"Corpus Callosotomy"
Corpus callosotomy is a palliative surgical
procedure for the treatment of seizures. As the corpus callosum is
critical to the interhemispheric spread of epileptic activity, the
procedure seeks to eliminate this pathway. “Efficacy and relatively low
permanent morbidity in corpus callosotomy for medically intractable
epilepsy have been demonstrated by more than six decades of experience.
In addition to seizure reduction, behavior and quality of life may
improve.”
The corpus callosum is usually severed in order to stop
epileptic seizures. Once the corpus callosum is cut, the brain has much
more difficulty sending messages between the hemispheres. Although the
corpus callosum is the largest white matter tract connecting the
hemispheres, some limited interhemispheric communication is still
possible via the anterior commissure and posterior commissure. When
tested in particular situations, it is obvious that information transfer
between the hemispheres is reduced.
The most prominent
non-surgical complications of corpus callosotomy relate to speech
irregularities. For some patients, sectioning may be followed by a brief
spell of mutism. A long-term side effect that some patients may suffer
is an inability to engage in spontaneous speech. In addition, the
resultant split-brain prevented some patients from following verbal
commands that required use of their non-dominant hand.
Another common complication is alien hand syndrome, in which the afflicted person's hand appears to take on a mind of its own.
http://en.wikipedia.org/wiki/Corpus_callosotomy
"Alien hand syndrome"
The
patient complained of a feeling of "strangeness" in relationship to the
goal-directed movements of the left hand and insisted that "someone
else" was moving the left hand, and that she was not moving it herself.
Goldstein reported that, as a result of this report, "she was regarded
at first as a paranoiac." When the left hand grasped an object, she
could not voluntarily release it. The somatic sensibility of the left
side was reported to be impaired, especially with aspects of sensation
having to do with the orienting of the limb. Some spontaneous movements
were noted to occur involving the left hand, such as wiping the face or
rubbing the eyes; but these were relatively infrequent. Only with
significant effort was she able to perform simple movements with the
left arm in response to spoken command, but these movements were
performed slowly and often incompletely even if these same movements had
been involuntarily performed with relative ease before while in the
abnormal 'alien' control mode.
Damage to the corpus callosum can
give rise to "purposeful" actions in the sufferer's non-dominant hand
(an individual who is left-hemisphere-dominant will experience the left
hand becoming alien, and the right hand will turn alien in the person
with right-hemisphere dominance).
In “the callosal variant”, the
patient’s hand counteracts voluntary actions performed by the other,
“good” hand. Two phenomena that are often found in patients with
callosal alien hand are agonistic dyspraxia and diagonistic dyspraxia.
Agonistic
dyspraxia involves compulsive automatic execution of motor commands by
one hand when the patient is asked to perform movements with the other
hand. For example, when a patient with callosal damage was instructed to
pull a chair forward, the affected hand would decisively and
impulsively push the chair backwards. Agonistic dyspraxia can thus be
viewed as an involuntary competitive interaction between the two hands
directed toward completion of a desired act in which the affected hand
competes with the unaffected hand to complete a purposive act originally
intended to be performed by the unaffected hand.
Diagonistic
dyspraxia, on the other hand, involves a conflict between the desired
act in which the unaffected hand has been engaged and the interfering
action of the affected hand which works to oppose the purpose of the
desired act intended to be performed by the unaffected hand. For
instance, when Akelaitis’s patients underwent surgery to the corpus
callosum to reduce epileptic seizures, one patient’s left alien hand
would frequently interfere with the right hand. For instance, while
trying to turn over to the next page with the right hand, his left hand
would try to close the book.
In another case of callosal alien
hand, the patient did not suffer from intermanual conflict between the
hands but rather from a symptom characterized by involuntary mirror
movements of the affected hand.
When the patient was asked to perform
movements with one hand, the other hand would involuntarily perform a
mirror image movement which continued even when the involuntary movement
was brought to the attention of the patient, and the patient was asked
to restrain the mirrored movement. The patient suffered from a ruptured
aneurysm near the anterior cerebral artery, which resulted in the right
hand being mirrored by the left hand. The patient described the left
hand as frequently interfering and taking over anything the patient
tried to do with the right hand. For instance, when trying to grasp a
glass of water with the right hand with a right side approach, the left
hand would involuntary reach out and grasp hold of the glass through a
left side approach.
More recently, Geschwind et al. described the
case of a woman who suffered severe coronary heart disease. One week
after undergoing coronary artery bypass grafting, she noticed that her
left hand started to ‘‘live a life of its own’’. It would unbutton her
gown, try to choke her while asleep and would automatically fight with
the right hand to answer the phone. She had to physically restrain the
affected hand with the righ hand to prevent injury, a behavior which has
been termed "self-restriction." The left hand also showed signs of
severe ideomotor apraxia. It was able to mimic actions but only with the
help of mirror movements executed by the right hand (enabling
synkinesis). Using magnetic resonance imaging (MRI), Geschwind et al.
found damage to the posterior half of the callosal body, sparing the
anterior half and the splenium extending slightly into the white matter
underlying the right cingulate cortex.
http://en.wikipedia.org/wiki/Alien_hand_syndrome
***I remember learning about this in Psychology when I was in college,
in the 1990's, only to actually work with someone that had that done
when I worked at a Marriott hotel as a banquet server.
He had some conflict. He told me his "Right brain is jealous of the left
because the right hand does all the work."
There was onetime he hit himself with the left hand.
I had to know what eye - side of the brain to look at to tell
him to knock it off. He thanked me for that!
But overall he was a happy guy! He had his bad times, but
found happiness by carrying two trays of food one in each hand.
"Im happy!" he said. The boss didn't like that but I pulled out
my old college books and showed her, hes not normal and needs
not to be chained to a standard due to his needs!
The Brain is amazing!
