Korean J Otolaryngol-Head Neck Surg.  1999 Dec;42(12):1501-1504.

The Effect on Acoustic Characteristics of Surgical Modification of the External Ear

• Jang CH
• Lee JS

Abstract

BACKGROUND AND OBJECTIVES: The peak resonance corresponds to the fundamental frequency whose wavelength is approxi-mately four times the canal length and is between 2 and 3 kHz in a normal ear canal. The possibility that creation of an open cavity mastoid alters the acoustical characteristics of the external ear has been suggested. The aim of this study was to ascertain the acoustical changes in the external auditory canal occasioned by the open cavity mastoidectomy, and compare it with the mastoid obliteration.
MATERIALS AND METHODS
We measured the external ear resonance (EER) characteristics in 40 normal ears, 20 ears with open cavity mastoid and 40 ears with obliterated mastoids. The EER characteristics were measured using 6500 hearing aid test system.
RESULTS
The means of the peak resonant frequency and the peak amplitude at open cavity mastoids (2350 Hz, 18.5 dB) showed significant differences (p<0.1) when compared with those at normal mastoids. However, the means at obliterated mastoids (2850 Hz, 20.5 dB) recovered to the near normal state.
CONCLUSION
While the open cavity mastoidectomy can affect the resonance frequency, the mastoid obliteration may help anatomical reconstruction as well as acoustical recovery.

Keyword

External ear resonance; Open cavity mastoidectomy; Mastoid obliteration

MeSH Terms

Acoustics*
Ear
Ear Canal
Ear, External*
Hearing Aids
Mastoid