In 2007, a
perfectly healthy 44-year-old man complaining of minor leg weakness baffled
doctors in France when a medical exam revealed that most of his brain was
missing. Although researchers can explain why he lost his brain, figuring out
how he managed to live so long without it is more difficult. However, a recent
study may shed light on the man’s survival, proposing that brain size and brain
function are largely unrelated.
The
middle-aged father of two, whose identity was not revealed for privacy concerns,
visited his doctor after suffering with mild weakness in his left leg for two
weeks. According to the 2007 study on the bizarre case published in the
scientific journal The Lancet, a more thorough medical examination revealed the
patient was missing a significant amount of brain matter. Although it was
difficult to measure exactly how much of the brain was absent, according to
Lionel Feuillet, a co-author of the study, the doctors estimated that the
patient was missing between 50 to 75 percent.
“The whole
brain was reduced — frontal, parietal, temporal and occipital lobes — on both
left and right sides. These regions control motion, sensibility, language,
vision, audition, and emotional, and cognitive functions,” Feuillet told New
Scientist.
Despite the
handicap, the married father of two held a full-time job as a civil servant and
showed no other signs of his missing body part other than a slightly below
average IQ.
Further
Investigation
A further
investigation of the patient’s medical history revealed a possible cause for
the strange condition. At 6 months old, the patient was diagnosed with
postnatal hydrocephalus, New Scientist reported. Hydrocephalus, which is Greek
for “water on the head,” is a condition that occurs when fluid build up in the
skull and causes the brain to swell. The cause of the patient’s hydrocephalus
was listed as unknown, but according to the National Health Institute most
cases of postnatal hydrocephalus, or hydrocephalus which occurs after birth,
are spurred by infections of the central nervous system, bleeding in the brain
caused by injury or during birth, or even tumors.
After his
diagnosis, the patient received shunts in his brain to help drain the excess
fluid. When untreated, hydrocephalus can cause brain damage and impaired
developmental, physical, and intellectual functions. At age 14 the shunts were
removed. Unfortunately, according to the study, removing the shunts allowed
more fluid to gradually build up in the patient’s brain. Over the next 30
years, this build-up slowly condensed and consumed the actual brain matter
until it only remained on the outer areas of the skull, much similar to a
shell.
The weakness
in the man’s leg subsided after doctors reinserted a shunt into his brain via a
procedure known as neuroendoscopic ventriculocisternostomy. While the cause of
the patient’s initial concern had been addressed, how he remained fully
functional despite missing the majority of his brain remained less clear.
The French
patient may be the most extreme case of an individual functioning without a
large percentage of his brain, but he is by far not the only example. According
to Dr. Donald Forsdyke in his paper recently published in Biological Theory,
these examples are proof that the brain size has little correlation with what
it’s capable of accomplishing. Because those missing large amounts of their
brains are able to function nearly the same as those with full brains, Fosdyke
proposes “it would seem timely to look anew at possible ways our brains might
store their information.”
Brain
Plasticity
Experts
believe the concept of brain plasticity may explain how the Frenchman was able
to function despite missing so much brain matter. Our brains are made up of
different sections designed to undertake specific tasks. For example, the
frontal lobe is associated with speech, movement, and problem solving, while
the cerebellum is associated with coordination of movement and balance. Brain plasticity, or neuroplasticity,
describes how the brain is able to reorganize its neural pathways to allow
areas of the brain to undertake other tasks other than those intended.
“If
something happens very slowly over quite some time, maybe over decades, the
different parts of the brain take up functions that would normally be done by
the part that is pushed to the side,” Dr. Max Muenke, a pediatric brain defect
specialist at the National Human Genome Research Institute, who was not
affiliated with the study, told New Scientist.
Other
examples of brain plasticity are found in individuals with hearing loss.
Researchers have observed that without auditory stimulation, the area of the
brain associated with hearing, the auditory cortex area, adjusts to help the
patient enhance their remaining senses. Recent research has also revealed that
brain plasticity may play a role in helping the brains of those with autism
improve their overall brain function.
Source= www.medicaldaily.com