Stéphanie Dehem , Maxime Gilliaux, Thierry Lejeune, Christine Detrembleur, Daniel Galinski, Julien Sapin, Martin Vanderwegen, Gaëtan Stoquart
Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, 1200 Brussels, Belgium
DOI: 10.2340/16501977-2248

Objective: To assess the capacity of the robotic device REAplan to measure overall upper limb peak resistance force, as a reflection of upper limb spasticity.
Methods: Twelve patients with chronic stroke presenting upper limb spasticity were recruited to the study. Patients underwent musculocutaneous motor nerve block to reduce the spasticity of elbow flexor muscles. Each patient was assessed before and after the motor nerve block. Overall the REAplan measured upper limb resistance force. The robot passively mobilized the patient’s upper limb at various velocities (10, 20, 30, 40 and 50 cm/s) in a back-and-forth trajectory (30 cm). The peak resistance force was analysed for each forward movement. Ten movements were performed and averaged at each velocity condition.
Results: The overall upper limb resistance force increased proportionally to the mobilization velocity (p < 0. 001). Resistance force decreased after the motor nerve block at 40 and 50 cm/s (p < 0. 05). Overall upper limb resistance force results showed excellent correlation with the Modified Ashworth Scale for elbow flexor muscles, for each velocity condition equal or higher than 30 cm/s (ρ >0. 6).
Conclusion: This study proposes a new, valid, reliable and sensitive protocol to quantify upper limb resistance force using the REAplan, as a reflection of upper limb spasticity.

Stroke patients often suffer from upper limb stiffness, named spasticity. Limb stiffness is usually assessed using subjective and qualitative scales. In the present study, we developed a quantitative protocol for the assessment of spasticity using a rehabilitation robot. The upper limb of twelve chronic stroke patients was passively mobilized at five different constant velocities. All along the extension movement, the robot measured the resistance force corresponding to the patient spasticity. The present study demonstrates that this new protocol is valid, reliable and sensitive.