The Corpus Callosum

As
reported in the journal, The Lancet, a man has
been found who had a
small brain, but a normal life. The article is subscription
only so I am not even going to link to it. But it is still
noteworthy.

There is a fair summary in the online version of href="http://www.spiegel.de/international/zeitgeist/0,1518,495607,00.html">Der
Spiegel, and it is even in English. It
describes the case of a 44-year-old man employed in a tax office.
He was married, father of two, holding down a job, seemingly
fine.
In 2003 he noticed some weakness in his left leg.
He ultimately was seen by Dr Lionel Feuillet of the
Universite de la Mediterranee in Marseille, France.

Upon evaluation, he did reveal that, as a child, he had been told he
had href="http://www.emedicine.com/NEURO/topic161.htm">hydrocephalus.
A href="http://www.sophysa.com/patient/hydrocephalus/hydrocephalus3.htm">shunt
was placed to drain the fluid. He was doing
fine, and at age 14 the shunt was removed. That would have
been around 1973, so href="http://www.pbs.org/wnet/brain/scanning/cat.html">CAT
scans and MRIs
would not have been available.

Of course, by 2003, detailed brain imagining studies had become
routine. The physicians were astonished at what they saw.

With more evaluation, he was found to have an IQ of 75.
Significantly below aerage, but adequate for what he had to
do.

Below is a drawing (from rel="tag">Gray’s Anatomy) showing what the
ventricular system in the brain is supposed to look
like. Notice in particular the size of the lateral
ventricles. It is not terribly clear in this line drawing,
but the ventricles are fluid-filled cavities in the middle of the
brain.

The
three-dimentional view is a bit easier to grasp with the MRI
images…

This is copied from Der Spiegel. The
patient is looking to the left. The eye socket is the white
circle on the left. The LV label indicates the lateral
ventricle.

For comparison, here are three different views of a normal brain:

href="http://www-psych.stanford.edu/%7Ekalina/BB/Lecture02/index.html">

Some
of the news reports quipped.
“size isn’t everything.”

Update: Cognitve Daily has a nice discussion of this phenomenon.

Comments

#1 Greg P
July 23, 2007

I’ve seen this kind of thing before. It’s surprising how something like this can develop. BTW, we wouldn’t call this a “small brain”. Hard to even necessarily say how much the volume of the brain is reduced — everything is compressed. One would expect the brain to expand after reshunting, though given the longevity not to a normal volume. Will his IQ go up? I suspect not so much, for one thing related to the fact that he’s an adult.
#2 han
July 24, 2007

it is incredible how adaptive our body, and its individual parts, can be. while the brain is one organ that has, relatively, less ability to compensate, if given a enough time and especially if the “insult” takes place at a young age, as is the case above, it can compensate enough for ‘sufficient functionality”. there are examples of children who have had entire one side of the cerebral hemisphere (part of the forebrain) removed at young age, being able to gain enough compensatory hypertrophy/hyperplasia from the other side to be relatively “normal” in life. removal of one cerebral hemisphere in an adult would be devastating, as we know from stroke patients. hydrocephalus, as in the case above, is not really loss of any brain tissue. it is dilatation of the ventricular system – there are various causes for this – and compression of the brain tissue. this does prevent the brain from maturing properly but there is no loss of tissue, per se. these patients do not usually have normal brain function, therefore decreased IQ, but depending on the severity of the hydrocephalus, they can have varying degrees of functionality. some can even go on to live a “full” life. these patients actually have large heads and large appearing brain on the surface. but the amount of brain tissue, thereby its weight, is less than average. in the case above and as is the case for children who is found to have hydrocephalus, the most common type is congenital stenosis of the aqueduct of sylvius (part of the ventricular system that drains cerebrospinal fluid from the third ventricle to the fourth). these patients do not get better on their own. the external shunt is usually kept indefinitely. it is somewhat surprising that this patient’s shunt was removed some time ago. i suspect that the removal of the shunt had contributed to the eventual outcome of the brain development and appearance. another interesting situation that are seen sometimes is patients missing a portion of the brain called corpus callosum (from improper development). the corpus callosum is the largest of the “bridges” that connect the left and right side of the brain, very important in allowing the two sides of the brain to function in unison and in coherent fashion. the patients missing this part of the brain usually are markedly dysfunctional, but once in a while, they lead “full lives” as in the case above. there are numerous cases of those who have other organs either partly missing from developmental mishap or surgically removed and are functional. truly amazing.
#3 Ian
July 26, 2007

Within the Canadian health care system we wouldn’t call this a “small brain” either,

We’d call them a “manager”

(eventually someone was going to say it)
#4 Jim
July 31, 2007

The most significant item is the occupation of the man:Tax office.

As we suspected, tax office workers are the lowest form of human life.
#5 Christie Dannewitz
July 15, 2008

I know this is way beyond late but I just wanted to comment that I found your site because of my search for anything corpus callosum-related. My son has Agenesis of Corpus Callosum or ACC as it is called by those familiar with it. My son was diagnosed when he was 6 weeks old because of another “midline” issue, he needed to have an operation on his sagittal sutures which were closing too quickly. So we found out about the ACC because of a cat scan and then a followup MRI. He is now 4 and is a healthy, happy boy with no developmental delays (yet.) He is one of the very few. Although I know I should be thrilled, I still worry about what’s ahead for him. And although we had genetic testing done (with no other abnormalities) I can see in my family alone, an older daughter recently diagnosed with ADHD, a grandmother (long passed away) who I and others in my family believe had Tourette’s. I’m sorry for giving you this life story. I suppose I wish your site was full of corpus callosum info. With the advent of the MRI, there are people literally finding out every day about this condition. And much research is being done. I know that none of it can predict the future. Thanks anyway for letting me vent. I do read your blog regularly and am grateful for your doing so.
#6 kristin
October 11, 2008

this is for Christie. Please contact me. I have an 11 yr old. we just found out she has ACC. I would love to tell you how she is doing. Everyone is amazed! She is awesome! Let’s talk. I can give you incredible hope for you and your family. And it is real! The diag. is so new to us, but I can tell you what all she has accomplished and what we are expecting. Great things! Love him for who God made him to be and expect great things from him.
Kristin ksalak@sbcglobal.net
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April 15, 2011

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