Place: 4274 Chamberlin Hall (Refreshments will be served)
Speaker: Jack Jiang, UW Department of Surgery
Abstract: Vocal fold vibration is key for human speech and communication. This vibration is driven by airflow and can be regular, irregular, or chaotic. Our study focuses on in what conditions vocal fold vibration will be regular or irregular. Many voice disorders, such as lesions or paralysis, can lead to irregular voice. We can surgically intervene to restore healthy and more regular vibration. We also use acoustic parameters, such as perturbation analysis (jitter and shimmer) and nonlinear dynamic analysis (correlation dimension, second order entropy, and Lyapunov exponents), to describe the irregularity of voice production. Clinically, these chaotic parameters show discriminatory power for pathological voice. Typically, we classify four types of voice: Type 1 (nearly periodic), Type 2 (contains strong modulations or subharmonics), Type 3 (aperiodic), and Type 4 (predominated by stochastic noise characteristics). The challenge is that when the voice has too much turbulence the degree of freedom approaches infinity. Such voice is difficult to quantitatively describe.