Test-Retest and Inter-Rater Reliability of the 20-Meter Ambulation Test in Patients with Parkinson's Disease.
Emilie Hutin, Mouna Ghédira, Valentina Mardale and 6 others
PMID 36943066WHAT IT FOUND
Manual timing and step counting during a 20-meter walk proved highly reliable in people with Parkinson's disease, even when asked to walk fast or take large steps.
Step length was the most consistent measure, offering a simple, equipment-free way to track gait changes.
Key findings
01Test-retest reliability for speed, step length, and cadence was excellent, with intraclass correlation coefficients all greater than 76%.
02Inter-rater reliability was also excellent, with intraclass correlation coefficients all greater than 95% across the three walking conditions.
03Step length showed the lowest mean absolute differences between test and retest, making it the most reliable parameter compared to speed and cadence.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The sample size was small (20 participants analysed), and the study was not powered to detect differences in reliability based on disease severity. Participants were in the 'off' medication state and were generally early-to-moderate stage (mean free speed 0.92 m/s), so the results may not apply to patients with advanced disease or those who use walking aids. Freezing of gait episodes were not specifically inventoried, though steps taken during freezing were counted. The study did not validate the AT20 against daily life step counts or disease stage classifications.
Declared interests
The authors have no conflicts of interest to declare.
The easy way to misread this
Do not assume this test is equally reliable for patients with advanced Parkinson's disease or those using walking aids. The study only included patients who could walk 20 meters without aids in the 'off' state, and the authors note that reliability may differ in more severe stages.