The art of speech is a feature that characterizes humans as distinct from animals. It is also an index of the mental development of humankind. Some people living a meager, simple existence may find that a few hundred words adequately cover their requirements for living. Conversely a highly intelligent person doing intricate work may need a vocabulary of thousands of words to explain adequately the nature of an advanced profession.
The expansion of speech usually runs hand in hand with the development of the mind. It is “the symbolic expression of thought in spoken language.” The next step forward is written speech in which symbols replace sounds. The function of speech is a very complex one, depending on a fine interaction of neuromuscular mechanisms.
When these are disturbed, the term Aphasia is used. The word aphasia means there is “a loss of symbolic expression or understanding.”
The most common cause for this is lack of an adequate blood supply to the brain. In younger persons, this is most likely the result of accidents (in which subdural hematomas have formed). In older people vascular occlusion (a blockage of the blood supply, either partial or complete) or a cerebral tumor are the two most likely causes.
The usual symptoms are use of the wrong words, or the misplacement of words. Once a word has successfully been pronounced, it may be repeated several times over. Often there is considerable difficulty in recalling words. In association with this, writing faults are most likely – letters and words being wrongly written or misplaced.
Often these patients show considerable reduction in mental acuity and general intelligence. There are varying degrees of mental dullness, mental confusion and depression of the normal speech function.
Frequently they present difficulties to the doctor during examinations, for the attention of the patient may be gained for only short initial periods.
The success of therapy depends on the age of the patient and the nature of the underlying lesions producing this symptom. The best results occur with young people who have undergone some form of traumatic lesion of the brain, which is correctable. For instance, if the symptoms are due to a subdural hematoma (a blood clot under the skull depressing the brain), and this can safely be removed surgically, the outlook may be good. Similarly, with a noncancerous superficial brain tumor that is successfully removed by the neurosurgeons, the outlook may also be good.
Therapy (often carried out by trained speech therapists) is similar to the initial training of a child. But the student may quickly regain the power of speech and finally assume fairly normal ability again. But with older persons, in which there are often irreversible diseases of the blood vessels or a diffuse untreatable tumor of the brain, the outlook is poor. There may be a gradual deterioration of speech, in keeping with the progress of the underlying disorder.