Bilateral cochlear implants in children : clinical and methodological studies
Author: Asp, Filip
Date: 2015-12-11
Location: Hörsal R64, Karolinska Universitetssjukhuset, Huddinge
Time: 09.00
Department: Inst för klinisk vetenskap, intervention och teknik / Dept of Clinical Science, Intervention and Technology
View/ Open:
Thesis (1.161Mb)
Abstract
A cochlear implant (CI) restores functional hearing in individuals with bilateral severe-
to-profound sensorineural hearing loss. Despite hearing loss in both ears, CIs
are usually provided unilaterally, excluding the alleged benefits associated with bilateral
auditory stimulation. Recently, however, bilateral cochlear implantation is
increasingly common, with the main objectives of enhancing sound localization abilities
and speech recognition, particularly in the presence of background noise. Here,
using a within-subject longitudinal design in a large clinical study sample of children
using bilateral cochlear implants (BiCI), a large, sustained, and significant bilateral
benefit in horizontal sound localization accuracy (SLA) was demonstrated. A significant
bilateral benefit also existed in speech recognition in noise spatially separated
from the target signal. Speech recognition in quiet, however, was comparable under
BiCI and unilateral CI listening conditions. Parental reports corroborated behavioral
findings. Yet, the bilateral benefit was not uniform across subjects, large intersubject
variability existed both with BiCI and unilateral CI, and neither SLA, nor speech
recognition performance, was restored to that found in children with normal hearing
(NH). Clinically important, a significant improvement of horizontal SLA with increasing
BiCI experience (21 percentage points per year) was demonstrated from onset
of bilateral stimulation until about 3 years post bilateral implantation (r = -0.51, p <
0.0001, n = 66), with a very similar developmental rate observed intraindividually
(mean of the individual slopes = 19 percentage points per year of BiCI experience,
n = 21), suggesting an experience-driven maturation of SLA. Of further clinical importance,
no relationship between SLA and age or age at implantations was found,
albeit, improvements in SLA as a function of BiCI experience were faster, and the
bilateral SLA benefit was larger, when bilateral implantation occurred before 4 years
of age.
In an attempt to accommodate measurements of spatial hearing to clinical requirements, a SLA method using objectively recorded gaze was developed. Pupil positions toward spatially distributed auditory and visual events were recorded using corneal reflection eye tracking technique. The spatial resolution of the methodology allowed detailed objective analyses of gaze patterns in NH listeners from 6 months of age. SLA was rapidly measured in children (age range = 29 – 157 weeks; mean = 168 seconds, n = 12) and adults (mean = 162 seconds, n = 8). Data showed immature SLA in children, with increasing performance as a function of age (r = -0.68, p = 0.015). Highly reliable results existed in adults, who revealed high SLA across the entire spatial range tested.
The findings in this thesis have important methodological implications for the clinical management of children with CI, and provide valuable data which may be used in counseling prior to bilateral cochlear implantation. Moreover, the objective and rapid SLA methodology may aid clinicians at an early stage of the process of early intervention with cochlear implants and/or hearing aids in children with hearing loss.
In an attempt to accommodate measurements of spatial hearing to clinical requirements, a SLA method using objectively recorded gaze was developed. Pupil positions toward spatially distributed auditory and visual events were recorded using corneal reflection eye tracking technique. The spatial resolution of the methodology allowed detailed objective analyses of gaze patterns in NH listeners from 6 months of age. SLA was rapidly measured in children (age range = 29 – 157 weeks; mean = 168 seconds, n = 12) and adults (mean = 162 seconds, n = 8). Data showed immature SLA in children, with increasing performance as a function of age (r = -0.68, p = 0.015). Highly reliable results existed in adults, who revealed high SLA across the entire spatial range tested.
The findings in this thesis have important methodological implications for the clinical management of children with CI, and provide valuable data which may be used in counseling prior to bilateral cochlear implantation. Moreover, the objective and rapid SLA methodology may aid clinicians at an early stage of the process of early intervention with cochlear implants and/or hearing aids in children with hearing loss.
