The precursors of dementia at the age of 55 mainly include memory loss, visuospatial disorders, changes in the ability to perform daily life, mental and personality changes, language disorders and other symptoms. 1. Memory loss: It is the earliest and more prominent symptom. The first symptom is memory loss of recent events, such as forgetting what has just been done, what has been said, and commonly used objects. With the progression of the disease, distant memory loss can occur, that is, forgetting things and people that have happened for a long time. 2. Spatial-visual impairment: Some patients may have spatial-visual impairment, i.e. they cannot find their way home after going out, or they cannot accurately copy three-dimensional drawings. 3. Changes in daily living ability: patients gradually become unable to perform daily living tasks, and may be unable to take care of themselves as the disease progresses. 4. Mental and personality changes: The patient may have mental abnormalities such as anxiety and negativity in the early stage, as well as personality changes such as uncleanliness and irritability. 5. Language disorders: patients may not be able to express their thoughts clearly and vaguely, and in severe cases, aphasia may even occur. Therefore, when the above precursors appear in the people around you, you should go to the hospital for examination in time, so as to achieve early detection and early treatment, and family members should also take good care of the old man’s mood and safety.