Showing posts with label MRI. Show all posts
Showing posts with label MRI. Show all posts

Tuesday 5 September 2017

Autism MRI

Source: Brain MR Imaging Findings and Associated Outcomes in Carriers of the Reciprocal Copy Number Variation at 16p11.2

In the early days of this blog, one medical reader told me that in cases of autism an MRI scan of the brain should appear normal.
This also fits with the idea that once you have a biological diagnosis, you no longer have a case of “autism”. It is only Autism, when it is of unknown origin.  
People who have a single gene type of autism actually can have significant variations in brain structure that appear clearly on an MRI.  This was the subject of a recent study and the source of the MRI in this post.

Many people with autism have abnormalities at a specific site on the 16th chromosome known as 16p11.2. Deletion or duplication of a small piece of chromosome at this site is one of the most common genetic causes of autism spectrum disorder.
People with deletions tend to have brain overgrowth, developmental delays and a higher risk of obesity.
Those with duplications are born with smaller brains and tend to have lower body weight, but also developmental delays. 
For regular readers of this blog there are some interesting points to note.

Agenesis of the Corpus Callosum

The corpus callosum is a wide, flat bundle of fibers about 10 cm long that connects the left and right sides of the brain.  It facilitates communication between the two sides of the brain.
Agenesis of the corpus callosum (ACC) is a birth defect in which there is a complete or partial absence of the corpus callosum.
ACC leads to behaviors compatible with a diagnosis of autism or Asperger’s in about half of cases.
Symptoms of ACC vary greatly among individuals, as they do in all types of autism.  Seizures are common, some people have poor motor coordination, and some people are non-verbal.  My original post on the subject:-

Agenesis of the Corpus Callosum (ACC)                                                                                 
You may recall that in the film Rain Man, Dustin Hoffman’s character was inspired by a man with ACC called Kim Peak.  It is now thought that Peak had FG Syndrome and this is what caused his ACC. It appears that his brain adapted and made unusual connections leading to his remarkable memory.
The Corpus Callosum is clearly visible on an MRI.
In 16p11.2. deletion you end up with an overgrown (thick) corpus callosum, while in 16p11.2. duplication you end up with a thin corpus callosum, which equates to a partial Agenesis of the Corpus Callosum.                                
At least one reader of this blog has a case of partial Agenesis of the Corpus Callosum and as he told me, it is not autism it is ACC.

Chiari 1 “brain hernia”
Another point of interest on the above MRI has been highlighted as Cerebellar Ectopia. Now if they had called it a Chiari malformation, you might have linked it to an old post on this blog.

In people with brain overgrowth and/or a small skull, what happens when there is no space left for a growing brain? Well it appears that pressure builds up and you get a kind of hernia with the brain expanding downwards into the spine.
This is called a Chiari 1 malformation and it seems to be quite common in the types of autism associated with over active pro-growth signalling pathways.
Since 16p11.2 deletion is associated with too much growth (thick corpus callosum, brain overgrowth and obesity) we should not be surprised that they often present with Chiari 1 “brain hernia”, which is treatable and this should improve symptoms. 


An MRI can sometimes tell you a lot, when you know what to look for and clearly should be carried out on anyone diagnosed with disabling autism.
Undoubtedly there are other areas of the brain where important variances occur.
This would provide useful data to assign individuals with autism into subgroups and hence improve the chance of finding effective therapy.  What works for Peter may help Paul, but what works for Zach probably will not help Amber.

Monday 21 November 2016

Agenesis of the Corpus Callosum

Today’s post is about another supposedly rare cause of autism called Agenesis of the Corpus Callosum (ACC).

As regular readers of this blog will have noted, extremely rare causes of autism, taken as a group are not so rare after all.  In fact it seems that autism is just a very large collection of somewhat rare biological conditions. 
Of the very few "Autism Dads" I have had a face to face conversation with, one has a child with ACC and another has a son with the even rarer Sotos syndrome. Sotos syndrome is characterized by gigantism, mild ID/MR and often autism. Mutations in the NSD1 gene cause Sotos syndrome

ACC is physical malformation of the brain that shows up clearly on MRI scans and potentially shows up on the mother’s regular ultrasound scans. 

