耳栓骨導の研究
スポンサーリンク
概要
- 論文の詳細を見る
The author studied the resonance effect of the external auditory canal on bone conduction hearing by connecting glass tubes of different length to the canal respectively.The resonance effect on B.C. hearing resulted in a threshold shift only when the glass tube is more than 3c m in length.Bekesy reported that the resonance of the mandibular joints caused an increase of bone condu- ction hearing at about 200cps.when the external auditory canal was occluded.According to his opinion the peak of B.C.hearing at 200cps.is due to resonance of the mandibule.Then the aut- hor tested blocked B.C.hearing of three patients whose mandibules were missing because of surgery and found the same resonance peak at 200cps.in their B.C.hearing when the external auditory canal was blocked.Therefore, Bekesys theory of the blocked B.C.should be corrected.In order to study the mechanism of the blocked B.C., the author measured by a probe tube blocked and when it opened, and found increased pressure about 10 to 20db in a freguency range of 200 to 1500cps.in the former than the latter.Such an increased pressure was found also in the blocked external auditory canal of the patient with middle ear disease.In addition the author could hear the tone through an otoscope connected to the subject ear canal when a B.C.vibrator was placed on the mastoid process, and compared the loudness heared by the examiner to the B.C.threshold of the subject.Interesting results were obtained in this study.