先端に窪みを有するナイロン製 ゾンデによるSchallsonde法の研究*
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概要
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A nylon bar, with the head notched to make easy adequete contact with the short process of the malleus, was used for an acoustic probe.The first part of this paper deals with the acoustic properties of the nylon probe in comparison with those of a piano wire probe and a silver wire probe. The following results are obtained :(1) Clinically the most suitable length of the nylon probe was 8cm.(2) The nylon probe proved to be capable of transmitting undistorted wave forms of test pure tones at the intensity level necessary for clinical measurment at the frequencies of 500, 1000, 2000 and 4000cps. Amplitude of the output through the nylon probe was a linear function of the intensity of input signals.(3) The intensity of the output through the nylon probe was kept almost constant to the test signals of 500, 1000, 2000 and 4000cps, when the fixing pressure of the nylon probe was in the range between 0.02gr and ibgr.(4) The nylon probe with a notched head showed the best fixation with the short process of the malleus in a corpse as compaired to the piano and silver wire probes.(5) When auditory threshold was measured at the short process of the malleus in a normal subject by the acoustic probe audiometry, the nylon probe showed more reliable values than the other probes.The second part deals with the clinical appli. cation of the acoustic probe audiometry with this nylon probe. A total of 82 ears with middle ear involvements were measured before surgical treatment. Auditory threshold test was carried out by fixing the notched head of the nylon probe at the short process of the malleus.The following results are obtained:(1) It was concluded that the ossicle hearing loss of less than 21db should be indicative of the existence of the normal ossicular chain, more than 25db indicative of interruption of the ossicular chain, whereas the ossicule hearing loss from 22db to 24db would indicate no definite pathological change in the ossicular chain.(2) Function of the ossicular chain might be represented by the value of auditory threshold measured by the nylone probe at the short process of the malleus, (3) It is not possible by the present test to detect the existence of the slightly interrupted ossicular chain, in which conductive connection was maintained to some degree by granulations.(4) The ossicle hearing loss was elevated with an increase in the degree of stapes fixation, however, very slight stapes fixation shown by slight negativity of Tsunodas liquid conduction test could not be identified by the nylon probe audiometry.
- 社団法人 日本耳鼻咽喉科学会の論文