非线性动力学方法研究声门下压对离体狗喉声音质量的影响

The Voice Effects of Sub-glottal Pressure in Excised Canine Larynx using Nonlinear Dynamics Method

目的探讨声门下压(sub-glottal pressure,SGP)变化与离体狗喉声音质量变化之间的关系及非线性动力学和扰动分析方法在区别发声信号中的作用。方法收集6只离体狗喉分别在SGP为2kPa和4kPa时的发声信号,分别采用非线性动力学方法和扰动分析方法进行分析,比较非线性动力学指标:相空间重构、关联维D2及扰动分析方法指标:频率微扰(jitter)、振幅微扰(shimmer)、基频(F0)、噪谐比(NHR)对SGP变化的敏感性。结果在SGP为4kPa时离体狗喉发声信号的相空间重构较SGP为2kPa时复杂,在SGP为4kPa时离体狗喉发声信号的D2和F0较SGP为2kPa时高,差异有统计学意义(P<0.05),在SGP为4kPa时离体狗喉发声信号的jitter、shimmer和NHR较SGP为2kPa时低,差异有统计学意义(P<0.05);60次声学信号中有21次因不能提取稳定频率无法使用扰动方法进行分析,其中,SGP为4kPa时16次,SGP为2kPa时5次,差异有统计学意义(P<0.05)。结论在SGP为4kPa时离体狗喉的声音质量较SGP为2kPa时更好;离体狗喉发声信号的不规则性与SGP大小有关;非线性动力学方法分析声学信号较扰动方法更具敏感性。

Objective To investigate the relationship between voice quality and sub--glottal pressure （SGP） in excised canine larynges by nonlinear dynamic method and perturbation. Methods Perturbation measures of ）itter percent, shimmer percent, fundamental frequency（F0） and noise harmonic ratio（NHR）, nonlinear dynamic meas- ures of phase space reconstruction and correlation dimension （D2） were applied to analyze the voice from the study including six excised canine larynges under 2 kPa and 4 kPa sub--glottal pressure. Results There was a significant difference between 2 kPa and 4 kPa sub--glottal pressure in D2, jitter, shimmer, F0 and NHR （P〈0.05）. Howev- er, 21 in 60 voice signals could not be analyzed by perturbation methods, there was a significant difference in percent defective of analysis when SGP was 4 kPa and 2 kPa （P〈0.05）. Conclusion The voice quality when SGP was 4 kPa may be better than that when SGP was 2 kPa. The regulation of voice signal was relevant with SGP in the ex- cised canine larynx. Nonlinear dynamic methods was applied more sensitive than perturbation methods for voice a- nalysis.