Cochlear Implants
by Cochlear Guest Author

Journal Club: Pediatric cochlear implant wear time and early language development

December 16, 2019
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By Amy Donaldson, Professional Education Manager, Cochlear Americas

Gagnon, Erika B., Eskridge, Hannah, Brown, Kevin D.

Pediatric cochlear implant wear time and early language development

Sep 29, 2019:1-6

Cochlear Implants Journal

In today’s busy clinical environment, clinicians who value research-based practice often struggle to keep up with current literature.  To help, we’re excited to offer a new ProNews Blog monthly feature – Journal Club!  Each month, rotating guest authors will present a current journal article summary.

This month’s Journal Club explores a recent study by the team at the University of North Carolina published in September 2019, Pediatric Cochlear Implant Wear Time and Early Language Development. This article may be especially useful for those clinics working with pediatric recipients as a resource for counseling on device use.

What did the study investigate?

This study was designed to examine the relationship between device wear time in pediatric recipients and their language development. 

For children with hearing loss, consistent access to auditory information with either hearing aids or cochlear implants is associated with better speech and language development.1,2,3,4 Unfortunately, clinicians can’t always rely on parental report of device use – some studies have shown that they overestimate device use by an average of 2.6 hours per day.5 

Modern cochlear implant systems now have datalogging available to help clinicians objectively track device use, but it can be unclear how these results should be interpreted or what is the impact of differences in wearing time.  If a one-year-old uses their device seven hours per day, is that enough to provide access to spoken language?  What about the same use per day for a five-year-old?  This study attempted to answer these questions.

How did they do it?

The authors utilized datalogging in the Nucleus® sound processor and applied a measurement called “Hearing Hour Percentage” or HHP to track the amount of device use: 

HHP = total wear time/median awake time * 100

This measurement provides more information than just hours per day since it considers the waking hours of each day for children of different ages.  For example, according to the American Academy of Sleep Medicine6 the average median awake time for a one-year-old is 11.5 hours; for a five-year-old, it’s 12.5 hours.  That makes sense – younger children sleep more.  So seven hours of device use for the one-year-old is 61% of their awake day; but for the five-year-old, it is only 56%.  See table below:

Here are the key features of the study:

  • 37 children implanted prior to age 5
  • Average age of implantation: 1.97 years
  • Followed for the first year of device use
  • All using Nucleus 6 technology or later
  • Language tests: The Preschool Language Scale: Fifth Edition (PLS-5) or Oral and Written Language Scales: Second Edition (OWLS-II)

Results

The study found HHP of the 37 children ranged from 18% to 117% with an average of 63%.  More than half of the group achieved an HHP of over 60% by the end of their first year of device use.  This is interesting since many professionals would recommend device use during “all waking hours” but this study demonstrated that average usage of cochlear implants in children may only be about 60% of waking hours. 

The study found a positive correlation between HHP and receptive language abilities – the more recipients used their device, the better their receptive language – although the correlation was not significant for expressive language abilities.  This may have been because they only followed the children for one year after device use and expressive language development lags behind receptive language development.  Device use accounted for 40% of the variability in receptive language for the children confirming that while device use is important, it is still only one variable in outcomes for children.

Discussion

The results of this study support the importance of consistent device use for language development in children and highlight device datalogging as a critical tool in measuring progress.  The findings may also encourage professionals to consider how they counsel parents of young children who are using cochlear implants.  Combining datalogging with information about average awake time allows clinicians to determine the HHP for an individual child.  Counseling a parent to have their child use the device “all waking hours” may be helpful, but it might be even more useful to encourage use for a percentage of the child’s awake time and measure their progress by increasing that percentage. 

Pediatric clinicians encourage families to achieve “full time” device use.  This study helps define what that number should look like for children of different ages and gives parents and caregivers specific goals.  While datalogging can help clinicians track progress during clinic visits, Hearing Tracker is now available for parents to use between visits.  Hearing Tracker is available for the Nucleus 7 sound processor in the Nucleus Smart App, and is available in both iOS and Android™ devices. 

With Hearing Tracker, datalogging and device use information is not just available to clinicians but can be seen real-time by parents and caregivers, supporting device use and helping to support language development in children who use cochlear implants. 

Learn  more about this exciting clinical strategy by accessing the publication here and stay tuned for next month’s edition of Journal Club!

About our guest author:

Amy Donaldson is an Audiologist and Professional Education Manager for Cochlear Americas.  She received her Master’s Degree in Audiology from the State University of New York at Buffalo and her AuD from the University of Florida.  She was privileged to begin her career as a pediatric audiologist and gain extensive clinical experience in implantable hearing devices at the University of Michigan in Ann Arbor and at the Manchester Cochlear Implant Programme in the United Kingdom.  After working for several years as an Educational Audiologist and Technical Support Audiologist in the hearing aid industry, she returned to hearing implants and Cochlear in 2011. 

