June 29, 2009
Wernicke’s area, in the upper rear part of the left temporal lobe, is named for Carl Wernicke (1848-1905), who first described it in 1874. Aphasia associated with this area—called Wernicke’s aphasia—differs dramatically from Broca’s aphasia. While speech in Broca’s aphasia is overly concise, in Wernicke’s aphasia it is filled with an abundance of words (logorrhea), but they are words which fail to convey the speaker’s meaning. Even though their pitch and rhythm sound normal, many of the words are used incorrectly or are made-up words with no meaning (aphasic jargon). Besides their speech difficulties, persons with Wernicke’s aphasia also have trouble comprehending language, repeating speech, naming objects, reading, and writing. An interesting exception to their comprehension impairment is their ability to respond readily to direct commands that involve bodily movement, such as “Close your eyes.”
Certain types of aphasia—called disconnection aphasias—are caused by damage to the connections of Broca’s or Wernicke’s areas to each other or to other parts of the brain. Conduction aphasia results from damage to the fiber bundles connecting the two language areas and is characterized by fluent but somewhat meaningless speech and an inability to repeat phrases correctly. In transcortical sensory aphasia, the connections between Wernicke’s area and the rest of the brain are severed, but the area itself is left intact. Persons with this condition have trouble understanding language and expressing their thoughts but can repeat speech without any trouble. Another type of aphasia, word deafness, occurs when auditory information is prevented from reaching Wernicke’s area. Persons affected by word deafness can hear sounds of all kinds and understand written language, but spoken language is incomprehensible to them, since the auditory signals cannot reach the part of the brain that decodes them.
Taken from : The Gale Encyclopedia Of Psychology 2ND Edition - Bonnie Strickland
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