Test your medical knowledge with the following true/false questions:
1. sugar causes hyperactivity in children
2. suicides increase over the holidays
3. poinsettias are a poisonous plant
4. a large fraction of body heat is lost through the head
5. nocturnal feasting makes you fat
6. there are ways to prevent or cure a hangover
7. you should drink at least 8 glasses of water a day
8. we only use 10% of our brains
9. hair and fingernails continue to grow after death
10. shaving hair causes it to grow back faster, darker or coarser
11. reading in dim light ruins your eyesight
12. eating turkey makes people especially drowsy
13. mobile phones cause considerable electromagnetic interference in hospitals
Done? Grading should be easy, since all 13 questions are almost certainly false. While some of these myths lack sufficient evidence to confirm them, others have been well-studied and proven wrong.
I answered a number of these questions as true, but hey -- I'm a radiologist -- what do I know about clinical medicine? My pediatrician spouse also missed a few, but fared better than I did.
These questions were compiled and researched by Rachel Vreeman and Aaron Carroll, pediatric researchers at the Indiana University School of Medicine. Their results [1, 2] are freely available on the British Medical Journal site, and make for a fun read. I especially enjoyed reading about the questions I got wrong.
The authors conclude:
Physicians would do well to understand the evidence supporting their medical decision making. They should at least recognise when their practice is based on tradition, anecdote, or art. While belief in the described myths is unlikely to cause harm, recommending medical treatment for which there is little evidence certainly can. Speaking from a position of authority, as physicians do, requires constant evaluation of the validity of our knowledge.
For extra points, try some of these questions out on your friends -- better yet, on your doctor.
"The queen had only one way of settling all difficulties, great or small. 'Off with his head!' she said without even looking around."
-- "Alice's Adventures in Wonderland"
There are certainly interesting political waters roiling around the U.S. these days. Since we're talking about politics, it can be hard to swim clear of the usual boatloads of punditry, rhetoric and demagoguery. However, amongst this noise and turbulence, it's nice to find occasional conservative and liberal islands of calm and rationality. It's especially interesting when some of them seem to be in agreement for a change.
Under the pressure of the financial crisis, one presidential candidate is behaving like a flustered rookie playing in a league too high. It is not Barack Obama...
...It is arguable that, because of his inexperience, Obama is not ready for the presidency. It is arguable that McCain, because of his boiling moralism and bottomless reservoir of certitudes, is not suited to the presidency. Unreadiness can be corrected, although perhaps at great cost, by experience. Can a dismaying temperament be fixed?
Another good read is The Choice, an equally thoughtful editorial by the editors of The New Yorker:
...The longer the campaign goes on, the more the issues of personality and character have reflected badly on McCain. Unless appearances are very deceiving, he is impulsive, impatient, self-dramatizing, erratic, and a compulsive risk-taker. These qualities may have contributed to his usefulness as a “maverick” senator. But in a President they would be a menace...
...Although his opponents have tried to attack him as a man of “mere” words, Obama has returned eloquence to its essential place in American politics. The choice between experience and eloquence is a false one––something that Lincoln, out of office after a single term in Congress, proved in his own campaign of political and national renewal...
This sort of bipartisan congruence of opinions is something that I have fantasized about ever since seeing "The Supremes", one of the best episodes ever of The West Wing. The story line therein revolves around an upcoming presidential nomination to the U. S. Supreme Court. The heart of the episode is when an arch-liberal (Glenn Close) and an arch-conservative candidate (William Fichtner) for the nomination meet unexpectedly in the White House. The wonderful conversation that ensues is one of my favorite moments ever on television.
IMHO, it's worth buying the whole 5th season of West Wing just for this one episode. The following YouTube clip captures a tiny bit of the flavor of that episode, albeit with distracting commentary.
This sort of meeting of the minds between smart conservatives and liberals is something the U. S. needs badly. Alas, unlike the TV version, the real U. S. continues to be hampered by the lack of an Emmy award-winning screenwriter to make it all come out right in the end.
