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Summary — Brain plasticity after early damage


Recovery of function after brain damage has aways been known to be more marked if the damage occurs while the brain is still growing, and this applies most obviously to basic motor functions after large lesions of motor cortex (Benecke et al 1991). Imaging studies confirm that early severe damage to one hemisphere results in the remaining hemisphere controlling both sides of the body (Benecke et al 1991; Carr et al 1993; Sabatini et al, 1994).

Surgical removal of a large part one one hemisphere is not uncommon for the relief of seizures (e.g. Vining et al, 1997 and Boatman et al 1997), and it is possible to interpret the cognitive outcomes as demonstrating “the remarkable ability of a single hemisphere, whether left or right, to support ... a wide range of cognitive functions, from visual perception.... to language and even speech” (Vargha-Khadem and Polkey, 1992).

There is evidence that even early left-hemisphere damage has worse effects than right on complex linguistic functions (Stark et al, 1995; Vargha-Khadem et al, 1991)

But speech and language deficits are less marked after early left-hemisphere damage than would be expected from adult neurological findings (Stark et al, 1995; Vargha-Khadem et al, 1992)


(see also the Vargha-Khadem et al 1997 overhead and the summary of the Boatman et al, 1997 paper)  


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