List of papers:
I. Horizontal Sound Localization in Children With Bilateral Cochlear Implants: Effects of Auditory Experience and Age at Implantation. Asp F, Eskilsson G, Berninger E. Otology & Neurotology, 2011, 32, 558-564
Fulltext (DOI)
Pubmed
View record in Web of Science®
II. Bilateral versus unilateral cochlear implants in children: Speech recognition, sound localization, and parental reports. Asp F, Mäki-Torkko E, Karltorp E, Harder H, Hergils L, Eskilsson G, Stenfelt S. International Journal of Audiology, 2012, 51, 817-832
Fulltext (DOI)
Pubmed
View record in Web of Science®
III. A longitudinal study of the bilateral benefit in children with bilateral cochlear implants. Asp F, Mäki-Torkko E, Karltorp E, Harder H, Hergils L, Eskilsson G, Stenfelt S. International Journal of Audiology, 2015, 54, 77-88
Fulltext (DOI)
Pubmed
View record in Web of Science®
IV. Corneal-Reflection Eye-Tracking Technique for the Assessment of Horizontal Sound Localization Accuracy from 6 months of Age. Asp F, Olofsson Å, Berninger E. Ear and Hearing, 2015, [Epub ahead of print]
Fulltext (DOI)
Pubmed
I. Horizontal Sound Localization in Children With Bilateral Cochlear Implants: Effects of Auditory Experience and Age at Implantation. Asp F, Eskilsson G, Berninger E. Otology & Neurotology, 2011, 32, 558-564
Fulltext (DOI)
Pubmed
View record in Web of Science®
II. Bilateral versus unilateral cochlear implants in children: Speech recognition, sound localization, and parental reports. Asp F, Mäki-Torkko E, Karltorp E, Harder H, Hergils L, Eskilsson G, Stenfelt S. International Journal of Audiology, 2012, 51, 817-832
Fulltext (DOI)
Pubmed
View record in Web of Science®
III. A longitudinal study of the bilateral benefit in children with bilateral cochlear implants. Asp F, Mäki-Torkko E, Karltorp E, Harder H, Hergils L, Eskilsson G, Stenfelt S. International Journal of Audiology, 2015, 54, 77-88
Fulltext (DOI)
Pubmed
View record in Web of Science®
IV. Corneal-Reflection Eye-Tracking Technique for the Assessment of Horizontal Sound Localization Accuracy from 6 months of Age. Asp F, Olofsson Å, Berninger E. Ear and Hearing, 2015, [Epub ahead of print]
Fulltext (DOI)
Pubmed
Institution: Karolinska Institutet
Supervisor: Berninger, Erik
Issue date: 2015-11-16
Rights:
Publication year: 2015
ISBN: 978-91-7676-145-8
Statistics
Total Visits
Views | |
---|---|
Bilateral ...(legacy) | 1284 |
Bilateral ... | 768 |
Total Visits Per Month
October 2023 | November 2023 | December 2023 | January 2024 | February 2024 | March 2024 | April 2024 | |
---|---|---|---|---|---|---|---|
Bilateral ... | 27 | 14 | 18 | 17 | 13 | 18 | 6 |
File Visits
Views | |
---|---|
Thesis_Filip_Asp.pdf | 1126 |
Thesis_Filip_Asp.pdf(legacy) | 581 |
Top country views
Views | |
---|---|
Germany | 620 |
United States | 265 |
Sweden | 181 |
Denmark | 160 |
United Kingdom | 101 |
Ireland | 80 |
Australia | 68 |
South Korea | 38 |
India | 34 |
China | 30 |
Top cities views
Views | |
---|---|
Kiez | 561 |
Ashburn | 76 |
Dublin | 72 |
Copenhagen | 67 |
Sydney | 63 |
Ballerup | 35 |
Seoul | 30 |
Stockholm | 29 |
Amsterdam | 25 |
Wilmington | 15 |