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Copyright: © 2015 Sinha VR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Volume: 1.2 Research Article
Cochlear Implants and Auditory Neuropathy
Spectrum Disorder
VR Sinha
1
, Ruchika Mittal
1
*, Ajith Nilkanthan
1
, Awadhesh Mishra
1
, DK Singh
1
, AV
Ramesh
2
, Satish Nair
3
, Poonam Raj
1
1
Army Hospital (R&R) Delhi Cantt – 110010, India
2
Command Hospital, Lucknow, India
3
Command Hospital, Kolkatta, India
Received date: 24 August 2015; Accepted date:
17 October 2015; Published date: 25 October 2015
Citation: Sinha VR, Mittal R, Nilkanthan A, Mishra A,
Singh DK, et al. (2015) Cochlear Implants and Auditory
Neuropathy Spectrum Disorder. Pediatr Neonatal Nurs
1(2): doi http://dx.doi.org/10.16966/pnnoa.105
Copyright: © 2015 Sinha VR, et al. This is an
open-access article distributed under the terms
of the Creative Commons Attribution License,
which permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
*
Corresponding author: Dr. Ruchika Mittal, M-37C Rajouri Garden, New Delhi 110027, India, Tel:
+919810961266; E-mail: ruchikamittal07@gmail.com
Abstract
Objective: The results of cochlear implantation in patients that present with auditory neuropathy spectrum disorder (ANSD) patients have
been variably reported. The effectiveness of the treatment modality varies in such patients. Hearing rehabilitation in this group of patients has
been very challenging. Considerable controversy exists whether to provide conventional ampliication (hearing aids or personal FM systems) or
cochlear implants (CI) to children with ANSD. With this background, we present our experience with select subset of ANSD cases that derived
beneit from cochlear implant.
Methodology: We studied and evaluated all the paediatric cases (i.e. less than 12 years of age) using audiological test battery. The cases
with other co-morbidities, abnormality of auditory nerve and cochlea were excluded. Diagnosed cases of ANSD were given bilateral, behind the
ear, digital hearing aids as per their behavioural responses for 6 months and enrolled for communication development in the auditory verbal
habilitation program. They were evaluated for auditory perception using Category of Auditory Performance scoring system. The ANSD cases that
derived “intermediate beneit” as per our criteria at 6 months post hearing aids were taken up for unilateral cochlear implant. All the implanted
ANSD cases continued in auditory verbal habilitation program of our hospital and their progress on auditory perception post cochlear implant
was monitored using CAP scoring system.
Results: A total of 1313 cases were evaluated for hearing loss. Out of these 65 cases were detected to have ANSD (42 bilateral and 23
unilateral ANSD).Unilateral ANSD cases were excluded from the study. Hearing aids were itted in all the bilateral ANSD cases. After 6 months
of hearing aid itting thirteen ANSD cases showed “intermediate beneit” and were taken up for cochlear implant. After 6 months of implant usage
all ANSD cases showed “good” progress on CAP.
Conclusion: Hearing aid trial should be given to all the cases diagnosed with ANSD and those who derive “intermediate beneit” from hearing
aids and AVT should be considered for cochlear implant.
Introduction
Auditory Neuropathy Spectrum Disorder (ANSD) is a pattern of
hearing loss characterized by preservation of outer hair cell function
despite absent brainstem auditory evoked responses. Intact outer hair
cell function is demonstrated by the presence of Otoacoustic Emissions
(OAEs) and / or measurable Cochlear Microphonics (CM) whereas
no synchronous neural activity is seen on acoustically evoked auditory
evoked brainstem response testing [1]. he underlying cause may be
congenital or acquired. Congenital causes include genetic abnormalities,
perinatal asphyxia, orhyperbilirubinaemia. Acquired causes include
infections, demyelination disorders and vascular causes. Postulated sites
of lesion in ANSD include selected outer hair cells, inner hair cells, the
synapse between hair cells and the auditory nerve, neural dendrite/axon,
myelin sheath, or spiral ganglion cells [2,3]. ANSD was initially believed
to be very rare. However, various studies have shown that ANSD is much
more frequent than previously believed, with its prevalence estimated to
range from 0.5% to 15% [4] and incidence ranging from 2.4% to 14-15% in
children with severe to profound sensori-neural hearing loss [1]. herefore,
dealing with hearing loss in ANSD is important. he efectiveness of the
treatment modality varies on an individual basis. Hearing rehabilitation in
this group of patients has been very challenging. Hearing aids, frequency
modulation (FM) system and cochlear implantation are current treatment
options for AN/AD, although the beneits of these interventions are
variable and under much investigation [5].
Considerable controversy exists whether to provide conventional
ampliication (hearing aids or personal FM systems) to children with
ANSD. About 50% of the children in one study gained signiicant beneit
[6], although some clinics report much lower success rates [7]. Moreover,
cochlear implants (CI) in ANSD are also a debatable issue. If the site of
the lesion is the cochlea, then bypassing the inner hair cells with direct
stimulation of the vestibulocochlear nerve should produce good results.
However, if the pathological condition lies in the nerve itself as in ANSD,
then electrical stimulation (cochlear implants) might be expected to be
subject to the same limitations as acoustic stimulation (hearing aids) [8].
hus it may be logically inferred that those ANSD cases that get some
beneit from hearing aids would beneit better from cochlear implants, as
it suggest that the nerve is at least partially functional.
With this background we planned to evaluate the hearing outcomes
in those ANSD cases that derived some beneit from hearing aids and
subsequently underwent implantation.
Methodology
We studied all the paediatric cases (i.e. less than 12 years of age) referred
to our tertiary care hospital’s outpatient department of ENT for hearing
evaluation from March 2008 to March 2013. All the cases were evaluated
using audiological test battery consisting of Behavioural Observation
Audiometry (BOA) / Pure Tone Audiometry (PTA), Impedance
Audiometry, Diagnostic Otoacoustic Emissions and click evoked
Brain Stem Evoked Response Audiometry (BERA). BERA with both