Call me Pollyanna, but when George Will and The New Yorker start seeing eye to eye on something, it gives me hope for the coming election. Maybe this time we'll get it right, and get the screenplay, director and cast that the country deserves.
In the tight-sphinctered world of academic medicine, it's always delightful to find a journal that still has a sense of humor. The following satirical paper from the British Journal of Medicine made me laugh and laugh.
Smith GCS, Pell JP. (2003). Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ, 327(7429), 1459-1461. DOI: 10.1136/bmj.327.7429.1459
In a nutshell, this paper rightfully points out that no one has ever done a randomized, controlled trial (RCT) on the efficacy of parachutes. Furthermore,
Advocates of evidence-based medicine have criticised the adoption of interventions evaluated by using only observational data.
To be funny, satire has to contain enough truth about its subject to properly skewer its underlying fallacies. Smith and Pell's excellent paper carries the concept of parachute efficacy through the usual machinery of evidence-based medicine, all the way to the following hilarious reductio ad absurdum conclusion:
We think that everyone might benefit if the most radical protagonists of evidence-based medicine organised and participated in a double-blind, randomised, placebo-controlled, crossover trial of the parachute.
From skimming through the comments stimulated by this paper, it seems that not all of the BMJ readers recognized it as satire, even though the article concludes with the following contributors' statement:
GCSS had the original idea. JPP tried to talk him out of it. JPP did the first literature search but GCSS lost it. GCSS drafted the manuscript but JPP deleted all the best jokes. GCSS is the guarantor, and JPP says it serves him right.
A Bit More on Evidence-Based Medicine
The formal term "evidence-based medicine" (EBM), is a relative newcomer on the medical research scene, and is based on early publications by Cochrane in 1972 and Sackett and Guyatt in the early 1990's. Their idea is a simple one: make clinical decisions based on a synthesis of the best available evidence about a treatment.
Just a few decades later, there are way many EBM advocates who are way too ready to blindly wield EBM like a mighty sword without understanding its limitations. IMHO, one of its biggest limitations is the current EBM definition of "best available evidence". For example, consider the Oxford Centre for Evidence-based Medicine Levels of Evidence (May 2001):
Level
Therapy/Prevention, Aetiology/Harm
1a
systematic review (with homogeneity*) of RCTs
1b
Individual RCT (with narrow Confidence Interval‡)
1c
All or none§
2a
systematic review (with homogeneity*) of cohort studies
2b
Individual cohort study (including low quality RCT; e.g., <80% follow-up)
2c
“Outcomes” Research; Ecological studies
3a
systematic review (with homogeneity*) of case-control studies
3b
Individual Case-Control Study
4
Case-series (and poor quality cohort and case-control studies§§)
5
Expert opinion without explicit critical appraisal, or based on physiology, bench research or “first principles”
I agree with the idea that all evidence is not created equal. However, there is something fundamentally wrong with the hierarchical list above. For one thing, it puts the principles of physics, chemistry and physiology down at the bottom of the heap in category 5, below even "poor quality case-control studies" in category 4. According to this table, a crappy case-series showing nerve conduction velocities faster than the speed of light would trump Albert Einstein's thoughts on the subject. I find this a bit troubling.
This is only one of the wacky conclusions that can arise from blindly following the precepts of EBM. I highly recommend Kimball Atwood's great Evidence-Based Medicine Primer on the excellent Science-Based Medicine blog. Therein he ably shows some of the limitations of EBM, and why it is not up to the task of evaluating highly implausible claims such as, say, homeopathy.
A Better Alternative: Science-Based Medicine
IMHO, EBM is a decent start, but is still a work in progress. The next logical step would be move to science-based medicine (SBM), wherein basic science is placed a lot higher on the food chain of evidence. This lets us start with this basic concept:
Therapeutic claims require evidence.
and come up with a somewhat more refined version:
Exceptional claims require exceptional evidence.
