07 décembre 2008

It's not what the papers say, it's what they don't

Ben Goldacre
The Guardian

Writing this column really scares me because I wonder whether everything else in the media is as shamelessly, venally, manipulatively, one-sidedly, selectively reported on as the things I know about. But this week the reality editing was truly without comparison.

On Tuesday the Telegraph, the Independent, the Mirror, the Express, the Mail, and the Metro all reported that a coroner was hearing the case of a toddler who died after receiving the MMR vaccine, which the parents blamed for their loss. Toddler 'died after MMR jab' (Metro), 'Healthy' baby died after MMR jab (Independent), you know the headlines by now.

On Thursday the coroner announced his verdict: the vaccine played no part in this child's death. So far, of the papers above, only the Telegraph has had the decency to cover the outcome. The Independent, the Mirror, the Express, the Mail, and the Metro have all decided that their readers are better off not knowing. Tick, tock.

Does it stop there? No. Amateur physicians have long enjoyed speculating that MMR and other vaccinations are somehow "harmful to the immune system" and responsible for the rise in conditions such as asthma and hay fever. Doubtless they must have been waiting some time for evidence to appear.

This month a significant paper was published by Hviid and Melbye in the December 1 issue of the American Journal of Epidemiology. They examined 871,234 children in a Danish birth cohort, comparing asthma in those who had MMR against those who didn't. MMR-vaccinated children were massively and significantly less often hospitalised with an asthma diagnosis, and used fewer courses of anti-asthma medication than unvaccinated children. This "protective" effect of the MMR vaccine was more pronounced for hospitalisations with severe asthma diagnoses.

Those results aren't just incompatible with an increased risk of asthma following MMR vaccination, they actually support the hypothesis that MMR vaccination is associated with a reduced risk of asthma in young children. Tick, tock.

And most astonishing of all is the tale of "the Uhlmann paper", or the "O'Leary paper". This came out in 2002 and claimed to have found evidence of vaccine measles virus in tissue samples from children with autism and bowel problems, to massive media acclaim.

As I've said previously, two similar papers, by Afzal et al and D'Souza et al, in 2006 found negative results on almost the same question, and were unanimously ignored by the media (even though D'Souza actively went out of his way to show how O'Leary et al got false positives).

Stephen Bustin is professor of molecular science at Barts and the London. He examined the O'Leary lab for the court case against MMR, as an expert witness for the drug company defendants. The case collapsed, and he was unable to discuss his findings. Then he was called to give evidence in the American "autism omnibus" case against the vaccine. The anti-vaccine movement did their best to prevent this. They knew what he had found: it appears to be incontrovertible evidence that the lab was detecting false positives.

Now Bustin has finally been able to write about what he found in O'Leary's lab. He published this month. Nobody who covered the original O'Leary paper has written about it. Not a soul will.

Measles cases are rising. Middle class parents are not to blame, even if they do lack rhetorical panache when you try to have a discussion with them about it.

They have been systematically and vigorously misled by the media, the people with access to all the information, who still choose, collectively, between themselves, so robustly that it might almost be a conspiracy, to give you only half the facts.

Today, I have merely given you some small part of the other half, and next week I will move on: but know that nobody else has.

01 décembre 2008

Brain's magnetic fields reveal language delays in autism

Psychology & Sociology

Faint magnetic signals from brain activity in children with autism show that those children process sound and language differently from non-autistic children. Identifying and classifying these brain response patterns may allow researchers to more accurately diagnose autism and possibly aid in developing more effective treatments for the developmental disorder. Timing appears to be crucial. "Children with autism respond a fraction of a second more slowly than healthy children to vowel sounds and tones," said study leader Timothy Roberts, Ph.D., vice chair of radiology research and holder of the Oberkircher Family Endowed Chair in Pediatric Radiology at The Children's Hospital of Philadelphia. Roberts used a technology called magnetoencephalography (MEG), which detects magnetic fields in the brain, just as electroencephalography (EEG) detects electrical fields.

Roberts presented his findings today at the annual meeting of the Radiological Society of North America in Chicago. "The brain's electrical signals generate tiny magnetic fields, which change with each sensation, and with communication among different locations in the brain," he added.

Roberts is working to develop "neural signatures" that can link recorded brain activity to particular behaviors in children with autistic spectrum disorders (ASDs), which are characterized by impaired development in communications and social functioning. "Our hypothesis is that speech and other sounds come in too fast for children with ASDs, and their difficulties in processing sound may impair their language and communication skills," said Roberts.

Physicians already use MEG to map the locations of abnormal brain activity in epilepsy, but the technology Roberts used is one of the few MEG machines available in a dedicated pediatric facility. In the current study, the researchers evaluated 64 children aged six to 15 at The Children's Hospital of Philadelphia. Thirty children had ASDs, the rest were age-matched, typically developing control subjects.

The MEG machine has a helmet that surrounds the child's head. The researchers presented a series of recorded beeps, vowels and sentences. As the child's brain responded to each sound, noninvasive magnetic detectors in the machine analyzed the brain's changing magnetic fields.

When sounds were presented, the MEG recorded a delay of 20 milliseconds (1/50 of a second) in the brain's response for children with ASDs, when compared with healthy control subjects. "This delay indicates that auditory processing is abnormal in children with autism, and may lead to a cascade of delay and overload in further processing of sound and speech," said Roberts. "Further research may shed light on how this delay in processing sounds may be related to interconnections among parts of the brain." Other testing, measuring a response to mismatched or changed sounds, found longer delays, up to 50 milliseconds (1/20 of a second).

Because autism disorders range across a spectrum of functional abilities, explained Roberts, neural signatures based on brain responses may allow clinicians to more accurately diagnose which subtype of ASD an individual patient has. Such diagnoses may be possible at an earlier age if future studies show that such signatures are detectable in infancy—at younger ages than in the children involved in the current study. "Earlier diagnosis of ASDs may allow clinicians to intervene earlier with possible treatments," said Roberts.

Furthermore, added Roberts, if a patient's neural signature overlaps with that found in another neurological condition, such as epilepsy or attention-deficit hyperactivity disorder, for which a treatment exists, that patient may benefit from such a treatment.