| Objectives:To establish a stable and reliable voice data collection methods. Thus, to provide a reliable basis for the study of the acoustic characteristics of children with cleft palate. The acoustic characteristics of glottal system and vocal system in alternative pharyngeal closure status were studied for screening reliable acoustic parameters to evaluate the velopharyngeal state. To study the energy distribution of cleft palate patients in sentences. The speech acoustic characteristics of cleft palate patients were fully explored. Discriminate function was established with application of multiple voice acoustic parameters by statistical analysis to evaluate velopharyngeal state. The application of the acoustic characteristics of speech analysis for evaluation of velopharyngeal state was studied preliminarily.Methods:1. Children with normal pronunciation and children with cleft palate were selected for the study. Intelligibility and nasality were evaluated by two listeners. The experiment was repeated to observe the stability and consistency of the two listeners. To compare the acoustic characteristics of speech across gender and age. To compare the difference of intelligibility, nasality and acoustic characteristics of speech between control group and clinical group. To study the relationship between intelligibility and nasality.2. Children with normal pronunciation, children with cleft palate, VPC and VPI children after cleft palate repaired were selected for the study. Sonagraph characteristics were observed. The formants (F1, F2, F3) of vowel/a/,/i/,/u/were analyzed for comparison of normal children and children with or without cleft palate repaired. Making acoustic vowel chart, the areas(S) of acoustic vowel triangle were compared between the normal children and children with or without cleft palate repaired. Comparison was also made between VPC and VPI patients.3. Jitter, shimmer, HNR, fundamental frequency (FO) and smoothed cepstral prominence peak (CPPs) were analyzed for comparison of normal children and children with or without cleft palate repaired. Comparison was also made between VPC and VPI patients.4. Energy distribution of vowel/a/,/i/,/u/was analyzed in each group. The energy distribution characteristics in statement were analyzed by long-term average spectra.5. Meaningful indicators (F2, F3, vowel triangle area, value of Jitter, HNR and CPPs) were selected to evaluate the state of velopharyngeal on preliminary results. Sensitivity, specificity and ROC curve of these indicators were analyzed. Discriminate function was established on these indicators. The states of velopharyngeal of20children with cleft palate surgery were analyzed by discriminate function.Results:1. Compared with normal children, children with cleft palate are significantly lower in speech intelligibility, and higher in nasality. There is a moderate negative correlation between nasality and intelligibility (r=-0.615). There is no significant difference in results of repeat test. The Intra-class Correlation Coefficient of the listeners is0.87(ICC=0.87). There is no significant difference across gender and age. F2, F3of vowel/i/of VPI group were significantly lower than those of the control group. The values of Jitter of children with cleft palate are significantly higher than those of control group. The values of HNR and CCPs of children with cleft palate are significantly lower than those of control group.2. The sonogram of children with cleft palate is mainly charactered by weakening, compensatory and replacement. There are no significant differences on the first formant of vowel/i/in each group. F2, F3of VPI group were significantly lower than the control group and VPC group. The VPI group was significantly lower than VPC group and control group on the value of S. And the value of S of VPC group was significantly lower than that of control group. The acoustic characteristics of children with cleft palate are similar to those of VPI children.3. There are no significant differences on the FO and Shimmer in each group. The values of Jitter of VPI group and VPC group are significantly higher than those of control group. The values of HNR and CCPs of VPI group and VPC group are significantly lower than those of control group.4. The centre of gravity, skewness and kurtosis of single vowel show no significant difference in each group. There is no significant difference in the low frequency zone (below2720Hz) about the energy distribution analyzed by long-term average spectra. There is an obvious platform in the intermediate frequency zone (2720Hz-4000Hz) in normal children. The energy in the high frequency zone (above4000Hz) of normal children was significantly higher than that of children with or without cleft palate repaired.5. The sensitivity and specificity are not ideal to evaluate the state of velopharyngeal by single acoustic parameters. The linear discriminate function is: Y=-15.635+0.682X1+2.982X2+0.023X3+0.589X4-0.066X5+0.035X6. The area under the ROC curve of discriminant function is0.951. The sensitivity is100%. And the specificity is82.9%. The value of Kappa is0.884. Consistency of20patients determined by the discriminate function is85%to the nasopharyngoscopy.Conclusions:1. There is a moderate negative correlation between nasality and intelligibility. The method to collect the data used in this study is reliable and stable. The children aged from6years to9years can be studied as one group.2. The F2, F3of vowel/i/and the value of S can be used to evaluate the state of velopharyngeal.3. The value of jitter, HNR and CPPs can be used to evaluate the state of velopharyngeal.4. The energy distribution of single vowel is similar in children with cleft palate and normal children. Normal children have higher energy distribution in the high frequency zone ascribe to the buffer of the platform in the intermediate frequency zone.5. It is less effective for single acoustic parameters to evaluate velopharyngeal state. It is more effective to evaluate velopharyngeal state by discriminate function integrated multiple parameters. |
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