Interactions of subglottal pressure and neuromuscular activation on fundamental frequency and intensity

Abstract

Objectives Fundamental frequency (F0) and intensity (SPL) of voice are controlled by intrinsic laryngeal muscle (ILM) activation and subglottal pressure (Psub). Their interactions were investigated.s Methods In an in vivo canine model, the thyroarytenoid (TA), lateral cricoarytenoid/interarytenoid (LCA/IA), and the cricothyroid (CT) muscles were independently activated from threshold to maximal contraction by neuromuscular stimulation in various combinations while airflow was increased to phonation onset pressure and beyond. The resultant acoustic output was analyzed for effects of Psub on vibratory stability, F0 and SPL. Muscle activation plots and vocal range profiles by individual ILM activation states were analyzed. Results CT activation increased phonation onset F0, but vibration was less stable in high CT conditions and displayed vibratory mode change. In addition, in high CT conditions, a decrease in F0 with increased Psub was observed. SPL increased with Psub in all conditions but the slope was greater at high CT, low TA/LCA/IA activations. LCA/IA activation improved vocal efficiency. To maintain same F0 with increasing SPL (messa di voce), TA activation was decreased and LCA/IA activation was increased. The same F0 and SPL could be achieved with a variety of ILM activation combinations. Conclusions CT is primarily required for increasing F0, while TA can increase or decrease F0 and SPL. LCA/IA likely maintains vocal fold adduction during increased Psub and improves vocal efficiency. This study also demonstrates laryngeal motor equivalence, the ability of the larynx to achieve the same target F0 and SPL with multiple combinations of ILM activation.

Effects of thyroplasty implant stiffness on glottal shape and voice acoustics

“…Each implant stiffness, shape, and position may be beneficial for some airflow/subglottic pressure combinations but not for others. This reflects the inherent limitation of MT in that implants of a single stiffness are used, while during in vivo phonation the body‐cover layer undergoes numerous changes in stiffness, tension, and glottal contour . Clinically, MT has poorer outcomes in some conditions such as high vagal paralysis and significant presbylarynx/tissue atrophy.…”

“…This reflects the inherent limitation of MT in that implants of a single stiffness are used, while during in vivo phonation the body-cover layer undergoes numerous changes in stiffness, tension, and glottal contour. 22 While we initially intended to find a correlation between glottal channel shape and acoustics, an obvious trend was not found. Although implants improved acoustics compared to baseline, the small differences in medialization (both D max and D t ) between implants did not translate to differences in acoustics.…”

Risco vocal em pastores: quantidade de fala, intensidade vocal e conhecimentos sobre saúde e higiene vocal

“…The intense vocal loudness observed in pastors in the labor situation (4.98 points) ( Table 2) is also higher than the mean value reported in the literature for economically active male professionals (4.6 points) (14) . Similarly to the high talkativeness value, intense vocal loudness can act as an internal risk factor of vocal impairment, considering that to produce loud sounds it is necessary to recruit more respiratory muscles (24) and increase the subglottic pressure and glottic adduction (25) . Increased subglottic pressure requires the vocal folds to increase the compression force between them, so that they remain mediated for voice production (26) , which may lead to phonotrauma.…”

Mapping Thyroarytenoid and Cricothyroid Activations to Postural and Acoustic Features in a Fiber-Gel Model of the Vocal Folds

“…These variables were chosen because they are essential for initiation and self-sustaining vocal fold oscillation at a desired fundamental frequency and intensity. Researchers have made attempts to find these relationships using electromyographic recordings in humans [22][23][24][25][26], in-vivo canine larynges experiments [21,[27][28][29][30][31], and computational models [32][33][34]. However, majority of these attempts were made to identify the relationship with fundamental frequency only and to a lesser extent with vocal intensity [35,36].…”

“…The outputs of the model are many time-varying signals, including oral pressure, oral flow, glottal flow, glottal flow derivative, and transglottal pressure. The findings from the fiber-gel model are compared to the results from human electromyography (EMG) studies (Titze et al 1989) [32], and in vivo canine model studies (Chhetri et al (2012) and Chhetri and Park, 2016) [30,31].…”