A brain-damage advantage for lefties?A brain-damage advantage for lefties?
For an as yet unexplained reason, people who are predominantly left-handed apparently are able to withstand moderate brain damage with relatively few of the motor problems observed in righthanded victims of brain damage.
Studies of a limited number of braindamaged left-handers also indicate that they have a quicker and superior recovery of other functions, such as language and visual-spatial processing, than do their right-handed counterparts, says neuropsychologist Neuropsychologist
A clinical psychologist who specializes in assessing psychological status caused by a brain disorder.
Mentioned in: Post-Concussion Syndrome Jordan Grafman of Walter Reed Army Medical Center Walter Reed Army Medical Center, major hospital complex in Washington, D. C., and Forest Glen, Md.; est. 1923 and named for U.S. army surgeon Walter Reed. It is composed of seven units including a general hospital and a research institute. There are several thousand beds. in Washington, D.C.
"You can speculate that more transfer of information and shared information processing information processing: see data processing.
Acquisition, recording, organization, retrieval, display, and dissemination of information. Today the term usually refers to computer-based operations. between left-handers' brain hemispheres might allow for their better recovery after brain damage,' observes Grafman. "But so far there is no evidence for this theory.'
Grafman and his colleagues chose subjects from a group of left-handed Vietnam veterans This article is about the French band. For veterans of the Vietnam War, see Vietnam veteran.
The Vietnam Veterans were a six-person French psychedelic group that released six records in the 1980s. The band was praised by many alternative music publications. who suffered brain wounds without paralysis about 15 years ago. The study sample was composed of 13 men with right-hemisphere damage, 11 with left-hemisphere damage and 13 healthy, non-brain-damaged veterans. The researchers administered eight tests of simple motor functions, including grip strength Grip strength is the force applied by the hand to pull on or suspend from objects. Optimum-sized objects permit the hand to wrap around a cylindrical shape with a diameter from one to three inches. , finger dexterity (manipulating pegs on a pegboard), coordination (finger tapping and movement tasks) and reaction tim (pressing a button as rapidly as possible after seeing a brief flash of light).
Left-handed veterans with damage to either hemisphere performed almost as well as the healthy controls and displayed no severe motor problems, report the investigators in the October PERCEPTUAL AND MOTOR SKILLS. The size of a brain would, language comprehension Sentence comprehension is the ability to derive from concepts linguistics input (through writing or speech acts). What is known about sentence comprehension
Local vs. Global Ambiguity
Sentence comprehension deals with lexical, structural, and semantic ambiguities. and preinjury intelligence scores were not related to motor performance, they note. Curiously, says Grafman, patients with left-hemisphere damage were more likely to have received both physical and occupational therapy, although the reasons for this are unclear.
In an unpublished study conducted by the same scientists, substantial deficits in motor functioning on the same tests appeared among right-handed veterans who suffered damage to either brain hemisphere, compared with a control group.
There are some data suggesting that left-handers have a more equitable distribution of motor and cognitive skills cognitive skill Psychology Any of a number of acquired skills that reflect an individual's ability to think; CSs include verbal and spatial abilities, and have a significant hereditary component across brain hemispheres than right-handers (SN: 8/17/85, p. 102), as well as indications that left-handers are more likely to have allergies, myopia myopia: see nearsightedness. and learning disabilities, and, paradoxically, are more likely to be intellectually gifted (SN: 4/27/85, p. 263). "It's not clear if left-handers have a developmental disadvantage [compared with right-handers] and an advantage in adapting to brain damage,' says Grafman. One reason he is reluctant to interpret his data is that it was not possible to conduct handedness handedness, habitual or more skillful use of one hand as opposed to the other. Approximately 90% of humans are thought to be right-handed. It was traditionally argued that there is a slight tendency toward asymmetrical physiological development favoring the right tests on braindamaged veterans before their injuries occurred. Also, it is not known if healthy left-handers have somewhat poorer motor skills than healthy right-handers across a critical range of performance affected by brain damage; if this were the case, explains Grafman, deficits would appear more pronounced in right-handers because they have more motor ability to lose.
"Unfortunately,' he notes, "there is a lack of studies on left-handers, and it's hard to develop an animal model of handedness.'