Minimal Detectable Change for Gait Speed Depends on Baseline Speed in Individuals With Chronic Stroke.
Michael D Lewek, Robert Sykes
PMID 30702510WHAT IT FOUND
For chronic stroke, a real gait speed change depends on baseline speed.
Slower walkers need 0.10 m/s to exceed day-to-day variation, while faster walkers need 0.18 m/s.
Key findings
01Minimal detectable change for comfortable gait speed was smaller for slower walkers than faster walkers: 0.10 m/s, 0.15 m/s, and 0.18 m/s across LOW, MOD, and HIGH groups.
02Comfortable gait speed reliability was high overall but lower in faster baseline groups: 0.955 overall, 0.879 LOW, 0.677 MOD, 0.522 HIGH.
03Fast gait speed reliability remained high across groups, 0.930, 0.845, and 0.842, while minimal detectable change values increased substantially for individuals with faster comfortable baseline speed.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only chronic stroke participants, so it does not tell whether the same baseline-specific changes apply in subacute stroke. Comfortable speed increased between visits without treatment, overall 0.05 m/s, which may mean participants were not fully comfortable at the first visit. The fastest walkers in the alternative classification were few, only 8 participants, and their reliability was very low, 0.176, so the estimate for that group is less stable. Participants used their usual ankle foot orthosis or assistive device, so results may differ if those devices are not allowed. The study calculated minimal detectable change, not minimum clinically important difference, so it says what change exceeds day-to-day variation, not whether the change matters to the patient. Data came from people undergoing baseline testing for clinical trials, which may not represent all clinic patients.
Declared interests
The authors report no conflicts of interest. The supplied text does not state a funding source.
The easy way to misread this
Do not use 0.10 m/s as a universal rule for meaningful gait speed change. That value applied to slower walkers in this chronic stroke group, while faster walkers needed 0.18 m/s, and the paper did not establish that these changes are clinically important.