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					                              IMPORTANCE OF EABR IN AUDITORY NEUROPATHY FOR
                                       COCHLEAR IMPLANT SURGERY
                                                                        Poster Title Kumar
                                                               G. Srinivas, I. Srikanth, E.C.Vinaya
                                                                     Apollo Hospitals, Hyderabad, India
                                                                                                                                         Trans Tympanic-EABR ( TT-EABR) was done by using GSI Audera
                                                                                                                                         system and cochlear’s implant in box (simulator) was used to
                       ABSTRACT                                                        AIMS / OBJECTIVES                                 simulate the cochlear implant under
Cochlear implantation has proven treatment option for                The aim of the study is to measure the                              general anesthesia in preoperative condition, good responses seen
auditory neuropathy. But the prediction of outcomes is               1) Pre operative Electrically evoked auditory brainstem             in right ear and poor responses in left ear. Based on the TT-EABR
                                                                                                                                         results patient was recommended
still a big challenge for clinicians. Electrically evoked            response (EABR) in patient with auditory neuropathy
                                                                     2) To measure the Neural response telemetry in intra operative      for cochlear implantation in right ear
auditory brainstem response audiometry provides
valuable information in selection of ear for surgery and             condition and EABR
                                                                                                                                         She was implanted with Nucleus 24 RE (CA) electrode array by using
also will provide useful information on responses of                                         METHODS                                     advanced off stylet (AOS) technique and all the electrodes were
auditory neurons to electrical stimulation.                                                                                              inside and neural response telemetry (NRT) was done by using
                                                                     A 19 years old female was referred to the Cochlear implant          custom sound E.P. 2.0, able to get responses for electrodes 6 and 12
                   INTRODUCTION                                      clinic, Apollo Hospitals for the examination of bilateral           with 32 pulse width and 40 probe rate and 40 gain.
                                                                     sensorineural hearing loss. Her main complaint was poor
Auditory neuropathy (AN) is a hearing disorder caused by             speech discrimination and onset of problem was at 8 years of
desynchronized neural discharges of the auditory nerve.              age, no significant cause of hearing loss. Earlier she had
                                                                     undergone Audiological evaluation at several medical centers
Auditory neuropathy is defined as impairment of auditory neural      and recommended to use hearing aids, even though she
function with preserved cochlear hair cell function.                 couldn’t find any benefit with the hearing aids and she is
                                                                     dependent on lip reading for verbal communication.                    EABR Responses in Right Ear           EABR responses in left ear
Clinical features of auditory neuropathy include:
1) Bilateral sensorineural hearing loss of any degree                She had been evaluated with routine Audiological evaluations
2) Normal outer hair cell function evidenced by preservation of      include pure tone audiometry, speech audiometry, impedance
otoacoustic emissions (OAEs) and/or cochlear microphonics            audiometry, oto acoustic emissions (OAE), auditory
(CM)                                                                 brainstem evoked response audiometry (ABR), auditory
3) Abnormal auditory brainstem responses (ABRs)                      steady state response audiometry (ASSR), radiological
4) disproportionate difficulties in speech discrimination.           evaluation.                                                         NRT traces of Electrode 6           NRT of Electrode 6 at 40 gain & 55
                                                                                                                                                                              delay, 32 pulse width & 240 CL
Conventional hearing aids are rarely effective in patients with                RESULTS & DISCUSSION
auditory neuropathy, which makes intervention and auditory
rehabilitation difficult in this patient population. On the other     Test                Right                Left
hand, the efficacy of cochlear implantation for patients with         PTA               Moderate to            Moderate to
auditory neuropathy is questioned because the site of lesion for                        moderately severe      moderately severe
patients with auditory neuropathy is still uncertain. Although        Rt: 48.3 dB HL
                                                                                        SN HL                  SN HL                    NRT traces of Electrode 12          NRT of Electrode 12 at 40 gain &
initial reports of cochlear implantation in patients with auditory    Lt: 55 dB HL
                                                                                        (Inconsistent)         (Inconsistent)                                               55 delay, 32 pulse width & 245 CL
neuropathy recommended caution, more recent studies of
people with auditory neuropathy have demonstrated the benefit         Speech Audiometry Poor                   Poor                     After 21 days switch on was done, able to elicit good behavioral
of cochlear implantation.                                                                                                               responses, she wasprovided with auditory training exercises and now
                                                                      Impedance           “A” type with        “A” Type with            she is able to discriminate ling sounds,
Multiple reports in the literature have claimed successful or         Audiometry          absent reflexes      absent reflexes          environmental sounds, syllable consonant discrimination, word
positive outcomes for individuals with ANSD who have received                             (Ipsi & Contra)      (Ipsi & Contra)          identification and 60% of general conversation.
cochlear implants. Although lacking some detail with respect to       DPOAE               Present              Present                                         CONCLUSION
outcome test results, several studies describe performance of         ABR                 No peaks even at     No peaks even at
cochlear implant recipients with ANSD to be comparable to that                            100 dB nHL           100 dB nHL                We suggest that TT-EABR is a useful tool in measuring auditory
of the general population with cochlear implants (Buss et al.,                                                                           nerve integrity, predicting performance outcomes & selection of ear.
                                                                      ASSR                No responses         No responses
2002; Madden, Rutter, Hilbert, Greinwald, & Choo, 2002;                                                                                  It can be include in a test battery for auditory neuropathy. Cochlear
Rodriguez Ballesteros et al., 2003).                                                                                                     implantation can be a valid option for patients with auditory
                                                                     Hearing aid trail was done by using Siemens Intuis S Dir hearing
                                                                                                                                         neuropathy, careful consideration should be given to the particulars
                                                                     aids, but no benefit with hearing aids was reported.
The following case presentation details the cochlear                                                                                     in each case and patients and parents should be informed about the
implantation of an adult patient with auditory neuropathy and                                                                            prognosis, outcomes and realistic expectations.
                                                                     Based on all the above results patients was diagnosed with
may serve as a representative example of its potential benefits.
                                                                     bilateral auditory neuropathy & counseled for cochlear                              ACKNOWLEDGMENTS
                                                                     implantation along with electrically evoked ABR.
The following case presentation details the cochlear                                                                                      ASHA 2010 Annual convention committee
implantation of an adult patient with auditory neuropathy and                                                                             Apollo cochlear Implant clinic members and Apollo Hospitals
                                                                     Radiological evaluation includes MRI Brain with IAC, CT scan of
may serve as a representative example of its potential benefits.                                                                          Management
                                                                     the Temporal Bones showed normal in both ears.

                           For More details: Apollo Hospitals, Jubilee Hills, Hyderabad, AP, India Ph:+9140-23607777 ext. 3737

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