Abstract TP92: Brain Activity Related To The Effects Of Augmented Feedback On Learning Movements In A Dynamic Environment In Healthy Subjects And Stroke Survivors
Augmented visual feedback has been shown to be effective for learning reaching movements in dynamic environments after a stroke. However, the mechanisms behind such changes are not known. In addition, how brain activity changes with age as we learn novel dynamic tasks is also not clear. The purpose of this study was to examine brain activity changes that are observed when healthy younger and older adults and stroke survivors learn reaching movements in dynamic environments using augmented visual feedback.
Healthy young and older adults and chronic stroke survivors were randomly assigned to either a control or an experimental group. They all performed reaching movements with the Inmotion2 robotic system (Interactive Motion Tech Inc., MA) using the dominant/affected arm in a velocity-dependent force field. Controls received actual feedback of their movement, while experimental subjects received augmented visual feedback. Electroencephalogram recordings were analyzed to determine Event Related Desynchronization percent (ERD%). The theta, alpha, and beta frequency bands were examined during movement and pre-movement phases.
With learning, the absolute power of the frequency bands increased from the baseline to the adaptation condition, which was then washed out when the force field was removed. With age, there was a reduction in ERD% in alpha and beta bands as the motor task was learned. Stroke subjects had a further reduction in the ERD% in comparison to the healthy older adults. In addition, augmented visual feedback led to a significant increase in the ERD% in comparison to controls during the planning and execution stages of the movement.
Past studies have shown when novel dynamics are learned, ERD% reduces indicating increased cognitive processing and memory load. We found that with aging, the cognitive processing and memory required for performing the same dynamic task, increased. After a stroke, there was a further increase. However, the utilization of augmented visual feedback may reduce such requirements and lessen the load on higher centers. These results provide mechanistic support for employing augmented visual feedback for stroke rehabilitation specific to reaching movements in dynamic environments.
- © 2012 by American Heart Association, Inc.