The corpus callosum is a wide, flat bundle of fibers about 10 cm long that connects the left and right sides of the brain.  It facilitates communication between the two sides of the brain.
Agenesis of the corpus callosum (ACC) is a birth defect in which there is a complete or partial absence of the corpus callosum.

ACC leads to behaviors compatible with a diagnosis of autism or Asperger’s in about half of cases.

Symptoms of ACC  vary greatly among individuals, as they do in all types of autism.  Seizures are common, some people have poor motor coordination, and some people are non-verbal.

It is suggested by many that a diagnosis of ACC is not compatible with a diagnosis of autism; this just shows a lack of understanding.
Autism is just a description of behaviors, ACC is a biological diagnosis, like Fragile X syndrome or Down Syndrome.  So if a person has autistic behaviors caused by ACC, it is still autism, it is just autism with an explanation of its origin.

The most famous person with ACC was Kim Peek who was the inspiration for the character played by Dustin Hoffman in the well-known film Rain Man.

In addition to having the physical ACC malformation it has been suggested that the cause of ACC in his case was likely FG Syndrome.

Most mutations that cause FG syndrome can be found in the MED12 gene. However, mutations have also been found in FMR1, FLNA, UPF3B, CASK, MECP2, and ATRX genes. Mutations on these different genes lead to the different types of FG syndrome, all with similar characteristics.  Congenital heart defects are common and Peek died of a heart attack aged 58, outlived by his father.  

Agenesis of the Corpus Callosum and broader Autism

Undoubtedly there are people diagnosed with autism, who have undiagnosed ACC, since they never had an MRI scan.  Just like there are many people with autism who have an undiagnosed, but treatable, Chiari “brain hernia”.

It also appears that having a smaller corpus callosum, but falling short of what would be diagnosed as ACC by the MRI scan, is a feature of some people’s autism. You could consider it as partial ACC, like we had partial biotin/biotinidase deficiency.

A very recent paper from the 2016 Society for Neuroscience annual meeting suggested one reason why autism is more prevalent in males.  The study looked at infecting pregnant rats with group B streptococcus to activate the mothers immune system.  Inflammation was then triggered in the fetal side of the placenta, but only in male fetuses.
The males go on to develop brain and behavioral features reminiscent of autism.
Female fetuses were somehow protected and developed normally.  Hopefully Barons Cohen will read this and stop looking for undiagnosed females with autism. There are many good reasons why autism is less prevalent in females, and they are not just “better at hiding it”, as the so-called expert claims. 

What is interesting is that in the male pups with “autism” they had an unusually thin corpus callosum. It turns out that such minor malformations occur in broader human autism. 

The largest of the white matter tracts is known as the corpus callosum, which allows communication between the two hemispheres (halves) of the brain.
"The size of the corpus callosum was smaller in the group with autism, suggesting that inter-regional brain cabling is disrupted in autism," Dr. Just said.

In essence, the extent to which the two key brain areas (prefrontal and parietal) of the autistic participants worked in synchrony was correlated with the size of the corpus callosum. The smaller the corpus callosum, the less likely the two areas were to function in synchrony. In the normal participants, however, the size of the corpus callosum did not appear to be correlated with the ability of the two areas to work in synchrony.

"This finding provides strong evidence that autism is a disorder involving the biological connections and the coordination of processing between brain areas," Dr. Just said.


These longitudinal results suggest atypical early childhood development of the corpus callosum microstructure in autism that transitions into sustained group differences in adolescence and adulthood. This pattern of results provides longitudinal evidence consistent with a growing number of published studies and hypotheses regarding abnormal brain connectivity across the life span in autism.

The study suggests that white matter abnormalities manifest early in autism, says Thomas Frazier, director of Center for Autism at the Cleveland Clinic in Ohio. “It also serves as a nice demonstration that brain abnormalities in autism will become clearest and most helpful for pointing to etiology when we look at them developmentally, longitudinally, rather than at a single age," he says.

The findings do not imply that corpus callosum abnormalities cause autism, cautions Ralph-Axel Müller, professor of psychology at San Diego State University, who was not involved with the work. Rather, any irregularities in the corpus callosum may stem from other abnormalities in the brain that have been associated with autism, Müller says.

