Researchers conducted an exploratory study to examine how the stiffness and neutral angle of a robotic AFO influenced stair ambulation and preference in seven people with spastic cerebral palsy (CP). The researchers compared nine robotic AFO stiffness-neutral angle configurations, solid AFOs, and shoes alone.
The participants completed modified Timed Up and Down-Stairs (TUDS) tests, with outcomes including TUDS time, ankle kinematics, soleus and vastus lateralis activity, exertion, balance confidence, trunk instability, stiffness preference, and device power and torque.
The results indicated that increased stiffness and more plantarflexed neutral angles decreased peak dorsiflexion and increased peak torque, according to the authors; few other outcomes were affected. Four of the participants preferred low stiffness across all tasks.
Robotic AFOs performed better than solid AFOs by decreasing TUDs time and increasing confidence in descent, but not better than shoes alone. During stair ascent, the only difference between the AFOs and shoes was a reduction in soleus activity between solid AFOs and shoes alone.
The study, “Exploratory assessment of robotic ankle foot orthosis stiffness and neutral angle on stair ambulation in individuals with cerebral palsy,” was published in the Annals of Biomedical Engineering.
