SYSTEMATIC AND RANDOM ERROR IN REPEATED MEASUREMENTS OF TEMPORAL AND DISTANCE PARAMETERS OF GAIT AFTER STROKE

Objective: To obtain intersession estimates of error for temporal and distance (TD) parameters of gait in a sample of stroke patients undert aking inpatient rehabilitation. Design: Thirty-one stroke patients wer e measured with an instrumented footswitch system (after a median of 4 6 days poststroke; interquartile range = 26 to 63) walking over a 10-m eter distance a total of four times on 3 consecutive days. Two familia rization walks provided intrasession retest data. Results: Metric esti mates of systematic and random error have been provided for obtained T D parameters. Proportional indices of reliability (ICC [2, 1] and Pear son's r) were generally high, ranging from .72 to .94, Conclusion: By quantifying systematic and random error associated with the process of repeated measurements, criteria have been provided for evaluating cha nge in TD variables during rehabilitation. Although error for gait vel ocity was small relative to individual differences in the stroke group , it was large relative to levels of change derived from measurements reported during typical periods of rehabilitation, Serial measurements of gait during rehabilitation may be better than two consecutive meas urements. This study highlights the need to interpret estimates of err or according to the purpose of measurement. (C) 1997 by the American C ongress of Rehabilitation Medicine and the American Academy of Physica l Medicine and Rehabilitation.