Development of a new method for objective assessment of spasticity using full range passive movements

Objective: To develop a method for assessment of spasticity, in which the whole range of motion (ROM) at a wide variation of speeds is applied. Design: Cross-sectional design to study construct validity. Setting: Research department affiliated with a rehabilitation hospital in the Netherlands. Participants: Nine patients with complete spinal cord injury recruited from the rehabilitation hospital. Interventions: Not applicable. Main Outcome Measures: Thirty to 45 stretches over the whole ROM were applied to the triceps surae muscle at varying velocities measuring from 30° to 150°/s. Electromyographic responses were measured in order to assess reflex excitability. The torque over the ankle joint was measured during the whole stretch. The angle and velocity at which the reflex was initiated was also determined. Results: The electromyographic responses increased significantly at increasing stretch velocities (P<.001). The applied maximum angles are reproducible (intraclass correlation coefficient, .81) and provide representative torque responses. Conclusions: The assessment method of spasticity using full range passive movements provides objective outcomes. The angular velocity is responsible for an exponential increase in amplitude of the electromyographic response.