Global aphasia is a type of language disorder caused by damage to the brain. It is a nonfluent aphasia with severe impairment of both expressive and receptive skills. Patients with global aphasia are unable to say or understand more than a few words and are unable to read or write.
Global aphasia is commonly associated with a large lesion in the perisylvian cortex, the area in the brain around the sylvian fissure. The damage to this area of the frontal, temporal and parietal lobes of the brain causes an almost total reduction of all aspects of spoken and written language. It involves a "left side blowout" which includes Broca's area, Wernicke's area and the Arcuate fasciculus. It can also be seen in the initial stages of large left middle cerebral artery injuries that may progressively improve to become expressive aphasia.
The presentation of global aphasia is that of severe expressive aphasia and receptive aphasia combined. There is absence or severe impairment of both comprehension and expression of language. Persons with global aphasia are often mute or reduced to a few stereotyped words or sounds, and are able to express themselves using facial expressions, intonation, and gestures. Other cognitive skills remain functioning - a phenomenon affirming that language faculty is indeed a separate domain. Patients with global aphasia are not impaired in reorientation tasks, either, confirming their ability to integrate spatial cues even in the absence of verbal assistance.
Persons with a large injury to the left perisylvian areas of the brain, often initially show signs of global aphasia in the first 1–2 days due to brain swelling (cerebral edema). With some recovery, impairment presentation may progress into expressive aphasia (most commonly) or receptive aphasia. Improvement may occur in one or both areas (expressive and receptive language) over time. However, studies show that spontaneous improvement, if it happens, occurs within six months, but complete recovery is rare.
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