Today, the family of Bruce Willis released a joint statement announcing that the actor will be “stepping away” from acting following an aphasia diagnosis. The actor joins more than two million Americans affected by the condition, according to the National Aphasia Association (NAA).

Aphasia, explained

Aphasia is a communication disorder that can affect the production or processing of language. Individuals may have difficulties with reading and writing, grammar, or language comprehension.The condition does not affect intelligence and is acquired following damage to brain regions associated with language. The American Speech-Language-Hearing Association (ASHA) cites stroke as the most common cause of this brain damage, but notes that any damage or progressive condition involving these regions can result in aphasia.

Aphasia differs slightly from apraxia, a motor impairment arising from cerebellar dysfunction. Apraxia patients experience difficulty coordinating movements required to produce speech. In aphasia, muscular coordination is intact but patients may lack fluency, meaning that speech is effortful and difficult to modulate.

Injury location dictates symptoms

The left hemisphere plays a more dominant role than the right hemisphere in language-related functions, and aphasia typically occurs following damage to the left hemisphere. The more specific subregion of the brain that is affected influences the symptoms that a patient may display. The infographic below from the NAA classifies different forms of aphasia based on a person’s ability to produce fluent speech, understand spoken messages, and repeat spoken language. These types are each associated either with a single brain structure, such as Wernicke’s and Broca’s aphasia, or the connections between those structures and the rest of the brain, such as transcortical and conduction aphasia.

Outcomes for patients with aphasia

Aphasia is typically treated by speech and language therapy. Patient recovery depends on the intensity of the therapy as well as how quickly treatment is initiated following the onset of the condition. Individual factors such as the site of the injury or a patient’s willingness to undergo treatment may also affect the outcomes of therapeutic intervention.