Investigating Cognitive Load and Autonomic Arousal During Voice Production and Vocal Auditory-Motor Adaptation

Cognitive load and autonomic arousal are hypothesized to affect voice production, yet the nature of these relationships is unclear. The purpose of this study was to assess how cognitive load and autonomic arousal differentially affect voice production and vocal motor control.

Physiological measures of autonomic arousal were recorded from 30 adults under different cognitive loads elicited by a Stroop task. In Experiment 1, voice acoustic measures were measured during speech production. In Experiment 2, fundamental frequency (f_o) responses to predictably altered auditory feedback (sensorimotor adaptation) were measured. Mixed linear-effects models assessed relationships between variables. Changes between cognitive loads were compared among the two experiments.

In Experiment 1, increased cognitive load was associated with increases in sound pressure level, whereas increases in autonomic arousal measures (i.e., decreases in skin conductance rise time, pulse amplitude, and period) were related to decreases in cepstral peak prominence. Increased autonomic arousal (i.e., decreased pulse amplitude) was related to increased adaptation in Experiment 2. Participants who responded to increased cognitive load by decreasing f_o during Experiment 1 showed more adaptation in Experiment 2.

Differential effects of cognitive load and autonomic arousal emphasize the importance of individual physiological variability when assessing how stress affects the voice.