I. Introduction
Alzheimer's disease (AD) is an insidious neurodegenerative disease that causes brain atrophy and cell death, and is the most common type of dementia [1]. However, there is currently no effective treatment that delays the onset or slows the progression of AD. Mild cognitive impairment (MCI) is conceptualized as a transitional state between normal aging and dementia. In the MCI stage, clinical practice has shown that enhancing patient care, quality of life, drug and mental treatment can markedly delay disease progression. Thus, accurate and timely diagnosis of MCI is critical to the early detection and treatment of AD [2].