Still, changes in the corpus callosum may help to explain why autism symptoms worsen in some individuals and improve in others, Travers says. "Is there some aspect of white matter micro-structure occurring early in the developmental pathology that locks in persistent autism across the lifespan? What are the mechanisms? Can they be unlocked?” she says. “These will be important questions for future research.”



It is estimated that at one in 4,000 individuals has a disorder of the corpus callosum. I suspect it is more, but you would need to routinely give MRI scans to people diagnosed with autism to find out.

It is clear that milder disorders of the corpus callosum may be a feature of many people’s autism and those changes over time in the corpus callosum may help to explain why autism symptoms worsen in some individuals and improve in others.

Monday 2 November 2015

Brain Hypoperfusion in Autism & Cocoa

Today’s post is simpler than many earlier ones and is actionable.

A known feature of many neurological conditions like Alzheimer’s and dementia is reduced blood flow to certain parts of the brain.  In the medical jargon this is called hypoperfusion.

This reduced blood flow is also present in autism and is measurable by MRI.

We encountered epicatechin in early posts on cocoa flavanols.  It would seem that one of epicatechin’s many effects is to increase cerebral blood flow. 

Two chocolate companies, Mars (Cocoavia) in the US and Barry Callebaut (ACTICOA) in France, have developed high flavanol cocoa.  10 g of their cocoa contains about 1 g of flavanols and produces cognitive benefits; even a quarter of this dose gives the cardiovascular benefits.  Mars, in particular, are funding a great deal of research and have committed to a five year project with Harvard.  The high flavanol products are available today.

Brain Perfusion Anomalies in Autism

While most research focuses on Alzheimer’s and other types of cognitive impairment and memory loss, there are studies on brain perfusion in autism.

Autism is a severe developmental disorder, the biological mechanisms of which remain unknown. Hence we conducted this study to assess the cerebral perfusion in 10 children with autism and mental retardation. Five age matched normal children served as controls. These cases were evaluated by single photon emission computed tomography (SPECT) using Tc-99m HMPAO, followed by segmental quantitative evaluation. Generalized hypoperfusion of brain was observed in all 10 cases as compared to controls. Frontal and prefrontal regions revealed maximum hypoperfusion. Subcortical areas also indicated hypoperfusion. We conclude that children with autism have varying levels of perfusion abnormities in brain causing neurophysiologic dysfunction that presents with cognitive and neuropsychological defects.
Significant hypoperfusion was observed at cortical and subcortical areas of brain in autistic subjects, suggesting that the structural abnormalities
of these brain areas may result in reduced cortical activity, thus causing dysfunction of these brain areas, and eventually producing some of the
emotional and behavioral disorders usually described in autistic subjects. These SPECT findings may help to explain several behavioral features of autism, such as impulsive and aggressive behaviours (to self and others), motor disinhibition (such as stereotypic and manneristic movements and echophenomena), and deficits in planning, sequencing and attention.

Abnormal regional cerebral blood flow in childhood autism

Neuroimaging studies of autism have shown abnormalities in the limbic system and cerebellar circuits and additional sites. These findings are not, however, specific or consistent enough to build up a coherent theory of the origin and nature of the brain abnormality in autistic patients. Twenty-three children with infantile autism and 26 non-autistic controls matched for IQ and age were examined using brain-perfusion single photon emission computed tomography with technetium-99m ethyl cysteinate dimer. In autistic subjects, we assessed the relationship between regional cerebral blood flow (rCBF) and symptom profiles. Images were anatomically normalized, and voxel-by-voxel analyses were performed. Decreases in rCBF in autistic patients compared with the control group were identified in the bilateral insula, superior temporal gyri and left prefrontal cortices. Analysis of the correlations between syndrome scores and rCBF revealed that each syndrome was associated with a specific pattern of perfusion in the limbic system and the medial prefrontal cortex. The results confirmed the associations of (i) impairments in communication and social interaction that are thought to be related to deficits in the theory of mind (ToM) with altered perfusion in the medial prefrontal cortex and anterior cingulate gyrus, and (ii) the obsessive desire for sameness with altered perfusion in the right medial temporal lobe. The perfusion abnormalities seem to be related to the cognitive dysfunction observed in autism, such as deficits in ToM, abnormal responses to sensory stimuli, and the obsessive desire for sameness. The perfusion patterns suggest possible locations of abnormalities of brain function underlying abnormal behaviour patterns in autistic individuals.

