Bilateral cochlear implantation

 

An introduction to bilateral cochlear implantation

Cochlear implants have provided a revolutionary solution for the treatment of bilateral, moderately severe to profound sensorineural hearing loss (SNHL) in the past 30 years. According to the Food and Drug Administration (FDA), as of December 2012, approximately 324,200 people worldwide have received implants.1 Initially cochlear implants were not offered bilaterally because of an assumed potential safety risk of surgery with new technology. Increasing evidence on the clinical effectiveness and safety of bilateral implantation has led to global changes in the standard care of bilateral severe to profound SNHL where the primary option is considered to be bilateral cochlear implantation.

Simultaneous and sequential bilateral cochlear implantation

Bilateral implantation can be carried out during one surgery (simultaneously) or two consecutive surgeries (sequentially). In the European consensus report, simultaneous bilateral cochlear implantation is recommended for children with clear bilateral severe to profound SNHL.2 In fact, simultaneous bilateral cochlear implantation promotes development of both auditory pathways at the same time and is less resource consuming for rehabilitation compared with sequential bilateral implantation in children.3

However, not all patients are suitable for a simultaneous implantation procedure due to their clinical situation and are therefore likely to be candidates for sequential implantation.4 When sequential implantation is considered the best option, the time between implantations should be kept to a minimum in order to maximise the outcomes (<1.5yrs).5

Today, following early diagnosis of bilateral SNHL, bilateral cochlear implantation is offered as a standard therapy in countries such as UK, Norway, Sweden, Denmark, Switzerland, Finland, Belgium, Germany,2 France and Netherlands, and is funded by the public health providers.

Factors that affect the outcomes of bilateral cochlear implantation

  • If the hearing loss is prelingual (before language acquisition) or postlingual (after language acquisition).
  • Age at first implantation - Duration of ‘bilateral deafness’ determines the auditory pathway development.
  • Age at second implantation - Duration of ‘unilateral deafness’ determines the bilateral auditory pathway and symmetrical auditory cortex development.

The advantages of bilateral Cochlear Implantation over unilateral Cochlear Implantation

Whether you are considering simultaneous or sequential bilateral implantation, the section below will help you understand the advantages. Bilateral implantation will give your child the advantages summarised below, compared to unilateral implantation.

  • Audiological benefits of binaural hearing6
    1. Improved speech recognition for separated sound sources
    2. Listening in noise
    3. More balanced and “natural” sound
    4. Ability to identify sound direction
  • Symmetrical auditory pathway and cortex development5
  • Better language and speech development7, 8 which can be translated into better educational outcomes, the potential for mainstream schooling and better employment opportunities.
  • Less fatigue as a result of less listening effort9
  • Increased opportunity for “overhearing” and incidental learning10
  • Reduced parental stress level11

Most importantly, bilateral implantation gives your child better opportunity to develop at the same rate as normal hearing children.

[1]  National Institute on Deafness and Other Communication Disorders, «National Institute on Deafness and Other Communication Disorders,» 2014. [Online]. Available: http://www.nidcd.nih.gov/health/hearing/pages/coch.aspx. [Accessed on 11 February 2015].

[2]  J. Ramsden, K. Gordon, A. Aschendorff, L. Borucki, M. Brunne, S. Burdo, N. Garabedian, W. Grolman, R. Irving, A. Lesinski , N. Loundon, M. Manrique, J. Martin, C. Raine, J. Wouters and B. Papsin, «European Bilateral Pediatric Cochlear Implant Forum Consensus Statement,»Otology&Neurology, Vol. 33, pp. 561-565, 2012.   

[3]  R. Peters, J. Wyss und M. Manrique, «Worldwide Trends in Bilateral Cochlear Implantation,» The Laryngoscope, Vol. 120, pp. S17-44, 2010.

[4]  J. Ramsden, V. Papaioannou, K. A. Gordon, A. James and B. Papsin, «Parental and Program’s Decision Making in Paediatric Simultaneous Bilateral Cochlear Implantation,» International Journal of Pediatric Otorhinolaryngology, Vol. 73, No. 10, pp. 1325-1328, 2009.

[5]  K. Gordon , D. Wong and B. Papsin, «Bilateral Input Protects The Cortex From Unilaterally-Driven Reorganization In Children Who Are Deaf,»Brain, Vol. 136, pp. 1609-1625, 2013. 

 [6]  C. Sammeth, S. M. Bundy and D. A. Miller, «Bimodal Hearing or Bilateral Cochlear Implants: A Review of the Research Literature,» Seminars in Hearing, Vol. 32, No. 1, pp. 3-31, 2011. 

 [7]  J. Sarant, D. Harris, L. Bennet and S. Bant, «Bilateral Versus Unilateral Cochlear Implants In Children: A Study of Spoken Language,» Ear and Hearing, Vol. 35, No. 4, pp. 396-409, 2014.   

[8]  T. Boons, J. Brokx, J. Frijins, L. Peeraer, B. Philips, A. Vermuelen, J. Wouters and A. van Wieringen, «Effect of Pediatric Bilateral Cochlear Implantation on Language Development,» Arch Pediatr Adolesc Med., Vol. 166, No. 1, pp. 28-34, 2012. 

[9]  K. Hughes and K. Galvin, «Measuring Listening Effort Expended by Adolescents and YoungAdults With Unilateral or Bilateral Cochlear Implants or Normal Hearing,» Cochlear Implants International, Vol. 14, pp. 121-129, 2013.   

[10]  L. De Raeve, S. Archbald and G. Diller, «Maximizing The Benefits from Bilateral Implantation, in Thereapy, at Home and at School,»Deafness & Education International, Vol. 15, pp. 52-68, 2013. 

[11]  J. Sarant and P. Garrand, «Parenting Stress in Parents of Children With Cochlear Implants: Relationship Among Parent Stress, Child Language, and Unilateral Versus Bilateral Implants,» Journal of Deaf Studies and Deaf Education, doi:10.1093/deafed/ent032, 2013. 

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The information on this website is for educational purposes, and is not intended to replace medical advice. Please consult a hearing healthcare professional to diagnose or treat a hearing or health problem.

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