In other words, when we evaluate some intervention, basic science can help us determine if there is a reasonable scientific mechanism that supports it. If not, why do the study? And, if someone does the study anyway (it happens), the scientific plausibility (or implausibility) of the mechanism can help us decide how credible are the results.
Let's look at two brief examples: homeopathy and parachutes.
Homeopathy
Homeopathy claims therapeutic benefits from extremely dilute solutions of various agents (e.g. Oscillococcinum). However, the solutions usually employed are so dilute there is not a single molecule left of the original agent. Scientific likelihood of any benefit over that of plain water = zip.
Homeopathy counters this with the claim that the diluting water has a "memory" of the original agent, even though it's all gone. However, there is no scientific evidence of such a "memory" effect. Besides, when one considers how much of our planet's water passes through human kidneys, it seems likely that any possible "memory" of Oscillococcinum would be swamped by just the "memory" of used beer.
Bottom line: scientific likelihood of any benefit of homeopathy over that of plain water again = zero/zed/zip.
In this case, the basic science is so overwhelmingly against any benefit that it seems ridiculous to perform an RCT of homeopathic claims. Even if a marginally weak effect were suggested by a clinical trial, the a priori implausibility of homeopathy makes it hard to put much confidence in the result.
Parachutes
The physics of falling bodies, on the other hand, has been understood for a long time, particularly when there is atmospheric drag. The terminal velocity of a falling human in air is about 55 m/s (120 mph). Scientific likelihood of survival = almost 0% (a few fluke cases have been reported of lucky folks surviving parachute failures).
A properly designed parachute can decrease this falling speed to as little as 2.1 m/s, about the speed you'd develop by jumping off a 9 inch stool. Scientific likelihood of survival = virtually 100%.
In this case, the basic science is overwhelmingly in favor of survival. Therefore, I'm willing to take my chances with a parachute during my next plunge from a height -- RCT or no RCT.
George Carlin, skeptic, atheist, and Jedi master of comedy and social commentary, died yesterday, June 22, at the age of 71.
He was known for many things, including the Seven Dirty Words you can never say on television. When his monologue on these words was aired in 1973, it set off a kerfuffle that led all the way to the U. S. Supreme Court, whose narrow ruling (5-4) formally established indecency regulation in American broadcasting.
Since then, American children who have grown up hearing these words from their parents and each other have been spared that special moral degradation that comes from also hearing them on the air. As Carlin told the Associated Press earlier this year:
So my name is a footnote in American legal history, which I'm perversely kind of proud of.
Rest in peace, friend. May your words ring on in the Internet forever.
With a name like The Amaz!ng Meeting, one expects a certain amount of hyperbole. However, in the words of Dizzy Dean, "It ain't bragging if you done it."
There have already been some truly amazing presentations, as I've described in my other posts on TAM6. One keeps wondering how any day can possibly top the last. I'm happy to report that Saturday provided a very satisfactory Big Finish™ to TAM6.
(Okay, okay, there were some fine papers on the schedule for Sunday morning, but I wasn't able to attend them.)
Saturday highlights follow:
Dr. Michael Shermer, executive director of the Skeptics Society, kicked things off with a fine talk on Why People Do Weird Things. He cited recent fMRI research suggesting that skeptical thought may actually require more effort and time than uncritical thought.
Sharon Begley, senior editor at Newsweek, is widely known for her ability to break down complex scientific theories and write about them in simple prose. She spoke on "Creationism and Other Weird Beliefs: The Role of the Press". If we were expecting the press to bail us out in the struggle against irrationality and scientific illiteracy, her suggestion is: "Don't get your hopes up."
Jeff Wagg, general manager for the JREF (James Randi Educational Foundation), gave some late-breaking news about TAM7. The contract has been signed, and TAM7 will take place in Las Vegas at the brand new South Point Casino from July 9 - 12. He also raised the possibility of a future edition of TAM in the UK (woot woot).
Dr. Phil Plait, astronomer, writer, skeptic and author of the Bad Astronomy Blog, was the first afternoon speaker. He was introduced by PZ Myers, who continued their daily game of conference badinage. Phil's rejoinder:
In a way that only a roomful of atheists can appreciate, PZ's writing is god-like.
