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

Abstract

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 officetype 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.

Quantitative Overload: a Source of Stress in Data-Entry VDT Work Induced by Time Pressure and Work Difficulty

“…A decrease in typing performance with additional workload has been mentioned in other studies 9,17) . The prolongation of initial response time in our study is consistent with a study by Sternberg et al 43) , as they concluded that it takes a progressively longer time to initiate the response of typing a string of characters as the number of characters in the string is increased.…”

“…In other words, the use of meaningless character strings instead of regular words, and typing with a single finger (index finger) instead of all the fingers, made the task in this study more controlled than an automatic processing task. Controlled processing is slow, serial, conscious, and voluntary, while automatic processing such as a regular typing task would be fast, unconscious, and often involuntary, and would be invoked to perform well-developed skilled behaviors with less probability of committing error 9) .…”

“…However, in this study the focus is merely on the overload condition and its likely psycho-physiological consequences on data-entry operators. Three classes of workload assessment measures were applied for this investigation 9,10) : (I) subjective assessment of workload; (II) performance-based assessment; and (III) physiological assessment.…”

Experimental manipulation of psychosocial exposure and questionnaire sensitivity in a simulated manufacturing setting

“…These studies, which manipulated either mental demands (e.g., Leyman et al 2004;Lundberg et al 2002) or psychological demands (e.g., Marras et al 2000), measured perceptions of the psychosocial environment indirectly through ratings of stress and perceived mental workload (Leyman et al 2004), anxiety and blood pressure (Marras et al 2000), and heart rate (Lundberg et al 2002). The current study expands previous research by examining four psychosocial manipulations under two levels of physical work exposure to gain a better understanding of how psychosocial manipulations change perceptions of the work environment.…”

Influence of Posture Variation on Shoulder Muscle Activity, Heart Rate, and Perceived Exertion in a Repetitive Manual Task

“…Our task did not impose any major cognitive demands, which may be consistent with some industrial assembly tasks, while others may entail considerable requirements for decision making. Whether combined physical and mental demands would influence MAWP more than physical demands alone needs to be investigated further; some studies suggest that combined demands in upper extremity work may, indeed, lead to larger exposures in the shoulder region, and, therefore, likely to a different level of fatigue development and performance from that observed for only physical demands (Leyman, Mirka, Kaber, & Sommerich, 2004;Shaikh, Cobb, Golightly, Segal, & Haslegrave, 2012;Wang, Szeto, & Chan, 2011).…”