Normative percentile ranking best reveals sensorimotor impairments of postural sway in type 2 diabetes

Abstract

Background Type 2 Diabetes (T2D) is associated with a higher magnitude of static postural sway. This investigation compared three statistical methods to explore the role of sensory modalities contributions to posture in T2D. Research design and methods Two groups were evaluated in this study ( n = 20); T2D group - 10 participants with T2D (age 54.6 ± 11.09 years), comparison group - 10 age/sex matched healthy participants (age 53.18 ± 9.89 years). Postural sway data was collected using the modified Clinical Test of Sensory Integration in Balance (mCTSIB), consisting of four 20-s trials on a balance plate with manipulations of vision and support surface to target the contributions of proprioceptive, visual, and vestibular senses. Scores were assessed by group wise analysis of path length, group wise analysis of percentile rank, and distribution of percentile rank. Results The two-way ANOVA used for the group wise analysis of path length and percentile rank showed significant differences between groups scores ( p < .05), but no significant interactions between group and condition. The frequency distribution of percentile rank of the T2D group revealed unimodal distributions for all conditions except for vestibular, which was found to have the highest and lowest percentile ranks of any condition. Conclusion The results show that the individualized normative analysis revealed aspects of individual impairments that would have otherwise been missed using a group-wise method. Though limited, our findings also suggest that impairments to the vestibular system may be more pronounced but less frequent compared to proprioceptive and visual impairments.