The Effects of Transcranial Direct Current Stimulation (tDCS) on Multitasking Throughput Capacity

Abstract

Background: Multitasking has become an integral attribute associated with military operations within the past several decades. As the amount of information that needs to be processed during these high level multitasking environments exceeds the human operators' capabilities, the information throughput capacity reaches an asymptotic limit. At this point, the human operator can no longer effectively process and respond to the incoming information resulting in a plateau or decline in performance. The objective of the study was to evaluate the efficacy of a non-invasive brain stimulation technique known as transcranial direct current stimulation (tDCS) applied to a scalp location over the left dorsolateral prefrontal cortex (lDLPFC) to improve information processing capabilities during a multitasking environment.Methods: The study consisted of 20 participants from Wright-Patterson Air Force Base (16 male and 4 female) with an average age of 31.1 (SD = 4.5). Participants were randomly assigned into two groups, each consisting of eight males and two females. Group one received 2 mA of anodal tDCS and group two received sham tDCS over the lDLPFC on their testing day.Results: The findings indicate that anodal tDCS significantly improves the participants' information processing capability resulting in improved performance compared to sham tDCS. For example, the multitasking throughput capacity for the sham tDCS group plateaued near 1.0 bits/s at the higher baud input (2.0 bits/s) whereas the anodal tDCS group plateaued near 1.3 bits/s.Conclusion: The findings provided new evidence that tDCS has the ability to augment and enhance multitasking capability in a human operator. Future research should be conducted to determine the longevity of the enhancement of transcranial direct current stimulation on multitasking performance, which has yet to be accomplished.

A Neuroergonomics Approach to Mental Workload, Engagement and Human Performance

“…This portable device can be combined with EEG and fNIRS and used in the context of real-life task performance for the purpose of on-line neuromodulation (McKendrick et al, 2015;Gateau et al, 2018). For example, a number of studies support the position that neurostimulation can: enhance mental flexibility and mitigate perseveration (Leite et al, 2011;Jeon and Han, 2012), improve visual attention (Falcone et al, 2012;Nelson et al, 2015), improve executive functioning in multitasking situations (Nelson et al, 2016) and increase alertness (McIntire et al, 2014;Nelson et al, 2014). There are other types of environmental stimulation such as vivid light exposure, especially during night flights, which can promote an optimal level of alertness (see Anund et al, 2015) without altering flight crew performance (see Caldwell et al, 2009).…”

Effects of Transcranial Direct Current Stimulation on Baseline and Slope of Prefrontal Cortex Hemodynamics During a Spatial Working Memory Task

“…The lateral prefrontal cortex is heavily involved in executive function and has been a brain region of interest in many tES studies. Anodal stimulation of the dorsolateral prefrontal cortex has been shown to improve sustained attention (Nelson et al, 2014a,b) and multitasking (Nelson et al, 2016), and anodal stimulation of the ventrolateral prefrontal cortex has been shown to improve visual perceptual learning Falcone et al, 2012). In clinical populations tDCS applied to left dorsolateral prefrontal cortex improves scores on the Hamilton Depression Rating Scale, suggesting a reduction in symptoms relating to major depression (Boggio et al, 2008).…”

No Evidence for Enhancing Prospective Memory with Anodal Transcranial Direct Current Stimulation Across Dorsolateral Prefrontal Cortex

“…One possibility is that tDCS may aid in tasks where executive processes are entirely devoted to a single task (i.e., vigilance), but not tasks where executive resources are spread across multiple tasks (i.e., prospective memory). Insights of this nature are an important development from the usage of neural modulation across related research domains where similar theoretical mechanisms (e.g., vigilant attention, executive functioning, or working memory; see also Nelson et al, 2016) are hypothesized to support task performance. Discrepant findings demand cognitive psychologists and cognitive neuroscientists to be more precise regarding our specifications of the underlying mechanisms of behavior.…”