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  • Study: FES and Fast-Walk Training May Help Keep Individuals Walking After Rehab Ends

    Authors of a new study say that for individuals poststroke, community walking ability may have more to do with reducing the energy cost of walking, and less to do with changes to timed walking evaluations such as the 6-minute walk test (6MWT). And they believe that functional electrical stimulation (FES) coupled with rehabilitation training at faster speeds can play a big role in helping to decrease that energy cost.

    The study focused on 50 individuals who had experienced a stroke 6 or more months earlier and demonstrated "observable gait deficits," but were able to walk without support for at least 6 minutes. Participants were assigned to 1 of 3 12-week rehabilitation programs: gait training at self-selected speeds (SS), gait training at fast speeds (FS), or gait training at fast speeds with the addition of FES (FastFES). Sessions were held 3 times a week for 36 weeks and comprised 5 bouts of 6 minutes of treadmill walking, followed by 1 bout of 6 minutes of overground walking (with breaks in-between). The training speeds of the FS and FastFES groups were based on each participant's maximum overground walking speed (MWS).

    While the SS and FS groups received similar sessions (albeit at different speeds), the FastFES group also received FES for 15 of the 30 minutes of the treadmill walking sessions. The FES was targeted to the paretic ankle plantarflexors during late stance phase and dorsiflexors during swing phase, triggered by switches attached to the sole of the participant's shoe, in an alternating pattern of 1 minute on and 1 minute off. Results of the study were published in Neurorehabilitation and Neural Repair (abstract only available for free). Authors of the study include APTA members Darcy S. Reisman, PT, PhD, and Stuart Binder-Macleod, PT, PhD, FAPTA.

    To evaluate the energy cost (EC) of walking, participants' oxygen consumption was measured after the participants walked overground at their comfortable walking speed for 5 minutes at baseline, at the conclusion of the 12-week program, and again 3 months later. Researchers found that the FastFES group reduced the energy cost of walking by 24%—a change that researchers describe as "substantial" given that at the beginning of the study, all participants averaged 61% more oxygen consumption per meter ambulated than healthy older adults.

    Authors of the study also conducted oxygen consumption tests after ambulation at fast walking speeds for the FS and FastFES groups. They found that the FastFES group reduced energy cost at that speed by 19%, while the group that did not receive FES recorded no significant reduction—"additional evidence supporting [the use of FES] during gait training," they write.

    Yet despite the reduction in energy costs, the FastFES group did not significantly outperform the other groups in the 6MWT, authors noted. All 3 groups improved, with both the FS and FastFES groups recording improvements slightly above the minimal detectable change. Authors write that this apparent "disconnect" between improvements in energy expenditure and 6MWT results "suggests that the 6MWT may not be sensitive to changes in EC" and that "persons poststroke may improve 6MWT performance through metabolically expensive compensatory mechanisms."

    That "disconnect" also prompted researchers to question how well the 6MWT really correlates to community walking after a stroke.

    "Walking performance in ecological contexts may be markedly different than what is observed during the 6MWT because individuals may not engage in long-distance walking-related activities that would necessitate frequent rests," authors write. "EC, in contrast, has been posited to be a variable able to bridge the disconnect between clinical measures of walking function and real-world walking performance."

    Authors acknowledged that their study has several limitations, among them the fact that participants were not blinded to the interventions used and that factors other than participants' baseline walking speed may have affected results. Additional studies, with larger sample sizes, would help to clarify whether these limitations had an effect, they write.

    Still they argue, results from this study show that FES coupled with faster-speed training does increase the energy efficiency of walking for individuals poststroke and that this important improvement may be overlooked by "gross measurers of walking function" such as the 6MWT. "A better understanding of how reductions in the energy cost of walking contribute to improved community walking participation is needed," they write.

    The value of FES was the subject of the 2015 Maley Lecture presented by Gad Alon, PT, PhD, during APTA's NEXT Conference and Exposition. In that lecture, Alon advocated for personalized rehabilitation programs in which FES is "a standard-of-care intervention option in rehabilitation medicine."

    Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.

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