Cerebral Hypoperfusion and HBOT?

One therapy proposed to treat Cerebral Hypoperfusion in autism is hyperbaric oxygen therapy (HBOT).  Some proponents go as far as to link specific areas of the brain to specific autistic features as below.

The mainstream view, among those using HBOT for other conditions, is that it would not help stimulate increased blood flow in autistic brains.  But there are proponents of the therapy like Rossignol.

You may have realized that the science exists to test, once and for all, whether HBOT can improve cerebral blood flow in autism.  It just takes two visits to an MRI.

I did see a report about a US neurologist who showed via MRI that the cerebral blood flow of his autistic patient improved using HBOT and he tried to use this to get access to the further HBOT on insurance.

Hypoperfusion in Alzheimer’s, Dementia  and Cognitive Impairment

Reduced cerebral blood flow is a marker of incipient dementia.  I expect one day this might even be used to trigger preventative therapy.

Cerebral hypoperfusion and clinical onset of dementia: the Rotterdam Study.


Cerebral blood flow (CBF) velocity is decreased in patients with Alzheimer's disease. It is being debated whether this reflects diminished demand because of advanced neurodegeneration or that cerebral hypoperfusion contributes to dementia. We examined the relation of CBF velocity as measured with transcranial Doppler with dementia and markers of incipient dementia (ie, cognitive decline and hippocampal and amygdalar atrophy on magnetic resonance imaging) in 1,730 participants of the Rotterdam Study aged 55 years and older. Cognitive decline in the 6.5 years preceding CBF velocity measurement was assessed with repeated Mini-Mental State Examinations in nondemented subjects (n = 1,716). Hippocampal and amygdalar volumes were assessed in a subset of 170 nondemented subjects. Subjects with greater CBF velocity were less likely to have dementia. Furthermore, in nondemented subjects, greater CBF velocity was related to significantly less cognitive decline over the preceding period (odds ratio per standard deviation increase in mean CBF 0.74 [95% confidence interval, 0.58-0.98]) and larger hippocampal and amygdalar volumes. A low CBF is associated with dementia, but also with markers of incipient dementia. Although we cannot exclude that this is caused by preclinical neurodegeneration leading to hypoperfusion, it does suggest that cerebral hypoperfusion precedes and possibly contributes to onset of clinical dementia.

Vascular dementia

Vascular dementia is the second-most-common form of dementia after Alzheimer's disease.  It is a much simpler condition, it is dementia caused by problems in the supply of blood to the brain, typically by a series of minor strokes.

The incidence peaks between the fourth and the seventh decades of life and 80% will have a history of hypertension. Patients develop progressive cognitive, motor and behavioural signs and symptoms.

Blood pressure rises with aging and the risk of becoming hypertensive in later life is considerable

It would seem that you could treat hypertension and vascular dementia with the same preventative therapy.  See the clinical trial on treating vascular aging with Cocoa, later in this post.

It has also been suggested that endothelial dysfunction and vascular inflammation may also contribute to increased peripheral resistance and vascular damage in hypertension. 

In essence you want to control peripheral resistance and before it is too late.  It really is a case of “a stitch in time saves nine”.

The research done in to peripheral resistance / vascular stiffness can be re-purposed to help us treat brain hypoperfusion.  In autism we may have Brain Hypoperfusion, but without high blood pressure (hypertension).

