Participant Selection Criteria

The inclusion and exclusion criteria that decide who may enroll — simultaneously an ethical safeguard, a scientific control, and a determinant of generalizability. Typical criteria for an implanted motor or communication BCI include a stable severe deficit of defined etiology, intact relevant cortex and viable target tissue on imaging, adequate cognition and capacity to consent, absence of surgical or imaging contraindications, a stable psychosocial situation with caregiver support, and the practical ability to attend frequent, often long-term sessions.

These filters produce a highly non-representative cohort of unusually motivated, well-supported, cognitively intact participants, which tends to inflate apparent performance relative to the eventual real-world population. Selection also raises equity concerns: requirements such as caregiver support and proximity to a specialist center systematically exclude the isolated and the under-resourced, so who is studied shapes who is later served.