Clinimetric properties of a postural assessment software in older people: reliability, standard error of measurement, and minimal detectable change

Objective: To evaluate intra- and inter-rater reliability, standard error of the measurement (SEM), and minimal detectable change (MDC) of the angles obtained with a Postural Assessment Software (SAPO) in older people. Methods: Postural evaluation of 32 older adults was performed using Postural Assessment Software (SAPO). Two raters performed the procedure independently, and one of the raters repeated the process 7 to 10 days later. Reliability was assessed through the intraclass correlation coefficient (ICC) and paired and independent t-tests. SEM and MDC95 values were calculated, and Bland-Altman plots were generated. Results: The inter-rater analysis showed that the raters were not different in any of the angles. Most angles achieved good to excellent inter-rater reliability (ICC = 0.34 – 0.81) and intrarater reliability (ICC = 0.33 – 0.88) and were not different between days. The SEM was lower than 10º in most angles. The MDC95 ranged from 2.88º to 18.49º. Bland-Altman analysis indicated that most angles were within the limits of agreement. Overall, angles generated in lateral view had better reliability properties. Conclusion: Postural Assessment Software (SAPO) showed angles with distinct reliability properties in older adults. Angles that reached good to excellent intra- and inter-reliability and exhibited lower variability could be considered for assessing postural changes in older adults. MDC95 values could be used as a reference for indicating changes greater than the variability of the measurement.