Influence of Cognitive Load on Voice Production: A Scoping Review

Cognitive-motor interactions in speech production have a strong theoretical basis. However, majority of the existing literature has primarily focused on subjective and objective measures related to speech and not voice. This systematic review gathered evidence on the potential relationship between cognitive load and voice production. A search of five databases, website, citation review, and author search were completed in a sequential order to find published and unpublished literature from 1992 to 2022 using a combination of search terms including voice, cognitive load/demand/effort/flexibility, dual task, and speech production/motor. Studies for which the primary dependent variables were linguistic, or speech measures were included if voice acoustics was also measured and described. A final sample of nine articles were identified as meeting inclusion criteria: completed between 1992 and 2022, healthy adults (18+), and American English speakers. The review indicated that existing literature on the influence of cognitive load on voice production is limited. Acoustic measures, such as fundamental frequency, sound pressure level, and cepstral peak prominence, do not show consistent patterns of change with an increase in cognitive load. It is likely that the inconsistencies in the speech or cognitive task type and measurement of individual reaction to cognitive load changes may have led to these varied results. Further research using a range/continuum of cognitive tasks varying in load/difficulty level and physiological measurements is warranted to understand the underlying mechanisms of behavioral performance with implications for clinical voice assessment and rehabilitation.