Using robotic mechanical perturbations for enhanced balance assessment.

Area of Science:

• Biomechanics
• Robotics
• Neurology

Background:

• Balance impairment affects patients with neural/musculoskeletal disorders and the elderly.
• Objective balance assessment relies on center of pressure (COP) measurement.
• Existing methods may lack controlled perturbation capabilities.

Purpose of the Study:

• To design and fabricate a robotic device for controlled mechanical perturbations during balance tasks.
• To evaluate the device's dynamics and its efficacy in enhancing balance assessment.
• To investigate the impact of perturbations on COP-based balance indices.

Main Methods:

• A robotic device with servo-controlled actuators and parallel mechanisms was developed.
• The device provided independent mediolateral and anterior-posterior rotations with visual COP feedback.
• Functional tests validated device dynamics (time constant 0.19 s, bandwidth 0.85 Hz).
• Ten healthy subjects performed balance tasks with and without perturbations, with seven COP indices measured.

Main Results:

• The robotic device demonstrated appropriate dynamics for controlled balance perturbations.
• The presence of mechanical perturbations significantly increased the sensitivity of all measured COP indices.
• Sensitivity enhancement was particularly notable in the anterior/posterior direction.

Conclusions:

• The developed robotic device effectively provides controlled mechanical perturbations for balance assessment.
• Perturbation-based balance assessment using this device improves the sensitivity of COP indices.
• This technology holds promise for more accurate and objective evaluation of balance in various patient populations.