• Objectives: determine the safety, feasibility and usability of the ABLE Exoskeleton for individuals with spinal cord injury (SCI) in a hospital setting. Assess the effect on gait and functional outcomes, the rate of perceived exertion, psychosocial impact and user satisfaction.
• Study design: multicenter prospective pretest–posttest quasi-experimental study.
• Clinical sites: Institut Guttmann (Spain) and Heidelberg University Hospital (Germany).
• Patient population: 24 individuals (45 ± 12 years) with SCI ranging from C5 to L3 (ASIA Impairment Scale A to D), mainly subacute (< 1 year after injury).
• Training programme: 12 sessions (3 sessions a week over 4 weeks) of 60 minutes duration.
• Assessments:
  • Safety outcomes: device-related adverse events (AEs), number of drop-outs.
  • Feasibility and usability measures: level of assistance, donning/doffing-time, gait usage metrics and function.
  • Patient-reported outcome measures: rate of perceived exertion (RPE), psychosocial impact of the device and satisfaction (both for therapists and patients).
  • Standardized walking tests (session 1 and 12): Walking Index for Spinal Cord Injury (WISCI) II, Timed Up and Go (TUG), 10 Metre Walk Test (10MWT) and 6 Minute Walk Test (6MWT).

• Clinical trial database: NCT04876794

In 242 training sessions, 8 device-related AEs (pain and skin lesions) were reported.

Total time for don and doff was 6:50 ± 2:50 min.

Improvements in level of assistance and gait parameters (time, steps, distance and speed, p < 0.05) were observed in all participants.

Walking function and RPE improved in participants able to complete walking tests with (n = 9) and without (n = 6) the device at study start (p < 0.05).

A positive psychosocial impact of the exoskeleton was reported and the satisfaction with the device was good, with best ratings in safety (participants), weight (therapists), durability and dimensions (both).

Our study results prove the feasibility of safe gait training with the ABLE Exoskeleton in hospital settings for persons with SCI, with improved clinical outcomes after training.

Our study protocol allowed for consistent comparison of the results with other exoskeleton trials and can serve as a future framework towards the standardisation of early clinical evaluations.

• Objectives: comparing a knee-powered exoskeleton (ABLE Exoskeleton) with conventional knee-ankle-foot orthoses (KAFOs) in terms of gait biomechanics and energetics. 
• Study design: Randomized, single-center, crossover clinical trial.
• Clinical sites: Asepeyo Sant Cugat Hospital (Spain).
• Patient population: 10 individuals (44 ± 6 years) with chronic (> 1 year after injury) motor-complete (ASIA Impairment Scale A or B) spinal cord injury ranging from T4 to T12. Previous experience with KAFOs.
• Training programme: 10 sessions (2 sessions a week over 5 weeks) of 90 minutes duration with each device.
• Assessments:
  • Energy consumption: metabolic cost of walking measured through gases exchange.
  • Biomechanics: gait kinematics, spatiotemporal parameters.
  • Patient-reported outcome measures: psychosocial impact of the device and satisfaction.
  • Standardized walking tests (session 5 and 10): Timed Up and Go (TUG), 10 Metre Walk Test (10MWT) and 6 Minute Walk Test (6MWT).

• Clinical trial database: NCT04855916

Walking with the ABLE Exoskeleton improved gait kinematics compared to the KAFOs, providing a more physiological gait pattern with less compensatory movements (38% reduction of circumduction, 25% increase of step length, 29% improvement in weight shifting).

However, participants did not exhibit significantly better results in walking performance for the standard clinical tests (Timed Up and Go, 10-m Walk Test, and 6-min Walk Test), nor significant reductions in energy consumption.

Our findings suggest that using a knee-powered exoskeleton improves gait kinematics in people with SCI.

Participants walked with a more physiological gait pattern (less compensatory movements, better weight shifting, and longer step length) using the ABLE Exoskeleton compared to using the KAFOs.

However, the improvements in gait kinematics did not extend to significant improvements in energy efficiency.

Probably the low contribution of the knee joint on the metabolic cost of walking, together with the lack of trunk stability in the sagittal plane, were not enough to reduce the effort that ambulation entails in people with complete SCI.

Active assistance of the hip or ankle joints seems to be necessary for that purpose.

Those insights served our team to develop the next version of the ABLE Exoskeleton, which includes hip assistance and additional trunk support.

In terms of user satisfaction, the ABLE Exoskeleton was considered significantly safer and presented on average higher scores than the KAFOs.