Phil then treated us to a quick and breezy tour of our solar system. His skeptical conclusion:
The Universe is Cool Enough Without Making Up Crap About It!!
Adam Savage, movie special effects artist and co-host of Mythbusters, quickly proceeded to make everyone's list of speakers they never, ever want to follow on stage. He started by regaling us with his ongoing quest to build the perfect replica of the Maltese Falcon. I'll just say that compared to Adam, I'm a lot less anal than I thought I was.
He wrapped up his presentation with a short video clip of "explosion porn" from the show. At the next break he gave away 1000 ping pong balls (and autographed many of them) that were used in one Mythbusters episode to raise a boat off the bottom of Monterrey Bay.
Concepts that the Discovery Channel has not yet allowed them to develop for Mythbusters:
Matthew Chapman, author, journalist, director and great-great grandson of Charles Darwin told us what he loves about America. He has written widely on the creation-evolution controversy in the U.S. Among other things, he visited Dayton, TN, home of the original Scopes Monkey Trial, to see if the town had evolved appreciably since the 1925 trial. Alas, it hadn't.
Mr. Chapman is founder and president of Science Debate 2008, which calls for a public debate of science issues by the two U.S. presidential candidates. To date, 28 Nobel laureates, 102 university presidents and quite a few other large names in science have signed this initiative.
Dr. Richard Wiseman, magician, psychologist and author of Quirkology, gave the final talk of the session. It was immediately apparent why he drew this slot, because it would be hard for even the other stellar speakers at TAM6 to top him.
Dr. Wiseman is not your usual psychologist, as can be seen from a glance at some of his prior research topics:
Do you consider yourself an observant person? Find out in the following Wiseman video:
Richard Wiseman definitely knows how to put the "grand" in grand finale -- in this case, by setting a new world record for simultaneous spoon-bending. His minions proceeded to pass out 800 metal spoons to this hall full of skeptics. But wait, there's more!
The next step: teaching 800 skeptics how to pull off (so to speak) this simple illusion. The key concept: "the more you stroke it, the softer it gets." Wiseman was quick to point out that this is one of the few contexts in which that happens to be good news.
Instead of teaching us spoon-bending himself, he delegated the task to someone else. In this case, that someone else happened to be one of the world's great magicians: Teller. After a quick post-graduate course in the theory, art and perils of spoon-bending by Teller, we were ready.
As the video camera rolled, we focused our skeptic energy fields on the spoons, and as one, bent and broke them all. Once the Quirkology SWAT team finishes editing all of their footage, keep an eye out for their final cut, coming soon to a YouTube theater near you.
Q & A Panel
At this point, there was no easy way to top Wiseman short of tactical nukes. Despite this, a blue-ribbon panel of skeptics stormed the stage for a brief Q & A session. My choice for most memorable quote is Adam Savage's:
Before you become a skeptic you might think the world is in color. But once you become a skeptic, it goes to HD!"
Dinner with Randi
About 60 of us then headed over to the Rio for dinner with Randi and other TAM6 faculty. After a fine evening of food and conversation, this group mitosed and half of the new organism headed for the Penn & Teller show at the Rio. In a word, awesome, in the original sense of awe. And, as an airport billboard promised, "Fewer audience injuries than last year!". (Extra tip: don't miss the 30 minute pre-show, and pay particular attention to the bassist...)
It's time for another report from TAM6, coming to you from sunny downtown Las Vegas, where it got up to 107° F (41.7 ° C) today.
Highlights from today:
Ben Goldacre, M.D. is a British physician and journalist, and author of The Guardian's weekly Bad Science column. He spoke today about homeopathy in the U.K. He pointed out that in 1846, John Forbes, the Queen's own physician, was a strong opponent of homeopathy. He contrasted that to today, where the Queen's personal physician is a homeopath. Only partially tongue-in-cheek, Dr. Goldacre wondered if this movement toward wacky medicine correlated with the loss of the British Empire.
