The Study of Electropalatographic patterns in Cleft Palate Patients

Yang, Sang Il; Shin, Hyo Keun

Abstract

Speech characteristics of cleft palate have been reported previously by hypernasality disorders. However, some cleft palate patients suffered from articulation disorders although they were taken surgery at an early time. Misarticulations of cleft palate patients are caused by abnormal lingual-palatal contacts. Traditionally, the Palatograpy has been used to see the lingual-palatal patterns. However, on this study, the Electropalatography(Palatometer) was used to investigate the comparison with lingual-palatal patterns between normal adult and cleft palate adult. The Nasometer model 6200-3 was used separately to measure the nasalance for cleft palate patient. The acoustic characteristics of cleft palate patients with respect to the palatographic patterns were examined by Computerized Speech Lab(IBM). The dental reflector was applied to measure the nasal airflow when cleft palate patient uttered. Test words were composed of meaningless mono syllabic words VCV (V: low center vowel /a/, C: alveolar stop, velar stop, affricate, fricative and lateral sounds). The subjects repeated the test words 10 times for statistic analysis. As a result of the palatographic patterns and the burst durations for stop consonants and the durations for fricative consonants, the cleft palate patients showed broader contact area, longer burst durations and fricative consonant durations than normal. It means that the cleft palate speech showed more tenseness of consonants than normal. By palatographic patterns, the misarticulation of cleft palate patient showed as follows : (1) Lingual-palatal contact of alveolar stop showed the palatalized misarticulation. (2) Lingual -palatal contact of velar stop moved forward in comparison with normal. However, posterior lateral contact areas were broader than normal contact area. (3) Lingual-palatal contact of affricate moved backward with narrower constriction than normal. (4) Fricative consonant showed lateral misarticulation.