A study of the reliability and validity of the Six-Spot Step Test Cognitive in ambulatory people with diabetic peripheral neuropathy.

ObjectivesCognitive decline and impaired balance are well-documented in people with diabetic peripheral neuropathy; however, no ambulation assessments currently address the cognitive dual-task demands specific to this population. The Six-Spot Step Test Cognitive is a brief, functional mobility test designed to equally emphasize cognitive and motor components. This study evaluated its construct validity and test-retest reliability in people with diabetic peripheral neuropathy.DesignCross-sectional study.SettingOutpatient clinics.ParticipantsFifty-five people with diabetic peripheral neuropathy.Main measuresThe Six-Spot Step Test Cognitive was completed twice within the same day and again three to seven days later. Additionally, the cognitive Timed "Up and Go" test and the Mini-BESTest were administered on the last day. Reliability and validity were estimated using Bland-Altman statistics, the minimal difference, Intraclass Correlation Coefficient, and Spearman's rank correlation coefficient.ResultsThe Six-Spot Step Test Cognitive was found reliable (Intraclass Correlation Coefficient: 0.88-0.92; minimal difference: 27.2%-31.4%) and showed moderate construct validity to the cognitive Timed "Up and Go" test (Spearman's rank correlation coefficient = 0.55, p < .001). Weak correlations with the Mini-BESTest (Spearman's rank correlation coefficient = -0.26, p < .06) indicated low construct validity. Significantly higher dual-task costs were observed when performing the Six-Spot Step Test Cognitive (58.7%) compared to the cognitive Timed "Up and Go" test (29.6%).ConclusionsIn people with diabetic peripheral neuropathy, the Six-Spot Step Test Cognitive demonstrated promising construct validity and acceptable to excellent reliability, making it a valid measure of functional mobility, including cognitive dual-tasking. Additionally, a higher dual-task cost indicated actual cognitive-motor interference while performing the test.