Foot-ground force quantifies impaired balance control mechanisms post-stroke

Area of Science:

• Biomechanics
• Neurorehabilitation
• Computational modeling

Background:

• Over 50% of stroke survivors experience persistent balance impairments, often managed with suboptimal compensatory strategies.
• Current understanding of post-stroke balance control is limited, hindering targeted rehabilitation efforts.
• Computational modeling has advanced balance control research in unimpaired individuals but is less explored in stroke populations.

Purpose of the Study:

• To identify distinct neuromechanical control strategies in post-stroke individuals during quiet standing.
• To compare balance control models between post-stroke and unimpaired participants.
• To explore the potential of computational modeling for informing stroke rehabilitation.

Main Methods:

• Modeled quiet standing using a double-inverted pendulum with full-state feedback control.
• Fit controller parameters to foot-ground force data from 12 post-stroke and 22 unimpaired participants.
• Analyzed joint-torque-coordination patterns and neural feedback reliance.

Main Results:

• Post-stroke participants exhibited a distinct joint-torque-coordination pattern in the paretic limb compared to unimpaired individuals.
• The non-paretic limb in post-stroke participants showed increased reliance on neural feedback, potentially compensating for paretic limb alterations.
• Model-based analysis revealed differences not apparent in traditional assessments.

Conclusions:

• Computational modeling can differentiate balance control strategies between post-stroke and unimpaired individuals.
• Altered coordination in the paretic limb and compensatory neural feedback in the non-paretic limb are key findings in post-stroke balance.
• Model-based analysis of foot-ground forces offers novel, clinically relevant insights for stroke rehabilitation.