Predictors of exoskeleton motor learning in spinal cord injured patients

Learning to use an exoskeleton is time consuming and diverse between users. Knowledge about trainability of exoskeleton skills is relevant for planning and expectation management. The objective was to assess predictors of exoskeleton skill performance during and after exoskeleton training.

Twenty-four participants with a motor complete spinal cord injury were given 24 training sessions in 8 weeks. Nine potential predictors were identified: lesion level, age, gender, age at injury, time since injury, BMI, sport, active lifestyle, and anxiety. Univariate and multivariate linear regression analyses were performed to examine predictors of skill performance after 2, 4, 6, and 8 weeks.

Twenty participants completed the training. Univariate analysis revealed that positive predictors were: low lesion level and more active lifestyle after 2 weeks, whereas low age at injury, low BMI, and more active lifestyle were positive predictors after 6 weeks. Multivariate regression model explained 65% of the performance after 2 weeks (predictors: lesion level, anxiety, active lifestyle) and 66% after 6 weeks (predictors: BMI, active lifestyle, age). Lesion level was a predictor during the first 4 weeks, but did not influence participants' final skill level. BMI, age, and active lifestyle were predictors toward the end of the training period.Implications for rehabilitationWith the help of wearable exoskeletons people with a complete spinal cord injury can regain their standing and walking mobility.Learning to use an exoskeleton is time consuming and the number of training sessions required to walk independently differs greatly between users.This study shows that lesion level was an important predictor of exoskeleton motor learning in the first 4 weeks of training.BMI, age, and active lifestyle were predictors of exoskeleton skill performance toward the end of the 8 week training period.