1984 Volume 77 Issue 9 Pages 1747-1754
The eustachian tube is well known as an organ serving for the ventilation and drainage of the tympanic cavity and mastoid.
Ventilation is carried out by the opening and closing of the eustachian tube that accompany swallowing movements. There has been no instrument for the quantification of these motor activities of the tube necessary for its function as a ventilator.
The author developed a generally applicable sonotubometer Model WIO-O1 with the help of Sagami Electric K. K. for automatic measurement of the aforesaid tubal function with the use of band noise.
In a sonotubometric trial with 32 adult females as subjects, the duration of patency of the eustachian tube was 288.5±138.5msec, and the amplitude eliciting response was 16.4±8.3dB. The positive response rate was 89.1%.
In 33 children aged 4-6yrs, a positive response was detected in 40 ears (60.6%): 14 of 16 ears (87.5%) in 6-year-olds, 16 of 34 ears (47.1%) in 5-year-olds, and 10 of 16 ears (62.5%) in 4-year-olds, with the lowest positive response rate in children aged 5yrs. The mean duration of patency was 265.9±151.5msec, and the amplitude 15.4±7.5dB.
The above subjects were divided into 4 groups according to amplitude, A (21dB or higher), B (11dB-20dB), C (10dB or lower) and D (no response), and the results were compared between adults and children in each group. The duration of patency was approximately 80msec longer in adults in group A, which seemed to be accounted for by the difference between adult (muscular open type) and juvenile (pressure open type) eustachian tubes.