References:

  1. Weisman KB, Warner-Czyz AD (2018) Inconsistent device use in pediatric cochlear implant users; Prevalence and risk factors. Cochlear Implants International, 19, 131-141.
  2. Toblin, JB, Harrison, M, Ambrose, S, Walker EA, Oleson, JJ, Moeller MP. (2015) Language outcomes in young children with mild to severe hearing loss. Ear and Hearing, 36(Suppl 1):76S-91S.
  3. Easwar V, Sanfilippo J, Papsin, B, Gordon, K. (2018) Impact of consistency in daily device use on speech perception abilities in children with cochlear implants: datalogging evidence. Journal of the American Academy of Audiology, 29:835-846.
  4. Guerzoni L, Cuda D (2017) Speech processor datalogging helps in predicting early linguistic outcomes in implanted children. International Journal of Pediatric Otorhinolaryngology, 101:81-86.
  5. Walker EA, Spratford M, Moeller MP, Oleson J, Hua O, Roush P, Jacobs S. (2013) Predictors of hearing aid use time in children with mild-to-severe hearing loss. Language, Speech & Hearing Services in the Schools, 44(1):73-88.
  6. Paruthi S, Brooks LJ, D’Ambrosio C, Hall WA, Kotagal S, Lloyd RM, Malow BA et al (2016) Recommended amount of sleep for pediatric populations: A consensus statement of the American Academy of Sleep Medicine. Journal of Clinical Sleep Medicine, 12(6):785-786.

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Author

Cochlear Guest Author

In an effort to keep our content fresh and reflective of a diverse industry, Cochlear Americas features a mix of employees and professional partners to contribute to Cochlear ProNews as Guest Authors.

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Related Posts

Science Spotlight: Electrode Tip Area and Scala Tympani Shapes Impact on Cochlea Health  

June 6, 2023

Morphometric Analysis and Linear Measurements of the Scala Tympani and Implications in Cochlear Implant Electrodes1 

Fujiwara RJT, Ishiyama G, Lopez IA, Ishiyama A. 

Research tells us that placement of an electrode within Scala tympani (ST) during cochlear implant surgery is desirable over placement in Scala vestibuli or a translocated array because it may lead to better performance outcomes.2,3 While we know placement in Scala tympani is desired, what about electrode positioning within that Scala? By analyzing the cross-section of 10 different electrode arrays as compared to the area of the ST at multiple points of insertion in human temporal bones, Fujiwara et al have shed new light on the impact on cochlea health in the delicate apical region.

Key Findings

  1. Scala tympani assumes an ovoid shape throughout the basal turn and, within the middle turn (360-450 degrees), develops into a triangular shape with its perimodiolar height greater than its lateral wall height. 
  2. At >360 degrees, perimodiolar height (0.71mm Mean, 0.23mm SD) was significantly greater than lateral wall height (0.53mm Mean, 0.21mm SD). This trend continued towards the apex with lateral wall height decreasing at a faster rate than perimodiolar height.
  3. The changing shape of the Scala tympani in the apex may be more likely to lead to translocation, fibrosis or osteogenesis with electrodes with larger cross-sectional tip areas due to higher insertion forces required for complete insertion
  4. Increasing amounts of new bone formation have been positively correlated with a degree of intracochlear insertional trauma, which may lead to worsened postoperative audiological outcomes.

Discussion

The study analysis results suggest that an ideal scenario for avoiding trauma occurs when the electrode has the smallest possible tip volume measurement, avoids the basilar membrane and is not inserted past the point at which ST height becomes too shallow. Now why is this important as it translates to the overall health of the cochlea?

This ideal scenario can have a positive impact on cochlea health in several important ways. Impeding the basilar membrane’s function may negatively impact hearing performance which is important to avoid. The deeper the lateral wall insertion, the more likely the electrode will cause trauma1. Blood supply to the cochlea primarily lives within the lateral wall4, and lateral wall electrodes with larger cross-sectional tip volume may require increased insertion force. The impact on the lateral wall may introduce a blood supply resulting in increased immune response to that foreign body4,5,6. 

