Enhancing lower-limb motor imagery using a paradigm with visual and spatiotemporal tactile synchronized stimulation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Technology

Background:

• Motor imagery (MI) performance is often guided by vibrotactile stimulation (VS).
• Single-point VS lacks spatiotemporal information, limiting vividness and effectiveness in MI guidance.
• Existing methods struggle to provide effective guidance, especially for individuals with poor MI performance.

Purpose of the Study:

• To propose and evaluate a novel visual and spatiotemporal tactile synchronized stimulation (VSTSS) paradigm.
• To enhance motor imagery (MI) guidance and improve MI-based brain-computer interface (MI-BCI) performance.
• To specifically benefit subjects with lower performance in lower-limb MI tasks.

Main Methods:

• Developed a VSTSS paradigm integrating visual cues with synchronized spatiotemporal tactile feedback.
• Recruited 14 healthy subjects, categorizing them into good and poor performers for lower-limb MI tasks.
• Analyzed electrophysiological features (event-related desynchronization - ERD) and MI-BCI classification accuracy under no VS (NVS), VS, and VSTSS conditions.

Main Results:

• VSTSS demonstrated more pronounced event-related desynchronization (ERD) in the sensorimotor cortex compared to NVS and VS.
• For poor performers, VSTSS increased average alpha rhythm ERD values by 34.70% (vs. NVS) and 14.28% (vs. VS).
• VSTSS significantly improved MI-BCI classification accuracy by 12.52% (vs. NVS) and 4.05% (vs. VS) for poor performers.

Conclusions:

• The VSTSS paradigm effectively enhances motor cortical activation during MI.
• VSTSS significantly improves MI-BCI classification performance by providing more vivid MI guidance.
• This approach shows promise for advancing lower-limb MI-BCI applications, particularly in stroke rehabilitation.