The Effect of Focus of Attention on Motor Performance and Learning During a Sit to Stand Task in Individuals Post-stroke

Introduction More than 795,000 people have a stroke in the United States each year, one every 40 seconds, leading to 7.6 million Americans who have had a stroke. Further, stroke remains the leading cause of long term disability, with greater than 50 percent of stroke survivors being chronically disabled. One factor contributing to disability is the difficulty with sit to stand transfers.

Individuals post stroke present with decreased knee moment on the affected side resulting in a less efficient sit to stand transition. In addition, individuals post stroke demonstrate increased trunk displacement in the mediolateral direction towards the unaffected side and weight distribution asymmetry. Cheng et al. found that individuals post stroke who were classified as fallers took more time to stand, had more mediolateral sway, and pushed less force through the affected lower extremity during sit to stand.

Sit to stand training is essential during rehabilitation post stroke to improve the ability to stand with a more normal biomechanical pattern and to positively impact other aspects of mobility. Several studies underline the importance of sit to stand training with a focus on increasing use of the affected lower extremity. Forced use training of the affected lower extremity has led to increased muscle activity in the affected limb, improved balance, gait kinematics, gait symmetry, gait velocity, and quality of life.

In order to make sit to stand training more effective the type of instruction and feedback is key. Based on a number of studies, simply changing two to three words of instruction can lead to more effective outcomes. This impactful change in instruction is based on focus of attention research, exploring the difference between internal and external focus instruction. An internal focus refers to thinking about one's own body movements, while an external focus is focusing on an outcome or impact on the environment. An example of internal focus is thinking about what one's shoulders or arm is doing while shooting a basketball, while an external focus would be thinking about the effect on the ball or the basket. Over 80 studies have supported an external focus being more effective than an internal focus of attention in the healthy adult and sports population.

The research in the stroke population related to focus of attention is sparse and contradictory. Some studies show an external focus being detrimental to movement fluency, while others find that an external focus leads to better outcomes. The remaining studies in the stroke population, however, have found no difference between internal and external foci. Most of these studies examined the effect of attentional focus during practice but did not include retention testing, thus the effects on motor learning have not been assessed. In addition, these studies have not examined the effects of focus of attention on functional movements such as sit to stand.