Lyapunov exponents for Japanese vowels in normal adult and cleft palate speakers.

OBJECTIVE: The purpose of this study was to explore the possibility of using Lyapunov exponents (LE) to evaluate the voice and speech in cleft palate (CP) patients. SUBJECTS AND METHODS: Fifty healthy adults (25 males and 25 females) and 17 adult patients (10 males and 7 females) with repaired CP, who had no hypernasality, were enrolled. Five Japanese vowels were recorded at 44.1 kHz. Nasalance scores were measured simultaneously. The first LE was computed for each 1-second interval, and the mean for the first LE from all intervals (mLE(1)) was then calculated. The delay time and embedding dimension were estimated at 13, 40, 34, 27 and 22 points for the vowels /a/, /i/, /u/, /e/ and /o/, respectively, and at 8 points for all vowels. RESULTS: The mLE(1)s for all vowels did not differ between normal males and females. The mLE(1)s for /a/ were significantly higher both in males and females with CP than in normal individuals. The correlation coefficient between the mLE(1)s and nasalance scores for all vowels was not significant for both normal and CP subjects. CONCLUSION: The LE seemed to be related to pathological disorders of the vocal cords in CP patients, but was independent of resonance parameters.

Relationships between nasalance scores and nasopharyngeal shapes in cleft palate patients.

OBJECTIVES: The aim of the present study is to clarify the relationship between nasalance scores and nasopharyngeal shapes obtained by lateral cephalograms. PATIENTS: Eight patients who underwent a Wardill-Kilner push-back palatoplasty were included in this study. Perceptual judgment by a speech pathologist indicated that these patients had no hypernasality and no nasal emission at blowing. As normal controls, 33 non-cleft individuals, 4 boys and 10 girls aged 6 years old and 5 boys and 14 girls aged 7 years old, were investigated. METHODS: Lateral cephalograms at rest were taken for both groups. For the cleft (palate) patients, lateral cephalograms at phonation /a/ and blowing were analyzed and nasometries were also performed using a kitsutsuki passage. RESULTS AND CONCLUSION: There was no significant difference in the velar length, the pharyngeal depth, the ratio of the velar length to the pharyngeal depth and the velar angle between the cleft patients and the non-cleft individuals. Multiple regression analyses indicated that standardized regression coefficients of ratios for the velar length to the pharyngeal depth and the velar ascent at blowing had higher nasalance scores for sentences 1 and 3, which had high coefficients of determination, respectively.

Dialectal and gender differences in nasalance scores in a Japanese population.

OBJECTIVES: The aim of the present study was to determine whether there are dialectal and gender-related differences in nasalance scores for normal Japanese speakers. MATERIALS: Sixty-eight volunteers consisting of 31 males (age 23.8+/-2.0) and 37 females (age 23.2+/-2.5) were included in this study. They had no diseases affecting speech, and lived in the same region until high school from birth. According to geography, they were divided into four regional groups: Chugoku region, Kinki region, Shikoku region, and other regions. METHODS: A kitsutsuki passage, which consisted of Japanese non-nasal consonants and vowels, and the Japanese vowels /a/, /i/, /u/, /e/ and /o/, were read three times, and the mean nasalance scores were then obtained with a Nasometer II 6400. The scores of males and females were compared statistically by means of a Student's t-test. The differences among the three regions, Chugoku, Kinki and Shikoku region, were also investigated by means of a one-way analysis of variance (ANOVA). RESULTS AND CONCLUSION: For all sentences and vowels, the nasalance scores were significantly different between males and females. The one-way ANOVA showed that there were no significant differences among the three regions in both males and females.