Answer:
The answer is dementia.
Explanation:
Dementia is a mental condition, usually appearing at old age, characterised by a gradual loss of memory, speech and other cognitive processes. Alzherimer's disease is the most common cause for dementia.
Dementia covers a great variety of diseases, all of them related to brain impairments. These may severely affect a person's life in areas such as family, the workplace and even the ability to perform everyday tasks.
There is no cure for dementia, although certain medication may improve its symptoms.