My 93 year old grandma is not talking and she has dementia. is this a side effect or just her regular attitude. i wish i knew what she is thinking.?

Hard to say: What you describe could be a result of (1) dementia, (2) medication side effects or (3) depression which may be difficult (but possible) to detect. I would wonder how long she has dementia, how long she has not been talking, and what other symptoms she was having in order to give better guidance. I'd recommend a geriatric psychiatrist.

Go to Dr: The question is whether or not she could have a new stroke or is just worsening of her dementia. I would suggest to take her to at least her pcp to determine if she has any other neurological deficit requiring new imaging ct or mri. Best is to make her see a neurologist for follow up. Doubt side effect from medicine unless too sedated.

Sign of disease: As dementia worsens over time the loss of the ability to speak is common. Even if she cannot speak it can still be important and helpful for you to talk to her.