Seventeen cases of postinflammatory acquired artresia of the external auditory canal in 14 women are described and analysed. Fourteen of these cases were solid atresias in which the auditory canal was more or less filled with fibrous tissue. Three patients had partial membranous atresia. The aetiology was external otitis and/or chronic otitis media. The formation of atresia is usually by jerks, and its steps are as follows: External otitis with destruction of the epithelium, formation of granulations, fibrosing of the granulations, and lining with new meatal skin.

Adult↗

PubMedDate not supplied

Middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation.

Changes in middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation were studied in 47 patients who had been intubated, for various reasons, during 1-24 days. All the patients had a negative middle ear pressure; in 84% of the ears the pressure was -200 mm of water or less. In most ears the pressure fell rapidly after the intubation, being most negative before extubation and during the first 2 days after. In all patients who could be followed the pressure returned to normal. The normalization was slow, depending upon the duration in intubation. Possible causes, such as abolished ventilation of the rhinopharynx, insufficient swallowing, mechanical occlusion of the tubal orifice, and the influence of anaesthetic gases are discussed. During the period after extubation the most probable cause is irritative and inflammatory reaction of the mucosa, leading to internal tubal occlusion.

Adult↗

PubMedDate not supplied

Middle ear pressure during brief pathological conditions of the nose and throat.

Middle ear ventilation was investigated by repeated tympanometry in different groups of patients with impaired air current in the upper airways. Among patients with total blocking of the nose by bilateral anterior packing, 46% had a negative pressure of -100 mm H2O or less, which quickly returned to normal after removal of the packing. Unilateral anterior packing produced no significant changes in middle ear ventilation. Unilateral posterior packing produced changes in 50% of ears, tonsillectomy in 60% of ears, amounting to a negative pressure of -100 mm H2O or less. Patients with infectious mononucleosis showed the poorest middle ear ventilation, 45% having pressure between -100 and -199, 45% between -200 and -350 mm H2O. Normalization of the pressure was very slow, but occurred in all cases after 2-4 weeks. The different pathogenetic possibilities, viz. direct occlusion of the tubal orifice, inflammatory mucosal reaction, insufficient swallowing, insufficient air current through the rhinopharynx, are discussed.

Acoustic Impedance Tests↗

PubMedDate not supplied

Experiments with a thinfilm multichannel electrode for cochlear implantation.

A series of experiments with a thinfilm multichannel cochlear implant is presented. A number of surgical difficulties at implantation on temporal bones were experienced. In vitro measurements of the electrode's technical properties revealed 1) large variations in the impedance, and 2) good separation between channels. From a theoretical point of view this complicated type of electrode is interesting, but a number of modifications are necessary before it may be used for implantation in man.

Biomedical Engineering↗

PubMedDate not supplied

Critical bandwidth in patients with a hearing loss induced by salicylates.

During a slight temporary salicylate-induced hearing loss, the normal loudness difference between broad-band noise and narrow-band noise was markedly reduced at all levels, except the highest. The critical band, measured at 1 kHz by means of a loudness summation method, appeared to become wider in 9 out of 16 subjects, to a degree roughly proportional to the degree of hearing loss. However, some discrepancies in the data and a rather large intersubject variability of the loudness estimates were present. The localization of the mechanism which forms the basis for the critical band concept is discussed in view of the results.

Acoustic Stimulation↗

PubMedDate not supplied

Critical bandwidth in Menière's disease.

The critical bandwidth in loudness summation was estimated in 20 patients with typical Menière's disease using noise bands centered around 1 kHz. A reduction of the normal loudness difference between broad-band noise and narrow-band noise was present at all except the highest levels. Judged individually, 7 of the 20 patients appeared to have a widened critical band, but in the pooled data the size of the critical band was normal. This was the case in patients with a hearing loss less than 50 dB HL as well as in patients with a hearing loss greater than or equal to 50 dB HL. Expressed in terms of the critical band mechanism as an internal filter system, the single filter appears to have normal bandwidth but the interaction between adjacent filters is defective. The anatomical localisation of this interaction is discussed.

Acoustic Stimulation↗