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Auditory neuropathy with bilateral bat ears--a rare case report.

INTRODUCTION: The finding of normal cochlear function accompanied with abnormal brainstem responses was defined as auditory neuropathy (AN) by Starr, Picton, Sininger, Hood & Berlin, in 1996. Hearing disorder in which the transmission of signals from inner ear to the brain is impaired. It may have normal hearing, or hearing loss ranging from mild to severe. The main cause is due to damage to the inner hair cells. The hallmark of auditory neuropathy is a negligible or very abnormal ABR reading together with a normal OAE reading. The treatment is Occupational Therapy, Hearing Aids, Frequency Modulation Systems, Lip Reading, and Auditory--verbal Therapy. We report a case of auditory neuropathy with associated features like bilateral bat ears, hyperactive attention deficit.

MATERIALS AND METHODS:

CASE REPORT: Patient Dharun 7 year male came to the ENT outpatient department with the history of hard of hearing, deformed both ears, inability to speak since birth. Perinatal history was prolonged labour, Neonatal hypoxic episode after delivery with prolonged assisted ventilation.

On examination bilateral bat ears, accessory auricles (Fig 2, 3), hypertelorism (Fig 1), hyperactive attention deficit. Play audiometry shows bilateral sensorineural hearing loss (Fig 4, 5), Brain stem evoked response shows both ears -no repeatable peaks could be obtained for click stimuli at 90 dbnHL with rate of 21.1. Cochlear microphonics was observed which reversed with change in polarity of stimuli suggestive of auditory neuropathy (Fig 6, 7). Otoacoustic emission we recorded which was present in both ears (Fig 8, 9).

Computerised tomography shows normal study (Fig 10 to 15). Treatment given was occupational therapy for increasing attention, complete inside canal (CIC) hearing aid trail for communication, speech stimulation and speech education for language development, sign language, and auditory verbal therapy lip reading.

RESULTS: A child with hard of hearing and inability to speak with negligible or very abnormal brainstem evoked response reading together with a normal otoacoustic emission reading suggestive of auditory neuropathy. A normal otoacoustic emission reading is a sign that the outer hair cells are working no Fia. 15

DISCUSSION: Auditory neuropathy is a hearing disorder in which sound enters the inner ear normally but the transmission of signals from the inner ear to the brain is impaired. It can affect people of all ages, from infancy through adulthood. People with auditory neuropathy may have normal hearing, or hearing loss ranging from mild to severe; they always have poor speechperception abilities, meaning they have trouble understanding speech clearly. Often, speech perception is worse than would be predicted by the degree of hearing loss. The cause is mostly damage to the inner hair cells specialized sensory cells in the inner ear that transmit information about sounds through the nervous system to the brain. Outer hair cells help amplify sound vibrations entering the inner ear from the middle ear. When hearing is working normally, the inner hair cells convert these vibrations into electrical signals that travel as nerve impulses to the brain, where the impulses are interpreted as sound. Some children who have been diagnosed with auditory neuropathy experienced certain health problems as newborns, or during or shortly before birth. These problems include jaundice, premature birth, low birth weight, and an inadequate supply of oxygen to the unborn baby. The hallmark of auditory neuropathy is a negligible or very abnormal ABR reading together with a normal OAE reading. A normal OAE reading is a sign that the outer hair cells are working normally.

For Neonatal screening an ABR test monitors brain wave activity in response to sound using electrodes that are placed on the person's head and ears. An OAE test uses a small, very sensitive microphone inserted into the ear canal to monitor the faint sounds produced by the outer hair cells in response to stimulation by a series of clicks. ABR and OAE testing are painless and can be used for newborn babies and infants as well as older children and adults. Treatment includes was occupational therapy for increasing attention, complete inside canal (CIC) hearing aid trail for communication, speech stimulation and speech education for language development,sign language ,auditory verbal therapy lip reading, frequency modulation (FM) systems are helpful. Cochlear implants and auditory brain implants are not useful effectively.

CONCLUSION: The child presenting with deaf mute and perinatal insult along with abnormal brainstem evoked response and normal otoacoustic emission suspect auditory neuropathy. The features of auditory neuropathy along with bilateral bat ears, hyperactive attention deficit, and hypertelorism are rarest clinical findings which are not reported in any ENT syndromes till date.

