I'm not sure why you are asking this. Alzheimers and UTI's are not related. Having symptoms like you'd have with a UTI would not mean anything about someone's mental state, dementia or neurological deterioration. Maybe more details would help us help you better.
A UTI will not 'cause' dementia or Alzheimers, however, it can exasperate even the mildest symptoms. If a person is young (ish) and otherwise healthy and gets a UTI, that person will feel the normal symptoms of it, but someone who is elderly (although someone does not necessarily have to be 'elderly' to have Alzheimers), and suffers from dementia or Alzheimers, will have a much different experience.
I went through this with my mother and currently, my MIL, and it is absolutely true.
Below is a short excerpt taken from the link I will share below...
"As the Alzheimer’s Society explains, UTIs can cause distressing behavior changes for a person with Alzheimer’s. These changes, referred to as delirium, can develop in as little as one to two days. Symptoms of delirium can range from agitation and restlessness to hallucinations or delusions."
If you have a loved one who has dementia and is suddenly displaying delirium or any other unusual behaviors outside of their everyday confusion (you will know your loved one best and will be able to tell if there are any changes in behavior), ask that they be checked for a UTI.
Also, dementia patients often have a catheter which easily can be a culprit for a UTI.