I Think I Can: Stroke, Self-Efficacy and AFO Usage

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By Phil Stevens, MEd, CPO, FAAOP

The results are in, and in the management of poststroke hemiparesis, "an AFO works,"1 according to Sarah Tyson, FCSP, MSc, PhD, of the University of Salford, School of Health Sciences, Manchester, England, and Ruth Kent, BMedSci, MBBS, MD, FRCP, of the University of Leeds, Academic Department of Rehabilitation Medicine, England.

The strength of this simple statement lies in the rigorous efforts undertaken to support it. Tyson and Kent performed a comprehensive systematic review to identify 13 crossover studies that compared function with an AFO versus no AFO in patients who have had a stroke. Throughout these studies, each subject acted as his or her own control, and the order of testing (AFO or no AFO) was randomized. The authors pooled the published observations of the 334 patients enrolled in these studies and performed a meta-analysis to determine the ultimate effects of AFO use on the patient's walking ability and balance after a stroke.1

Their results are summarized in Table 1 and include the following: With an AFO, subjects walk faster and more independently with a longer step and stride length. The use of an AFO appears to facilitate quicker negotiation of stairs and improved performance on the Timed Up and Go (TUG) test. In addition, the use of an AFO allows participants to bear more weight through their weak leg and appears to reduce postural sway.1

Figure 1

The strength of the evidence from the pooled data sets is encouraging. However, there is a growing awareness that these somewhat artificial, laboratory-derived measures may not tell the entire story. In addition to these functional performance measures, an individual's "self-efficacy," the patient's belief that he or she can safely accomplish a range of necessary activities, also ultimately appears to play a substantial role in rehabilitation. This article introduces the related concepts of falls, selfefficacy, and balance confidence in stroke rehabilitation, and the role that AFOs may play in improving them.

Predicting Functional Returns

The first study of interest monitored the rehabilitation of a convenience sample of 37 subjects following their cerebral vascular accident (CVA).2 Subjects were assessed upon admission to the inpatient rehabilitation setting, at discharge from that setting, and ten months later. It is beyond the scope of this article to thoroughly introduce and explain all of the specific outcome measures that were used to track the progress of the study subjects. For our purposes, it is sufficient to say that these included such domains as balance performance, motor function, walking ability, and a measure of the "level of ADL disability," or the extent to which subjects could independently accomplish a series of activities of daily living (ADLs) in such domains as self-care, transfers, and locomotion. Subjects were also asked to complete the Falls Efficacy Scale (FES), a survey instrument that preceded the more familiar Activities-specific Balance Confidence (ABC) Scale, which assesses an individual's perception of his or her ability to perform 13 commonly encountered tasks without falling.

Several key observations were made based on tracking the changes that occurred within this population over time. Across the various outcome indices, it was observed that individuals generally improved over time. In addition to this broad trend, the authors wanted to determine which attributes appeared to predict improvement. It may be surprising to learn that across the spectrum of performance measures, the index that was the most predictive of the level of ADL disability ten months after discharge was the concept of falls self-efficacy. Each individual's perception of his or her ability to perform common tasks was ultimately more predictive than his or her measured balance performance, observed motor function, or recorded walking ability.2

The authors then divided their cohort into two groups according to their FES scores. Those with FES scores above the median FES values were assigned to the "high self-efficacy group," while those scoring below the median were assigned to the "low self-efficacy group." Tracking performance scores over time, the authors observed that the motor function and balance performance scores of the low self-efficacy group actually declined between discharge and follow-up. By contrast, motor function and balance performance scores demonstrated continued improvements at follow-up among the high self-efficacy group.2 Thus, falls self-efficacy may be a strong predictor of an individual's longer-term return to functional independence.

