As you note, aphasia is a symptom. As such it can have multiple causes. Some varieties of aphasia are caused by a degenerative disease, not injury, for example

As you note, aphasia is a symptom. As such it can have multiple causes. Some varieties of aphasia are caused by a degenerative disease, not injury, for example Primary Progressive Aphasia [1]. Stroke is a very common cause of aphasia, of course, but as our populations age (and as the causes of death and disaility that strike earlier are eliminated), the many varieties of age related dementia are making themselves known. 1. http://www.aphasia.org/aphasia-resources/primary-progressive-aphasia/ http://www.aphasia.org/aphasia-resources/primary-progressive...