Acoustic radiation effects on bone conduction threshold measurement.
Acoustic radiation is the sound energy escape from a bone vibrator that may be detected by air conduction mechanisms. The presence of acoustic radiation may result in an unreal bone conduction threshold, promoting an unreal air/bone gap in the high frequencies.


OBJECTIVE
aim to analyze the acoustic radiation effect on the extension of air/bone gap at 2,000, 3,000 and 4,000 Hz.


METHODS
our clinical and experimental study had a sample of 101 individuals, who matched inclusion criteria: to have an air/bone gap higher than 10 dB in the frequencies of 2,000; 3,000 and 4,000 Hz. All of them had their bone conduction threshold measured in two conditions: open ear canal and closed ear canal.


RESULTS
we found that major differences between the two conditions evaluated occurred at the 4,000 Hz; data analysis showed significant difference in the extension for the air/bone gap; analysis of the number of cases of mixed hearing loss that changed to sensorineural was significant too.


CONCLUSIONS
These studies concluded that when the MAE is occluded, the acoustic radiation phenomenon is controlled or avoided, enabling bone measures at the frequencies of 3,000 and 4,000Hz to be more accurate.
Matos
Renata das Merces Bastos de
Rd
UNIPAC-JF.
Valle
Silvania de Paula
Sde P
Dias
Anna Marcella Neves
AM
Santos
Teresa Maria Momensohn dos
TM
Leite
Isabel Cristina Gonçalves
IC
D000161:Acoustic Stimulation; D000162:Acoustics; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone / Q000379:methods*; D001309:Auditory Threshold; D001844:Bone Conduction / Q000502:physiology*; D016009:Chi-Square Distribution; D004424:Ear Canal / Q000502:physiology*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D055815:Young Adult