THE EFFECT OF WORD LENGTH, ORAL-MOTOR MOVEMENT, ARTICULATION, AND LEXICALITY ON GAIT AND BALANCE

Performing two tasks in dual-task situations is a requirement in activities of daily living. An inability to dual-task is demonstrated generally by diminished performance on one or both of the tasks. Performing a verbal task can produce a reduced ability to perform a gait task and to maintain balance. Impairment on either of these postural tasks can increase the likelihood of falling, particularly among older adults. Dual-task interference has been demonstrated to be significantly impacted by a number of characteristics of secondary verbal tasks (including dimensions of both motoric and cognitive complexity]. Previous studies have not, however, exerted sufficient control over articulation or cognitive-linguistic processing, within the secondary task. The studies presented in this thesis used a dual-task paradigm that manipulated word length, oral-motor movement, articulation, and lexicality, within a verbal task, while assessing the affects of dual-task interference on both gait and balance. A sample of healthy young adults (pilotstudy: 15 women; gait and balance studies: 20womenand20 men) were asked to repeat a series of verbal stimuli while walking approximately 6m, and while maintaining an independent upright posture for 10 seconds at a time. Participants also were asked to complete a test of perceptual speed, as an indicator of information processing speed, separate from the dual-task protocol. Results suggest that oral-motor movement, articulation, and lexicality had unique effects on dual-task performance, with women demonstrating significantly more dual-task interference than men. Furthermore, results suggested that the ability to dual-task is directly related to an individual’s information processing capacity. Results supported the capacity-sharing model of dual-task interferenc