Monday, October 29, 2018

Manuel and Emily Casanova's New Autism Book

Husband and wife researchers Manuel and Emily Casanova have recently come out with a new book about the current state of the art about knowledge of the science of autism, titled "Defining Autism".

Manuel Casanova is a neuropathologist, known for his discovery of abnormalities of minicolumns in the brain having a relationship to the etiology of autism.  He's also experimented in transcranial magnetic stimulation as a treatment for autism.  He's unique to autism scientists in that he has a blog, cortical chauvinism in which he does a good job of explaining the results of very technical scientific research (his own and others)to laypersons such as myself.

His wife, Emily, a Ph.D. scientist, also has a blog "science over cuppa" in which she explains scientific research.  I don't know as much about Emily and her blog, so I won't comment on that further.

I met Manuel some years ago at a conference in Long Beach and had a brief conversation with him, after he gave his presentation.  He spoke of minicolumns, inhibitory neurotransmitters, and the broken shower curtain effect that a lack of inhibitory neurotransmission could cause that would result in problems in an autistic brain.  I knew that norepinephrine was an inhibitory neurotransmitter existing in purkinje cells which have been implicated in autism.  I asked him if norepinephrine could be involved in the etiology of autism and if that related to the problems with autistic minicolumns.  He replied that the neurotransmitter in question that was deficient was GABA, also an inhibitory neurotransmitter.  Purkinje cells in the brain also use these as well as GABA.

Shortly afterward, Dr. C started his blog, cortical chauvinism.  I was one of the first persons to comment on it.  I asked him if he remembered me from our meeting in Long Beach, not expecting he would as we only spoke a moment and he did not know of me before.  I was pleasantly surprised when he said he remembered me.  I commented on his blog not infrequently and we developed a sort of internet friendship.  This resulted in his plugging my novel, "The Mu Rhythm Bluff", asking me for an autobiographical post which he published, as well as republishing posts I'd written about the controversial book "neurotribes" I'd written on autism's gadfly.   I hope to someday again meet Manuel in person. 

There has been a dearth of books explaining the science of autism to the layperson.  Emily and Manuel have done a reasonably good job of closing that gap with their new book.

The first two chapters are written by Manuel.  The first deals with a historical overview of how Leo Kanner discovered, wrote about and promoted autism.  It also deals with Bernard Rimland's influence.  The second does a good job of summarizing an overview of MC's research on minicolumns and work in transcranial magnetic stimulation.  He also describes blatant pathologies in postmortem brains, such as heterotopias, which negates the neurodiversity dictum that an autistic brain is not an abnormal brain, but just an alternatively wired brain--something which unfortunately given today's state of the art is probably not possible to prove in living tissues.  He neglects to cite a lot of the problems in his TMS research such as lack of random assignment of individuals as well as the problems of using a control group of sham TMS treatments which research subjects would be able to differentiate from the real deal, and are a formidable problem in evaluating this as a potential autism treatment.

The subsequent chapters are written by Emily.  One details what is known about the genetics of autism and how certain mutations are involved, both inherited and spontaneous mutations.  She discusses the twin data in autism genetic studies.  One thing she neglects to discuss are the twin studies, such as the one done by Hall et. al. in California showing a higher autism concordance in fraternal twins than in non-twin siblings.  This suggests autism is at least partially environmentally mediated.  A discussion of this study as well as a few others along this line would have made the book better.

Next, Emily discusses known environmental components associated with autism in the past such as thalidomide and CMV.  These also provide evidence against the neurodiversity dictum that autism is solely a natural genetic variation.

The book also discusses autism regression.

It also touches upon oxidative stress and how free radical atoms can result in brain problems in autism and other disorders, as well as mitochondrial influences in autism. Interestingly, it cites a reference showing that women produce far more anti-oxidants than men, leading to a four fold decrease in mutations.  Does that four fold difference sound familiar? 

One of the most interesting portions of the book is a discussion of the neural mechanisms that can cause self-stimulatory behaviors in autistics, such as my twiddling.  This involves an imbalance in areas of the basal ganglia, but I won't discuss further as it might be a spoiler for anyone who wants to read the book.

It also discusses savantism and intellectual disabilities.

The book does fall short in a few areas.  There is no discussion of  Dr. C's (Manuel's) research in gamma resynchronization, and his attempt to integrate TMS with neurofeedback.

The book also goes into arcane areas not pertinent to autism as a lead-in to introduce authors to subjects of autism.  It would be better if the authors could cut to the chase and get into the more relevant topics more quickly.  Also, there was a fair amount of footnoting, which distracted from the regular text.  However, this is just a preference of mine as I don't like footnoted books and articles.

Though the book provides evidence for the validity of high male to female autism sex ratios, it does touch on diagnostic bias without giving much evidence.  Similarly, the book talks about assortative mating without much evidence for its validity. 
Other than these minor flaws.  It's one of the best books on autism ever written in my opinion and I highly recommend it. 


Unknown said...

Thanks for your critique, Jonathan. If the book ever goes to a second edition, we'll definitely keep them in mind. :)

schaferatsprynet said...

Thanks for this review. It might be the next book of autism I read.
ps. Spoilers generally require material that contains a plot.

Anonymous said...

John, What is the ratio of the higher end (like what used to be called Aspergers or High functioning) to the classic severe types?

jonathan said...

I'm not sure, but it's likely high and likely gotten higher and higher over the years as diagnostic criteria for autism has changed and nowadays apparently anyone with a few quirks can be diagnosed well into adulthood even if they're a lawyer or college professor. Not to mention the fact that there's a movement claiming autism has been greatly underdiagnosed in higher end females, encouraging more females with milder impairments to be diagnosed.