Predicting Community Reintegration

The next paper under consideration goes beyond the performance of ADLs to investigate the ability of subjects to reintegrate into their former lives after a CVA and the apparent role of balance self-efficacy in that process.3 Sixty-three community-dwelling adults who were at least one year removed from their CVA were recruited to participate. At the core of the study was an 11-item questionnaire called the Reintegration to Normal Living (RNL) Index, described by the authors as measuring "a person's perception of and satisfaction with her or his reintegration into normal daily functional activities, social and recreational activities, and interactions with family members and other people."3 In addition, the authors collected outcomes across other domains that they felt might influence this idea of reintegration. These included cognitive abilities, depression, balance performance, and walking endurance. Balance self-efficacy was also evaluated using the ABC, a 16-question survey derived from the FES that asks participants to rate their perception of their ability to accomplish a number of common functional tasks without losing their balance or becoming unsteady.

With regard to the RNL Index, scores were diverse, ranging from 44 to the maximum score of 100, with a mean of 83 ± 14. Ultimately, 83 percent of the study participants were found to have "mild to moderate deficits"  (RNL scores between 60 and 99), with an additional 6 percent presenting with severe deficits (RNL score < 60). Correlations between RNL Index scores and the other presentation variables were drawn, and much like the previous study, balance confidence was found to show the highest correlation with the ultimate outcome variable, in this case, community reintegration.3 ABC scores were more closely correlated to RNL scores than performance on the Berg Balance Scale (BBS), the Six-minute Walk Test (6MWT), or depression scale scores. Once again, this concept of balance efficacy was shown to have a substantial influence on the ultimate rehabilitation of patients in the chronic stage of their CVA.

Activity and Participation

A related publication examines the effects of falls self-efficacy and balance self-efficacy as they pertain to the broad concepts of "activity and participation," as defined by the International Classification of Functioning, Disability, and Health (ICF).4 In this effort, a convenience cohort of 77 participants, all at least six months removed from their CVA, was assembled. The dependent variable of interest in this study was the individual scores of the participants on the ICF Measure of Participation and Activities (IMPACT) scale. This self-report measure is a 33-item scale designed to identify those restrictions an individual may have in any of the nine categories of activity and participation that have been identified by the ICF.

In addition to IMPACT scores, participants were evaluated to determine their gait speed (ten-meter walk test), walking capacity (6MWT), balance performance (BBS), balance selfefficacy (ABC), and falls self-efficacy.4 The latter was measured using a modified version of the FES in which four items were added that represent activities considered to be complex for individuals who have had a stroke. As with the previous studies, researchers drew correlations between the variable of interest, the IMPACT scores, and the other patient characteristics. Once again, balance self-efficacy, followed closely by falls self-efficacy, had the closest correlations to IMPACT scores.4 Much like the previous studies, self-efficacy was more strongly associated with poststroke activity and participation than the physical performance measures of gait and balance ability.4

The Influence of AFO Use on Balance Self-Efficacy

The results of the systematic review cited at the beginning of this article clearly document the beneficial effects that AFOs can have on standardized measures of gait and balance performance. However, until recently there has been no work done on the potential effects AFOs may have on questions of self-efficacy as they pertain to falls and balance. Given the apparent importance of this variable on those outcomes that would appear to matter most to patients-independence, community reintegration, and overall participation-this is an important relationship for our profession to understand.

A study undertaken by researchers at the Northwestern University Prosthetics-Orthotics Center (NUPOC), Chicago, Illinois, provides the first step in this understanding.5 In it, the authors assembled a cohort of 15 subjects who were on average about 12 years post-CVA and were currently using a non-rigid AFO. The subjects went to the research facility on two occasions as part of a separate research study. At each visit, subjects were asked to complete the ABC scale with the additional instruction that they imagine completing the described activities with or without an AFO but with no other assistive device. The order of the two ABC scenarios was randomized.

