A comprehensive study of Eustachian tube function in 84 aspirants accepted for flight training was made. Using a pressure chamber, both static and dynamic pressure changes, as in ascent and descent, were applied to test the tubal pressure equilibrating capacity in the sitting position. While all 84 were otologically healthy, a wide range in the pressure equilibrating capacity was found--20% could not equilibrate static over- and underpressures of 10 cm H2O completely, 8% could not equilibrate at all during simulated descent, 3 subjects reported acute vertigo during simulated ascent in combination with high unilateral middle ear pressure. Asymmetry between ears of single subjects in pressure equilibrating capacity was also found to a large extent. It was not possible to identify subjects with poor equilibrating capacity by simple tests like Valsalva's or Toynbee's manoeuvres. The results may indicate that today's criteria for Eustachian tube function in the selection of airmen can be made more efficient.

Adolescent↗

PubMed1980

Current status of pressure chamber treatment.

Forty-five patients with unilateral and one patient with bilateral Meniere's disease were exposed to underpressure in a pressure chamber during an acute attack that was primary in 24 and recurrent in 23. The patients were instructed to avoid active equilibration during reduction of the pressure, in order to induce an overpressure in the middle ear. Treatment was promptly followed by improvement of hearing in 20 patients (21 ears) and by a remission for more than three years in seven cases. No side effects were observed. We therefore believe that this procedure may be useful in the prevention of damage to the cochlear hair cells with secondary permanent loss of hearing.

Atmospheric Pressure↗

PubMed1979

Hearing improvement in attacks of Meniere's disease treated with pressure chamber.

A method to reduce endolymphatic pressure by exposing patients with Meniere's disease to underpressure has earlier been described. In this work the possible mechanisms are discussed. A material of 36 patients with acute attacks, treated in this way, is now presented. 15 out of these patients experienced a rapid hearing improvement. In 11 cases the remission has lasted for more than 1 year. The method seems to be of great value for those who improved, since at least an early permanent damage to the cochlea can be avoided.

Atmosphere Exposure Chambers↗

PubMed1979

Comparison of the hearing threshold measured by pure-tone audiometry and by Békésy sweep audiometry.

The hearing thresholds of 115 subjects, workers in a shipyard, were determined both by Békésy sweep audiometry and by conventional individual pure-tone audiometry at fixed audiometric frequencies. The Békésy method gave the lowest values for the hearing thresholds. It has been possible to find a useful linear relation between pure-tone and Békésy hearing thresholds. With the help of a retest experiment it has been established that the standard deviations of hearing thresholds, obtained under similar conditions in a pure-tone investigation, are about twice as large as those obtained in a Békésy investigation.

Adult↗

PubMed1979

Comparison between stationary and personal noise dose measuring systems.

In most of the investigations which have been made to survey occupational noise, a stationary sound level meter has been used either alone, or in combination with a stationary dosimeter. In this investigation, which was performed in a ship-building yard, an ear-borne noise dosimeter has been used. The Leq values which were obtained have been compared with those of the pocket-borne dosimeters. In many processes, considerable differences exist between pocket-borne and ear-borne dosimeters.

Acoustics↗

PubMed1979

Comparison of the hearing threshold measured by manual pure-tone and by self-recording (Békésy) audiometry.

The hearing threshold of 115 subjects aged 25--63 years and working on a shipyard were determined both by Békésy sweep audiometry and by conventional manual octave pure-tone audiometry at fixed audiometric frequencies. The attenuation rate was 2.5 dB s-1 with pulsed-tone presentation and the sweep time from 0.25 to 10 kHz was 400 s for the Békésy audiometer. Manual pure-tone audiometry was performed in 5-dB steps. The Békésy method gave the lowest values for the hearing thresholds. It has been possible to find a useful linear relation between pure-tone and Békésy hearing thresholds. With the help of a retest experiment, it has been established, that the standard deviations of hearing thresholds obtained under similar conditions in a pure-tone investigation are about twice as large as those obtained in a Békésy investigation.

Adult↗

PubMed1979

Congenital dilatation of the distal part of the common bile duct.

Explore the source record for details and available documents.

Cholangiography↗

PubMed1977

Eustachian tubal function during immersion.

The effects of head-out immersion on active and passive middle ear pressure equilibration were studied in three otologically normal scuba divers. Results were compared with the equilibration capacity recorded in the nonimmersed sitting and supine positions. Head-out immersion had only a minor effect on the ability to equilibrate the middle ear pressure actively during descent; passive ear clearing during ascent was slightly more difficult compared with this capacity in the sitting nonimmersed position. In the supine position ear clearing was significantly more difficult during both ascent and descent, which indicates that it is preferable to assume an upright body posture during exposures to pressure changes in dry pressure chambers. Mechanisms that might influence the ability to equilibrate the middle ears are discussed.

Adult↗

PubMed1976