Abstract
Among 72 patients who were subjected to the laryngectomy in the department of otorhinolaryngology of Kyushu University, 67 cases used the artificial larynx. The statistical observation of the state of application and the frequency analytical studies of speaking by the artificial larynx were studied with the following results.
1) In the vocalisation of laryngectomized patients, 67 cases (93%) used the artificial larynx, and 5 cases (6.9%) the esophageal voice.
2) On the state of mutual understanding in the artificial larynx 25 cases among 67 suffered no inconvenience in everyday life, and 11 cases lacked in understanding.
3) On the term of becoming proficient in simple conversation by the artificial larynx, 44.8% was within 5 days, 31.3% 6 to 10 days and 76.1% within 10 days.
4) 33 cases in the artificial larynx used Tapia type, however, the materials of these constitu- tion were great variety and the vibrating membrane used rubber.
5) The direct relation between the method of operation and the proficiency of pronounciation by the artificial larynx was not observed. 6) In the examination of articulation score in pronounciation, articulation was good at the vowel and pronounciation (wa), and was worse at the “Ha” series, even in the man of experien ce, no improvement was shown.
7) On the comparative studies of artificial larynx with a normal voice by the frequency an alyser, the field of overtone reduced in the artificial larynx compared with the normal, and the formant which characterize the vowel made indistinct. This may be one of reasons that the voice of artificial larynx is not clear, has dry tone, and feel in a monotone.
8) The author examined the variation in the voice by changing the component parts of the artiftcial larynx. The examination revealed that the overtone in the high frequency range increas- ed if the mouth piece was short, and that the overtone in the low frequency range increased if the connecting tube was long.
It also revealed that the overtone increased when the tension of the rubber membrane was small and when the hole in the voice box was large. The variation in the overtone due to the width of the tracheal edge and to the material of the atrificial larynx was not perceivable.
