Inter-rater reliability and concurrent validity of step length and step width measurement after traumatic brain injury

Abstract

Purpose: To determine the inter-rater reliability and concurrent validity of step length and step width measurement after traumatic brain injury.Method: Twelve people with traumatic brain injury completed six comfortable and six fast paced walking trials over a 10 m distance. Step length and step width were measured by five observers using two procedures. First, using pens taped on the subjects' heels which marked the floor at each heel strike and a tape measure. Second, by videotaping the subjects' feet as they walked on a mat marked with 5 cm grids and using a computer program to digitize foot position and calculate step length and width.Results: The inter-rater reliability of step length and width measurements was very high, with intraclass correlation coefficients between 0.94 and 1.00, for both procedures. Concurrent validity was excellent, with correlations between the procedures ranging from 0.93 to 1.00. However, attaching pens to the heels did cause a slight reduction in right step length and walking speed when walking at a fast or comfortable pace, respectively.Conclusions: Assessing step length and width using pens taped to the subjects' heels and a tape measure is a reliable and valid clinical measure after traumatic brain injury.