This page holds a number of papers and reports. It is designed as a reference point for anyone looking for information about Cochlear Implants from an academic point of view. If you would like to add papers to this collection, please contact us via the Contact Us menu.
AV UK have a very good page of research papers that can be found here.
Oral only verses Mixed/Bilingual Approaches for habilitation of CI Recipients
A 2016 paper by Anne E. Geers. A 100 strong cohort studied.
“…Contrary to earlier published assertions, there was no advantage to parents’ use of sign language either before or after CI.”
This paper by Ann E. Geers, Johanna G. Nicholas, and Allison L. Sedey was published in 2003 and remains one of the largest studies comparing the outcomes for CI recipients who chose an oral only approach verses a mixed/bilingual approach.
A second paper by Ann E. Geers that looks at oral verses mixed/bilingual language approaches
“Conclusion: Despite equivalent child demographic characteristics at the outset of this study, by 3 years postimplant, there were significant differences in AV, AO, and BB groups. Results support consistent emphasis on oral/aural input to achieve optimum spoken communication outcomes for children using cochlearimplants.”
Kirk et. al (2012), found no evidence to support claims that using baby signing with babies helps to accelerate their language development. While babies did learn the signs and begin using them before they started talking, they did not learn the associated words any earlier than babies who had not been exposed to baby signs, and did not show any overall enhancement in language development. The study did find that helping parents become more attentive to their children’s gestures served to increase responsiveness and bonding, but this is a standard part of early intervention in auditory verbal therapy, and not unique to baby sign programs.
Unilateral verses Bilateral Approaches for CI Children
“Children with bilateral CIs achieved significantly better vocabulary outcomes, and 8-year-old children with bilateral CIs had significantly better language outcomes than did children with unilateral CIs. These improvements were moderated by children’s ages at both first and second CIs.”
“We find that providing bilateral cochlear implants to children after a period of unilateral deafness of longer than 1.5 years drives abnormal mismatches in activity at the level of the brainstem and cortex. This is characterized by abnormal strengthening of activity to both the contralateral and ipsilateral auditory cortices from the first implanted ear. These abnormalities in auditory development are associated with more asymmetric speech perception, poorer hearing in noise, abnormal sound localization, and an inability to identify inter-aural timing cues. These skills are important for normal integration and processing of auditory input. We therefore suggest that binaural hearing is compromised in children who receive bilateral cochlear implants after a period of unilateral implant use exceeding 1.5 years. With that in mind, cochlear implants should be provided to children early as well as bilaterally within very limited or no delays between implants (i.e., simultaneously).”
“A further novel finding of this study is that parent stress was lower in parents of children with bilateral CIs than in parents of children with unilateral CIs. This finding fits in with reports in the literature that parents find communication with children who have bilateral CIs easier and that the effort required in communication for these children is reduced. Given the close and well-documented relationship between parent stress, or psychological state, and child development in many areas, this is important information to consider when decisions about unilateral versus bilateral implantation are being made.”
“Recently, controversy in the care of severely-profoundly deaf children has centred on whether they should be provided with bilateral cochlear implants (two implants, one in each ear) rather than a unilateral cochlear implant (one implant in one ear). Potentially, implanting both ears rather than one could improve children’s spatial listening skills, meaning the ability to localise sources of sound (by comparing the intensity and timing of sounds arriving at the two ears) and to perceive speech in noise (by attending to whichever ear gives the better signal-to-noise ratio).”
Qualitative and quantitative data show clearly that bilateral CI improves the children’s communicative behaviour, especially in complex listening situations. Children examined with the speech in noise test scored significantly better under the bilateral condition compared to the unilateral condition. Integration of the second implanted side and use of binaural information was observed to be easier and faster in children with a short time lag between both implants.
This paper concludes “Profoundly deaf bilaterally implanted children are significantly more likely to use vocalisation to communicate, and to use audition when interacting vocally with an adult, compared with unilaterally implanted children. These results are independent of age at implantation and length of deafness.”
This is a modern paper with a relatively large sample conclusively showing that bilateral implantation produces significant benefits for language acquisition and expression. It also finds a significantly negative link between the gap between first and second implantation.
This article summarises the research of Tel Aviv University into binaural processing with Cochlear Implants. It concludes that the second Cochlear Implant needs to be done either simultaneously or very soon after the first to be able to gain binaural processing.