Richard Saunders gave a short summary of skeptical matters in Australia. The best part of his session was an audience-participation experiment of dousing. This elegant experiment was designed to help teach critical thinking to school children. With 5 plastic buckets, a bottle of water, a simple dousing rod, and about 15 minutes, he showed how elementary school kids can grasp and even derive for themselves the principles of randomization, and single and double blinding of an experiment. The next time one of my residents seems a bit hazy on these concepts, I'll bring out the dousing gear.
Penn and Teller hosted a short but zesty Q & A session about their Bullshit! TV series, politics and skepticism. As a longtime fan of their stage act, it was a great treat for me to hear Teller actually speak, which he does quite eloquently, by the way. My favorite Teller quote today:
Q. What skeptical accomplishment are you most proud of? A. Bringing bare breasts, genitals and profanity to the service of skepticism.
My favorite Penn Jillette quote today:
Q. On your Bullshit! show, are you trying to be fair and unbiased? A. No. We are trying to be fair and extremely biased.
Alexander Jason told us about some of his exploits as a crime scene analyst, and pointed out how helpful a critical mind was in his line of work. He also described his work with James Randi in the 1980's to help debunk fake faith healer Peter Popoff. The video clip below summarizes some of the events of this scandal.
George Hrab, singer, songwriter, and author extraordinaire entertained us with a number of his creations. My favorite Hrab line, when he had some early sound problems with his guitar: "It's a PC guitar." To a Mac user, 'nuff said.
Dr. PZ Myers, biologist and author of the excellent Pharyngula blog, did not actually disembowel a Christian on stage, as was earlier predicted by some. Instead he gave a nice discussion of the evolution of bat wings. He wrapped up his presentation with a slide of "gratuitous squid porn". It is noteworthy that his presentation is the only one so far in which video clips have worked flawlessly. As you might expect, he uses a Mac.
These "droppings" covered a wide variety of topics, all built around the central theme of the close relationship between the scientific literacy of a population and the intellectual and creative health of their nation. Tyson gave a vivid account of the role of rising religious fundamentalism in the fall of the Islamic intellectual empire around 1100 CE -- a disaster from which the Islamic scientific community has never recovered. Parallels drawn by Dr. Tyson between this disaster and the current U.S. decline in scientific literacy were quite chilling. One hopes that the next administration can begin to repair some of the great damage done in the last 8 years to U.S. scientific research by the current administration.
A brief list of some of the questions considered in this 90-minute talk:
would an iPhone user have been burned at the stake 10 years ago (maybe so)
is there life on other planets (almost certainly)
does swami levitation work (yes, but only with sufficient flatus)
should we put pictures of scientists on our money (yes, and equations too!)
can lunar tidal forces affect your brain (yes, but they are a trillion times less than those exerted by your pillow)
is breathing, eating and drinking through the same orifice evidence of intelligent design (duh, no -- this is a stupid design that actually kills people)
Note to self: Never, ever, ever speak after this man. I'm pretty sure that everyone on the program following Dr. Tyson was thinking the same thing. Neil deGrasse Tyson combines a keen intellect and a strong background in science and history with the passionate lecture style of an evangelical preacher. He makes a powerful advocate for science and its essential role in society. One can only hope that we begin to elect politicians worthy of such an advocate.
The title of this post is appropriate for two reasons:
1. this post is my 100th post on this blog 2. this was a phrase used today at TAM6 by Dr. Art Benjamin, the Mathemagician.
The Art of Memory
My favorite afternoon workshop was The Art of Memory by Banachek. Banachek is billed as the world's leading Mentalist, and he kicked off his session by memorizing an entire deck of cards in about 47 seconds. Over the next 2 hours, he showed us several ways to do this. This has got to win the prize for the most practical first day talk ever at a Las Vegas convention!
By the end of this two hour session, he had given us mnemonic tools for memorizing a grocery list, a speech and a 74 digit number. Knowing these techniques back in my pre-med and med school days would have been worth the price of admission, all by themselves.
