Quantification of Gait Disorder from Asymmetry in Explicit and Implicit Gait Measures of Hemiplegic Post-Stroke Individuals using a Wearable System

Hemiplegic individuals are characterized by reduction in their ability on the paretic side leading to gait asymmetry and proneness to fall while walking. Gait asymmetry can be quantified in terms of asymmetry in implicit (related to lower limb muscle activation) and explicit (e.g., step time, %stance, etc.) measures. Although the implicit and explicit measures can be complementary in nature, yet none of the previous studies have looked into the asymmetry in both the explicit and implicit measures of gait of hemiplegic individuals. This is necessary, since similar walking pattern can possibly cause different lower limb muscle activation (affecting implicit measures), though the explicit measures of gait might remain the same/different. Thus, investigating the complementarity in such measures is crucial. Again, the asymmetry measures can be pronounced when one executes multiple tasks during walking simultaneously. In our present study, we computed the asymmetry in the implicit and explicit measures of gait in a time- synched manner by using a wearable system. We conducted a study with 12 healthy and 14 age-matched hemiplegic individuals who walked under single, dual, and multiple task (MTC) conditions. Results of hierarchical clustering showed the importance of complementarity in the asymmetry of implicit and explicit measures under MTC while distinguishing those with gait disorder from their healthy counterparts (classification accuracy: 88%) and identifying the extent of the disorder (classification accuracy: ~85%). Also, the asymmetry in these measures under MTC was found to have clinical relevance with regard to fear of fall.