Aphasia is any difficulty with communication, including speaking, understanding, reading, or writing. It can be caused by a stroke, brain injury, or dementia. When dementia is the first cause of communication changes, it’s called primary progressive aphasia. Unlike aphasia from a stroke or injury, which may improve, dementia-related aphasia tends to get worse over time. Primary progressive aphasia is linked to certain types of dementia, like frontotemporal dementia and some forms of Alzheimer’s