Imagine the following scenario: You wake up one morning and instead of speaking English, everyone around you--including your family and friends--is speaking Hungarian. This is a problem because you don't speak Hungarian and you don't have a clue what they're saying. You become frustrated. The people around you become frustrated, too, but instead of switching back to English, they speak Hungarian more loudly.
Somebody gets the bright idea of writing you a note. You take the note in your hands and study it. Unfortunately, it's in Hungarian, too, and you can't read it. So they write you another note, still in Hungarian, but this time with large, block letters. You can't read the second note, either.
This strange scenario is almost exactly what happens to people who have a stroke (circulation impairment) to the left side of the brain, except that the family and friends aren't really communicating in Hungarian. They're speaking and writing English--same as ever--but to the stroke victim their words are suddenly incomprehensible. This sudden disruption in language-processing is called aphasia.
Different patterns of aphasia occur with damage to different parts of the left side of the brain. The preceding scenario, in which comprehension of language is impaired, is called a receptive aphasia and is associated with injury to the upper portion of the brain's left temporal lobe, roughly adjacent to the temple and top of the ear. In receptive aphasia the affected individuals can still produce sentences, but, in an odd twist of fate, they can't make sense of or properly monitor their own words, so their output is riddled with errors.
A pattern of language impairment opposite of receptive aphasia is called expressive aphasia, in which individuals can understand what others say or write, but cannot produce much, if any, speech or writing of their own. In 1861 Pierre Paul Broca, a French surgeon, recognized a case of expressive aphasia and followed through with an autopsy of the patient's brain.
For much of the nineteenth century most scientists and physicians believed that the brain was homogenous, and that its different actions were spread diffusely throughout the entire brain. They did not believe that functions were localized to specific regions of the brain. (The phrenologists believed otherwise, but that is a story of its own.)
However, when Broca treated a patient who lost his power of speech (the only word he could still say was "tan") he was able to correlate this language impairment with damage to the left side of the man's brain. Instead of being in the temporal lobe, the destroyed brain-tissue was in the frontal lobe in an area now referred to as Broca's area. In fact, expressive aphasia is also known as Broca's aphasia. Dr. Broca's case was the principal salvo in a reversal of understanding about how the cerebral cortex (the brain's wrinkled gray surface) operates. Now we realize that many functions--not just language--are localized to specific regions of the cortex.
Receptive and expressive aphasias are not the only patterns of language impairment, but nicely convey the basic idea of a sudden disconnect in language processing. What becomes of these cases? As is seen with strokes affecting other parts of the brain--for example, those causing weakness or paralysis of muscles on the opposite side of the body--recovery varies widely among patients. Some patients become normal again and others don't improve at all, but the usual outcome is somewhere in between.
Improvement in language function that occurs within the first week or two following a stroke is due to brain cells that were sick from the stroke--but not quite dead--becoming healthy and operational again. By contrast, improvement in language function occurring over ensuing weeks, months and even years is due to the retraining of surviving brain cells that take over for their fallen comrades. A younger stroke patient with more brain cells in reserve has a better chance for recovery than an older patient with fewer reserves.
Is there anything that can be done to improve outcome? First of all, there is the management of the stroke itself which generally takes place in a hospital. One important point to emphasize is that a stroke causing aphasia is no less a stroke than one causing paralysis of muscles. Sometimes it seems that the latter receives more serious attention than the former. Management of fundamental issues--like blood pressure, body temperature and blood sugar--can set the stage for the best possible outcome.
Following a first stroke, physicians also implement "secondary stroke prevention" to decrease the odds of a second stroke. In cases of stroke due to hardening of the arteries (atherosclerosis) this often takes the form of ratcheting down blood pressure, blood sugar and cholesterol, along with elimination of smoking and other unhealthy behaviors. Also, the doctor usually prescribes a medicine to reduce blood-clotting. Other causes of stroke might call for other measures.
Does speech therapy help stroke-patients with aphasia? So far, this form of treatment has not been proved beneficial. Randomized, controlled trials (the standard of proof in clinical medicine in which patients receiving the treatment are compared to similar patients receiving either a dummy-treatment or no treatment) have not clearly demonstrated that speech therapy is better than either no treatment or treatment provided by family or friends.
Sometimes patients with aphasia are perceived as "confused" in the sense of having a delirium or dementia. But this is not the case. Acutely aphasic patients need to be recognized as having suffered a stroke to a specific part of the brain so they can be triaged for appropriate medical care. Over the longer term, family and friends need to remember that the stroke victim is still a perceiving, self-aware human being who happens to have a communication problem. He or she should be loved, appreciated and otherwise included in activities just as before.
(C) 2005 by Gary Cordingley
Gary Cordingley, MD, PhD, is a clinical neurologist, teacher and researcher who works in Athens, Ohio. For more health-related articles see his website at: http://www.cordingleyneurology.com