Test-Retest and Inter-Rater Reliability of the 20-Meter Ambulation Test in Patients with Parkinson's Disease.

Objective: In patients with Parkinson's disease, limited sit-to-stand, walk and turn contribute to decreased independence and quality of life. The 20-meter Ambulation Test (AT20) evaluates walking a total of 20 m, over a 10-m distance, back and forth between 2 chairs, starting and ending in a seated position. The aim of this study was to evaluate test-retest and inter-rater reliability of the AT20 in patients with Parkinson's disease.