Invited Commentary

Excerpt

Morris and colleagues have provided an excellent article outlining reliability of gait variables for people who have Parkinson's disease (PD). In a series of related experiments, Morris et al demonstrated the reliability and stability of gait measures across time, both within a day and across days. Furthermore, these authors demonstrated that the measures of gait investigated were not stable when results were compared from “on” to “ off” medication times.

For the most part, documentation of physical performance for patients with PD reported in the literature has used self-report rating scales rather than direct measurement.^1–4 The results of Morris et al join a growing body of evidence,^5–7 indicating that reliable measurements can be obtained for physical performance of these people. Results reported in this article should give confidence to both researchers and clinicians that variables related to gait can be measured with reliability in individuals with PD.…