Development of Objective Nasometer Using a Vibratory Sensor and its Clinical Application

진동 센서를 이용한 객관적 비강공명 측정 장치의 개발 및 그 임상적 이용

Authors devised an objective test for nasal resonatory disorders using a vibratory sensor(Piezoelectric receiver) which is relatively cheap. The vibratory sensor was covered with duralumin to eliminate contamination of acoustic sound except a small hole which is attached on ala nasi during the test. Electrical signals front the vibratory sensor and the microphone while the subject is phonating vowel/a/ and nasal consonant /ng/ and phonating 8 syllable sentence /papa/ passage and /mama/ passage were digitized with n 12 bit A/D converter. For the evaluation of the hypernasality, the ratio of /ng/ to /a/ and /mama/ passage to /papa/ passage were used instead of individual values to reduce the observational error. For the evaluation of the hyponasality, the cul-de-sac resonation was induced by obstructing the nasal aperture of the ipsilateral side with the finger. In the normal control group, the ratio of /ng/ to /a/ and /mama/ passage to /papa/ passage was larger than 8. In the hypernasality with nasal emission group. the ratio was decreased markedly(p＜0.01). When the nasal aperture was obstructed with the finger, the vibratory signals of /a/ and /ng/ were increased markedly in the control group and hypernasality group(p＜0.01). However, in the hyponasality group(severe), the increment was minimal. So this system can be used to detect the nasal resonatory disorders objectively and differentiate the hypernasality front hyponasality easily.