[Correlation between electrically-induced stapedius reflex and discomfort threshold in cochlear implant patients]. / Beziehung zwischen dem elektrisch ausgelösten Stapediusreflex und der Unbehaglichkeitsschwelle bei Cochlear-Implant-Patienten.

Electrically elicited stapedius reflex thresholds are an objective criteria for the fitting of speech processors in very young children. Reflex thresholds generally fit well within the upper third of a subject's individual dynamic range, the difference between electrical threshold of hearing, (T) and maximum comfort (C) levels and can be used to predict ultimate behavioral maximum comfort levels. In acoustically elicited stapedius reflexes a saturation of impedance amplitude can be registered at approximately 110 dB, which is 90% of the dynamic range. Assuming a similar relationship for the electrically elicited stapedius reflex there would be two values within the dynamic range which could be used for extrapolation of the threshold level. In the present study, the electrically elicited stapedius reflex was examined in 16 deaf patients who had received 22-channel Clark/NUCLEUS cochlear implants. Using an apical, a medial and a basal electrode pair, different stimulation positions within the cochlea were tested. The contralateral reflexes could be elicited in 11 patients (69%). A saturation of the reflex amplitude was recordable in 10 subjects, at least in one of the electrode pairs. The reflex saturation in all cases was located close to the uncomfortable loudness level within the subjects' dynamic ranges (at 95% dynamic). This finding is comparable to acoustic matter. As a result, these data together with reflex threshold data suggest a means for predicting to predict the threshold levels.

Kinetic experiments with radionuclides concerning the perilymph-blood barrier in a guinea pig model.

Since 1950 many animal radiotracer experiments have been performed to study inner ear kinetics. For the most part in these studies, radionuclides were applied systemically, following which a discontinuous probing of inner ear fluids or of inner ear tissues was done. Two techniques have been developed in the Section for Experimental Otorhinolaryngology of the University of Würzburg. These have been adapted to the direct and continuous measurements of inner ear efflux kinetics for several hour periods. For this purpose, only a tiny amount of radiotracer need be applied directly to the inner ear. Experiments were done on the anesthetized guinea pig as an animal model. In the first technique, a collimator-detector system is focused precisely on the cochlea, which had been quickly resealed after application of the radionuclide bolus via two small holes in the basal turn of the cochlea. The second technique makes use of a perilymph cycling system, whereby a small outer volume includes a microcuvette with a so-called artificial round window. By this latter cycling technique, perilymph clearance kinetics of all kinds of radiotracers--with the exception of tritium labelled ones--can be measured. Calculations from clearance kinetics show that quite small particles with particle weights up to 100, such as the chlorine anion and the potassium cation, as well as urea, glycerol, pyruvate, and lactate, exhibit perilymphatic half-lives varying from 45 to 60 min. These half-live data are plausible in regard to cochlear blood flow measured previously via an independent technique developed by Angelborg et al.(ABSTRACT TRUNCATED AT 250 WORDS)

Secretory otitis media and its sequelae in children living in charitable institutions.

Children living in two Brazilian institutions were studied otologically and audiologically. Group I comprised 100 children (52 males and 48 females) ranging from 1 year to 2 years and 5 months of age. Group II comprised 50 male children ranging from 4 to 14 years of age. Secretory otitis media was found in 31% of the children (22% of the male population and 9% of the female population) of group I. Suppurative otitis media (17%), perforation of ear drum (2%) and retraction of the ear drum (34% with middle ear pressure more negative than -100 mmH2O) were found in group I. Secretory otitis media (15 subjects, 30% of population) and permanent tympanic perforation (3 cases, 6% of the population) were observed among children of group II. All children under investigation showed delay of speech and language development that could not be correlated to hearing loss.

[Actinomycosis of the middle ear]. / Zur Aktinomykose des Mittelohres.

A recent patient with actinomycosis of the middle ear has stimulated us to call attention to this very rare disease. The differential diagnosis, pathophysiology, the pathways of spread, diagnosis and therapy of this disease are discussed. Combined therapy by antibiotics such as ampicillin with clindamycin is the best treatment currently available. Surgery is confined to taking a biopsy for histology and to the draining of inflammatory foci.