Reliability and minimal detectable change of nonlinear analysis measure of postural control in older adults with mild cognitive impairment

Background: Evaluating quiet stance under various conditions using nonlinear analysis may be an effective method of measuring postural control in older adults with mild cognitive impairment (MCI). However, no studies have examined the reliability of using sample entropy (SampEn) in older adults with MCI.

Research question: What are the within- and between-session reliability and minimal detectable change (MDC) of a nonlinear analysis measure of postural control during quiet stance in older adults with MCI?

Methods: Fourteen older adults with MCI performed static standing under four conditions, and the center of pressure signal was calculated and applied to SampEn nonlinear analysis. The within- and between-session reliability and MDC were explored.

Results: Within-session reliability was found to be fair to good and excellent (ICC = 0.527-0.960), and between-session reliability was excellent (ICC = 0.795-0.979). MDC values were less than 0.15.

Significance: The between-session reliability of SampEn in all conditions demonstrates SampEn's stable performance. This method may be useful in assessing postural control in older adults with MCI, and MDC values may be helpful in detecting subtle changes in patient performance.