Intra-rater and inter-rater reliability of the portable gait rhythmogram in post-stroke patients

[Purpose] Gait analysis, such as portable gait rhythmogram (PGR) provides objective information that helps in the quantitative evaluation of human locomotion. The purpose of this study was to assess the reliability of PGR in post-stroke patients. [Subjects and Methods] Two raters (A and B) examined 44 post-stroke patients. To assess intra-rater reliability, rater A tested subjects on three separate occasions (Days 1, 2, and 3). To assess inter-rater reliability, raters A and B independently tested participants on the same occasion (Day 3). [Results] There was no significant systematic bias between test occasions or raters. Intraclass correlation coefficient values were 0.93-0.97 for intra-rater reliability at both the comfortable speed and maximum speed, and 0.97-0.98 (comfortable speed) and 0.87-0.99 (maximum speed) for inter-rater reliability. The standard error was 1.25-1.49 (comfortable speed) and 1.62-1.77 (maximum speed) for intra-rater investigation, and 1.04-1.32 (comfortable speed) and 0.91-1.26 (maximum speed) for inter-rater investigation. At the 90% confidence level, the minimum detectable change ranged from 2.9-4.1%, and the error of an individual's score at a given time point ranged from ±2.1-2.9%. [Conclusion] Based on this excellent reliability of the PGR in post-stroke patients, it can be recommended as a simple test of gait analysis in this population.