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

Abstract

Purpose: 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.

Method: 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.

Results: 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.

Conclusions: 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.