As for the pcbs zapping the Purkinjes, lots of things zap lots of things, and it doesn’t necessarily follow that the pcbs cause any significant level of autism.

Well, Purkinjes do seem to be particularly vulnerable to a variety of insults, however, I’m curious if you are aware that deficiencies of Purkinje cells are among the most widely observed neuroanatomical difference observed in autism? I don’t want to earn another commendation on link spamming, so I’ll leave that research up to you, but even with everyone being wrong somewhat, it is difficult to paint a scenario where Purkinje cell development (or abnormal development) is involved with at least a subset of autism cases.

Re understanding my position, it is that everyone else is partly wrong.

This sounds a lot like my ideas, to tell the truth.

Finally, the flooring in the mentioned study was vinyl, something not so exocit as pvc piping as floors. I believe the salient idea is the breakdown of the materials.

– pD

That sounds a lot like data dredging, and reminds me a bit of Dr H-P’s pet shampoo finding. Even if they did control for multiple comparisons, it’s prudent to wait for an independent replication to start to believe it’s possibly true.

According to the author, this was supposed to be a studyregarding asthma, but the numbers of children with autism that were correlated to vinyl flooring were so significant that it warranted publication.

http://www.scientificamerican......-and-vinyl

I don’t know if that is data dredging or not. (?)

The authors make a similar call for caution and additional study before any conclusions can be reached.

– pD

But I think nevertheless I got overdone with my ‘boredom’ there. The first and last look like worthy studies. I’d put them alongside the evidence about Lyme disease being autism-associated too. (It soon starts to look like everything causes autism doesnt it?!)

I’d then tie all these envirofactors in with my mercury-caused-increase updated concept, as follows. They all, I hypothesise, as nasty toxins, stress certain detox capabilities and thus tend to throw the system into a detox failure (such as is hypothesised by those DAMN! people). Thereby these organic nasties make the victim more vulnerable to the effects of the increasing dental mercury onslaught. So everything (at a rough approximation) adds up. Someone with more time and energy (and months of ‘life’ left) could do a great job of precisely calculating the exact factor analysis of it all.

As for the directions of the arrows, some higher class parents might prefer the latest Swedish fashionable gimmick of PVC in their bedrooms and the higher autism be caused by their genetics alone with no causality from the pvc. Or such like. Until you have an anchoring theory and a good knowledge of the context, anything goes.

As for the pcbs zapping the Purkinjes, lots of things zap lots of things, and it doesn’t necessarily follow that the pcbs cause any significant level of autism. They might merely damage the Purkinjes specifically and this tend to spuriously inflate autism diagnoses. I’d compare this with the famous youtube of mercury decomposing a neuron with allegedly great similarity to Alzheimers; again I’m sceptical of this as “proof” that mercury is a main cause of AD by that mechanism or anyhow.

(pD: Re understanding my position, it is that everyone else is partly wrong. More precisely, there is firstly my 1993-published paper. To which is now added a draft of an update review paper. The latter is not puttable on web until accepted by a journal, but can be got by emailing a request to rpclarke[at]autismcauses[dot]info, cheers.)

Hm. Well, have you read this study, Associations between indoor environmental factors and parental-reported autistic spectrum disorders in children 6-8 years of age, where researchers report a rough doubling of autism risk if raised in home with PVC flooring? [as does a smoking mother]

That sounds a lot like data dredging, and reminds me a bit of Dr H-P’s pet shampoo finding. Even if they did control for multiple comparisons, it’s prudent to wait for an independent replication to start to believe it’s possibly true.

. In the absence of Mengeleian interventionist experiments or any “outside” pointers to the directions of the causality arrows, some very boring books could easily be written consisting entirely of speculations about how those arrows might link together into nice diagrams.

Hm. Well, have you read this study, Associations between indoor environmental factors and parental-reported autistic spectrum disorders in children 6-8 years of age, where researchers report a rough doubling of autism risk if raised in home with PVC flooring? [as does a smoking mother]

One of the links I sent indicated changes to the brain in very specific areas associated with autism by many studies, purkinje cells, Disrupting effects of hydroxy-polychlorinated biphenyl (PCB) congeners on neuronal development of cerebellar Purkinje cells: a possible causal factor for developmental brain disorders?

