Aphasia is an acquired language disorder caused by brain injury or disease that affects a person’s ability to speak, understand spoken language, read or write. It arises from damage to the language-processing areas of the brain, which in most people are located in the left hemisphere, specifically in and around Broca’s area (frontal lobe) and Wernicke’s area (temporal lobe). Aphasia does not affect intelligence but profoundly affects the ability to communicate.
Several types of aphasia are recognised. Expressive aphasia (Broca’s aphasia) produces difficulty finding and producing words, resulting in slow, effortful speech, while comprehension is relatively preserved. Receptive aphasia (Wernicke’s aphasia) affects understanding of language; the person may speak fluently but produce sentences with errors or nonsense words. Global aphasia involves severe impairment of both expression and comprehension and follows extensive damage to language areas. Anomic aphasia, perhaps the most common mild form, involves specific difficulty retrieving names for objects and people.
After cardiac arrest, hypoxic-ischaemic brain injury affecting the left hemisphere can cause aphasia. In practice, focal language deficits are more commonly associated with stroke, but survivors of cardiac arrest can develop aphasia, particularly when the hypoxic injury has a cortical watershed distribution or when an embolic stroke occurs as a complication of the event or its management. The term dysphasia is also used, technically referring to partial rather than complete loss of language, though in practice the two terms are often used interchangeably.
Speech and language therapy (SALT) is the primary treatment for aphasia. Therapeutic approaches include naming exercises, supported conversation techniques, augmentative and alternative communication (AAC) tools such as communication boards and apps, and environmental modifications to reduce communication barriers. Recovery varies: some people regain most of their language function with therapy over months to years, particularly younger patients with focal injury. The charity Speakability and the Stroke Association provide resources and peer support specifically for people with aphasia.