Efficacy and biomechanical effects of the powered lower-limbs exoskeletons Keeogo in adults with neuromuscular diseases

BACKGROUND: Neuromuscular diseases (NMD) result in progressive muscle weakness, significantly impairing functional abilities and quality of life. Assistive devices like the Keeogo, a lightweight, non-self-supported powered exoskeletons have the potential to enhance mobility and independence in NMD. This study seeks to fill the gap in our understanding of how these devices impact mobility and function in this specific population. METHODS: We investigated efficacy, perceptions and biomechanical effects of the powered exoskeleton Keeogo in adults with NMD during a 2-min walk test (2MWT), 10-m walk test (10mWT), 30-s sit-to-stand test (STS30), and postural stability test (SWAY). Patient’s perception of stability, exertion, dyspnea and pain, muscle strength, gait parameters, joint kinematics, and muscle activation were evaluated. RESULTS: Knee extensor strength was 45.5 ± 63.5 Nm, corresponding to 27.6 ± 42.9% of predicted value based on normative data. Walking performance during 2MWT and 10mWT were significantly reduced while wearing the Keeogo, with decreased gait speed, stride length, and cadence. Hip flexion–extension range of motion was reduced and gastrocnemius medialis, rectus femoris, and vastus lateralis muscle activation were diminished when using the device. Major contributors to reduced gait performance when using the device identified using LASSO model was as follows: knee extension and ankle dorsiflexion strength, cadence, ankle angle at toe-off, and late hip extension and ankle dorsiflexion peak angles. The gluteus maximus muscle activation was lower during chair tests when using the Keeogo. No changes in static postural stability were observed. CONCLUSIONS: The Keeogo exoskeleton, while not improving static postural stability, adversely affected dynamic walking and transfer performance and kinematics the studied groups of adults with NMD, proportionally to the level of weakness and functional impairments. However, muscle loading was lessened in several muscle groups, emphasizing the potential of the device for alleviating muscle load. These findings highlight the need for customized exoskeleton hardware and software design to optimize assistance to the severity and distribution of muscle weakness.