3. Severe dementia or neurodegenerative disease, defined as either impairment that prevents the patient from living independently at baseline or IQCODE >4.5, measured using a patient's qualified surrogate. This exclusion also pertains to mental illnesses requiring long-term institutionalization, acquired or congenital mental retardation, severe neuromuscular disorders, Parkinson's disease, and Huntington's disease. It also excludes patients in coma or with severe deficits due to structural brain diseases such as stroke, intracranial hemorrhage, cranial trauma, malignancy, anoxic brain injury, or cerebral edema.