Aphasia occurs after some parts of the brain responsible for language are damaged. In most cases, this damage involves the left side of the brain. This results in impairment in language production or understanding and can affect both written and spoken language. A person is not born with aphasia. Usually, this disorder occurs suddenly as a result of a head injury, but can also happen slowly in patients with brain tumors or as a result of an infection, such as encephalitis. Most aphasia patients are middle aged or older, but anyone can get this disorder including children. The younger the patient, the better the prognosis after aphasia typically is. The symptoms of aphasia vary significantly depending on the size and location of the damage inflicted on the brain.
Trouble Understanding Speech
The main problem many aphasia patients have is that they do not understand spoken or written language. Typically, in these situations, the person suffers from fluent aphasia, which is also called Wernicke's aphasia. It is usually caused by damage to the left temporal lobe. The speech of a patient may have no meaning as she adds unnecessary words to her sentences and often comes up with made-up words. Typically, a child is not aware of his difficulties and may become upset when people do not understand him.
Trouble Producing Speech
Some aphasia patients have great difficulties producing language. These patients typically suffer from non-fluent, or Broca's aphasia, where the damage has usually occurred in the left frontal lobe. The speech of these patients is understandable, but their sentences are very short and it takes a patient a long time to produce speech. Frequently, a child with non-fluent aphasia leaves out certain words such as “and” or “the,” and only use the most essential words. Thus, his language may resemble the telegraphic language used by a young toddler who is just learning to speak. In Broca’s aphasia, the patient typically has no difficulties understanding other people.
Some aphasia patients have no difficulties using language spontaneously but cannot repeat words. These patients commonly suffer from conduction aphasia, where the associate tracks that connect the various language centers are damaged. When a patient with conduction aphasia tries to repeat a sentence spoken by another person, he may skip or repeat words, or replace one word with another. Typically, these patients have no problems understanding language.
Other less frequent aphasia symptoms can also be seen in patients with this disorder. A patient may, for example, have difficulties starting to speak but once the beginning of the sentence has been said, she has no difficulties continuing. The main problem with some patients is that the language that they are using is grammatically incorrect. It is also possible that a patient has problems with written language but has no trouble with spoken language. These types of problems may be difficult to diagnose in a young child who is only learning to read and write.
The prognosis after aphasia is much better in young children than in adults. This is mainly due to the fact that in young children, the brain has not specialized yet the way the adult brain has. A mature brain has specialized areas that take care of specific functions. The brain of a young child is much more flexible. If a certain area of the brain gets damaged, another area can often take over tasks performed by the other area prior to the accident. Dr. Lucie Hertz-Pannier and colleagues, for example, showed in their magnetic resonance imaging study published in Brain Journal in February 2002 that a young boy with aphasia was able to shift his language processing from the left to the right hemisphere while he was recovering from the condition.