Brain Overgrowth in the 1st Year Linked to Autism
December 10, 2007 by Kristina Chew, PhD
Filed under Health
Brain overgrowth in the latter part of an infant’s first year has been found to be connected to autism in some cases. Today’s Ars Technica reviews the findings of Joseph Piven, the director of the Neurodevelopmental Disorders Research Center at the University of North Carolina Chapel Hill, and also issues a caveat.
Under normal brain development, neural connections are formed, but some are subsequently eliminated through a process known as “pruning.” The pruning refines normal brain conditions and increases the efficiency of the remaining connections in the brain. According to Piven, one hypothesis is that some autistic children’s brain undergo less pruning, which could lead to the larger brain sizes observed. Even with this apparent link, Dr. Piven urges caution from reading too much into it. Since the autism label represents a spectrum of disorders, saying one form of brain overgrowth is solely responsible isn’t appropriate at this point. It should also be noted that this work has yet to undergo a peer review process, as this research was presented at a conference this week.
Dr. Piven presented his research in a lecture at last weekend’s annual meeting of the American College of Neuropsychopharmacology (ACNP).
My own son has a notably large head circumference and we’ve long had to buy him an adult-size bike helmet and hats. I’m not sure if his development coheres with Dr. Piven’s findings, as my son was born with a large head—leading his first pediatrician to say “that means he has a big brain, but not necessarily that he’s really smart.”
(I had no comment at the time.)
This is amazing. I was just talking to my husband about this last night. I have a gigantic head. My son with Asperger’s has a HUGE head…off the charts most of his life. My baby also has a large head, and he’s showing…signs. His head also grew so fast in the first few months that it outdistanced his hairline; for while there, he looked like he had male-pattern baldness. Given my ancedotal experiences with the Big-Head family (my father, who didn’t talk until he was at least two, also has a huge head), I actually worried about his head growth rate those first few months. Maybe now I know why.
With the reports of the overgrowth in the parietal area, the “noise” I personally experience in my own head and that I know my oldest feels (so much input), our large heads, etc….I do “feel” (not very scientific of me, I know) that there is something to the head growth/head size thing. I can almost feel the need for more pruning in my own brain, for running along cleaner lines, the synaptic highways not so cluttered and overwhelming and noisy with indiscernible messages. It’s one reason I can’t stand places like Chuck E. Cheese. Too. Much. Input.
Ahem. I have to add that, when my Yeh Yeh (my dad’s dad) first saw me at the hospital, Yeh Yeh said, “She has a big forehead! She’s going to be very smart!” My hat size is L not S/M.
Charlie’s head growth does seem to have slowed down as he has aged. When he was younger, I often thought he tended to fall on his face because of all that, er, weight, and long spindly, and uncoordinated legs; Charlie was 6 when he learned to put out his hands to cushion his fall.
We had to cut T-shirts along the shoulder line and put buttons in to get them over our guy’s head when he was young.
Kristina, our oldest walked around for about two years with what was practically a permanent knot on his forehead from falling and whacking his head on the ground. We used to joke–before we wised up–about how it was just gravity pulling on that oversized head and bringing it the ground before everything else. Of course, the big head AND the fact that he wasn’t catching himself as he fell are far more meaningful to us now. Hindsight can really make ya feel dumb, you know?
Both my son and I have very large heads. I recall the earliest measurements of his head circumference being in the 98 percentile. Not sure what mine is, but hats need to be large!
My son’s head circumference was really large when he was born, and then it got better. Basically the top of his head was very flat, and the back of the head was longer than usual (kinda like E.T. in the movie). I thought that was because he was breech and my stomach was pressing the top of his head. In a few months the shape of his head went back to normal, and his head doesn’t look big now. But he still has that “bump” on the back of his head, maybe there’s where the brain grew abnormally. In any case, that happened before birth and not after it.
…I’m the weirdo here. I’m decidedly autistic but with a teeny head. My winter hat is from the toddler section.
None of us here have particularly large heads either.
Not that that stopped me from falling over a lot and not realising you can also stick your hands out in front of you so your head doesn’t crack open.
Interesting.
Yep, we’re another family with big-head-syndrome…parents who can’t find hats to fit from the rack, and girls with adult hats at the age of 8.
Eleanor had a big head, and more specifically, a big brain, in utero, and that remained true after birth as well. Doctors have commented on it quite a few times.
Well being the wrong side of 50 nobody is interested in scanning my brain any more, not that it would be a lot of fun having had my neck MRI’d recently and being able to feel the effect of the magnetic field. (now there is sensitivity for you)
If anything I have a microcephalic tendency so whatever is up there in my thick and bruised skull has gotto be either very dense or located in hyperspace, I opt for the latter given the problem I have in the diodes down my left side.
And with the pruning and the shearing, sont les idees qui sont abougre (there is an acute on the e) avec les neiges d’antan, quein sabe?
I do recall incidentally my first aquaintance with Annouilhs rather boring Antigone a particular phrase that was amusing at the time “ce ne sont pas des mauvais bougres” and I thought WTF they ain’t bad at what!!!!!
never mind le chat qui pissent sur la tapis, cos I thought these profanities out of place considering the propriety of school rules.
