Development of a neural efficiency metric to assess human-exoskeleton adaptations

Area of Science:

• Biomechanics
• Neuroscience
• Human-Exoskeleton Interaction

Background:

• Passive exoskeletons aim to reduce lumbar spine load and enhance productivity.
• Limited research exists on the neurocognitive effects of short-term human-exoskeleton adaptation.

Purpose of the Study:

• Develop a novel neural efficiency metric to assess short-term adaptation to passive lower back exoskeletons during repetitive lifting.
• Investigate the effects of exoskeleton use on biomechanics and neural activation.

Main Methods:

• Twelve participants performed simulated asymmetric lifting tasks with and without a passive exoskeleton.
• Data collected across early, middle, and late phases to examine adaptation.
• Analyzed biomechanical parameters, neural activation, and a new neural efficiency metric.

Main Results:

• Exoskeleton use significantly reduced peak L5/S1 superior lateral shear forces compared to no exoskeleton.
• Other biomechanical and neural activation measures were similar between conditions.
• The neural efficiency metric tracked motor adaptation, showing lower efficiency with exoskeleton use over time.

Conclusions:

• The novel neural efficiency metric effectively tracks short-term adaptation in exoskeleton-assisted manual handling.
• Exoskeleton-assisted lifting demands a longer adaptation period and is less efficient, potentially affecting user acceptance and intent to use.