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During injection of artificial endolymph into scala media of the guinea pig, fluid pressure was simultaneously measured in endolymph and perilymph with micropipettes. Pressure differences in the order of 10 Pa could reproducibly be measured upon injection of 2-4 microl of artificial endolymph with a rate of 50 nl/s. Injection of larger volumes damaged the(More)
The inner ear fluid pressure was measured in scala media of the guinea pig through one barrel of a double-barreled micropipette after a sudden volume increase or decrease, caused by injection or withdrawal of artificial endolymph through the other barrel. During injection or withdrawal, the inner ear pressure changed in the order of 1-10 cm water, but it(More)
The aim of this study was to reinvestigate many of the claims in the literature about hearing loss in patients with Menière's disease. We carried this out on a well-defined group of patients under well-controlled circumstances. Thus, we were able to find support for some claims and none for many others. As part of a diagnostic protocol, pure-tone and speech(More)
In this study, short latency vestibular evoked potentials (VsEPs) were recorded in five guinea pigs in response to alternating linear acceleration pulses with and without acoustic masking. A steel bolt was implanted in the skull and coupled to a shaker. Linear acceleration pulses (n = 400) in upward, downward or alternating directions were given, with a(More)
The superior colliculus (SC) or optic tectum of mammals consists of seven layers, numbered I-VII from superficial to deep, each of which has distinct connectivity patterns and electrophysiological response properties. The present study is devoted to a morphometrical analysis of neuronal diameters, densities, and numbers in different layers and regions of(More)
OBJECTIVE To describe the current ideas about the manifestations of neural plasticity in generating tinnitus. DATA SOURCES Recently published source articles were identified using MEDLINE, PubMed, and Cochrane Library according to the key words mentioned below. STUDY SELECTION Review articles and controlled trials were particularly selected. DATA(More)
The MMS-10 Tympanic Displacement Analyser (TDA) is a new device to measure the perilymphatic pressure of the human inner ear in a non-invasive way. In this study, the instrument was used in 50 normal hearing subjects (100 ears) in three different conditions: i) sitting upright and supine; ii) in the morning and afternoon; iii) before and after physical(More)
OBJECTIVE To evaluate cortisol and catecholamine levels in patients with Ménière's disease. STUDY DESIGN Prospective, controlled study. SETTING Tertiary referral center. PATIENTS Thirty patients with Ménière's disease and 18 healthy controls. MAIN OUTCOME MEASURES Serum and saliva cortisol, serum cortisol after the dexamethasone suppression test,(More)
The early ultrastructural changes of the organ of Corti in the guinea pig after obliteration of the endolymphatic sac and duct were examined in a time-sequence study. Initial loss of outer hair cells was followed by inner hair cell degeneration, both starting at the apical part of the cochlea. Morphological changes of the sensory cells were found to start(More)
When guinea pigs are deafened with ototoxic drugs spiral ganglion cells (SGCs) degenerate progressively. Application of neurotrophins can prevent this process. Morphological changes of rescued SGCs have not been quantitatively determined yet. It might be that SGCs treated with neurotrophins are more vulnerable than SGCs in cochleae of normal-hearing guinea(More)