Cases reported "Deafness"

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1/14. Fractionation of visual memory: evidence from a case with multiple neurodevelopmental impairments.

    It is known that the adult visual memory system is fractionable into functionally independent cognitive subsystems, selectively susceptible to brain damage. However, it is unclear whether these cognitive subsystems can fractionate developmentally. The present study describes an investigation of visual memory of a patient (PE) with multiple developmental disorders. PE was congenitally deaf, had Gilles de la tourette syndrome and autism, with non-verbal ability in the normal range. The patient presented with a recognition memory impairment for unknown human faces. This contrasted with his superior recognition memory for unknown buildings, landscapes and outdoor scenes. PE's memory impairment for faces could not be explained by a general deficit in face processing. Interestingly, PE also showed a recognition memory impairment for animals. These findings indicate that different domains of the visual memory system can be fractionated developmentally. In particular, it demonstrates that topographical memory can develop independently from other aspects of visual memory.
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keywords = animal
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2/14. The ototoxic effects of ethacrynic acid in man and animals.

    A review of the literature was carried out to summarize the ototoxic effects of ethacrynic acid on man and animal. The effects of this drug on the electrolytes of the endolymphatic and perilymphatic systems, on the cochlear potentials and the auditory cortical-evoked responses, were reviewed. Histological animal studies determined by light and electron microscopy were described. Potentiation of this drug with previous aminoglycoside therapy was discussed. In this paper, a human case report with temporal bone findings was present in addition to the histopathological effects of this drug which were shown in a series of animals receiving this drug over a period of time. Edematous and cellular changes in the stria vascularis, especially with animals receiving large doses of the drug, were described. No permanent alterations in the cochlear potentials resulted from the long-term therapy with ethacrynic acid.
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keywords = animal
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3/14. Histopathology and molecular genetics of hearing loss in the human.

    hearing loss is among the most common disabilities of man. It has been estimated that over 70 million individuals in the world are hearing impaired with pure tone averages greater than 55 dB. A genetic etiology is thought to be responsible for over half of early onset hearing loss and at least one third of late onset hearing loss. In this review, examples of the histopathology of the inner ear in known genetic syndromes in the human will be presented in order to provide a structural basis for understanding molecular mechanisms of development and maintenance in the inner ear, and to serve the essential function of validating the applicability of animal genetic models of hearing loss to the human condition.
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keywords = animal
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4/14. A histologic study of nonmorphogenetic forms of hereditary hearing impairment.

    It appears that many forms of syndromic and nonsyndromic hereditary hearing impairment are secondary to either neuroepithelial or cochleosaccular dysfunction. Making this distinction can be difficult in human temporal bone specimens; however, this added knowledge may ultimately provide prognostic and therapeutic information in hearing habilitation. Fundamental studies using animal models of different types of hereditary deafness may also prove useful in this respect.
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keywords = animal
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5/14. Are vestibular sensory cells preserved after destruction of Scarpa's ganglion? A study based on metastatic tumors of temporal bone.

    OBJECTIVE: The contribution of nerve fibers to the maintenance of vestibular sensory cells is a controversial issue in previous studies using animals and has not yet been studied in humans. The authors investigated this issue by observing vestibular end organs in the temporal bone of three patients in whom the internal auditory canal was infiltrated with tumor cells, and Scarpa's ganglion cells showed complete degeneration. STUDY DESIGN: Retrospective case review. SETTING: University Hospital, Department of otolaryngology. patients: Three patients with malignant metastatic temporal bone tumors. INTERVENTION: We investigated the preservative state of vestibular sensory hair cells with the Scalpa's ganglion was destructed. MAIN OUTCOME MEASURES: Maintenances of vestibular sensory hair cells. RESULTS: We found that sensory cells were intact despite the severe destruction of Scarpa's ganglion cells in two of the patients. CONCLUSION: The findings suggest that human vestibular sensory cells can be maintained for an indefinite period after denervation.
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keywords = animal
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6/14. Middle ear implantable hearing device: ongoing animal and human evaluation.

    The first five patients have been permanently implanted with an electromagnetic middle ear implantable hearing device. hearing tests were performed at the time of operation and at 8 weeks postoperatively with a coil held at the isthmus of the ear canal. All patients reported clear, high fidelity sound, as proven by speech discrimination scores. Improvements were seen in all frequencies, including 4,000 Hz. Improvement in pure tones as tested with an audiometer monitoring sounds amplified by a 3-V sound processor was as high as 50 dB sound pressure level. That which remains to be done is the final design of a compact, wearable sound processor with filtering and signal-processing capabilities to meet the needs of the sensorineural hearing-impaired population.
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ranking = 4
keywords = animal
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7/14. Histopathological features of the spiral ganglion and cochlear nerve in temporal bones from three patients with profound hearing loss.

    In the following study the condition of the spiral ganglion and the cochlear nerve of ears from patients suffering from profound hearing loss is described. The number of spiral ganglion cells has been related to the clinical diagnosis. The number of spiral ganglion cells in the two temporal bones of a patient with neomycin ototoxicity was almost normal. A reduction of less than one-third of spiral ganglion cells has been observed in the temporal bones of a child who died after a bacterial labyrinthitis. The temporal bone with a Mondini dysplasia revealed a pronounced reduction of ganglion cells of more than two-thirds. The cochlear nerve trunk in the internal auditory canal appeared normal in all three cases. The present findings are discussed in respect to the degenerative behaviour of the cochlear neural elements in human being compared to animals.
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keywords = animal
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8/14. The association of waardenburg syndrome and Hirschsprung megacolon.

    We describe four patients with waardenburg syndrome and Hirschsprung aganglionic megacolon. In view of pathophysiologic relationships and animal studies, we conclude that the association of these two uncommon disorders is pathophysiologically significant.
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keywords = animal
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9/14. Auditory deprivation--an intrinsic or extrinsic problem? Some comments on Kyle (1978).

    The relevance of animal work to early auditory deprivation, as discussed by Kyle (1978), is questioned. It is argued that auditory experience from birth, or even much later, is not necessarily required for subsequent hearing for spoken language. It is also questioned whether concern for intrinsic difficulties, such as possible cortical damage resulting from auditory deprivation, is appropriate. A more productive approach may be to pay more attention to the extrinsic aspect--the linguistically principled rehabilitation of the hearing-impaired child.
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ranking = 1
keywords = animal
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10/14. Electrophysiological and biochemical findings in four cases of Meniere's disease.

    In 4 cases of Meniere's disease, E.P., concentrations of Na, K, Cl, and protein, and osmolality were determined in endolymph from the basal coil of the cochlea. In 3 cases, endolymph was found normal in nature as compared with normal animals. In one long-standing (11 years) case, a strial dysfunction was evidenced. In 2 cases, the surgical treatment consisted in the mere withdrawal of endolymph. This resulted in the transitory aggravation of the hearing loss. This observation might suggest that, at the considered stages of the disease: 1) hearing loss is not related to the excess of fluid; 2) the rate of endolymph production averages 0.35 microliter per day; 3) the water displacement induced by the glycerol test concerns rather perilymph than endolymph; 4) any pharmacological or surgical therapy aiming at reducing the excess of endolymph is unlikely to succeed as far as hearing is concerned.
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keywords = animal
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