Yes you’re right. Depending on what area of the brain is affected a patient loses cognitive ability, speech is affected, motor skills, co ordination.
My mother suffered two strokes from Alzheimer’s fifteen years ago and passed away. It was heart breaking.
My Mon suffered a Stroke in 2017 and within three months passed from Dementia that she did not have up to the time point of the Stroke. My sister had several Strokes and died from Dementia a few years before our mom.