The addition of a fourth type of voice to Titze's voice classification scheme is proposed. This fourth voice type is characterized by primarily stochastic noise behavior and is therefore unsuitable for both perturbation and correlation dimension analysis. Forty voice samples were classified into the proposed four types using narrowband spectrograms. Acoustic, perceptual, and correlation dimension analyses were completed for all voice samples. Perturbation measures tended to increase with voice type. Based on reliability cutoffs, the type 1 and type 2 voices were considered suitable for perturbation analysis. Measures of unreliability were higher for type 3 and 4 voices. Correlation dimension analyses increased significantly with signal type as indicated by a one-way analysis of variance. Notably, correlation dimension analysis could not quantify the type 4 voices. The proposed fourth voice type represents a subset of voices dominated by noise behavior. Current measures capable of evaluating type 4 voices provide only qualitative data ͑spectrograms, perceptual analysis, and an infinite correlation dimension͒. Type 4 voices are highly complex and the development of objective measures capable of analyzing these voices remains a topic of future investigation.

Objective: We aim to examine the abilities of objective acoustic analysis methods (nonlinear dynamic and traditional perturbation measures) to describe voices from individuals with vocal nodules and polyps. Subjects and Methods: Sustained vowel recordings from normal subjects, patients with vocal nodules, and patients with vocal polyps were analyzed. Perturbation measures of jitter and shimmer were obtained with the Multi-Dimensional Voice Program (MDVP) and CSpeech. Signal-to-noise ratio was calculated using CSpeech. Nonlinear dynamic measures of phase space reconstruction and correlation dimension were also applied to analyze the voices. Results: A significant difference between normal and polyp groups was found in jitter and shimmer obtained from MDVP, as well as in jitter and signal-to-noise ratio from CSpeech. However, no parameters significantly differentiated between normal and nodule groups. Shimmer from CSpeech did not reveal any significant differences among any of the groups. Correlation dimension values for the nodule and polyp groups were significantly higher than the normal group. Conclusion: Nonlinear dynamic analysis has great potential value for the characterization of voice from patients with vocal nodules and polyps. The combination of traditional perturbation and nonlinear dynamic measures may improve our ability to provide objective clinical analysis of voices with vocal mass lesions.

Background-Phonation threshold flow (PTF) may provide a tool to assess laryngeal function and could differentiate between normal and pathological voices. Both polyps and nodules contribute to an increased PTF by creating an incomplete glottal closure and increased vocal fold mass and thickness.

Femtosecond laser corneal lenticule transplantation in rabbits is feasible, as the lenticule was shown to thrive and integrate with the recipient stroma. Nerve regeneration begins after 1 month.

Acoustic analysis may provide a useful means to quantitatively characterize the tremulous voice. Signals were obtained from 25 subjects with diagnoses of either Parkinson's disease or vocal polyps exhibiting vocal tremor. These were compared to signals from 24 subjects with normal voices. Signals were analyzed via correlation dimension and several parameters from the Multi-Dimensional Voice Program (MDVP): percent jitter, percent shimmer, amplitude tremor intensity index (ATRI), frequency tremor intensity index (FTRI), amplitude tremor frequency (Fatr), and fundamental frequency tremor frequency (Fftr). No significant difference was found between the tremor and control groups for ATRI and Fatr. Percent jitter, percent shimmer, FTRI, Fftr, and correlation dimension values were found to be significantly higher in the tremor group than in the control group. We conclude that these parameters may have utility for the clinical quantification of tremor severity and treatment effects.