Date Presented 3/30/2017
We compared the effects of an external focus vs. internal focus of attention on upper-extremity motor training for people with stroke. Participants improved significantly over time, but there were no differences between the two groups. Practice intensity was more important than attentional focus during arm training.
Primary Author and Speaker: Grace Kim
Contributing Authors: Jim Hinojosa, Mitchell Batavia, Ashwini Rao
PURPOSE: We compared the effects of an external vs. internal focus of attention on upper-limb motor training for individuals with chronic stroke. Attentional focus is defined as what someone pays attention to during a motor task (Wulf, 2007a). A therapist can use specific instructions to direct a patient to focus on different aspects of a motor task. The two most commonly used approaches are external focus (thinking about the end goal of a task) and internal focus (thinking about the actual movement of your body during a motor task; Wulf, 2007a). For healthy individuals, a robust body of research supports the use of an external focus rather than an internal focus to facilitate learning of new motor skills (Wulf, 2007b). In contrast, few studies in the stroke literature address the effects of attentional focus during temporary motor performance, and even less research exists on how attentional focus affects the retention of motor skills. Our study addresses this gap in the literature.
DESIGN: This study used an experimental, randomized, mixed analysis of variance (ANOVA) design. A power analysis using G*Power software (V3.1; Faul, Erdfelder, Lang, & Buchner, 2007) was completed a priori to determine the sample size (N = 30). Participants were randomly assigned to either the internal focus or external focus group (n = 15 per group). Both groups were balanced for level of arm impairment, dosage of treatment, and arm training protocol. A blinded assessor completed the clinical outcome measures.
Study eligibility was determined using the following criteria: >6 mo past stroke, moderate to severe arm impairment defined as Fugl–Meyer Assessment (FMA) scores 1–19 (severe) and 20–47 (moderate), Mini-Mental State Exam score >25/30, intact for visual tracking, and medically stable. Participants were excluded for the following: concurrent occupational therapy or physical therapy for the affected arm; joint contractures at the wrist, forearm, elbow, or shoulder; Modified Ashworth Score >2 at the elbow or shoulder; botulinum toxin injections in the affected arm <3 mo prior; and 0/5 at the shoulder or elbow on the manual muscle test.
Participants received 12 training sessions over 4 wk on the InMotion 2 robot (Bionik, Watertown, MA). Smoothness and joint independence (kinematic outcomes), FMA, and Wolf Motor Function Test (WMFT) were used to measure change in arm status at baseline, discharge, and 4-wk follow-up. A mixed ANOVA was used to analyze the effects of attentional focus between the two groups over three time points.
RESULTS: Sixteen women and 14 men completed the study. On average, participants were age 58.1 (±12.6) yr and were 5.08 (±3.44) yr since stroke. Both groups improved significantly on all outcome measures from baseline to discharge and maintained those changes at follow-up regardless of group assignment: smoothness, F(1.49, 38.61) = 26.28, p < .001; joint independence, F(1.6, 42.6) = 17.20, p < .001; FMA, F(2, 52) = 27.55, p < .001; WMFT, F(2, 52) = 14.05, p < .001]. There were no differential effects of attentional focus on the retention of motor skills after 4 wk of arm training.
CONCLUSION: Participants with moderate to severe arm impairment did not demonstrate greater motor improvements with an external focus of attention, suggesting that current theories of motor learning may not consistently apply to the stroke population. Attentional focus may not be an active ingredient for retention of trained motor skills in individuals with stroke, whereas practice intensity appears to be pivotal. Clinicians can use an internal or external focus of attention during therapy depending on the client’s response to different instructional cues with the ultimate goal of maximizing treatment intensity.
References
Faul, F., Erdfelder, E., Lang, A., & Buchner, A. (2007). G*Power 3: A flexible statistical power and analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods, 39, 175–191. http://dx.doi.org/10.3758/BF03193146
Magill, R. A., & Anderson, D. (2014). Motor learning and control: Concepts and applications (10th ed.). New York: McGraw-Hill.
Wulf, G. (2007a). Attention and motor skill learning. Champaign, IL: Human Kinetics.
Wulf, G. (2007b). Attentional focus and motor learning: A review of 10 years of research. Bewegung und Training, 1, 4–14. Retrieved from http://www.sportwissenschaft.de/fileadmin/pdf/BuT/hossner_wulf.pdf
