Does Ankle Exoskeleton Assistance Impair Stability During Walking in Individuals with Cerebral Palsy?

Taryn A. Harvey, Benjamin C. Conner, Zachary F. Lerner

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Lower-limb exoskeletons have the potential to improve mobility in individuals with movement disabilities, such as cerebral palsy (CP). The goal of this study was to assess the impact of plantar-flexor assistance from an untethered ankle exoskeleton on dynamic stability during unperturbed and perturbed walking in individuals with CP. Seven participants with CP (Gross Motor Function Classification System levels I-III, ages 6–31 years) completed a treadmill walking protocol under their normal walking condition and while wearing an ankle exoskeleton that provided adaptive plantar-flexor assistance. Pseudo-randomized treadmill perturbations were delivered during stance phase by accelerating one side of a split-belt treadmill. Treadmill perturbations resulted in a significant decrease in anteroposterior minimum margin-of-stability (− 32.1%, p < 0.001), and a significant increase in contralateral limb step length (8.1%, p = 0.005), integrated soleus activity during unassisted walking (23.4%, p = 0.02), and peak biological ankle moment (9.6%, p = 0.03) during stance phase. Plantar-flexor assistance did not significantly alter margin-of-stability, step length, soleus activity, or ankle moments during both unperturbed and perturbed walking. These results indicate that adaptive plantar-flexor assistance from an untethered ankle exoskeleton does not significantly alter dynamic stability maintenance during unperturbed and perturbed walking for individuals with CP, supporting future research in real-world environments.

Original languageEnglish (US)
Pages (from-to)2522-2532
Number of pages11
JournalAnnals of Biomedical Engineering
Volume49
Issue number9
DOIs
StatePublished - Sep 2021

Keywords

  • Exo
  • Gait
  • Margin-of-stability
  • Moment
  • Perturbed walking
  • Soleus

ASJC Scopus subject areas

  • Biomedical Engineering

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