蝸電図よりみたヒト聴器の加令現象
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概要
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The present study was designed to investigate the spontaneous process of aging in human hearing ability in terms of changes in endocochlear potentials. Electrocochleography was performed on 50 patients with normal ability of hearing between the ages of 14 and 84. The transtympanic leading method was employed and the endocochlear potentials (action potential, summating potential and cochlear microphonics) were recorded. The correlation between the measurement results and the age was investigated. The mean values of the individual parameters were calculated in each of the following age groups: 10-19, 20-29, 30-39, 40-49, 50-59 and 60-69 years old; and examination was made on whether or not significant differences were observed between these values.The AP amplitude responding to click stimulation decreased significantly with age, while the AP threshold significantly increased and the latency of AP was significantly prolonged. The SP amplitude was significantly reduced and the SP/AP ratio increased only slightly with age. The CM amplitude responding to pure tone burst significantly decreased, the CM threshold being significantly elevated with age.As a result, the following conclusions were obtained:(1) The changes in the inner ear are induced by the damage of the hair cells and nerve fibers mainly associated with the cochlear basal turn.(2) The increment in the threshold responding to pure tone-burst was caused by, at least, the damage of the inner ear and the first neuron.(3) The damage described in the above (1) and (2) occurs in the fifth decade of life and further progresses in the seventh decade.
- 耳鼻咽喉科臨床学会の論文