Aphasia is a neurological disorder in which a person loses part or all of the ability to comprehend language. Problems are almost always related to a brain injury, usually in the form of a stroke. Severe head trauma, brain infections, and congenital abnormalities may also play roles in the development of the disorder. There are dozens of different types of aphasia that are classified based on the parts of the brain that are affected and the resulting symptoms. The four main types of aphasia are called receptive, nominal, expressive, and global, and each type presents unique challenges to sufferers.
Receptive aphasia involves difficulties understanding language that is written or spoken. It is one of the most common types of aphasia, and many different subtypes exist. Wernicke's aphasia, the most recognizable variety, is characterized by an injury to a part of the cerebral cortex called Wernicke's area. Individuals with the disorder lose their ability to follow conversations and comprehend text. They can usually speak and write somewhat fluently, though they may create long, difficult-to-follow sentences and insert wrong or made-up words.
Nominal aphasia is a disorder that is closely related to receptive types of aphasia. People with the condition have extensive trouble understanding and recalling the names of items. They may be able to comprehend spoken descriptions of things to a limited degree, but are unable to restate what certain things are called. For example, a person might see a stapler and want to say the word, but forget what it is called and resort to describing its function or parts.
An injury to Broca's area, a part of the cortex connected to Wernicke's area by nerve fibers, can result in expressive aphasia. Sufferers can usually understand what others are saying and comprehend text, but they cannot form their own meaningful words. It is common for a person with expressive aphasia to take a long time to say or write what they are thinking, and the result may not be coherent. He or she might leave out key words in sentences or make major grammatical mistakes.
Global aphasia typically involves a combination of several language disorders. It is considered one of the most severe types of aphasia because it makes communication nearly impossible. People may be unable to write, read, hear, or speak coherently. An individual may need to use pictures, point at items, and make facial expressions to convey needs. Global aphasia is often the result of a major stroke or traumatic injury that affects a large area of the brain.
Aphasia cannot be cured in a traditional sense, but many patients are able to improve their communication abilities over time. In some cases, language skills return somewhat spontaneously when brain injuries heal. Most of the time, however, patients need to participate in speech and language courses for years to develop more effective speaking and comprehension skills.