Did you know that children with autism have been found to have reduced levels of molecules used in detoxification of organic pesticides? Paraoxonase 1 activities and polymorphisms in autism spectrum disorders

The direction of these arrows seems pretty straightforward to me, but may be boring to some. (?)

Such an analysis does not result in anything like total clarity about everything about autism. But I would argue that it allows a start on climbing out from that boring books quagmire.

Maybe. (?) Unfortunately, I’m not sure I understand your position clearly enough to say for myself.

– pD

However the problem with these sorts of association is that it soon gets to feel like just about everything is associated with everything else. In the absence of Mengeleian interventionist experiments or any “outside” pointers to the directions of the causality arrows, some very boring books could easily be written consisting entirely of speculations about how those arrows might link together into nice diagrams. (Actually, come to think of it, one such boring book may have already been written in Cambridge uk!)

A way out of this insoluble maze could be to look at other evidence, such as the nature of the symptom syndrome, as for instance I did in my own explanation. I asked the question of quite what the autism characteristics have in common. Answer: they are suppressions of innate programmings/tendencies. But then the handflapping, webbed feet etc contradicted that. To address that we add in the established concept of reversions to atavisms, which enables the handflapping and other peculiar things to be explained with due Occam’s Razor principle.

Such an analysis does not result in anything like total clarity about everything about autism. But I would argue that it allows a start on climbing out from that boring books quagmire.

However there is another logical fallacy committed by the self proclaiment anti neurodiversionists and that is to assume that because I do not believe that x, y or z causes autism, that I believe that x, y or z is necessarily a good thing.

Well, I’m trying very hard lately not to assign arguments to people they do not make. My line of reasoning allows for improved diagnostics and the like to be impacting our observations, but the notion of a static rate of autism allows for no environmental impacts; your argument that there is no real increase in autism implies a non impact of these types of chemicals. A good thing versus a bad thing is difficult to assign here.

I dare say there are lots of background effects from toxic chemicals in the environment, however they are not significant enough to cause the rather specific (however ill defined at the edges) phenomenon of autism.

Well, this gets murky pretty quickly, as part of your argument (I think), is that we can’t even quantify autism sufficiently.

However, what we are finding is that these chemicals are capable of causing neurological differences and/or interferring with metabolic processes that we already have associated with autism, or other neurological conditions.

For example, hypothyroidism is associated with autism, again in autism, and impaired intelligence and motor skills and more. We have a good body of evidence on the importance of thyroid metabolism in brain development. It turns out, we also have detailed information on how some of these environmental pollutants can modify thyroid metabolism, and indeed, affect the developing brain.

For example, here, here, here, or here.
Or, we can look to this study that found associations between PFOA levels and thyroid problems. Or many, many others. The fact that people have smoked during pregnancy for some time does absolutely nothing to change these findings.

Pure genetic arguments won’t wash, neither will pure environmental ones, there has to be some threshold of genetic complexity that maybe triggers specific susceptibilities that then encounter a sort of multiplier effect, you know the equivalent of the butterfly effect in the chaos mathematics of the weather system.

I have no problem with very complicated genetic and environmental interactions, but I’m not sure that it necessarily involves application of chaos level theory.

The problem too with a lot of this looking for new causes for autism is the assumption that is is increasing, which I do not buy, if it is toxins you are looking for, something that has an effect prenatally, there is plenty that has been around since before PCB’s

Speaking of fallacies, using the fact that because there have been mechanisms by which the prenatal environment could be affected for a long time, that therefore, our newly minted forces must not be having a significant impact is a whooper. By way of example, examination of smoking and altered thyroid hormone levels was recently found in NHANES data in Cigarette smoking and iodine as hypothyroxinemic stressors in U.S. women of childbearing age: a NHANES III analysis. Smoking levels may have decreased somewhat over time, but when your mother was of child bearing age, a great many of our current suite of sythentic chemicals hadn’t been invented, much less distributed widely.

– pD