Quantification of Dual-task Performance in Healthy Young Adults Suitable for Military Use

Dual-task performance, in which an individual performs two tasks simultaneously, is compromised following mild traumatic brain injury (mTBI). Proficient dual-task performance is essential in a military setting for both military member safety and execution of skilled tasks. To address the unique needs of military members, a portable dual-task assessment was developed incorporating an auditory dual-task task as a novel assessment module utilizing mobile-device technology. The aim of this study was to develop and validate a dual-task mobile device-based application that accurately quantifies cognitive and motor function. Materials and Methods Fifty, healthy, military-age civilians completed three cognitive tasks in single- and dual-task conditions with eyes open and closed: visual Stroop, auditory Stroop at 1.5- and 2.5-second stimulus presentation, and number discrimination. All dual-task conditions required the maintenance of postural stability while simultaneously completing a cognitive task. Results There were no differences between single- and dual-task conditions for cognitive performance on any of the tests, and a ceiling effect was observed for the visual Stroop and auditory Stroop 1.5-second stimulus presentation (P > .05). Significant differences in postural stability were observed between the eyes-open and eyes-closed conditions in all single- and dual-task conditions (P < .01). Significant differences in postural stability were observed between the eyes-open single-task condition and all dual-task conditions (P < .01). Conclusions Based on the performance of healthy young adults, the number discrimination task may be optimal for detecting subtle changes in dual-task performance. The detected differences found between the eyes-open and eyes-closed conditions provide discriminatory value and insight into the reliance of vision of postural stability performance. While dual-task cognitive performance was not observed in this healthy population, individuals with mTBI may exhibit decreased dual-task performance. The independent evaluation of cognitive and motor function under dual-task conditions has the potential to transform the management and treatment of mTBI.