Suddenly, the patient can’t remember anything, which can be mainly seen in cerebrovascular diseases, mainly in hemorrhagic cerebrovascular diseases or ischemic cerebrovascular diseases, mainly in lesions of temporal lobe hippocampus, which is in charge of memory, and the patient can also have emotional abnormalities. After treatment, the patient may recover from memory loss and slow reaction. Sudden loss of memory can also be seen clinically in patients with cerebral contusion or concussion, which can lead to transient memory loss or retrograde amnesia, and after oral administration of drugs to improve neurological function, the patient’s symptoms can be improved. Sudden loss of memory can also be seen clinically in elderly people with Lewy body dementia, memory loss, and slow reaction time in episodic form.