Review Prepared by: Janette Oliver, Global Outcomes & Rehabilitation Manager, Cochlear Limited
BA., Dip Teach., M.Ed., PG Dip.Ed(Hearing Impaired) Dip.Aud., MA., MAudSA,CCP, Cert AVT ®
Adults with cochlear implants experience a wide variety of outcomes which may be partly explained by differences in auditory perception and the way they process information. New research casts light on how outcomes in adults with cochlear implants may be improved.
Auditory perception processes
There are two general processes involved in auditory perception. Bottom-up processing is about processing information as it is received and refers to the way perception is built up from small pieces of sensory input.
Top-down processing, however, refers to perception that is driven by cognition and how the brain considers context and applies what is known and what the individual is expecting to perceive and fills in the gaps.
In considering outcomes for adult cochlear implant recipients, research indicates that only about 50% of the variability in outcomes observed in this population can be satisfactorily explained. Furthermore, those factors that have been confirmed to contribute to variability seem largely concerned with “bottom up” auditory sensitivity processes associated with the cochlear implant signal or the peripheral auditory system.1-4
However, it is highly likely that “top-down” cognitive and linguistic factors critically assist cochlear implant users to recognize speech and these factors may well help explain additional variability in outcomes for adults.
Drouin and Theodore (2020) take an interdisciplinary perspective in their research which seeks to bridge findings from the clinical rehabilitation literature with findings from the psycholinguistics domain, highlighting the role of top-down lexical feedback on adaptation to atypical speech input such as a cochlear implant signal.
Adults continue to learn new skills, but often require more exposure or practice to do so. Even extended passive exposure may therefore be insufficient for adult cochlear implant listeners.
Active auditory training
The authors argue that lexically-oriented active auditory training may be necessary to optimally target the plasticity mechanisms underlying improvements in speech perception for listeners adapting to a CI.
In a recent state-of-the-art review, Stropahl et al (2020) conclude that intensive auditory-cognitive training protocols are a valid tool to improve auditory communication skills.
Individuals with hearing loss seem to benefit the most using a combination of sensory rehabilitation (device fitting) and training to enhance holistic auditory rehabilitation.
The variability experienced in adults with hearing loss is potentially explained by differences in cognitive abilities such memory, speed of processing and executive function.
As such, active training of auditory and cognitive skills in combination is emerging as a path to enhance communication skills for adults with hearing loss.
Read more on Cochlear ProNews.
References
1. Dornhoffer JR, Reddy P, Meyer TA, Schvartz-Leyzac KC, Dubno JR, McRackan TR.(2021) Individual Differences in Speech Recognition Changes After Cochlear Implantation. JAMA Otolaryngol Head Neck Surg. Published online January 07, 2021. doi:10.1001/jamaoto.2020.5094
2.Drouin, J. R., & Theodore, R. M. (2020). Leveraging interdisciplinary perspectives to optimize auditory training for cochlear implant users. Language and Linguistics Compass. https://doi.org/10.1111/lnc3.12394
3.Glennon E, Svirsky MA, Froemke RC. (2020) Auditory cortical plasticity in cochlear implant users. Curr Opin Neurobiol. 2020 Feb;60:108-114. doi: 10.1016/j.conb.2019.11.003. Epub 2019 Dec 18. PMID: 31864104; PMCID: PMC7002179.
4.Moberly AC, Bates C, Harris MS, Pisoni DB. (2016) The Enigma of Poor Performance by Adults with Cochlear Implants. Otol Neurotol. 2016 Dec;37(10):1522-1528. doi: 10.1097/MAO.0000000000001211. PMID: 27631833; PMCID: PMC5102802.
5. Strophal, M., Besser, J., & Launer, S. (2020). Auditory Training Supports Auditory Rehabilitation: A State-of-the-Art Review [Review]. Ear and Hearing, 41(4), 697-704. https://doi.org/10.1097/aud.0000000000000806
