Aphasia

Approximately 1 million Americans currently suffer from a relatively unknown condition called aphasia, with 80,000 new cases being diagnosed annually. Aphasia is caused by damage to the brain and consists of an individual's partial or complete loss of the ability to comprehend language. This condition has a high prevalence among individuals who sustain a stroke; however, it also occurs in individuals, irrespective of age, who have experienced other forms of brain damage (i.e., trauma, hemorrhage, tumor, or infection).

The pathophysiology of aphasia varies, necessitating an understanding of the different regions and functions of the brain to determine the type and extent of the condition. In general, the brain consists of two cerebral hemispheres with various regions therein. Overall, the right hemisphere of the brain deals with context, spatial orientation, analytic thought, creativity, and intuition, whereas the left hemisphere handles logic and language. When a person suffers from brain damage to the left hemisphere of the brain, the language capabilities of the person are affected as well as movement in the right side of the body.

There are several different types of aphasia, but they are generally characterized as Broca's aphasia, Wernicke's aphasia, and global aphasia. Broca's aphasia is categorized by labored, stilted speech, in which the speaker drops words and can only speak in short sentences. Conversely, Wernicke's aphasia results in speech that incorporates nonsensical words. Sufferers of Wernicke's aphasia speak fluently, but the words are awkwardly expressed. Furthermore, such individuals also have difficulty understanding the speech of others. In contrast to other more region-specific aphasia, global aphasia is the most severe type and is noted for damage to the entire hemisphere of the brain, resulting in severe limitations of speech and a general inability to comprehend the language of others.

The diagnosis of aphasia is performed by the physician in his or her examination of a patient who has sustained a traumatic brain-related episode. Aphasics can have expressive language difficulties, such as problems in speaking, naming, or word repetition. Problems with receptive language, more commonly known as the lack of oral language comprehension, are also symptoms. Other problems related to reading and writing, wordfinding, fragmented speech, motor speech inability that also includes swallowing difficulties, and the inability to make various speech sounds are associated with aphasia. In addition, there are many other conditions that can occur along with aphasia. Many stroke-induced aphasia sufferers can also suffer from some form of paralysis of the body, apraxia (the inability to control speech producing muscles), alexia (the inability to read), or dysgraphia (the inability to write).

Approximately eight to nine percent of children have a speech sound disorder, often attributed to sustaining a brain-related injury. Aphasia in children is commonly referred to as acquired childhood aphasia. Another condition in children that results in aphasia is called Landau-Kleffner syndrome (LKS), which is a rare epilepsy syndrome. Symptoms of LKS include difficulties in speech, behavioral problems, and seizures. Because the symptoms of LKS are similar to the symptoms of other conditions, such as autism, attention deficit disorder, or mental retardation, many children with LKS are misdiagnosed.

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