All the participants received a battery of neuropsychological tests to assess general mental status and other cognitive domains, including visual-spatial ability, executive function, language, memory, attention, and general intellectual ability. These tests included the CDR scale, the Mini-Mental State Examination(MMSE), the Montreal Cognitive Assessment(MoCA), clock drawing test (CDT), Auditory Verbal Learning Test (AVLT), activities of daily living scale(ADL) and Hamilton Depression Scale and HIS. All these evaluations were performed by two attending neurologists.