Can Lokomat therapy with children and adolescents be improved? An adaptive clinical pilot trial comparing Guidance force, Path control, and FreeD

Abstract

BackgroundRobot-assisted gait therapy is increasingly being used in pediatric neurorehabilitation to complement conventional physical therapy. The robotic device applied in this study, the Lokomat (Hocoma AG, Switzerland), uses a position control mode (Guidance Force), where exact positions of the knee and hip joints throughout the gait cycle are stipulated. Such a mode has two disadvantages: Movement variability is restricted, and patients tend to walk passively. Kinematic variability and active participation, however, are crucial for motor learning. Recently, two new control modes were introduced. The Path Control mode allows the patient to walk within a virtual tunnel surrounding the ideal movement trajectory. The FreeD was developed to support weight shifting through mediolaterally moveable pelvis and leg cuffs. The aims of this study were twofold: 1) To present an overview of the currently available control modes of the Lokomat. 2) To evaluate if an increase in kinematic variability as provided by the new control modes influenced leg muscle activation patterns and intensity, as well as heart rate while walking in the Lokomat.MethodsIn 15 adolescents with neurological gait disorders who walked in the Lokomat, 3 conditions were compared: Guidance Force, Path Control, and FreeD. We analyzed surface electromyographic (sEMG) activity from 5 leg muscles of the more affected leg and heart rate. Muscle activation patterns were compared with norm curves.ResultsSeveral muscles, as well as heart rate, demonstrated tendencies towards a higher activation during conditions with more kinematic freedom. sEMG activation patterns of the M.rectus femoris and M.vastus medialis showed the highest similarity to over-ground walking under Path Control, whereas walking under FreeD led to unphysiological muscle activation in the tested sample.ConclusionsResults indicate that especially Path Control seems promising for adolescent patients undergoing neurorehabilitation, as it increases proximal leg muscle activity while facilitating a physiological muscle activation. Therefore, this may be a solution to increase kinematic variability and patients’ active participation in robot-assisted gait training.Electronic supplementary materialThe online version of this article (doi:10.1186/s12984-017-0287-1) contains supplementary material, which is available to authorized users.

A robot-based gait training therapy for pediatric population with Cerebral Palsy: goal setting, proposal and preliminary clinical implementation

“…89 It provides means for adapting the therapy to the user's necessities through different 90 levels of assistance in multi-joint over-ground training. Other gait trainers, such as 91 Lokomat [14] or LOPES [6], could have been also used to evaluate this training 92 method, since they are also able to tailor each therapy session to the patient's needs. 93…”

“…The proposed protocol could be applied to any current 506 robotic device for gait rehabilitation making minimal changes on it: e.g. in treadmill 507 pediatric platforms as Lokomat [14], despite the impossibility of over-ground walking, 508 it already has different controllers, whose operation modes are close to the levels of 509 impedance of CPWalker, ensuring the progression of the therapy into the sessions. 510…”

Getting the Best Out of Advanced Rehabilitation Technology for the Lower Limbs: Minding Motor Learning Principles

“…When steps are produced actively, several cortical and subcortical areas are activated to a much larger degree than when the steps are produced passively [29]. Muscle activation is greater in training conditions with less guidance and more freedom [30]. Hence, for optimized results, the patient should be motivated to be as engaged and active as possible during training and constantly challenged to put forth as much effort as possible.…”

An Increase in Kinematic Freedom in the Lokomat Is Related to the Ability to Elicit a Physiological Muscle Activity Pattern: A Secondary Data Analysis Investigating Differences Between Guidance Force, Path Control, and FreeD

“…Both publications point out that broad practical knowhow is essential, especially for the rehabilitation of young patients. Additionally, it is important to completely understand the mechanisms underlying these technologies (Aurich- Schuler et al, 2015Schuler et al, , 2017Schuler et al, , 2019van Hedel and Aurich-Schuler, 2016).…”

“…Path Control offers a spatiotemporal tunnel around the predefined gait trajectory in the sagittal plane which allows a certain degree of individualization (Duschau-Wicke et al, 2010a;Schück et al, 2012). FreeD performs an actuated movement of the pelvis of the patient (coupled lateral translation and transverse rotation) and allows mediolateral movements of the leg cuffs (Aurich- Schuler et al, 2017Schuler et al, , 2019.…”