Cervicobrachial muscle response to cognitive load in a dual-task scenario

• Published in: Ergonomics 2004-05, Vol.47 (6), p.625-645
• Main Authors: Leyman, Elke LC, Mirka, Gary A, Kaber, David B, Sommerich, Carolyn M
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Adult; Applied physiology; Attention; Biological and medical sciences; Cognition; Cognitive task; Electromyography; Ergonomics; Ergonomics. Work place. Occupational physiology; Female; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Mental Processes; Mental workload; Movement; Multiple-task performance; Muscle, Skeletal - physiology; Muscular system; Physiological measures; Postural Balance - physiology; Psychomotor Performance - physiology; Secondary-task performance; Space life sciences; Spine; Stress; Task Performance and Analysis; Visual display unit; Workload - psychology; Workloads
• ISSN: 0014-0139; 1366-5847
• DOI: 10.1080/00140130310001629766

People working in an office environment often have to deal with significant cognitive workload due to the coordination of multiple, simultaneous tasks. The objective of this research was to examine the impact of cognitive load in office-type tasks on physical-stress response, using a dual-task paradigm involving a primary cognitive task and secondary typing task. The central hypothesis of this research was that altering the demands of the cognitive task would lead to a difference in physical stress-level and performance. Cognitive load was manipulated by presenting participants with three different types of cognitive tasks described in Rasmussen's ( 1983 ) taxonomy, including skill-, rule-, and knowledge-based tasks. Dependent variables examined in the study included: (1) electromyographic activity of the upper trapezius (pars descendens) and cervical erector spinae muscles, (2) performance in a secondary typing task, and (3) subjective measures of stress and cognitive workload. The results of this study revealed that the primary task causing the highest level of perceived workload also produced 61% higher muscle activity in the right trapezius, and 6 and 11% higher activity in the left and right cervical erector spinae, respectively, in comparison to muscle activity associated with the cognitive task causing the lowest perceived workload. With respect to performance, a 23% decrease was observed in typing productivity when the rule-based task was completed simultaneously vs. typing in the absence of any additional cognitive task (the baseline condition). This information may be used to better organize work activities in office environments to increase performance and reduce stress.