Neural and biomechanical tradeoffs associated with human-exoskeleton interactions

Area of Science:

• Ergonomics and Human Factors
• Neuroscience
• Biomechanics

Background:

• Industrial passive low-back exoskeletons are increasingly explored for mitigating risks in manual handling.
• Understanding the neural and biomechanical effects of human-exoskeleton interaction (HEI) is crucial for effective implementation.
• Short-term HEI effects require quantification, especially under varying cognitive loads.

Purpose of the Study:

• To quantify the neural and biomechanical tradeoffs of short-term HEI during asymmetrical lifting.
• To compare HEI effects under single-task versus dual-task cognitive paradigms.
• To assess the utility of ambulatory near-infrared spectroscopy (fNIRS) in measuring HEI-related neural costs.

Main Methods:

• A two-armed experimental approach using single vs. dual-task paradigms.
• Utilized a dynamic, electromyography-assisted spine model for biomechanical analysis.
• Employed ambulatory near-infrared spectroscopy (fNIRS) for brain connectivity analyses.

Main Results:

• The exoskeleton provided statistically significant but marginal biomechanical benefits during lifting.
• These biomechanical benefits diminished when a cognitive dual-task was introduced.
• fNIRS revealed increased neurocognitive and motor adaptation efforts, engaging action monitoring and error processing networks.

Conclusions:

• Cognitive demands in the workplace can negate the mechanical advantages of passive low-back exoskeletons.
• The neural cost of HEI can be captured using ambulatory fNIRS without complex dual-task manipulations.
• Findings highlight the importance of considering cognitive load in exoskeleton design and application.