Effects of Cognitive Load on Vocal Motor Control: A Model-Based Analysis in Individuals With Hyperfunctional and...

This study examined how cognitive load (CL) influences vocal motor control by integrating acoustic measures with biomechanical trajectories derived from a model-based approach. The aim was to determine whether speakers with vocal hyperfunction (VH) exhibit distinct modulation patterns in laryngeal control compared with healthy control (HC) speakers.

Recordings from female speakers (63 with VH and 62 HC speakers) performing a Stroop task were analyzed. Trajectories of fundamental frequency (f_o) and sound pressure level (SPL) were extracted and used as inputs to a computational model that estimated cricothyroid (a_CT) and thyroarytenoid (a_TA) muscle activations, as well as subglottal pressure (P_S). Acoustic and model-derived measures were segmented and analyzed using mixed-effects models.

Significant condition effects were found across acoustic and biomechanical features, with parallel patterns in f_o - a_CT and SPL - P_S across segments and groups. No consistent differences were observed for a_TA. The strongest effects occurred in SPL, which increased under CL, especially among speakers with VH, with P_S showing a similar but weaker trend. For f_o and a_CT, opposite group patterns emerged at task onset: HC speakers showed slight decreases, whereas those with VH showed increases.

The correspondence between acoustic and estimated biomechanical modulations under CL supports the utility of this model-based approach for physiologically interpretable inference of laryngeal motor behavior. Speakers with VH showed greater modulation of a_CT and P_S control, with no systematic changes in a_TA, suggesting that arousal-related laryngeal tension primarily affects more superficial control dimension.