Figure 1.

Flowchart of inclusion and exclusion criteria, n=number of subjects, nt=total number of visits/observations.

* Excluded if diagnosis of vitamin B12 deficiency, thyroid disease, alcohol abuse, other substance abuse, Down syndrome, Huntington disease, traumatic brain injury, hydrocephalus, central nervous system neoplasm, bipolar disorder, schizophrenia, anxiety, delirium, post-traumatic stress disorder, other major psychiatric illnesses, cognitive impairment due to alcohol abuse, cognitive impairment due to systemic disease/medical illness, cognitive impairment due to medications, brain cancer or CDR sum of boxes score greater than 16 at first qualifying visit