Vocalization subsystem responses (Croake et al., 2018)

Method

A perturbation paradigm was used to obtain respiratory kinematic, aerodynamic, and acoustic formant measures from 10 healthy participants (8 women, 2 men) with normal voices. Group and individual data were analyzed to provide a multilevel analysis of the data. A 3-dimensional state space model was constructed to demonstrate the interactive relationships among the 3 subsystems before, during, and after perturbation.

Results: During perturbation, group data revealed that lung volume initiations and terminations were lower, with longer respiratory excursions; airflow rates increased while subglottic pressures were maintained. Acoustic formant measures indicated that the spacing between the upper formants decreased (F3–F5), whereas the spacing between F1 and F2 increased. State space modeling revealed the changing directionality and interactions among the 3 subsystems.

Conclusions: Group data alone masked important variability necessary to understand the unique relationships among the 3 subsystems. Multilevel analysis permitted a richer understanding of the individual differences in phonatory regulation and permitted subgroup analysis. Dynamic systems theory may be a useful heuristic to model the interactive relationships among vocalization subsystems.

Supplemental Material S1. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Supplemental Material S2.

Descriptive statistics: group means, standard deviations, and ranges by condition (pre recurrent laryngeal nerve [RLN] block [PRE], during RLN block [DUR], and post-RLN block recovered [REC]). Supplemental Material S3. Repeated measures analysis of variance (ANOVA).

Tukey’s honestly significant difference test was applied to determine significant differences between conditions. ** p < .05. Croake, D. J., Andreatta, R. D., & Stemple, J. C. (2018). Vocalization subsystem responses to a temporarily induced unilateral vocal fold paralysis.

Journal of Speech, Language, and Hearing Research, 61, 479–495. doi.org/10.1044/2017_JSLHR-S-17-0227