ged with positron emitting isotopes, that has been ingested by the patient. Finally, EEGs collect data from the electric fields that are produced by the brain.
Damage to either the right or left hemisphere, and its resulting deficits provide insight into the function of the damaged area. Right hemisphere damage has many effects on language production and perception. Damage or lesions to the right hemisphere can result in a lack of emotional prosody or intonation when speaking. Right hemisphere damage also has monumental effects on understanding discourse. People with damage to the right hemisphere have a reduced ability to generate inferences, comprehend and produce main concepts and a reduced ability to manage alternative meanings. Furthermore, when engaging in discourse people with right hemisphere damage, their discourse is often abrupt and perfunctory or verbose and excessive. They can also have pragmatic deficits in situations of turn taking, topic maintenance and shared knowledge.
Lateral brain damage can also have effects on spatial frequency. People with left hemisphere damage are only able to see low frequency, or big picture, parts of an image. Right hemisphere damage causes damage to low spatial frequency, so people with right hemisphere damage can only see the details of an image, or the high frequency parts of an image.
If a specific region of the brain, or even an entire hemisphere, is injured or destroyed, its functions can sometimes be assumed by a neighboring region in the same hemisphere or the corresponding region in the other hemisphere, depending upon the area damaged and the patient's age. When injury interferes with pathways from one area to another, alternative (indirect) connections may develop to communicate information with detached areas, despite the inefficiencies.
Broca’s aphasia is a specific type of expressive aphasia and is so named due to the aphasia that results from damage or lesions to the Broca’s area of the brain, that exists most commonly in the left inferior frontal hemisphere. Thus, the aphasia that develops from the lack of functioning of the Broca’s area is an expressives and non-fluent aphasia. It is called ‘non-fluent’ due the issues that arise because Broca’s area is critical for language pronunciation and production. The area controls some motor aspects of speech production and articulation of thoughts to words and as such lesions to the area result in the specific non-fluent aphasia.
Wernicke’s aphasia is the result of damage to the area of the brain that is commonly in the left hemisphere above the sylvian fissure. Damage to this area causes many deficits in language production and cognition. Although the speech produced by a person with Wernicke’s aphasia sounds like regular speech, it is riddled with mistakes. They include mild impairments in word selection, grammar, and segmental phonology. Wernicke's aphasia is characterized by phonemic paraphasias, neologism or jargon. Comprehension of spoken language is also mildly impaired in people with Wernicke's aphasia. Another characteristic of a person with Wernicke’s aphasia is that they are unconcerned by the mistakes that they are making.
Misapplication of concept
Terence Hines states that the research on brain lateralization is valid as a research program, though commercial promoters have applied it to promote subjects and products far outside the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as EMDR and neurolinguistic programming, brain training equipment, or management training.
Advantages of brain lateralization
The widespread lateralization of many vertebrate animals indicates an evolutionary advantage associated with the specialization of each hemisphere. In one experiment, baby chicks were lateralized before hatching by exposing their eggs to light. These chicks were set to a task of picking out food from a bed of pebbles. Neither the lateralized, nor the non-lateralized chicks had a problem with this task, but the lateralized chicks 