Effect of Acoustic Tumor Extension into the Internal Auditory Canal on Distortion-Product Otoacoustic Emissions

Abstract

We studied the effects on distortion-product otoacoustic emissions (DPOAEs) of internal auditory canal (IAC) extension of acoustic neuromas (ANs) with the hypothesis that cochlear patterns of DPOAEs would be more commonly observed when the IAC was completely filled with tumor because of direct tumor involvement of either the inner ear or its blood supply. In a retrospective analysis of 86 patients with surgically proven ANs, DPOAEs were classified as having cochlear or noncochlear patterns on the basis of comparisons with the behavioral pure tone thresholds. The results of behavioral audiometry and DPOAEs were compared with the extension of the tumor into the IAC, which was categorized as full or partial. Of the 86 patients, 58 had tumors with full IAC extension, and 28 had tumors with partial IAC involvement. Cochlear patterns of DPOAEs were found in 55.2% of the tumors in the full IAC group and in 71.4% of those in the partial IAC group (not statistically different). It was concluded that the extent of IAC involvement by ANs was not significantly related to the negative effects of the tumor on cochlear function as represented by DPOAEs.

Keywords

acoustic neuroma internal auditory canal otoacoustic emissions

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References

Kemp

. Stimulated acoustic emissions from within the human auditory system. J Acoustic Soc Am 1978;64:1386–91.

Brownell

. Outer hair cell electromotility and otoacoustic emissions. Ear Hear 1990;11:82–92.

Kim

. Cochlear mechanics: Implications of electrophysiological and acoustical observations. Hear Res 1980;2:297–317.

Telischi

Roth

Stagner

Lonsbury-Martin

Balkany

. Patterns of evoked otoacoustic emissions associated with acoustic neuromas. Laryngoscope 1995;105:675–82.

Bonfils

Uziel

. Evoked otoacoustic emissions in patients with acoustic neuromas. Am J Otol 1988;9:412–7.

Ohlms

Lonsbury-Martin

Martin

. Acoustic-distortion products: Separation of sensory from neural dysfunction in sensorineural hearing loss in human beings and rabbits. Otolaryngol Head Neck Surg 1991;104:159–74.

Whitehead

Lonsbury-Martin

Martin

. Relevance of animal models to the clinical application of otoacoustic emissions. Semin Hear 1992;13:81–101.

Lonsbury-Martin

Whitehead

Martin

. Clinical applications of otoacoustic emissions. J Speech Hear Res 1991;34:964–81.

Thomsen

Tos

. Diagnostic strategies in search for acoustic neuromas. Findings in 300 acoustic neuroma patients. Acta Otolaryngol Suppl (Stockh) 1988(suppl 452):16–25.

10.

Nadol

Jr Levine

Ojemann

Martuza

Montgomery

de Sandoval

. Preservation of hearing in surgical removal of acoustic neuromas of the internal auditory canal and cerebellar pontine angle. Laryngoscope 1987;97:1287–94.

11.

Schuknecht

. Pathology of the ear. Philadelphia, Pa: Lea & Febiger, 1993:460–72.

12.

Kaga

Iwasaki

Tamura

Suzuki

Haebara

. Temporal bone pathology of acoustic neuroma correlating with presence of electrocochleography and absence of auditory brainstem response. J Laryngol Otol 1997;111:967–72.

13.

Lonsbury-Martin

Martin

Telischi

. Otoacoustic emissions in clinical practice. In: Musiek

Rintelman

, eds. Contemporary perspectives in hearing assessment. Boston, Mass: Allyn and Bacon, 1999:167–96.

14.

Jahnke

Neuman

. The fine structure of vestibular end organs in acoustic neuroma patients. In: Tos

Thomsen

, eds. Acoustic neuroma. Amsterdam, the Netherlands: Kugler Publications, 1992:203–7.

15.

Jackler

. Acoustic neuroma (vestibular schwannoma). In: Jackler

Brackmann

, eds. Neurotology. St Louis, Mo: Mosby, 1994:729–85.