Soft Rehabilitation Actuator With Integrated Post-stroke Finger Spasticity Evaluation

Area of Science:

• Biomedical Engineering
• Rehabilitation Science
• Neurology

Background:

• Stroke frequently results in upper extremity impairment due to spasticity.
• Current spasticity assessments, like the Modified Ashworth Scale (MAS), are subjective and lack quantitative data.
• Objective evaluation is crucial for effective post-stroke neural plasticity and rehabilitation.

Purpose of the Study:

• To develop and validate the first soft actuator for objective measurement of post-stroke finger spasticity.
• To establish a quantitative method for assessing finger stiffness in stroke survivors.
• To enable progress tracking in hand rehabilitation.

Main Methods:

• A 3D-printed soft actuator was designed to interact with the finger.
• Spasticity (stiffness) was calculated using a pressure-angle relationship derived from the finger-actuator interaction.
• The method was validated using finite element analysis (FEA), mannequin fingers, and human subjects (stroke survivors and healthy individuals).

Main Results:

• The soft actuator successfully quantified finger stiffness.
• Finger stiffness was significantly higher in stroke subjects compared to healthy subjects.
• Significant variations in stiffness were observed among stroke patients, even those with similar MAS scores.

Conclusions:

• The developed soft actuator offers an objective and quantitative method for evaluating post-stroke finger spasticity.
• This technology can provide valuable insights into individual patient conditions and aid in monitoring rehabilitation progress.
• The soft actuator facilitates the development of advanced hand rehabilitation robots for personalized therapy.