Spasticity is difficult to quantify consistently, plagued with inter and intra-rater reliability errors. The objective of this study was to determine whether variables captured by a robotic ankle training device could be used to provide a more reliable measurement of spasticity.
The study included 4 subjects with spastic hemiplegia. Spasticity in the gastrocnemius, soleus, and tibialis posterior muscles were assessed wearing the robotic ankle device, Anklebot. Spasticity was rated by a single clinician on the Modified Ashworth Scale (MAS). The Anklebot recorded the clinician’s actions and then played back the same actions. Testing was done at the time of chemodenervation and again approximately 6 weeks post-chemodenervation. A spastic catch was defined by the point of peak deceleration. Factors of interest were examined during clinician testing for correlation with an increase in MAS, including percent range of motion the catch occurred, speed pre and post-catch, acceleration post-catch, and change in acceleration post-catch. A model of spasticity scoring was created using linear regression and applied to the Anklebot recreations.
Using an Anklebot to recreate spasticity testing maneuvers, a consistent quantifiable measure of spasticity can be created. The current model is limited by its basis on the MAS and assumption of a linear nature of spasticity. A larger sample size may provide better insight to factors of interest, allowing a more independent model (e.g. piecewise linear) for scoring of spasticity.
Anthony Manfredo– Resident, Sinai Hospital of Baltimore
Angela Davis– Senior Physical Therapist, University of Maryland Rehabilitation & Orthopedics Institute
Bradley Hennessie– CEO, NextStep Robotics Inc.
Richard Macko– Professor, Department of Neurology, School of Medicine, University of Maryland, Baltimore
Larry Forrester– Associate Research Professor, Dept of Kinesiology, School of Public Health, University of Maryland, College Park
Anindo Roy– Chief Technology Officer, NextStep Robotics
Michael Dimyan– Assistant Professor, University of Maryland, Baltimore, School of Medicine