Inter-joint coordination during obstacle crossing in people with diabetic neuropathy

Sensori-motor deficit due to diabetic peripheral neuropathy (DPN) alters the quality of obstacle-crossing which may increase the risk of falling. The aim of this study was to compare inter-joint coordination (IJC) during obstacle-crossing between people with DPN and healthy controls. Fifteen DPN and 15 healthy people crossed over obstacles with heights of 10% and 20% of the subject's leg length. The mean absolute relative phase (MARP) and deviation phase (DP) of both leading and trailing limbs were used to calculate the phase dynamic and variability of IJC. Furthermore, correlation between Berg Balance Scale (BBS), Fall Efficacy Scale (FES-I), Timed Up and Go (TUG) and MARP, DP were assessed in DPN group. There was no significant interaction between group and obstacle height on measured variables. However, Group had significant main effect on DP of hip-knee in leading limb (p < 0.05). Additionally, the main effects of the obstacle's height were significant on MARP of hip-knee of trailing limb (p < 0.01) and knee-ankle in leading limb (p < 0.05). FES-I was significantly correlated to hip-knee and knee-ankle MARPs of leading limb for crossing over 20% and knee-ankle MARP for crossing over 10% height obstacle (r = 0.68, 0.69, 0.59, respectively, p < 0.05). This score was also significantly correlated with hip-knee DP of both trailing and leading limbs when crossing 10% obstacle (r = 0.59, 0.57, respectively, p < 0.05). In conclusion, IJC during obstacle-crossing was less variable and more out-of-phase, as a result of DPN and obstacle height, respectively. Moreover, when crossing over lower obstacles, fear of falling is related to IJC dynamics and variability of more proximal segment, especially in the leading limb.