Ying Fang1, Greg Orekhov1, Zachary F Lerner2. 1. Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011, USA. 2. Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011, USA; Department of Orthopedics, the University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USA. Electronic address: Zachary.Lerner@nau.edu.
Abstract
BACKGROUND: Gait abnormalities from neuromuscular conditions like cerebral palsy (CP) limit mobility and negatively affect quality of life. Increasing walking speed and stride length are essential clinical goals in the treatment of gait disorders from CP. RESEARCH QUESTION: How does over-ground gait training with an untethered ankle exoskeleton providing adaptive assistance affect mobility-related spatiotemporal outcomes and lower-extremity muscle activity in people with CP? METHODS: A diverse cohort of individuals with CP (n = 6, age 9-31, Gross Motor Function Classification System Level I - III) completed four over-ground training sessions (98 ± 17 min of assisted walking) and received pre- and post-training assessments. On both assessments, participants walked over-ground with and without the exoskeleton while we recorded spatiotemporal outcomes and muscle activity. We used two-tailed paired t-tests to compare all parameters pre- and post-training, and between assisted and unassisted conditions. RESULTS: Following training, walking speed increased 0.24 m/s (p = 0.006) and stride length increased 0.17 m (p = 0.013) during unassisted walking, while walking speed increased 0.28 m/s (p = 0.023) and stride length increased 0.15 m (p = 0.002) during exoskeleton-assisted walking. Exoskeleton training improved stride-to-stride repeatability of soleus and vastus lateralis muscle activation by up to 51 % (p ≤ 0.046), while the amount of integrated stance-phase muscle activity was similar across visits and conditions. Relative to baseline, post-training walking with the exoskeleton resulted in a soleus activity pattern that was 39 % more similar to the typical pattern from unimpaired individuals (p < 0.001). SIGNIFICANCE: This study demonstrates acute spatiotemporal and neuromuscular benefits from over-ground training with adaptive ankle exoskeleton assistance, and provides rationale for completion of a longer randomized controlled training protocol.
BACKGROUND: Gait abnormalities from neuromuscular conditions like cerebral palsy (CP) limit mobility and negatively affect quality of life. Increasing walking speed and stride length are essential clinical goals in the treatment of gait disorders from CP. RESEARCH QUESTION: How does over-ground gait training with an untethered ankle exoskeleton providing adaptive assistance affect mobility-related spatiotemporal outcomes and lower-extremity muscle activity in people with CP? METHODS: A diverse cohort of individuals with CP (n = 6, age 9-31, Gross Motor Function Classification System Level I - III) completed four over-ground training sessions (98 ± 17 min of assisted walking) and received pre- and post-training assessments. On both assessments, participants walked over-ground with and without the exoskeleton while we recorded spatiotemporal outcomes and muscle activity. We used two-tailed paired t-tests to compare all parameters pre- and post-training, and between assisted and unassisted conditions. RESULTS: Following training, walking speed increased 0.24 m/s (p = 0.006) and stride length increased 0.17 m (p = 0.013) during unassisted walking, while walking speed increased 0.28 m/s (p = 0.023) and stride length increased 0.15 m (p = 0.002) during exoskeleton-assisted walking. Exoskeleton training improved stride-to-stride repeatability of soleus and vastus lateralis muscle activation by up to 51 % (p ≤ 0.046), while the amount of integrated stance-phase muscle activity was similar across visits and conditions. Relative to baseline, post-training walking with the exoskeleton resulted in a soleus activity pattern that was 39 % more similar to the typical pattern from unimpaired individuals (p < 0.001). SIGNIFICANCE: This study demonstrates acute spatiotemporal and neuromuscular benefits from over-ground training with adaptive ankle exoskeleton assistance, and provides rationale for completion of a longer randomized controlled training protocol.
Authors: Azadeh Kian; Giwantha Widanapathirana; Anna M Joseph; Daniel T H Lai; Rezaul Begg Journal: Sensors (Basel) Date: 2022-03-14 Impact factor: 3.576