Acta oto-laryngologica
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Acta oto-laryngologica · Mar 1993
The otolithic organ in the developing chick embryo. Scanning electron microscopic study on the utricular macula.
The long and short axes of utricular maculae were measured to calculate growth curves using an ocular micrometer under stereomicroscope. The mean lengths of the long and short axes on the 6th incubation day were 0.06 mm and 0.05 mm, respectively. Thereafter: 1.00 mm and 0.74 mm on the 11th incubation day; 1.34 mm and 1.03 mm on the 15th incubation day; and on hatching 1.51 mm and 1.07 mm, respectively. ⋯ Immature otoconia were first seen on the 6th incubation day. Mature otoconia were recognized on and after the 11th incubation day, and they were observed on the whole surface of the utricular maculae. Global substances on the macula with a rough surface and spongy structure were observed suggesting otoconial precursors transforming themselves into otoconial crystals.
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We report on a new method of stimulating the facial nerve through Stensen's duct. Electrical resistance of the skin and subcutaneous tissue is one of the major problems of neurophysiological facial nerve testing. ⋯ The NET, ENoG, and antidromic facial nerve responses are recordable at less than a third of the current required for conventional percutaneous stimulation. It is our belief that nerve stimulation through Stensen's duct will be a new and useful method for assessing facial nerve dysfunction in the early stage of palsy.
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Acta oto-laryngologica · Jan 1992
Threshold shift, hair cell loss, and hair bundle stiffness following exposure to 120 and 125 dB pure tones in the neonatal chick.
One-day old chicks were exposed to one of two pure tone stimuli (0.9 kHz at 120 or 125 dB SPL) for 48 h. Three major results arose from a variety of tests that assessed the structural and functional consequences of the exposure on the peripheral auditory system at either 0 days or 12 to 15 days recovery. First, brainstem response data showed that the 120 and 125 dB groups had maximum evoked potential threshold shifts of 57 and 71 dB immediately after removal from the sound. ⋯ Second, scanning electron microscopic measurements of hair cell density within the lesion showed that at 0 days recovery, the 120 and 125 dB groups had a 30% and 59% short hair cell loss, respectively, but by 15 days no differences could be identified between the exposed and control animals, regardless of exposure level. Finally, at 0 days of recovery, micromechanical stimulation data did not reveal any significant difference in stiffness between the control and surviving hair cells in the lesion area. Although the more intense exposure induced greater structural and functional damage in the chick cochlea, the birds retained or even enhanced their ability to replace lost hair cells and had partial hearing recovery by 15 days post-exposure.
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Acta oto-laryngologica · Sep 1987
Influence of altered middle ear pressure on cochlear microphonics.
Patients with otitis media with effusion often have impaired hearing loss caused by bone conduction. Among several possible causes for this hearing loss, the influence of middle ear pressure upon hearing was examined. Cochlear microphonics (CM) of guinea pigs were recorded under positive or negative pressure created simultaneously in the middle ear and in the external ear canal. ⋯ Whereas under negative pressure CM decreased suddenly but soon became stable, under positive pressure CM normalized gradually after the initial drop. Thus, in the stable state, CM amplitude was low under negative pressure but was slightly subnormal under positive pressure. One possible explanation is that perilymphatic efflux appears to cause such recovery of CM under positive pressure. it is postulated that perilymphatic inflow does not seem to occur under negative pressure, since CM and perilymphatic pressure were stable.
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Acta oto-laryngologica · Mar 1985
The meaning of life-threatening disease in the area of the head and neck.
The revelation that one has a life-threatening disease creates a sentient flood of emotions that infuse the patient with fear, confusion and depression. It contains the spectrum of pain, suffering, deterioration of life-style, crippling and possible annihilation. ⋯ The ongoing process is the most dynamic encounter of being alive, and before it is finished will have used and drained a large percentage of the vulnerable emotions that identify our humanness. An overview of these involvements as they relate to the area of the head and neck shows how complex the process has become, the remoteness of its solution and the truth of its experience.