Earlier this month a Texas Rangers sportscaster went from calling live highlights of a baseball game to talking about a botched robbery. The sportscaster's incoherent switch confused listeners, but doctors saw the symptoms of aphasia, a disease not known to many but which affects 1 million people.
It is more common than Parkinson's disease, cerebral palsy or muscular dystrophy, according to the National Aphasia Association. The disorder weakens the expression and understanding of spoken language, making it difficult for someone to read, write and say what they mean. It is most common in adults who have had a stroke or brain injury. Dr. Argye Elizabeth Hillis, a professor and executive vice chair of the department of neurology at the Johns Hopkins University School of Medicine, answers questions about the diagnosis and treatment of aphasia.
What are the different types of aphasia?
When aphasia is caused by stroke — the most common cause — it is often associated with the occlusion of a particular cerebral artery. Broca's aphasia (effortful, distorted speech and difficulty forming grammatical sentences, but relatively normal comprehension) and Wernicke's aphasia (fluent, well-articulated but meaningless speech, but poor comprehension) are two types of aphasia associated with this sort of vascular constriction.
Aphasia can also be caused by traumatic brain injury or by a neurodegenerative condition known as primary progressive aphasia. Different types of primary progressive aphasia are associated with distinct areas of atrophy in the left hemisphere of the brain (the "language hemisphere"), which cause different types of language problems. The nonfluent/agrammatic variant (with effortful, distorted speech and difficulty forming grammatical sentences, but relatively normal comprehension) and the semantic variant (with fluent, well-articulated speech, but prominent impairment in word comprehension) are usually caused by frontotemporal lobar degeneration. The logopenic variant of primary progressive aphasia (with marked difficulty with word-retrieval and sentence repetition) is usually caused by the same pathological disease process as Alzheimer's disease, although the symptoms are different from typical Alzheimer's disease.
How many people get it and who can get it?
About 1 million people in the United States have aphasia, and about 80,000 new cases of aphasia are diagnosed each year, according to the National Institutes on Deafness and Communication Disorders. People who have risk factors for stroke (high blood pressure, diabetes, smoking or high cholesterol) are most likely to acquire aphasia.
How is aphasia diagnosed?
It is diagnosed by evaluating language abilities, either with standardized language examinations (including tests of naming of objects, word and sentence comprehension, repetition, narrative speech, reading and writing) or through neurological examinations.
What are the symptoms?
The symptoms include impairment in any domain of language, such as naming of objects, word or sentence comprehension, repetition, narrative speech, reading or writing. Someone with the disorder may show deficits in semantics (meaning) or syntax of language or both. Many people say the wrong words, such as substituting "dog" for "cat" or "cap" for "cat" or may even speak nonsense words. Or they may have trouble speaking at all. When a person only has difficulty in reading or writing, but not speaking, the diagnosis is alexia or agraphia (a specific type of aphasia).
How is aphasia treated? Is there a cure?
The mainstay of treatment is language therapy (individual or group therapy), which may involve facilitation of language production or comprehension through cues, or may involve learning to communicate through a new modality, such as an IPad or computer or [paper] notebook. There are investigational therapies that also involve medications or brain stimulation to add to language therapy. Many people recover completely. For more information on treatment or services for aphasia, contact the National Aphasia Organization, at http://www.Aphasia.org. Here in Baltimore, a nonprofit organization, the Snyder Center for Aphasia Life Enhancement provides information and services for people with aphasia, from people with aphasia.
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