system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why people with Alzheimer's forget things like their age, name, friend's faces etc but not how to breath, talk or walk?
gpt
Alzheimers is degenerative disease of the cerebral cortex.  This is the part of the brain that deals with memory, attention, thought, language, awareness and the like.  So the disease affects a part of the brain that controls a separate function from the examples you gave.

The Brain Stem is the part of the brain that controls things like breathing, circulating blood, digesting food.. etc.

As for talking, many people who have Alzheimer's do forget how to speak certain words.  They won't remember what a word for something is or might not know what a word stands for with out having the object to use as a relation.

The Cerebellum is the part of the brain that controls voluntary movement, posture and balance.