Whether patients with memory loss or other cognitive dysfunctions that are suspicious of dementia, such as language comprehension and expression impairment, decreased ability to handle complex things, decreased calculation ability, etc., they may have the question: which department should they register for when they visit the hospital? In fact, cognitive dysfunction in the elderly is a cross-cutting discipline, involving multiple fields such as neurology, psychiatry and geriatrics. Retrospective studies at home and abroad have also found that the departments where elderly people with cognitive impairment first visit are usually: neurology, psychiatry, geriatrics and internal medicine. However, the familiarity and diagnostic ability of the doctors in these departments in different hospitals in different regions vary greatly, and the manifestations of cognitive impairment are very insidious and complex, which causes many patients with cognitive impairment to be underdiagnosed or even misdiagnosed. In recent years, with the increasing understanding of mild cognitive impairment and dementia, cognitive impairment has gradually become a professional discipline. Many hospitals have established memory loss clinics, and specialty wards are increasingly providing more specialized services for those who visit them. Therefore, patients can choose to go to memory loss clinics, neurology, psychiatry or geriatrics to see a specialist depending on the setting of the medical institution in their area.