Definition

     Aphasia is a communication disorder caused by damage to one or more regions of the brain that control language skills. People with aphasia may not be able to express themselves verbally or in writing, or they may not understand spoken or written language.

Causes

     The most common cause of aphasia is stroke — the blockage or rupture of a blood vessel in the brain. This disruption of the blood supply leads to brain cell death or damage in areas of the brain controlling language. Aphasia may also be caused by a severe head injury, a brain tumor or an infection.

Signs and Symptoms

     A person with aphasia may:

• Speak in short abbreviated sentences

• Speak in sentences that don't make sense

• Make up words

• Have difficulty finding the right word

• Not comprehend other people's conversation

• Interpret figurative language literally

• Not understand written words

• Write sentences that don't make sense

• Make significant spelling errors

     Your doctor may refer to one of three broad categories of aphasia (nonfluent, fluent and global) that describe what region of the brain was damaged and how communication is usually affected. The two primary language networks for most people are located in the brain's left hemisphere.

• Nonfluent aphasia. Damage to the language network toward the front of the brain usually results in Broca's aphasia. It's also called nonfluent aphasia. People with this disorder struggle to get words out, speak in very short sentences and leave out words. A person might say, "Want food" or "Walk park today." Although the sentences aren't complete, a listener can more or less decipher the meaning. A person with Broca's aphasia may comprehend what other people say to some degree. They're often aware of their own difficulty in communicating and may get frustrated with these limitations.

• Fluent aphasia. Wernicke's aphasia is the result of damage to the language network in the middle left side of the brain. It's often called fluent aphasia. People with this form of aphasia may speak fluently in long, complex sentences that don't make sense or include made-up, incorrect or unnecessary words. They usually don't comprehend spoken language well and often aren't aware of their own difficulty communicating.

• Global aphasia. Global aphasia results from extensive damage to the brain's language networks. People with global aphasia have severe disabilities with expression and comprehension.

Screening and Diagnosis

     A speech-language pathologist will conduct tests and informal observations to assess your speech-language skills, such as your ability to:

• Engage in a conversation

• Understand and use words correctly

• Answer questions about something you've read or heard

• Follow instructions

• Explain steps of a process

• Answer yes-no questions and respond to open-ended questions about common subjects

• Tell a story or explain the plot of a story

• Explain a joke or a figurative phrase, such as "I need to unwind"

• Read and write letters, words and sentences

Treatment

     Is aimed at the underlying cause, and may involve rehabilitation by a speech therapist.