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Regan E.1, Merlo A.2, Fritz S.3
1University of South Carolina, Exercise Science, Columbia, United States, 2Northern Arizona University, Department of Physical Therapy and Athletic Training, Phoenix, United States, 3University of South Carolina, Exercise Science / Physical Therapy Program, Columbia, United States
Background: The Six-Minute Walk Test (6MWT) is a measurement of an individual's endurance and ability to complete the walking required in many activities of daily life. Walking capacity and endurance are an essential part of community ambulation and are often lacking in survivors of stroke who are deconditioned. The inability to walk community distances due to poor endurance and walking capacity can limit active community participation.
Purpose: The purpose of this study was to determine if there were significant differences in demographics or functional capability at baseline for responders versus non-responders to the 6MWT after intensive mobility training for survivors of chronic stroke and to determine if those responders also improved on other measures of functional capacity.
Methods: 29 individuals with chronic stroke participated in Intensive Mobility Training for 3 hours a day for 10 consecutive weekdays. The model of intensive intervention was standardized for time but was individualized to the participants functional and endurance level. Individuals participated in a series of mobility interventions primarily including gait training, balance, and functional / coordination activities. Rest periods were allowed as needed up to 30 minutes. Assessments were performed before (baseline), immediately before (pre), immediately after (post) and approximately 3 months after (follow up). In addition to the 6MWT, measurements included gait velocity (fast and self-selected), Berg Balance Scale, the Timed Up and Go, and the Stroke Impact Scale. The groups were dichotomized into responders and non-responders. Responders had a minimal improvement of 28 meters (minimal detectable change) on the 6MWT between pre-test and follow up.
Results: 14 (48%) responders had an improvement in the 6MWT > 28 meters with an average improvement of 43.7 (17.5) meters from pre-test to 3 month follow up, while 15 non-responders had an improvement 28 meters or a decline in distance with an average of -36.2 (48.3) meter decline. There was no significant difference between groups (responders vs. non-responders) at baseline for any outcome measure nor for age or time since stroke (unpaired t-tests). When comparing 6MWT responders to non-responders at follow-up exam, the groups were significantly different for following tests of capacity: 6MWT (p .001) and Timed up Go(p=.04). There were no significant differences between 6MWT responders and non-responders at follow-up for the other outcome measures (Berg Balance Scale, self-selected and fast walking speed, Stroke Impact Scale), nor for demographic variables (age, time since stroke).
Conclusion(s): Improvements in the 6MWT did not correspond to any differences in baseline values on other outcome measures or demographic variables. It is unclear what separated the responders from the non-responders. It is possible measures that would delineate these differences were not included in the study.
Implications: Identifying which clients will improve endurance with intensive intervention is challenging and appears unrelated to age, chronicity of stroke or other functional markers. Additional measures related to co-morbidity, motivation, depression, and recovery perception may aid in identifying responders/non-responders and predicting walking capacity improvements. Including the 6MWT among standardized measures in the chronic stroke population may reveal limitations in community ambulation not captured by other physical therapy measures.
Funding acknowledgements: Financial support was provided by a grant from the American Heart Association (Scientist Development Grant, AHA Award #0835160N).
Topic: Neurology: stroke
Ethics approval: University of South Carolina IRB
All authors, affiliations and abstracts have been published as submitted.
