Clinical investigation on spontaneous otoacoustic emission (SOAE)

Clinical investigation on spontaneous otoacoustic emission (SOAE)

Auris Nasus Larynx 35 (2008) 597–598 www.elsevier.com/locate/anl Letter to the Editor Clinical investigation on spontaneous otoacoustic emission (SOA...

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Auris Nasus Larynx 35 (2008) 597–598 www.elsevier.com/locate/anl

Letter to the Editor Clinical investigation on spontaneous otoacoustic emission (SOAE)§

Keywords: Spontaneous otoacoustic emission (SOAE); Otoacoustic emission (OAE); Bell’s palsy; Vascular loop

Dear Editor, The article by Tsutomu Kuroda [Auris Nasus Larynx 34 (2007) 29–38] presents interesting observations dedicated to ‘‘Clinical investigation on spontaneous otoacoustic emission (SOAE) in 447 ears’’ [1]. In an attempt to clarify how useful could be SOAE for objective hearing assessment, he studied in 447 ears, hearing level and SOAE, SOAE frequencies and levels and presence of SOAE and background factors, (hearing level, age, gender, laterality and relation between SOAE and transient evoked otoacoustic emissions (TEOAE), or SOAE and distortion product otoacoustic emissions (DPOAE). He concluded that SOAE is a useful tool for objective hearing assessment and he proposed to measure SOAE in addition to TEOAE or DPOAE. We also in our ENT department measure the SOAE in every audiologic evaluation, in an effort to established SOAE as an objective test in diagnosis of neurootologic disease. Doing this investigation we identified a young male (25 years old), who presented to our outpatient ward, complained for unilateral not pulsate tinnitus in the right ear, unexplained from his medical and family history, without concomitant hearing loss. Eight years ago the patient appeared Bell’s palsy in the right side of his face. He received for this, medical treatment and he had total recovery of his right facial nerve function [2]. This young man underwent pure tone audiometry, measurements of acoustic immitance, TEOAE and DPOAE, auditory brainstem response (ABR) recording and caloric test. The results did not reveal any pathologic finding.

DOI of original article: 10.1016/j.anl.2008.01.004.

Measuring SOAE in the right ear, we detected three spontaneous otoacoustic emissions with 1462, 1805 and 4297 Hz frequencies. Their intensities were 10.8, 5.1, and 1.7 dB HL. The SOAE were almost unchanged in multiple measurements after 24 h, 1 week and 1-month time. Moreover patient received magnetic resonance imaging and magnetic resonance angiography (MRI/MRA) of head and neck, which revealed a vascular loop in the right internal auditory canal (IAC). The presence of vascular loop within the IAC pressing on or not the right vestibular, facial and cochlear nerve may explain the unilateral not pulsate tinnitus, as well as the appearance of stable SOAE, in the same ear [3,4]. This vascular loop also, may act as predispose factor for Bell’s palsy of the ipsilateral facial nerve [2]. Subsequently the presence of SAOE in normal hearing adults with unexplained not pulsate tinnitus and pre-existent Bell’s palsy may be an indication of ‘‘abnormal cochlear function’’, caused by structures like vascular loops running the IAC and pressing on or not the VII and VIII nerve. From this point of view SAOE may be a useful tool for clinical investigation of this type of tinnitus. References [1] Kuroda T. Clinical investigation on spontaneous otoacoustic emission (SOAE) in 447 ears. Auris Nasus Larynx 2007;34:29–38. [2] Ziavra N, Kastanioudakis I, Papakostas V, Assimakopoulos D. Spontaneous otoacoustic emissions and not pulsatile tinnitus, in a young adult with normal hearing. Otorhinolaryngol Head & Neck Surg 2006;24:25–30 (Hellenic Journal). [3] De Ridder D, Ryu H, Moller AR, Nowe V, Van de Heyning P, Verlooy J. Functional anatomy of the human cochlear nerve and its role in microvascular decompressions for tinnitus. Neurosurgery 2004;54: 381–90. [4] De Ridder D, Moller A, Verlooy J, Cornelissen M, De Ridder L. Is the root entry/exit zone important in microvascular compression syndromes? Neurosurgery 2002;51:427–33.

0385-8146/$ – see front matter # 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2008.01.005

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Letter to the Editor / Auris Nasus Larynx 35 (2008) 597–598

Assimakopoulos Dimitrios* Department of Otorhinolaryngology, Medical School, University of Ioannina, Ioannina, Greece

*Tel.: +30 2651097489; fax: +30 2651097890 E-mail address: [email protected] 23 October 2007