Test-retest reliability and limits of agreement of the Six-Spot Step Test in people with Parkinson's disease.

The Six-Spot Step Test has an acceptable within-day and day-to-day agreement and reliability in mild to moderately disabled people with Parkinson's disease. A change of 2.2 seconds can be regarded as a true change. To minimize learning effects, test trials of the Six-Spot Step Test are recommended before use.