REFERANCES:

(1.) Berlin CI. Auditory neuropathy. Using OAEs and ABRs from screening to management. Seminars in Hearing 1999; 20:307- 15.

(2.) Berlin CI, Bordelon J, St John P, et al. Reversing click polarity may uncover auditory neuropathy in infants. Ear Hear 1998; 19:37-47.

(3.) Berlin CI, Hood LJ, Jeanfreau J, et al. The physiological bases of audiological management. In: Berlin CI, Hood LJ, Ricci A, editors. Hair cell micromechanics and otoacoustic emissions. New York: Thomson Delmar Learning; 2002. p. 139-54.

(4.) Konishi T, Butler RA, Fernandez C. Effects of anoxia on cochlear potentials. J Acoust Soc Am 1961; 33:349- 56.

(5.) Shera CA, Guinan Jr JJ. Evoked otoacoustic emissions arise by two fundamentally different mechanisms: taxonomy for mammalian OAEs. J Acoust Soc Am 1999; 105:782-98.

(6.) Berlin CI, Hood LJ, Morlet T, Li L, Brashears S, Tedesco S, et al. Auditory Neuropathy/Dyssynchrony (AN/AD): management and results in 193 patients. Ass Res Otolaryngol 2003; 755:191 [abstract].

(7.) Amatuzzi MG, Northrop C, Liberman MC, et al. Selective inner hair cell loss in premature infants and cochlea pathological patterns from neonatal intensive care unit autopsies. Arch Otolaryngol Head Neck Surg 2001; 127:629-36.

(8.) Sobkowicz HM, Inagaki M, August BK, et al. Abortive synaptogenesis as a factor in the inner hair cell degeneration in the Bronx Waltzer (bv) mutant mouse. J Neurocytol 1999; 28:17 38.

(9.) Starr A, Picton TW, Sininger Y, et al. Auditory neuropathy. Brain 1996; 119:741-53.

(10.) Hood LJ, Berlin CI, Bordelon J, et al. Patients with auditory neuropathy/dys-synchrony lack efferent suppression of transient evoked otoacoustic emissions. J Am Acad Audiol, in press.

(11.) Hirsh IJ. The influence of interaural phase on interaural summation and inhibition. J Acoust Soc Am 1948; 20:536- 44.

(12.) Licklider JCR. The influence of interaural phase relations upon the masking of speech by white noise. J Acoust Soc Am 1948; 20:150-9.

(13.) Rance G, Beer DE, Cone-Wesson B, et al. Clinical findings for a group of infants and young children with auditory neuropathy. Ear Hear 1999; 20:238-52.

(14.) Rance G, Cone-Wesson B, Wunderlich J, et al. Speech perception and cortical event related potentials in children with auditory neuropathy. Ear Hear 2002; 23:239- 53.

(15.) Hood LJ, Berlin CI, Morlet T, et al. Considerations in the clinical evaluation of auditory neuropathy/auditory dys-synchrony. Seminars in Hearing 2002; 23:201-8.

A. Sivakumar [1], V. Narendrakumar [2]

AUTHORS:

[1.] A. Sivakumar

[2.] V. Narendrakumar

PARTICULARS OF CONTRIBUTORS:

[1.] Associate Professor, Department of ENT, Post Graduate Institution, Aarupadai Veedu Medical College and Hospital, Puducherry.

[2.] Junior Resident, Department of ENT, Post Graduate Institution, Aarupadai Veedu Medical College and Hospital, Puducherry.

NAME ADDRESS EMAIL ID OF THE CORRESPONDING AUTHOR:

Dr. A. Sivakumar, Associate Professor, ENT Department,

Post Graduate Institution, Aarupadai Veedu Medical College and Hospital, Puducherry - 607402.

Email--drsivakumar63@gmail.com

Date of Submission: 20/09/2013. Date of Peer Review: 21/09/2013. Date of Acceptance: 01/10/2013. Date of Publishing: 04/10/2013
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Article Details
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Author:Sivakumar, A.; Narendrakumar, V.
Publication:Journal of Evolution of Medical and Dental Sciences
Article Type:Clinical report
Geographic Code:9INDI
Date:Oct 7, 2013
Words:1248
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