Aristophanes, now that is another story.
AJ has a permanent scab on his forehead from falling in the same place…the left side.
The twins couldn’t wear T-shirts until they were 2 and a half. They looked very preppy for a while there, because they could only wear shirts with buttons. When they were slow to sit up, crawl, etc, several doctors blamed it on their big heads.
For the first year of their lives, I kept seeing other babies and thinking to myself, “Poor kid…his head is tiny!”
My boy has big head from birth. He was way over the 98 percentile. His head is still big, but in much better proportion. He used to look like a lollipop from far.
It’s the upper part of Charlie’s head that is big, especially.
Large head sizes have been reported in 20% of autistic people, but small head head size is also reported in 20% autistic people.
Large head size is also associated with schizophrenia and mental retardation:
http://www.psychiatrictimes.com/topic/Schizophrenia/showArticle.jhtml;jsessionid=HVVKTG5K2R40MQSNDLQSKICCJUNN2JVN?articleID=197002520&topic=Schizophrenia
Piven has the same problem that many autism researchers have, they look only at one condition, and fail to recognize that most of the theories they propose are nonspecific to autism and are found in all sorts of neurological conditions including normal people.
Piven is also one of the true believers in the polygenic hypothesis (multiple genes interacting to cause autism) yet no autism specific gene has ever been reported let alone dozens of genes of small effect.
My non-autistic son was breech and has always had a very large head. It’s adult size and it has a big bump in the back. I assumed it was because his head was squeezed under my ribs (the shape anyway).
My autistic son has a small-in-comparison sized head. I think he’s pretty average on the charts. I imagine some autism is linked in some way to head size and shape.
RAJ, citation on the 20% data? Also, the fact that it might be attributable to many small genes interacting would make it less likely that we’ve identified any of them to date because they’ll be a lot harder to trace and localize than a single gene would, especially if they have other “duties” or pleiotropic effects or are under environmental regulation that results in…um…like…you know, a spectrum of phenotypes.
Ha! My side of the family is definitely big-headed. We are a clan of bobble-heads, but no autistics (that I can think of). Both my kids have big nuggets, but only one is autistic. Moreover, they were born with big heads – there was no rapid growth during the first year. They started off at 98th percentile (thank god for C-sections!) and stayed there.
Oh ye of little faith, you “big heads” you are like the mercurians, wedded to a personal thery of autism, and it is an affront, a nasty piece of cognitive dissonance when anybody pricks your bubble.
Raj is right there is various research that does not support this thery, in any case it’s not about head circumference anyway, but rapid initial growth, not continued cranial capacity like the Mekon’s.
Furthermore a statistically significant incidence of larger head size indicates that it is a tendencey in some, not a universal fact for all!!!
Besides every single study in autism, including the one I am about to do, is flawed by one simple fact, no one can agree on who is autistic.
Studies may have internal consistency with themselves, but when it comes to comparing studies, some would count as NT those whom others wouldn’t some would not think to go through any diagnostic test of the supposedly NT controls to rule out any significant autistic or other neuro diverse trait that might skew results. Oh the faults are endless, but I’ll wager that if you were to take any slew of studies and map each of the participants with venn diagrams, and then take your own measure of autism of choice, you would find different overlaps for each of the study groups, but certainly not universal agreement that they were all autistic according to your study criteria. That is the nature of the beast and if head circumference were to emerge as a diagnostic tool, all it would diagnose is a big head, because the disorder is epistemologically constructed out of its diagnostic components and you change one the whole construct shifts. It is constructed from the outside in, not the inside out, so it is practically impossible to rigidly define from a total knowlege position.
Now here is an interesting paper for those who believe we all have pointed ears
Minor physical anomalies in children with autism
spectrum disorder☆
Gabriele Tripi a,⁎, Sylvie Rouxb, Tatiana Canziani a,c,
Frédérique Bonnet Brilhault b, Catherine Barthélémy b, Fabio Canziani
Bobby is definitely big-headed. Not quite lollipop-proportioned, but big enough so that he was a surprise “Oops he’s stuck” c-section.
As for me, I’m like Kassiane in that said my hats come from the little kids’ department. My glasses frames used to be kids’ frames, too.
Didn’t have a C-section—-Charlie didn’t have an easy time being born. That big head has been an “issue” for him from the first.
Sammie and I both have a small head size- something the paediatrician remarked on at a checkup when she was 6 months old (he couldn’t understand why her head circumference was on the 25th centile while her weight was on the 50th and her height/length on the 98th). He then measured my head and discovered mine is also on the 25th- my height is around the 98th.
I don’t suppose my small head size is a one of freak either, because my head is exactly the same size as my mums who used to struggle to find hats that fitted aswell.
As for my Brother I don’t know, his head is the same shape as mine, but he is about 4 inches taller, so his might be larger in proportion to that
Yes, my son with autism has a 98%+ percentile head. In fact, it grew so fast as an infant that one ped was getting ready to see why, but then the growth stabilized – then, the autism diagnosis 1.5 years later. The upper half of his head is notably larger. Definitely a big brain up there.