Quantifying step length using two-dimensional video in individuals with Parkinson's disease.

Individuals with Parkinson's disease demonstrate a shorter step length compared to individuals without the disorder, which may place them at greater risk for falls. As a result, rehabilitation professionals often attempt to increase or maintain step length in this population. The ability to quantify step length may be useful for tracking changes or identifying individuals who may be at risk for a fall. However, there are few approaches to precisely/directly measure step length that are feasible for clinical use. The purposes of this study were to evaluate the reliability of step length measurements from two-dimensional (2D) video in individuals with Parkinson's disease and to compare the step lengths of individuals with/without a recent history of falls. A video camera recorded 24 individuals with Parkinson's disease as they walked at a comfortable pace. Step length measurements from the video demonstrated excellent intra- and inter-rater reliability (intraclass correlation coefficients greater than 0.90). In addition, individuals with Parkinson's disease who had experienced a fall within the previous year demonstrated shorter step lengths compared to individuals who had not experienced a recent fall. The ability to quantify step length from 2D video could be a useful tool when managing patients with Parkinson's disease.