Swing-through gait with free-knees produced by surface functional electrical stimulation

Area of Science:

• Biomedical Engineering
• Rehabilitation Science
• Neuroscience

Background:

• The swing-through gait is an efficient walking method but often unachievable for paraplegic individuals with thoracic lesions.
• Spinal cord injury (SCI) at thoracic levels frequently impairs lower limb function, limiting independent ambulation.
• Developing practical assistive technologies is crucial for enhancing mobility in individuals with SCI.

Purpose of the Study:

• To investigate the feasibility of using functional electrical stimulation (FES) to assist individuals with complete thoracic spinal cord injuries in achieving a swing-through gait.
• To evaluate the gait parameters and efficiency of FES-assisted swing-through gait in SCI subjects.

Main Methods:

• Three SCI subjects with complete thoracic lesions (T11, T11, T6) were recruited.
• An eight-channel surface electrode system delivered electrical stimulation to bilateral knee extensors, knee flexors, hip extensors, and hip flexors.
• A computer-controlled, rule-based strategy based on sensor inputs managed the stimulation sequence.

Main Results:

• Subjects with T11 lesions achieved average speeds of 0.40 m/s and 0.38 m/s over 56 m and 51 m, respectively.
• The subject with a T6 lesion averaged 0.30 m/s over 43 m.
• Motion analysis revealed SCI subjects spent more time in double support phases compared to non-impaired individuals, resulting in reduced momentum and gait efficiency.

Conclusions:

• Functional electrical stimulation (FES) can assist individuals with thoracic spinal cord injuries in performing a swing-through gait.
• While gait efficiency is reduced due to increased double support time, FES-assisted swing-through gait presents a potentially useful ambulation strategy for SCI.
• Further research and technological refinement may optimize FES-assisted gait for improved speed and energy efficiency.