High-frequency electrostimulation hearing after mastoidectomy.
This study was undertaken to measure the degree of high-frequency sensorineural hearing loss following mastoid surgery. Twenty-five patients undergoing mastoidectomy procedures were tested preoperatively, less than 2 days postoperatively, and at 30 days postoperatively using the Tonndorf Audimax 500 high-frequency audiometer. Electrostimulation thresholds in 1-kHz intervals, from 1 to 20 kHz, were measured, and the highest detectable frequency was determined to within 0.1 kHz. Surgical drilling time was recorded. Average drilling time was 51 minutes. A significant temporary threshold shift was observed, measurable at multiple frequencies, less than 48 hours after mastoidectomy. There was no clinically significant change in electrostimulation thresholds (measured in 1-kHz increments, from 1 to 16 kHz) preoperatively to 30 days postoperatively. A statistically significant average loss of 0.89 kHz in the highest frequency producing a measurable response was noted (p less than 0.05). Determinations of the highest measurable frequency may be the most sensitive measure of surgically-induced, high-frequency sensorineural hearing changes.
Hegewald
M
M
Division of Otorhinolaryngology, University of Texas Health Science Center, San Antonio 78284-7777.
Heitman
R
R
Wiederhold
M L
ML
Cooper
J C
JC
Gates
G A
GA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001299:Audiometry; D002648:Child; D005072:Evoked Potentials, Auditory; D005260:Female; D006316:Hearing Loss, High-Frequency / Q000209:etiology; D006317:Hearing Loss, Noise-Induced / Q000209:etiology; D006319:Hearing Loss, Sensorineural / Q000209:etiology*; D006801:Humans; D008297:Male; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D013997:Time Factors