Increased vascular stiffness, endothelial dysfunction, and isolated systolic hypertension are hallmarks of vascular aging. Regular cocoa flavanol (CF) intake can improve vascular function in healthy young and elderly at-risk individuals. However, the mechanisms underlying CF bioactivity remain largely unknown. We investigated the effects of CF intake on cardiovascular function in healthy young and elderly individuals without history, signs, or symptoms of cardiovascular disease by applying particular focus on functional endpoints relevant to cardiovascular aging. In a randomized, controlled, double-masked, parallel-group dietary intervention trial, 22 young (<35 years) and 20 elderly (5080 year) healthy, male non-smokers consumed either a CF-containing drink (450 mg CF) or nutrientmatched, CF-free control drink bi-daily for 14 days.
The primary endpoint was endothelial function as measured by flow-mediated vasodilation (FMD). Secondary endpoints included cardiac output, vascular
stiffness, conductance of conduit and resistance arteries, and perfusion in the microcirculation. Following 2 weeks of CF intake, FMD improved in young (6.1±0.7 vs. 7.6±0.7 %, p<0.001) and elderly (4.9 ± 0.6 vs. 6.3 ± 0.9 %, p < 0.001).
Secondary outcomes demonstrated in both groups that CF intake decreased pulse wave velocity and lowered total peripheral resistance, and increased arteriolar and microvascular vasodilator capacity, red cell deformability, and diastolic blood pressure, while cardiac output remained affected. In the elderly, baseline systolic blood pressure was elevated, driven by an arterial-stiffness-related augmentation.
CF intake decreased aortic augmentation index (9 %) and thus systolic blood pressure (7 mmHg;

Cocoa Flavanols

I did write an earlier post about the various benefits of Cocoa Flavanols. 

Here is a very good review paper:-

Norman Hollenberg, at Harvard, has been an advocate of high flavanol cocoa for decades.  Here is one of his papers.

Using functional MRI, the following study measures the effect on brain blood flow, before and after taking a high flavanol cooca drink

There is now good evidence that the acute benefits for cognitive function and blood flow exerted by cocoa flavanol consumption peak approximately 90120 min postconsumption (Schroeter et al. 2006; Francis et al. 2006; Scholey et al. 2010; Field et al. 2011); however, it is presently unclear whether separate chronic mechanisms exists following cumulative consumption over several weeks and months, or indeed whether chronic consumption enhances the effectiveness of acute mechanisms in a cumulative fashion. Despite several plausible mechanisms for increased neuronal activity (as described above), it remains to be seen whether a single cocoa flavanol dose-induced increase in CBF is associated with concomitant benefits in cognitive performance in the immediate postprandial period. More broadly, recent reviews of acute interventions and epidemiological surveys provide good evidence that flavonoids and their subclasses are beneficial for cognitive function

In conclusion, the present findings support the hypothesis that flavanol-rich cocoa beverages are associated with increased CBF within a 2-h post-prandial time frame. More specifically, increased brain perfusion following the HF drink relative to the LF drink was observed in the anterior cingulate cortex and a region in the left parietal lobe. These data add to the substantial body of literature demonstrating that flavanol consumption is beneficial for peripheral and cerebral vascular function and thus for maintaining, protecting and enhancing cardiovascular health.

Does High Flavanol Cocoa have an effect in Autism?

This is probably the question you have been asking yourself.

I did acquire some ACTICOA, high flavanol cocoa some time ago.  I was wondering how I was going to administer enough of it to make a trial.  In the trials on improving memory in older adults 10g a day was needed.

While adding it to milk seems an obvious choice, Hollenberg suggests that the milk may neutralize the flavanols.  This is true with black tea; once you add milk you lose its healthy antioxidant properties.

In the end I choose to add 5ml to the breakfast broccoli powder and water concoction and mix with a frappe mixer.  Monty, aged 12 with ASD, was the ever willing test subject.

Two and a half hours later there was unprompted laughter and smiling.  This is repeated each time I give the ACTICOA  cocoa.

According to the literature, the peak level of epicatechin occurs 2 to 3 hours after consuming cocoa.

Then I tried a regular raw cocoa powder at the same dose; no laughter.

So I conclude that ACTICOA is indeed different to regular non-alkalized cocoa powder.  The more common alkalized cocoa has virtually no flavanols at all, and this is what is used to make most chocolate and is sold in supermarkets as "cocoa".

There are potentially other sources of epicatechin, but you really want a reliable standardized product.  If you live in the US/Canada this is easy; you can buy the Cocoavia product from Mars.  It is not cheap if you want 1g of flavanols a day.

