This is really strange but also interesting!
ABSTRACT. Purpose. To report the outcomes of the
58 hemispherectomies performed at Johns Hopkins be-
tween 1968 and January 1996.
Methods. Charts were reviewed of the 58 hemi-
spherectomies performed at Johns Hopkins Medical In-
stitutions by the Pediatric Epilepsy Group during the
years 1968 to 1996. Twenty-seven operations were done
for Rasmussen’s syndrome, 24 operations for cortical dys-
plasias/hemimegalencephalies, and 7 for Sturge-Weber
syndrome or other congenital vascular problems. Seizure
control alone did not seem to adequately describe the
outcomes of the procedure. Therefore, a score was con-
structed that included seizure frequency, motor disabil-
ity, and intellectual handicap. This burden of illness
score better described the child’s handicap before and
Results. Perioperative death occurred in 4 out of 58
children. Of the 54 surviving children, 54% (29/54) are
seizure-free, 24% (13/54) have nonhandicapping seizures,
and 23% (12/54) have residual seizures that interfere to
some extent with function. Reduction in seizures was
related to the etiology of the unilateral epilepsy. Eighty-
nine percent of children with Rasmussen’s, 67% of those
with dysplasias, and 67% of the vascular group are sei-
zure-free, or have occasional, nonhandicapping seizures.
All operations were considered by the parents and the
physicians to have been successful in decreasing the
burden of illness. In 44 the procedure was very success-
ful, in 7 it was moderately successful, and in 3 it was
minimally successful. Success was related to the etiology,
and early surgery was preferable.
Conclusion. Hemispherectomy can be a valuable pro-
cedure for relieving the burden of seizures, the burden of
medication, and the general dysfunction in children with
severe or progressive unilateral cortical disease. Early
hemispherectomy, although increasing the hemiparesis
in children with Rasmussen’s syndrome, relieves the
burden of constant seizures and allows the child to re-
turn to a more normal life. In children with dysplasias,
early surgery can allow the resumption of more normal
development. Pediatrics 1997;100:163–171; hemispherec-
tomy, burden of illness, epilepsy surgery, quality of life.
Why should removal of half a brain be of benefit to
a child? Decrease in constant, uncontrollable seizures
and the attendant decrease in medications with their
side-effects may be part of the reason. However, it is
tempting to speculate, that the continuous electrical
activity of these severely dysfunctional hemispheres
interferes with the function of the other, more nor-
mal hemisphere. This might explain why motor
function improves after hemispherectomy and why
language recovers after removal of the dysfunctional
but does not seem to fully transfer
before surgery. Perhaps it also partially explains in-
tellectual improvement in these children after re-
moval of half of the cortex. We are awed by the
apparent retention of memory after removal of half
of the brain, either half, and by the retention of the
child’s personality and sense of humor. Yet we look
forward to the time when there are less mutilating
approaches to these problems. Until then it seems
that half of a brain is less burdensome to these chil-
dren than a whole brain where one side is badly
The more interesting thing was that these people didnt get personality changes or memory loss. How can that be? I have a theory. Think of RAID (RAID 1) systems for computers. The idea is that the brain has a similar mirror-setup. It may compartmentalize the functions, but the information is stored in both brains.
This theory has the added benefit of also explaining why people that get a Corpus callosotomy remain roughly the same person in both brains even tho they are independent. The reason is that they have access to broadly the same information.
In general, split-brained patients behave in a coordinated, purposeful and consistent manner, despite the independent, parallel, usually different and occasionally conflicting processing of the same information from the environment by the two disconnected hemispheres. When two hemispheres receive competing stimuli at the same time, the response mode tends to determine which hemisphere controls behavior. Often, split-brained patients are indistinguishable from normal adults. This is due to the compensatory phenomena; split-brained patients progressively acquire a variety of strategies to get around their interhemispheric transfer deficits.