Perception of Disordered Voice: Reaction Time, Accuracy, and Neural Processing

In many professional settings, such as emergency dispatch, aviation, healthcare, and the military, voice is used to deliver short, precise instructions. Voice disorders can affect both professional voice users and listeners, altering speech perception, listening effort, and task performance. This study investigated the impact of disordered voice on behavioral performance (reaction time and accuracy) and neural processing (as measured by event-related potentials, ERPs) in short spoken instructions.

Forty-three right-handed, healthy, Latvian-speaking university students (21 female, mean age 21.1 ± 2.4 years) responded to auditory spatial instructions (left, right, up, and down) produced in disordered and normophonic voices. Disordered voice stimuli were recorded from a male with severe adductor spasmodic dysphonia (44 years, G3R3B1A0S3I3, DSI -7.2) and a female with mild dysphonia due to chronic laryngitis (52 years, G1R1B0A1S0I0, DSI -0.35), along with matched healthy controls. Each participant completed 576 trials by moving a joystick in the instructed direction. The mobile EEG recording solution, featuring 64 referential channels (ANT Neuro), was used for ERP measurements.

Listeners responded faster to dysphonic than to normophonic voices (P < 0.001), with the strongest effect for severe dysphonia. Accuracy declined significantly only for severe dysphonia, whereas mild dysphonia had no impact on performance. ERP analyses revealed that instructions spoken in severely dysphonic voice elicited larger N200, P300, and late potentials' amplitudes than those spoken in healthy voice, reflecting greater attentional, perceptual, and evaluative processing. For female voices, differences between mildly disordered and healthy stimuli were observed only in brief late-stage effects, with slightly higher amplitudes to the healthy voice.

Severe spasmodic dysphonia significantly alters both behavioral and neural responses, leading to faster but less accurate task execution and greater cognitive load. Mild dysphonia primarily affected response speed without impairing accuracy or increasing cognitive effort.