This study examined the feasibility of the Microsoft Kinect sensor for assessing mediolateral trunk sway and its associations with cognitive abilities. To this end, young adults and elderlies were sampled and performed various gait and balance tasks under single- and dual-task paradigms. Although reliable, Kinect's ability to assess cognition through movement was not conclusive. Specifically, the Kinect distinguished between young- and old-adults gait, but not between young-adults with and without attention-deficit-disorder. However, gait under divided-attention and balance in the absence of visual-information interacted and affected performance in the Trail Making Test (TMT). The simple-effects showed that TMT-performance among participants with better stability in the absence of visual information was not affected by increased attentional demands. In contrast, attentional demands ill-affected TMT-performance among those who did not maintain their stability in the absence of visual information. We discuss these findings in terms of interoceptive attention, awareness, and control over movement.