Acta oto-laryngologica. Supplementum
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Meniere's disease can only be studied in patients, since it does not occur spontaneously in animals nor can it be induced in them. However, aspects of the disease such as endolymphatic hydrops can be usefully studied in animals. A study of the natural history (epidemiology) of Meniere's disease demonstrated the three major symptoms (triad) to be vestibular symptoms, auditory symptoms, and aural pressure. ⋯ Longitudinal flow, however, appears to be more important than radial flow, especially in advanced Meniere's where perilymph in the scala vestibuli and vestibule disappears and is replaced by membranous labyrinth. Meniere's disease (idiopathic) and Meniere's syndrome (cause known) probably occur as a result of endolymphatic absorptive dysfunction (the site being endolymphatic duct and sac). Hypocellularity of the mastoid and periaqueductal air cells, hypodevelopment of Trautmann's triangle, and anterior displacement of the lateral sinus are likely to be important findings associated with developmentally dysfunctional absorption of endolymph.(ABSTRACT TRUNCATED AT 400 WORDS)
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Acta Otolaryngol Suppl · Jan 1984
Implanted material tolerance studies for a multiple-channel cochlear prosthesis.
We have performed a number of temporal bone and animal studies in order to evaluate the histopathological effects of intracochlear electrode implantation and chronic electrical stimulation. Our results indicate that (a) the insertion of a free-fit scala tympani array results in minimal damage to the membranous labyrinth; (b) the materials used in the electrode array evoke mild tissue reactions when implanted subcutaneously, in muscle, or within the scala tympani; (c) intracochlear electrical stimulation for periods of 500 to 2000 hours, using carefully controlled biphasic pulses, does not adversely affect the population or neural activity of the primary auditory neurones; (d) labyrinthine infection severely reduces the number of viable spiral ganglion cells; (e) an adequate fibrous tissue seal of the round window can prevent the spread of infection from the bulla to the implanted cochlea in cats, following inoculation of the bulla cavity with bacteria; (f) bone growth is not associated with electrical stimulation per se; (g) the electrode arrays show minimal platinum dissolution and no apparent degradation of the Silastic carrier following periods of long-term intracochlear electrical stimulation.
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Acta Otolaryngol Suppl · Jan 1984
Benign paroxysmal vertigo in childhood. Diagnostic significance of vestibular examination and headache provocation tests.
Sixteen children with benign paroxysmal vertigo (BPV) are presented. The great majority had a family history of migraine, neurological and autonomic signs associated with vertiginous attacks, and headache or other sign of the periodic syndrome (motion sickness, cyclic vomiting, abdominal pain) unrelated to the attacks. ⋯ Headache provocation tests with nitroglycerin, histamine and fenfluramine were positive in 9 of the 13 patients examined, and in 4 cases induced a typical vertiginous attack instead of headache. BPV can be considered a migraine precursor or a migraine equivalent, attributable to the same vascular and/or biochemical disturbances responsible for migraine.