Gary Taubes pointed to this PNAS paper about climate change and noted that one of the authors, Stephen Schneider, had a big non-financial conflict of interest: If it turns out the whole argument is wrong, he looks like a fool. The accompanying statement (“The authors declare no conflict of interest”) is, if taken to mean the authors have no conflict of interest, wildly inaccurate. Readers unaware of Schneider’s history wouldn’t know this.
I came across a similar example today. A reader of this blog wrote extensive criticisms (here and here) of the idea that prenatal ultrasound may cause autism. He believed Caroline Rodgers, my source for that idea, misrepresented the evidence. In particular, Rodgers pointed to a study that found ultrasound disturbed neuronal migration in mouse fetuses. She said it supported her idea. The reader disagreed, saying,
The bottom line for me is that Dr. Rakic (from the mouse study) clarified, “Our study in mice does not mean that use of ultrasound on human fetuses for appropriate diagnostic and medical purposes should be abandoned. Instead, our study warns against its non-medical use.” Yes. Okay. No more boutiquey, keepsake ultrasounds. Great. But for Rodgers to skew this data (along with the FDA’s and others’) into claiming that ultrasounds under the care of an Obstetrics professional (and for medical use) are causing autism is disingenuous at best, unethical propaganda for the Midwifery Way at worst.
The reader is a professor who teaches composition. Maybe an English professor. He or she takes Rakic seriously, where I completely ignore his statement because of a conflict of interest. If Rakic questions “appropriate” ultrasound, he will be attacked in many ways, making his life unpleasant. I have no idea whether this swayed Rakic, but he would be only human if it did.
Of course developing neurons are unable to distinguish appropriate and inappropriate ultrasound. Rakic’s statement is ridiculous as Rakic and all insiders (neuroscientists) know, I believe. All insiders know that there are dozens of examples where findings from mouse brains have turned out to be true for human brains, in spite of the many differences between them, and that there are thousands of grant proposals in which mouse brains are claimed to be a worthwhile model for human brains. All insiders know this, realize the pressure on Rakic to say what he said, and, like me, just ignore it. As far as I can tell, Rakic pays no price for misleading outsiders because the outsiders don’t know they are being misled. (Just as with political lobbying: the public doesn’t understand what’s happening.) The composition professor doesn’t know this, as far as I can tell.
Rodgers is not claiming that ultrasounds “are causing autism”. She is saying they might cause autism, that there are several reasons to think so, and therefore (a) the ultrasound-autism idea deserves further scrutiny and (b) ultrasounds should be avoided as much as possible until more is known.
Is Gary Taubes’s analysis available on-line somewhere? I couldn’t find it through Google.
What is interesting is the paper I saw comparing ultrasounds and the loss of diagnosis quality with them vs. patients who were not receiving them.
At present ultrasounds are performed for entertainment value, not diagnostic value, and as a revenue source.
Interesting discussion, all in all, especially in context.
Perhaps Rakic changed the wording based on a referee’s request.
I’m not sure why some people think the only possible effect of ultrasound is thermal. It is well known that ultrasound can produce light (sonoluminescence), which is surprising in the same way it would be if a light breeze would occasionally ignite a fire. In controlled studies of this phenomena, the spectra of the light generated in a single ultrasonically driven collapsing bubble was measured, and the spectra appeared to be the tail of a black body spectra suggesting a transient temperature in the tens of thousands of degrees K.
In any case, if the sound waves can produce light it isn’t unreasonable to expect chemical changes too, and in fact books (Cavitation Reaction Engineering) have been written about its use chemical processes. Why anyone should think it is 100% safe for a fetus and no further study is needed is mystery to me.
This 1988 paper considers the safety issue of ultrasound induced cavitation:
https://iopscience.iop.org/0031-9155/33/11/003/pdf/pbv33i11p1249.pdf
Alex, Taubes conveyed this to me by email.
David, that’s a good point about transient temperature. Rather than produce uniform heating, ultrasound may produce a power-law distribution of heating with a tiny fraction of places getting very hot. Only if one of those very hot places is important is any damage done. So a given dose of ultrasound might do no harm at all for 99 usages (with 99 fetuses) but then badly damage the 100th fetus. Conventional statistics are bad at picking up such effects; they are more sensitive to treatments that change each individual the same amount.
I suspected the imaging ultrasound was probably done at power levels significantly lower than the levels mentioned in that 1988 paper where light was generated during tests, but I was curious to check. It appears to be the case, at least 10 to 20 times less than the .5 to 1 W/cm2 threshold for sonoluminescence mentioned:
“At the opposite end of the ultrasound-intensity spectrum,
much lower magnitudes of 1 to 50 mW/cm2 are used to
drive diagnostic devices that noninvasively image vital organs,
fetal development, peripheral blood flow, and metabolic bone
diseases such as osteoporosis7 and, coincidentally, to evaluate
fracture callus during healing8,9. The intensity level used for imaging,
which is five orders of magnitude below that used for
surgery, is regarded as nonthermal and nondestructive10. Nevertheless,
low-intensity ultrasound is still a mechanical force,
and it therefore holds the potential to influence bone mass and
morphology through bone tissue’s strong sensitivity to physical
stimuli.”
Every time a scientist publishes, if the argument turns out to be all wrong, he risks looking like a fool; but we don’t consider that a conflict of interest. So I’m sure Taubes means something more.
This paper claimed that the most actively publishing researchers in the field believe in anthropogenic climate change; also true of the most respected. I guess the criticism is that Schneider believes in ACC, hence if the paper is all wrong then that would mean he doesn’t publish very much and is not respected in his field. But those propositions are objectively false. What is Taubes’ angle that makes Schneider a fool if wrong?
Hal, by “wrong” Taubes meant wrong about global warming, not wrong about the thesis of the paper.
Great post, Seth.
My wife and I just had our first child and I brought up the question of ultrasounds with our obstetrician.
Our obstetrician’s response: “They are just sound waves. How could that hurt?”
I was stunned by her obvious ignorance, obtuseness and lack of any introspection — as I discussed this with my wife afterwards, I too noticed an “Unnoticed Conflict of Interest” — namely, this obstetrician will never even consider the hypothesis that ultrasounds could be damaging or injurious because if she were to and recommend against ultrasounds in case where they are not medically needed, she might open herself up to litigation as hitherto she has been doing just that.
She is simply stuck in this intellectual trajectory – where she is aware of it or not.
We passed on all ultrasound that were not medically indicated, as well as the keep sake-y 4D type, which I would have loved to have seen, but wasn’t worth the unknown uncertainty.
How can you advocate avoiding ultrasounds “as much as possible until more is known” without any data on what the harm caused by that alternative might be? Are ultrasounds never used for a legitimate diagnostic/harm-preventing purpose? By “as much as possible” do you mean in any case where the harm of giving the ultrasound is less than the harm of not giving it? But the very thesis of this post is that the former is unknown. I am very confused by your recommendation; it’s vague, and to the extent it can be quantified doesn’t appear to be very reasonable.
I was searching rates of autism increase and use of ultrasound in pregnancy. I did that because I have been working with a Chinese women who was pregnant and I was surprised to learn no use of ultrasound. (she is economically upper class). Based on that (plus my interest – grand son with autism) it occurred to do some searching i see there is a body on literature on concept. If they are not using ultrasound in China or other countries has anyone looked for correlations?