Besides his prodigious feats of memory, Banachek performs some pretty swell illusions, as shown in the video clip below.
If Art Benjamin were John Henry, the steam drill would have had its ass handed to it in a handbasket. Art demonstrated this right off the bat, by outperforming 5 people with calculators in several numerical feats.
It's hard to wow a room full of practicing skeptics, but Art accomplished this pretty quickly, spouting out the squares of 4 digit numbers about as fast as the audience could call them out. Before the calculator dudes on stage could even enter the digits for most of the problems, he was writing the answer down on a flip chart.
It's usually a let-down when a magician tells us the secret behind a trick. Benjamin, however, is a great exception to this rule. Even after he explained to us the details of how he did all of these mental calculations, it remained jaw-dropping to watch him blasting through these techniques at warp 4.
In the following video clip from the TED Talks, you'll see why we also gave him a standing ovation:
Besides being a great stage performer, Art Benjamin is a professor of mathematics at Harvey Mudd College, with a special interest in combinatorics and Fibonacci numbers. In the Q & A session, someone asked him for the URL of his website. He joked that despite these credentials and being able to recite the first 100 digits of pi, he was unable to remember his own web address. How does he find his site online? He googles himself.
I'm spending four days at the Flamingo Hotel in Las Vegas, Nevada, attending the 6th annual edition of The Amaz!ng Meeting, aka TAM6. The following blurb is direct from the TAM website:
The Amaz!ng Meeting is a celebration of critical thinking and skepticism sponsored by the James Randi Educational Foundation. Thinking people travel the world to share learning, laughs and life with fellow skeptics and distinguished guest speakers.
The Amazing Randi tells an anecdote about Art Benjamin
With a name like that, one would expect the talks to be a lot more, well, amazing than the fare at the usual radiology meeting. The program includes some stellar talent, including James Randi, Dr. Neil DeGrasse Tyson (astrophysicist and PBS Nova host), Adam Savage (Mythbusters co-host), Matthew Chapman (author and great-great grandson of Charles Darwin), Dr. PZ Myers (biology professor and Pharyngula blogger) and Penn and Teller.
Critical thinking is one of the many things I try to teach my students and residents, and I'm always up for new ways of teaching this material. From the partial TAM6 faculty list above, one can see an unusually large fraction of the Jedi Council of critical thinkers. If one can learn by osmosis alone, I should get a lot out of this meeting.
June in Las Vegas is pretty much what you would imagine - 103° F (39.4 ° C) today, with 107 ° F (41.7 ° C) predicted for tomorrow. However, the air-conditioning at the Flamingo is so relentless that I shivered my way through the afternoon sessions. That pile vest I felt silly packing at home will stay on me for the rest of the meeting.
I'll post some meeting highlights as time permits.
Grand Rounds is a weekly collection of the best writing in the medical blogosphere. I was delighted to host Volume 5, no. 20 here on February 3rd, 2009.
What does a radiologist do? Who are these rarely glimpsed and mysterious figures that float through the background of medical care?
Why would someone want to spend all of that time in medical school learning to be a Real Doctor™, and then throw it all away by becoming a radiologist?
Welcome to Not Totally Rad.
As the masthead suggests, most, but not all, of the topics discussed here will have something to do with radiology, medical imaging and imagers. Hopefully light will be shed on these matters, even if it's invisible to the naked eye.
The Samurai Radiologist has spent more than 20 years as a diagnostic radiologist, most of them professing at various university medical centers.
The "samurai" part is a nod to the late, great John Belushi, whose samurai skits on Saturday Night Live featured a samurai with a day job in some other field, such as dry-cleaning or a delicatessen. The plot usually gave him some hilarious job-related excuse to use his sword.
Since much of medical imaging (e.g. CT and MR) involves digital "cuts" through the body in various planes, I always hoped to someday see him portray a "samurai radiologist". I guess I'll just have to play that role myself.
) reveals them all within its pages.
