Aphasia: The Result of Broken Cables in the Brain
I was shell-shocked and disoriented, unaware of what was happening to me. Every time I tried to express myself nothing came out. I was forced to remain silent and could not follow either verbal or written commands. Words sounded to me like jargon… the people around me spoke a foreign tongue. I could neither comprehend nor use language...I lay in bed, staring blankly and feeling helpless. (1)
This account sounds like the description of some horrible nightmare, yet it is a condition that an estimated 1 million people have (3), a condition that approximately 80,000 individuals acquire each year (2); aphasia. Aphasia is best described as the “symptom of brain damage” (4). Aphasia is a language disorder that follows some type of brain damage or trauma, although it can be caused by brain tumors as well. The damage occurs in the left hemisphere of the brain, the area that controls language. Individuals often have difficulty speaking properly, understanding others, understanding text, naming objects, verbalizing descriptions and problems with overall general comprehension. There are different types of aphasia and some are paired with paralysis. There are treatments for aphasia, however there is no cure.
Aphasia often as the result of stroke, brain injury, or trauma to the left hemisphere has a sudden onset and therefore cannot be prevented or planned for. However, aphasia may be the result of a brain tumor, thus having a gradual onset. There are four different types of symptoms that are seen as the result of brain damage. In one type, expressive aphasia, the individual is unable to coherently express themselves and their thoughts through speech or writing. A second type is receptive aphasia where the individual often cannot understand what they are reading or what someone is saying to them. Anomic or amnesia aphasia is the least severe form and is when an individual has trouble remembering the names of objects or individuals. Finally, in global aphasia there may be unspecified severe brain damage to the brain over all resulting in loss of all language function, including spoken or written language.
The two most prevalent types of aphasia occur in two very specific language areas in the brain. These two types of aphasia are Broca’s aphasia and Wernicke’s aphasia, and are the result of damage in the two respective areas. Accordingly, there is a difference in the symptoms and prognosis of these two conditions. In Broca’s aphasia the brain damage is limited to the frontal lobe. This type is called “non fluent” and consists of short meaningful phrases that the individuals may need to work hard to produce (2). These phrases are often missing function words, articles, conjunctions and modifiers (3). Someone with Broca’s aphasia may say “Walk Dog.” This could mean any number of things “I walked the dog,” “she is walking the dog” or “the dog needs to be walked” (4). Comprehension is variably affected and can change over time. Affected individuals who can understand others often experiences frustration as they are aware of their difficult in speaking. This type of aphasia is often accompanied by paralysis or weakness in the right side of the body as these tracts run close to Broca’s areas and may also be damaged (2).
Wernicke’s aphasia is the result of damage to the temporal lobe. Individuals are able to form long fluent sentences however; these sentences often do not make sense. These individuals may create neologisms. In example, an individual with this type of aphasia may say "You know that smoodle pinkered and that I want to get him round and take care of him like you want before," (4) when what they really mean is "The dog needs to go out so I will take him for a walk” (4). These individuals usually have trouble understanding speech so they are generally not aware of their language deficit. These individuals often do not experience paralysis (2).
Treatment for aphasia depends on the severity of the brain damage and the location. Certain type of aphasia may have spontaneously recovery as blood is spontaneously readmitted into the damaged area of the brain, however, this is unlikely. Most individuals with aphasia face a long road of therapy and a constant battle to regain coherent speech. Treatment includes speech therapy and may focus on mouth shape and the repetition of word and writing. Individuals very often have to rely on other sources of physical expression to better present their feelings, this very often may include stressed physical or facial gestures. Family members and friends of the individual will have to be patient and encouraging as the individuals tries to regain recognizable correct speech patterns.
In aphasia there is a disconnect between the input the individuals receives and the outputs they generate. In Broca’s aphasia individuals very often (to a varying degree) can understand what other individuals are saying to them, in this manner these individual often become aware of their language problems through these inputs. The cables that connect the speech input to the boxes that make up the brain and then eventually to the I-function seem to be in working order. However, if the individuals want to generate an output to this input they often cannot and their speech comes out punctuated or not at all. This causes frustration in the person because they know what they want to say but simply cannot form the complete sentence. In this case it appears that the cables that connect the I-function to the boxes in the brain that connect to the output of speech are linked by broken or faulty cables. This is also true of speech outputs spontaneously generated in the nervous system, the connection from the I-function to the out put do not function correctly or completely. In individuals with Wernicke’s aphasia the cables that connect the speech input to the I-function do not work properly. Individuals with Wernicke’s aphasia cannot understand speech inputs of others and because these cables are faulty, there is no connection to the I-box, hence, these individuals do not understand that they are have speech impairment. However, these individuals are able to generate fluent speech output or, the output cables are working. There seems to be the addition of a second (spontaneous) cable or a specific way in which the cable connection to the I-function is in such a way that the out put of speech generates neologisms. Due to the fact that these outputs are not generating inputs the individuals do not understand that they are creating these neologisms. Finally in both Wernicke’s and Broca’s individuals do not understand written inputs and cannot generate outputs. In this area not only are the cables malfunctioning, but there is also a malfunction in the boxes that make up these areas of the brain (the brain areas that are damaged.) In this paradigm aphasia can be understood as the result or symptom of damaged cables, due to brain damage, that connect inputs and outputs as well as the boxes that make up the brain.
1) http://www.aphasia.org/NAAwords.html; The Words I Lost. New York Times, 1992.
2) http://www.nidcd.nih.gov/health/voice/aphasia.htm; National Institute on Deafness and Other Communication Disorders, Aphasia page
3) http://www.emedicine.com/NEURO/topic437.htm; eMedicine, Aphasia page\
4) http://www.ninds.nih.gov/disorders/aphasia/aphasia.htm; National Institute of Disorders and Stroke, Aphasia Info Page
5) http://www.googlesyndicatedsearch.com/u/serendip?hl=en&ie=UTF-8&sitesearch=http://serendip.brynmawr.edu/bb/neuro/&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=aphasia&spell=1; Serendip, Search aphasia page