This submission covers a broad array of issues around Cochlear Implants, including the recommendation for bilateral implantation for “…Children with permanent bilateral profound sensorineural hearing loss…”
A recent Cochlear America paper on the benefits of bilateral implantation.
This is a modern literature review around use of Cochlear Implants with children. The author has a major study underway which is scheduled for publishing in 2014. It should provide definitive view of the benefits of bilateral implants.
A unilateral cochlear implant does not guarantee the development of language, speech production, academic or social skills comparable to those of children with normal hearing. Although there are many children with a unilateral cochlear implant who are able to develop these skills at an age-appropriate rate, there also remain many who show delayed development in these areas, some of whom maintain or increase their delay through to adulthood. Given the difficulties of unilateral hearing loss, giving children bilateral cochlear implants could potentially improve outcomes.
This is a literature review undertaken by Cochlear. It is now getting a little dated.
A 2011 news item from University of Wisconsin–Madison that discusses research into the benefits of bilateral implantation. It concludes:
The most exciting finding is that having two implants does correlate with an improvement in receptive language
This paper provides very good coverage of the research on Bilateral Cochlear Implants as at 2010.
Thirty CICI and 30 CI-Only subjects were tested on a battery of speech perception tests in noise that utilize an 8-loudspeaker array. The CICI group showed significantly better performance on speech perception in noise compared to the CI-Only subjects, supporting the hypothesis that bilateral cochlear implantation is more beneficial than unilateral implantation.
Bilateral CI users expend less effort in hearing than Unilateral CI users. A small but objective study.
A 2009 longitudinal study that confirms implantation before 12 months old leads to better language acquisition.
“Early (<18 months) intervention with CI was associated with greater and longer quality-of-life improvements, similar direct costs of implantation, and economically valuable improved classroom placement, without a greater incidence of medical and surgical complications when compared to CI at older ages.”
This is a superb US literature review across a broad spectrum of issues connected with optimising language outcomes for children with Cochlear Implants.
This is an interesting Australian paper looking at issues around the decision to get a Cochlear Implant. It has some good anecdotes that may be helpful for some parents making this decision.
An extremely well written article on the interface and conflict between cochlear implants and Deaf culture. Also available here.
New Zealand Studies
This paper presents data on under 5 year olds with hearing loss. It was compiled by the Ministry of Education.
This is a paper which assesses the cost-benefit of EI programmes in Australasia. It shows that First Voice centres provide a positive cost-benefit outcome.
New Zealand Documents
In 2005 a national plan was developed that covered the provision of the education, therapy and support services for Cochlear Implant children. It represented the thinking in the New Zealand deaf education sector in 2005. Even then it was well behind the thinking and practice in equivalent countries like Australia. In 2012, seven years on, it is still seen as a guiding document for the deaf education sector and heavily influences the majority of the sector.
This is a 2012 version. There may be an Oct 2013 version.
This is the 2006 version of the Cochlear Implant Specification. Unfortunately this document is a WORD document (not PDF).
New Zealand Papers
Cochlear implantation: a panacea for severe hearing loss? – Phil Bird and Darryn Murray
Effects of Auditory-Verbal Therapy for School-Aged Children with Hearing Loss: An Exploratory Study – Elizabeth Fairgray, M.Sc., LSLS Cert. AVT; Suzanne C. Purdy, Ph.D.; and Jennifer L. Smart, Ph.D.
New Zealand News Items
Radio NZ report on Cochlear Implants in NZ
The hearing Deaf – New Zealand Listener – This article looks at what was happening in the sector in 2005.
These are two papers introducing and examining music therapy, the issues and the benefits.
This website is contains the output of a national audit of UK Cochlear Implant services. It includes some fascinating information on the implant programmes in the UK. In the UK, children are, as a matter of policy, provided with simultaneous bilateral Cochlear Implants.
Binaural Hearing and Speech Lab – A large collection of papers related to binaural hearing, both in adults and children.
A paper from the UK focused on adult cochlear implantation. However it covers a broad array of research and discussion, much of which is pertinent to children.
In 2009 the UK equivalent of our Ministry of Health undertook a major review of what the optimal policy should be for funding Cochlear Implants. They concluded that children should receive bilateral Cochlear Implants. These guidelines were reviewed again in 2011 and it was concluded that the guidelines were correct.
“The literature is clear that both children and adults perform better with 2 CIs than with 1. The William House CISG acknowledges the findings reported in the literature and strongly endorses bilateral CI in clinically appropriate adults and children. Bilateral CI is now considered as an accepted medical practice.”