Encoder-Controlled Functional Electrical Stimulator for Bilateral Wrist Activities-Design and Evaluation.

Area of Science:

• Neuroscience
• Rehabilitation Engineering
• Biomedical Devices

Background:

• Stroke often causes upper limb impairment, affecting voluntary control and motor coordination in both arms.
• Rehabilitation needs to improve affected arm control and synchronize bilateral upper limb activity.

Purpose of the Study:

• To develop and evaluate an encoder-controlled functional electrical stimulator for precise contralateral wrist movement mirroring.
• To assess the device's ability to synchronize wrist movements between the unaffected and affected sides.

Main Methods:

• An encoder-controlled functional electrical stimulator was developed for precise contralateral control of wrist flexion/extension.
• The device was calibrated individually, dynamically adjusting stimulation based on wrist angle differences.
• Real-time graphical feedback was provided, comparing stimulated and normal wrist performance.

Main Results:

• The stimulator successfully mirrored wrist movements from the unaffected to the affected side in 25 volunteers.
• Minor differences were observed: mean peak flexion difference of 2.3 degrees and extension difference of 1.9 degrees.
• A mean time lag of 1 second was recorded between the set and stimulated wrist angle graphs.

Conclusions:

• The encoder-controlled functional electrical stimulator shows promise for stroke rehabilitation by enabling precise mirroring of wrist movements.
• This technology can aid in restoring motor control and improving bilateral arm synchronization after stroke.
• Further research is warranted to validate its clinical efficacy in stroke patients.