Incidence of aphasia refers to the number of new cases identified in a specified time period. It is estimated that there are 180,000 new cases of aphasia per year in the United States (National Institute on Deafness and Other Communication Disorders [NIDCD], 2015).
Prevalence of aphasia refers to the number of people who are living with aphasia in a given time period. NIDCD (2015) estimates that approximately 1 million people, or 1 in 250 in the United States today, are living with aphasia.
Aphasia after stroke is more common for older adults than younger adults (Ellis & Urban, 2016). Fifteen percent of individuals under the age of 65 experience aphasia after their first ischemic stroke; this percentage increases to 43% for individuals 85 years of age and older (Engelter et al., 2006).
No significant differences have been found in the incidence of aphasia in men and women. However, some data suggest that differences may exist by type and severity of aphasia. For example, Wernicke’s aphasia and global aphasia occur more commonly in women, and Broca's aphasia occurs more commonly in men (Hier, Yoon, Mohr, & Price, 1994).