There is one rare form of aphasia called primary progressive aphasia, or PPA, which is not caused by stroke or brain injury, but is actually a form of dementia in which language loss is the first symptom.

有一种罕见的失语症叫做原发性进行性失语症 简称PPA，它不是由中风或者大脑受损引起的，而实际上是失智症的一种表现，语言能力退化是失智症的第一症状。