Definition and causes of Aphasia
Aphasia is the loss of previously acquired ability to speak and/or loss of language comprehension and reading and writing ability. It is not the same as dysphasia, which is an inability to speak and write and/or understanding speech or writing caused by damage to the related regions of the brain.
Aphasia, is always preceded by normal language ability. The state should not be confused with dysarthria, which is a disorder of the muscles responsible for speech. Dysarthria is a speech and pronunciation problem, whereas with aphasia the problem is finding the words and putting them together into a comprehensible sentence.
However, there might be combinations of aphasia and dysarthria. With aphasia there might also be problems with comprehending speech and problems with reading and writing.
Aphasia follows damage of the cerebrum usually after a stroke - blood clot in the brain or brain haemorrhage, often referred to as seizure. It can also be a brain tumor, pressing on the speech center. In most people the speech center is located in the left part of the brain and it is usually injuries to this part which result in aphasia. Damage to the front of the brain, known as Broca's area, results in non-fluid aphasia. Damaging the rear, Wernicke's area, results in fluid aphasia (see: symptoms).
Aphasia without brain damage can be transient as so called aura symptoms preceding an epileptic seizure or migraine attack (see: migraine).
Symptoms of Aphasia
Aphasia is in itself a symptom of a damage to the brain. Often there would also be other symptoms than aphasia (see also stroke, blood clot in the brain or brain haemorrhage).
There are two subtypes of aphasia - fluid and non-fluid.
Fluid aphasia: Speech can be generated with the right language intonation and normal speed, but words cannot be combined into meaningful phrases. The patient often invents new words, or correct words are used wrongly. Usually the patient is unable to understand normal speech.
Non-fluid aphasia: There is no standard intonation, and speech becomes slow and staggered with long breaks. The words used are normally nouns, resulting in something of a telegram-style and there is often very poor pronunciation of words. Often the person fully understands what others are saying and suffers terrible frustration being unable to communicate.
There are different degrees of severity of aphasia; from being unable to speak at all and unable to understand others' speech to only having problems with parts of the vocabulary. It may, for example, be difficult to find the right word for a designated object. There might also be problems with writing and reading.
Precautions and diagnosis of Aphasia
Since aphasia is the expression of damage to the brain the appearance of this condition calls for immediate medical attention. The neurological examination includes the nervous system functions to determine other forms of damage and will invariably involve either a CT or MRI scan.
Treatment of Aphasia
Generally, the cause of aphasia is treated first to prevent further damage to the brain. See also stroke (blood clot in the brain or stroke) or brain tumor.
In addition, a speech therapist can help improve the speech. Therapists focus only on the parts of speech where there is trouble, and then take a position on how best to organize the speech training. It is very different how much training is needed, but generally the therapy is continued as long as the patient shows improvement.
In some cases the speech improves fairly quickly whereas in other cases the progress is limited and slow. Overall, however, the speech is usually a little better with time. This is partly due to the fact that the brain to some degree can compensate for the function of the damaged area, but also because the patient learns to use the remaining speech function better.