearing aid clinical care. He received his B.A. in Speech and Hearing Science at the University of Iowa and his Au.D. from Vanderbilt University. During his graduate education, Dr. Kessler authored several papers while working in the Cochlear Implant research lab under Dr. René Gifford at Vanderbilt University.  

Elizabeth Perkins, MD was born and raised in Columbus, Ohio and she attended Albion College in Albion, MI where she obtained her undergraduate degree in biochemistry. Dr. Perkins received her medical degree from the University of Cincinnati and attended the University of North Carolina for Otolaryngology, Head and Neck residency. She then completed a two-year fellowship in Neurotology and lateral skull base surgery from Vanderbilt University Medical Center. She is now assistant professor at Vanderbilt and director of pediatric neurotology with special interests in pediatric hearing loss, cochlear implantation, and vestibular schwannomas. 

René Gifford, Ph.D., CCC-A is a Professor in the Department of Hearing and Speech Sciences at Vanderbilt University Medical Center. Her research interests include speech and auditory perception via combined electric and acoustic stimulation (EAS), auditory-based speech and language development following cochlear implantation in children, and spatial hearing abilities of individuals combining hearing aids and cochlear implants. For more information, please visit our lab’s website: https://www.vumc.org/cochlear-implant-lab

Alejandro Rivas, MD, serves as the Division Chief of Otology and Neurotology at University Hospitals in Cleveland, Ohio where he is also the Director of the Cochlear Implant Program. Dr. Rivas is a Professor in the Department of Otolaryngology-Head and Neck Surgery and the Department of Neurological Surgery at Case Western Reserve University School of Medicine. Dr. Rivas’s interests include endoscopic ear surgery, cochlear implantation, single-sided deafness, congenital malformations of the ear, ear canal atresia, bone conduction implantation, acoustic neuromas and other skull base surgeries.