Balance confidence, as measured by the mean ABC scores in the two conditions, was significantly greater with an AFO (68/100) than without an AFO (52/100).5 Fortunately, the ABC scale has been so widely studied that additional insights can be extrapolated from these numbers. Originally developed for use in geriatric communities, the ABC scale was once administered to a cohort of 475 older adults, allowing for the establishment of some very general cut-off scores.6 According to this matrix, ABC scores greater than 80 percent tend to be typical of community dwelling, physically active, older adults. Scores between 50 and 80 percent are typical of moderate physical functioning as might be observed among patients in retirement homes or patients with chronic health conditions. Scores less than 50 percent are generally seen in individuals with low physical function as might be found in a homecare setting.6

Against these standards, the apparent influence of AFOs on the study participants becomes more meaningful. The ABC scores with AFOs averaged 68 percent, a score that, while it could certainly be improved upon, is largely consistent with the generalization of older adults with chronic health conditions. However, the mean ABC scores in the no-AFO condition averaged 52 percent, a figure dangerously close to the cut-off value for low-functioning, homecare clients. Within this context, the value of AFO use to this study cohort would appear to be substantial.

The authors of the study framed their observations in a slightly different way, also drawing upon the cut-off values observed in the geriatric community. Without their AFOs, only 7 percent of the study participants were classified as high functioning (ABC score = 80-100 percent). Fifty-three percent were classified as moderate functioning (ABC score = 50-80 percent), with a disturbingly high 40 percent being classified as low functioning (ABC score < 50 percent).5 With their AFOs, the distribution of the subjects noticeably improved. In this condition, 27 percent of study subjects were classified as high functioning, 53 percent as moderate functioning, and only 20 percent were low functioning.5 Using either interpretation of the data, the beneficial effects of AFO use in this population is readily apparent.

Summary

Treating gait deficits is an important part of stroke rehabilitation. A recent meta-analysis, considered by most to be one of the highest forms of published evidence, has identified a number of domains where AFO use has been shown to improve several aspects of gait and balance. However, these performance deficits fail to fully capture the losses that may be experienced after a stroke. A compromised sense of self-efficacy with respect to balance and falls during daily activities also appears to be a prevalent concern within this population. A series of studies has shown this compromised self-efficacy to be more closely associated with factors like independence in ADLs, community reintegration, and activity and participation than such considerations as performance-oriented gait and balance measures. However, preliminary data suggests that AFO use may have a substantial beneficial effect on balance confidence in this population as well, indicating its potential benefits to larger questions of independence, reintegration, and overall activity and participation.

Phil Stevens, MEd, CPO, FAAOP, is in clinical practice with Hanger Clinic, Salt Lake City, Utah. He can be reached at

References

  1. Tyson, S. F., and R. M. Kent. 2013. Effects of an anklefoot orthosis on balance and walking after stroke: A systematic review and pooled meta-analysis. Archives of Physical Medicine and Rehabilitation 94 (7):1377-85.
  2. Hellström, K., B. Lindmark, B. Wahlberg, and A. R. Fugl-Meyer. 2003. Self-efficacy in relation to impairments and activities of daily living disability in elderly patients with stroke: A prospective investigation. Journal of Rehabilitation Medicine 35 (5):202-7.
  3. Pang, M. Y. C., J. J. Eng, and W. C. Miller. 2007. Determinants of satisfaction with community reintegration in older adults with chronic stroke: Role of balance self-efficacy. Physical Therapy 87 (3):282-91.
  4. Schmid, A. A., M. Van Puymbroeck, P. A. Altenburger, T. A. Dierks, K. K. Miller, T. M. Damush, and L. S. Williams. 2012. Balance and balance self-efficacy are associated with activity and participation after stroke: A cross-sectional study in people with chronic stroke. Archives of Physical Medicine and Rehabilitation 93 (6):1101-7.
  5. Zissimopuolos, A., S. Fatone, and S. Gard. 2013. The effect of ankle-foot orthoses on self-reported balance confidence in persons with chronic poststroke hemiplegia. Prosthetics and Orthotics International. Epub 2013/06/24.
  6. Myers, A. M., P. C. Fletcher, A. H. Myers, and W. Sherk. 1998. Discriminative and evaluative properties of the Activities-specific Balance Confidence (ABC) scale. Journals of Gerontology, Series A, Biological Sciences Medicine Sciences 53 (4):M287-94.