The literature does suggest that there is a cumulative effect of taking epicatechin and Hollenberg has documented that regular consumption of unprocessed cocoa (rich in flavanols) is associated with numerous health benefits, particularly related to blood flow (strokes, heart attacks, endothelial dysfunction, cholesterol etc.)

Since Mars are now funding considerable research into the health benefits of these flavanols, I did think of suggesting they look at autism.

They could take a group of people with autism, measure their IQ and then score their autism using one of the standard scales.  Then off to the MRI to measure blood flow and velocity in different parts of the brain.

Give half of the test subjects a daily high flavanol drink and the other half a low flavanol drink.  After three months, repeat the IQ test, autism test and measure blood flow again via MRI.

I suspect that reduced blood flow/hypoperfusion would be more present in those with lower IQ and that they might show improved IQ at the end of the trial.  I suspect that in terms of autism, most would show an improvement on the high flavanol treatment.

I would like to think that after three months, blood flow/velocity would have increased.

You could then repeat on people with Down Syndrome and more general MR/ID.

Sunday 30 August 2015

Treatable Chiari 1 “brain hernia” present in 7% of Autism

Today’s post is again prompted by a reader’s comment.

Regular readers will be accustomed to learning here about “rare”, often treatable, disorders that may cause, or just aggravate autism; add Chiari 1 to that list.
The Chiari 1 brain hernia occurs when part of the brain is forced downwards into the spinal column.  It is supposedly very rare, occurring in only one person per thousand.  It is generally not life-threatening and can be surgically repaired.  The symptoms of Chiari 1 do rather overlap with those of autism.

You can diagnose Chiari 1 using an MRI scan.  Very few people with autism ever receive any diagnostic follow up, be it genetic testing, metabolic testing or a scan of their brain.

There have been anecdotal reports associating Chiari with autism, and indeed of the corrective surgery greatly improving autism symptoms.  This goes back to the day of Bernie Rimland (Autism Research Institute and DAN).

Finally we have some genuine data:-

Patients with symptomatic Chiari malformation Type I (CM-I) frequently present with headaches, neck pain, difficulty swallowing, and balance disturbances. In children with autism spectrum disorder (ASD), diagnosing CM-I can be a challenging task. Moreover, even if symptomatic, some patients do not undergo further evaluation or management, as their presentations are attributed to autism and its myriad symptoms. Therefore, cranial MRI findings were reviewed after evaluating and treating patients with coexisting ASD and CM-I. In this paper, the authors report on 5 children with ASD and symptomatic CM-I, including their clinical presentation, imaging studies, management, and outcomes, and discuss the likely under recognized coexistence of these conditions.
All pediatric patients with ASD and cranial MRI conducted for any reason in the period from 1999 to 2013 were considered for analysis. All cases with concomitant symptomatic CM-I were eligible for this retrospective analysis.
One hundred twenty-five pediatric patients diagnosed with ASD had undergone MRI, and 9 of them had evidence of cerebellar tonsillar herniation. Five patients were symptomatic and underwent suboccipital craniectomy, a C-1 or a C-1 and C-2 laminectomy, and duraplasty with bovine pericardium or Type I collagen allograft. There were no intraoperative complications. All patients showed symptom improvement and/or resolution of presenting symptoms, which included headache, dysphasia, speech, and irritability.
There is no identified cause of autism. Children with ASD can be difficult to assess specifically in a neurological examination. Thus, cranial MRI considered when completing a comprehensive diagnostic evaluation. While cranial MRI is not a routine part of ASD evaluation, this study demonstrates that CM-I and ASD may coexist and be underrecognized. The study reinforces the importance of a comprehensive medical evaluation designed to elucidate neurological findings in children with impaired communication abilities and suggests the judicious use of neuroimaging.
ASD = autism spectrum disorder; CM-I = Chiari malformation Type I; Chiari malformation I; autism; autism spectrum disorder; suboccipital craniectomy


We know that in many cases of classic autism there is accelerated brain growth until the age of five (Courchesne, UC San Diego) and frequently this is associated with large heads (Macrocephaly).