The modelling of a fibrotic sheath or osteogenesis response demonstrates fibrosis or new bone growth around the electrode5. If the electrode is abutting the basilar membrane, the fibrotic sheath or bone growth may further impede its function4. The positioning of lateral wall electrode arrays results in fibrous tissue and new bone growth emerging between the electrode array and the spiral ganglion cells whereas this reaction occurs on the back side of perimodiolar electrode arrays. This reaction may be responsible for lower and more consistent impedances as well as reduced current levels required for stimulation on perimodiolar electrodes.7 

 Fig 1. Re-modelling of the cochlea occurs after implantation which may negatively impact cochlea health. Peri-modiolar electrodes provide additional benefits promoting long term cochlea health by avoiding certain issues that impact lateral wall electrodes.

This analysis would indicate that best outcomes may be achieved with electrode arrays of smaller volume that avoid both the basilar membrane and the most apical region of the ST where it is most shallow. In the chart below1 we see that lateral wall vs Peri-modiolar height is similar up to about 180 degrees. Beyond that point however, the lateral wall height begins to decrease at a faster rate than perimodiolar height.

Table from Reference 1

Looking at the height of ST in a perimodiolar position, Cochlear™ Nucleus® electrodes are both positioned further away from the basilar membrane and have more tolerance for ST height to accommodate an atraumatic insertion. Specifically looking at the Slim Modiolar electrode, it’s mean cross sectional area of ST was 12.51% (SD, 2.78%) compared to other manufacturers electrodes with 22.34% (SD, 4.97%) for Midscala, and 32.16% (SD, 7.16% for Helix respectively. Among lateral wall electrodes, the CI622 occupies 7.82% (SD, 1.74%); FLEX24, 13.40% (SD, 2.98%); and SlimJ, 12.78% (SD, 2.84%).

Avoiding trauma during cochlear implantation helps promote long term hearing outcomes through structural preservation. Further minimizing the impacts of implanting a foreign body into the cochlea can provide long term benefits over the patient’s lifetime. The Slim Modiolar electrode not only offers performance benefits over lateral wall electrodes7, but the unique design offers the additional benefit of providing an atraumatic insertion to further promote the long-term health of the cochlea.

The impact on cochlea health is critical to a lifetime of hearing performance. Visit our website to explore additional data on outcomes with the Cochlear Nucleus System.

References:

  1. Fujiwara RJT, Ishiyama G, Lopez IA, Ishiyama A. Morphometric Analysis and Linear Measurements of the Scala Tympani and Implications in Cochlear Implant Electrodes. Otol Neurotol. 2023 Mar 8. doi: 10.1097/MAO.0000000000003848. Epub ahead of print. PMID: 36893208.
  2. Holden L, et al. Factors Affecting Open-Set Word Recognition in Adults With Cochlear Implants. Ear & Hearing. 2013;34(3):342-360
  3. Shaul C, et al. Scalar localisation of peri-modiolar electrodes and speech perception outcomes. The Journal of Laryngology & Otology. 2018;132(11):1000-1006.
  4. Bester C, et al. Four-point impedance as a biomarker for bleeding during cochlear implantation. Scientific Reports. 2020;10(1).
  5. Somdas M, et al. Quantitative Evaluation of New Bone and Fibrous Tissue in the Cochlea following Cochlear Implantation in the Human. Audiology and Neurotology. 2007;12(5):277-284.
  6. Verberne J, et al. The Effect of Scala Tympani Morphology on Basilar Membrane Contact With a Straight Electrode Array: A Human Temporal Bone Study. Otol Neurotol. 2017 Jan;38(1):47-53.
  7. Holder JT, et. al. Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays. Otol Neurotol. 2019 Oct;40(9):1160-1166.

Science Spotlight

3 practical Science Spotlights for optimal care

June 18, 2021

1. New Active Osseointegrated Steady-State Implant System

The aim of this international, multicenter study was to demonstrate clinical performance, safety and benefit of the Cochlear™ Osia® System, an active osseointegrated steady-state transcutaneous bone conduction hearing implant system that uses piezoelectric technology.

2. Speech Understanding and Quality-of-Life Outcomes After Cochlear Implantation

The purpose of this study  was to measure speech understanding in quiet, speech understanding in noise, and health utility using a cochlear implant and hearing aid (bimodal hearing) in 96 subjects versus their pre-operative condition of two hearing aids (HAs).

3. Speech perception and QoL effectiveness CI in a group of adults 65 years or older

The purpose of this study was to to explore speech perception and quality-of-life (QoL) effectiveness of cochlear implants (CI) in a group of adults 65 years or older compared with an optimized bilateral hearing aid (HA) condition, and to examine the improvement on the AzBio Sentence Test for Medicare beneficiaries who meet the expanded criteria of a score of 41% – 60% in the best-aided condition.

For more article summaries, read this article and subscribe to Cochlear ProNews!

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