Walking outdoors requires one to deal with a wide range of visual and cognitive perturbations, i.e., multiple object tracking and making timely decisions while ignoring irrelevant information, etc. Using dual-task gait paradigm, the purpose of this thesis was to evaluate the age effects of different types of visuospatial cognitive tasks, i.e. designed cognitive game tasks and commercial computer games on gait and cognitive performances in older adults as compared to the younger adults. A standardized dual-task assessment approach, i.e. objectively evaluating both gait and cognitive performances simultaneously, has potential to be the screening tool to detect gait and cognitive impairments in early stages. Further, evaluating the training value of commercial computer games by comparing them with the designed cognitive games with objective outcome measures will help in developing multimodal dual-task intervention platform to treat and prevent age-related physical and cognitive impairments. / October 2016