As usual in autism, both extremes exist and so Microcephaly (small brains/heads) is also present.  The result is that in studies the average head size is meaningless.  Just as with many other possible markers, like cholesterol levels.  The same is true with signaling pathways like mTOR, Wnt, ERK and BDNF; both hypo function and hyper function exist and both can lead to “autism”.

Data from a series of 126 autistic children ages 2-16 years and referred to an Autism Diagnosis Unit in South-West France were examined. Macrocephaly (head circumference > 97th centile) was observed in 16.7% of the sample, a significantly higher proportion than that expected. Macrocephaly was more frequent among older subjects but was otherwise not associated with gender, developmental level, the presence of epilepsy or of medical disorders, or severity of autistic symptomatology. Microcephaly (head circumference < 3rd centile) was also significantly raised and found in 15.1% of the sample. Microcephaly was significantly associated with the presence of medical disorders. Results support those from recent studies suggesting a raised rate of macrocephaly in autism which, pooling published data, can be estimated to be 20%. It is argued that the raised incidence of microcephaly among low-functioning autistic subjects with medical disorders might have contributed to delay the recognition of an increased head circumference among a minority of subjects with idiopathic autism.

It is not hard to imagine what might happen if the brain is expanding faster than the skull is growing.  It would be reasonable to think that, in some cases, autism might cause Chiari malformation I.

Most people consider Chiari malformation I to be genetic.  In people with no underlying cause(s) of autism, the hernia itself may be the sole cause of the associated symptoms.

Since we know that autism is often caused by multiple “hits”, in some people the Chiari malformation might just be one of those handful of hits/triggers.  Oxidative stress and inflammation are both key drivers and consequences of autism; clearly hernia(s) growing in the spinal column are going to aggravate this.

To Treat or Not?

Surprisingly, some neurologists/neurosurgeons are unwilling to repair Chiari malformation I in children with autism.

If you recall my recent post on the history of autism, the reason becomes clearer.

Those neurologists/neurosurgeon hold the historical view that autism is untreatable and so how could surgery possible help?  It seems that in as many as 7% of autism cases, surgery might indeed help.  That is a surprise to me.

Fortunately, enough people with autism and Chiari 1 have been treated for it to be known that it does improve autism.

Since treatment involved a brain operation, it is not without risks.  Not treating the brain hernia likely also has risks.

Dr. Manuel Casanova on Chiari and Autism

Dr Casanova is a neurologist with a blog and an interest in autism. He is of the opinion that Chiari does not cause autism, but just makes it worse.

I am not a neurologist, but if you accept that autism, like cancer, is often caused by multiple hits, Chiari would seem like quite a dangerous hit, and perhaps more so than an immune over-reaction to childhood vaccines. In my recent autism history post we saw that for Hannah Poling the vaccine was enough to cause profound autism; she had two hits the first being a genetic mitochondrial dysfunction and the second an inflammatory reaction to the vaccines.

Over to Dr Casanova:-

"If you ever do a search through the internet you will find a lot of interest among multiple health boards on the possible correlation between the Chiari malformation and autism. Dr. Neil Felstein, Director of the Pediatric Neurosurgery Division of the Morgan Stanley Children’s Hospital, has seen many children with both conditions ( ). He believes that there is an association but can’t provide an explanation. Although a Chiari malformation is certainly not the cause of autism, it can aggravate the same. It may be worth noting that the Chiari malformation is seen as a comorbidity to both the Ehlers-Danlos and Marfan syndromes (Milhorat et al., 2007).  Both of these conditions manifest autistic symptomatology in a high percentage of cases ( )."

Head Circumference

Since data on head circumference is routinely collected during childhood, it would not be difficult to go back to the 125 cases studied by MRI in the research study, quoted at the start of this post.  You could then look for a correlations between head size, brain size and the Chiari hernia.

This might show that in autism the head was just not big enough at some critical point in time.

More links


It looks like you might want to add an MRI to those metabolic and genetic tests that most children with autism never receive, but perhaps should.

Or, as put in today’s study:-

“The study reinforces the importance of a comprehensive medical evaluation designed to elucidate neurological findings in children with impaired communication abilities and suggests the judicious use of neuroimaging.”