Modification of spastic gait through mechanical damping.

Area of Science:

• Biomechanics
• Neurology
• Rehabilitation Engineering

Background:

• Spastic gait, characterized by abnormalities like equinus and back-kneeing, may stem from uninhibited, velocity-dependent stretch reflexes.
• Mechanically damped orthoses offer a potential therapeutic approach to mitigate these gait issues.

Purpose of the Study:

• To evaluate the feasibility of using mechanically damped orthoses to improve spastic gait.
• To investigate the relationship between dissipative mechanical loads and spastic reflex activity.

Main Methods:

• Ankle rotation experiments and filmed gait analysis were used to screen subjects and quantify reflex behavior.
• A wearable, computer-controlled orthosis simulator applied controlled damping loads to the ankle during walking in a spastic subject.

Main Results:

• A velocity threshold for reflex behavior was identified.
• Appropriate ankle damping by the orthosis simulator improved local joint kinematics.
• Damping reduced muscle stretch velocity, leading to decreased spastic reflex activity.

Conclusions:

• Mechanically damped orthoses can functionally improve spastic gait by targeting velocity-dependent stretch reflexes.
• The findings support the use of controlled damping as an intervention for spastic gait abnormalities.