The achievement of community ambulation after stroke is critical for active participation in everyday activities, preventing social isolation and depression, and enhancing quality of life
]. In the period following discharge, many stroke survivors report low levels of participation in activities outside the home, with walking ability being a major factor influencing community reintegration
]. Functional community ambulation requires an ability to perform cognitive tasks while walking, and an ability to adapt to extrinsic environmental factors that increase the complexity of mobility, such as obstacle avoidance (e.g., curbs) and time-critical tasks (e.g., crossing the street within the time constraints imposed by traffic signals)
]. A reduced capacity for dual-task walking and/or limited ability to adapt to changes in environmental context may substantially restrict the degree to which a person is able to participate in his/her life roles.
After stroke, performance of a cognitive task concurrently with walking results in a profound reduction in gait speed
], with corresponding effects on stride duration
], stride length
], double limb support time
], and cadence
] (referred to as dual-task interference,
or cognitive-motor interference
). Diminished capacity to walk with adequate speed while performing a cognitive task may increase disability in the community or lead to curtailing of participation in everyday activities. Although dual-task performance can also affect the cognitive task
], most research indicates that patients with stroke prioritize the cognitive task, sacrificing gait performance
Current evidence suggests that conventional rehabilitation does not adequately address gait-related dual-task impairments after stroke. Although Cockburn and colleagues
] found that 7 out of 10 patients showed a reduction in dual-task cost on stride duration after customary rehabilitation, most patients continued to exhibit considerable dual-task interference during walking at discharge, as well as simultaneous interference in the cognitive task. Specific training in dual-tasking may be necessary to improve dual-task walking in people with stroke. A reduction in dual-task interference may be achieved via at least two possible mechanisms: (1) improving automatization of walking by repetitive practice; gait automaticity reduces the attentional requirements of gait, thereby increasing the capacity to perform simultaneous cognitive tasks; and (2) improving dual-task coordination by task-specific training; targeted practice of gait-related dual-tasks may improve performance in these activities. Theoretically, DTGT should result in greater improvement in dual-task performance (reduced dual-task cost) than STGT; however, both may act to increase gait automatization
], since both approaches involve repetitive practice of walking. There is mounting evidence of the value of task-specific training in neurological rehabilitation
]. This evidence indicates that practice should be task-specific and relevant to the patient and context. Based on the principles of task-specific training, practice of dual-task activities during locomotion in a variety of environmental contexts is needed to improve dual-task performance.
Although dual-task training in older adults has been shown to have promise
], there has been little research on dual-task training in stroke. In a randomized controlled trial, Yang et al.
] compared a motor-motor dual-task intervention (walking while manipulating either one or two balls of various size) to a no-intervention control. Compared to 12 patients who did not receive any intervention, the 13 patients who received dual-task training significantly improved their gait speed during both single-task and dual-task (tray carrying) walking. Our pilot data
] provide preliminary evidence that a cognitive-motor dual-task intervention can reduce dual-task interference in gait and increase community participation in community-dwelling stroke survivors. However, due to absence of a control intervention in either study, it is not possible to know whether improvements were due to repetitive walking practice (i.e., gait automatization) or the inclusion of dual-task activities (i.e., task-specific training in dual-task coordination). Research is needed to directly compare dual-task gait training to more traditional, single-task gait training approaches in order to identify the optimal parameters of gait rehabilitation that can improve walking and reduce dual-task interference after stroke.
The primary aim of this study is to investigate the effects of dual-task gait training (DTGT) compared to single-task gait training (STGT) on dual-task interference in community-dwelling adults within one year of stroke. Our hypothesis is that DTGT mediates the coordination of dual-tasks and will reduce cognitive-motor interference more than STGT. By measuring dual-task effects in both gait and cognitive tasks, we will be able to examine whether the intervention affects the voluntary allocation of attentional resources during dual-task walking. The second aim is to investigate the effect of DTGT on a more ecologically valid attention-demanding task: obstacle avoidance. Although obstacle crossing has been studied in people with stroke
], there have not been any studies investigating whether training in attentionally-demanding tasks can improve locomotor control during obstacle avoidance. The third aim is to examine the effect of the intervention on participation by quantitatively measuring ambulation and physical activity in the participants’ natural environment using innovative, wireless sensor technology. Despite the considerable threat to participation in everyday life posed by diminished dual-task capacity, research has not previously investigated the relationship between dual-task interference and community participation. This study addresses this important question, and will determine whether DTGT increases community participation more than STGT. Knowing whether an intervention has resulted in meaningful change in a person’s ability to participate in the real world is the ultimate indicator of therapeutic effectiveness.