Monthly Archives: March 2012

Trying to deny that helmets can aggravate brain injury

Abstract

Several studies have reported that bicycle helmets can increase rotational acceleration. Rotational acceleration is the primary cause of brain injury.

The Australian government commissioned a study to defend its controversial helmet law. The study set up unrealistic conditions fostering low rotational acceleration. The study claims that helmets do not increase brain injury. This is deceitful. The study unrealistic conditions are not representative of real life accidents.

An interview with a study author revealed the study was not set up to address rotational acceleration. The author said:

“soft-shell helmets are for cosmetic purposes, not really for protection, …
current helmets do not appear to protect against brain injury.”

Look at a bicycle helmet. It has been designed with comfort in mind. It is made of light weight material that grip the road on impact rather than glance off it (as is the case with motorcycle helmets).

Helmets increase the volume of the head. In the event of an accident, this increases the risk of the head hitting the road.

The increase in the volume of the head, coupled with the gripping of the road surface, means that when a head comes into contact with the ground at speed, the head rotates quickly. This quick rotation is the main cause of brain injury.

What causes brain injury?

An old popular belief is that brain injury is caused by a direct hit the head, like a head hitting a wall, causing linear acceleration. This is focal brain injury. Bicycle helmets are designed to reduce focal injury. The polystyrene reduces linear acceleration by compressing on impact.

Scientific research done in the 1970′s has revealed that the main cause of severe brain injury is not focal injury but diffuse axonal injury:

“Protecting the brain from injury that results in death or chronic disablement provides the main motivation for wearing helmets. Their design has been driven by the development of synthetic polystyrene foams which can reduce the linear acceleration resulting from direct impact to the head, but scientific research shows that angular acceleration from oblique impulse is a more important cause of brain injury. Helmets are not tested for capacity to reduce it and, as Australian research first showed, they may increase it.“

Rotational acceleration means the head turning quickly. This can create shearing inside the brain, tearing apart brain tissue. This is diffuse axonal injury. It can lead to permanent disability. This article reports from a surgeon who operates on cyclists:

” “The ones with brain swelling, that’s diffuse axonal injury, and that’s bad news” …

the whole brain is shaken up, creating many little tears in its inner structure …

Such patients undergo personality change, can contract epilepsy and have difficulty controlling their anger. They might become unemployable. Depression is a common accompaniment to brain injury. Rosenfeld sees patients’ families shattered, too. “They’re never the same. It often leads to marriage disharmony and family breakdown.” …

Rosenfeld’s opinion is candid. “I don’t know if [helmets] do much to protect the inner part of the brain,” “

Helmets cannot protect against rotational injury but they can increase it, according to research done in Sweden:

“The non-shell helmet did in all trials grab the asphalt surface, which rotated the head together with
the helmet. The consequences were in addition to the rotating of the head, a heavily bent and compressed neck, transmitted on through the whole test dummy body after the impact. …

This gives an average angular acceleration of 20800 rad/s² for rotating the head from 0 to 0.26 rad during the 5 ms. Löwenhielm proposes 4500 rad/s² to be the maximum angular acceleration that can be tolerated for a limited time period.”

Soft-shell helmets amplified rotational acceleration to four times higher than the tolerable maximum. Soft-shell helmets are helmets without a hard shell. They are the most common type of bicycle helmet.

On impact, the larger head volume amplifies rotational acceleration. A 3cm increase in helmet circumference increases rotational acceleration by 150%:

“the 3000rad/s² to 8500rad/s² measured during abrasive and projection oblique tests with size 54cm (E) helmeted headforms. However, for the most severe cases using a size 57cm (J) headform, rotational acceleration was typically greater than 10,000rad/s² and increased to levels of 20,000rad/s², a level at which a 35% – 50% risk of serious AIS3+ injuries is anticipated.”

The difference between a helmeted and non-helmeted head is about 20cm.

In 1987, an Australian government agency released research that highlighted deficiencies with bicycle helmets:

“The substantial elastic deformation of the child head that can occur during impact can result in quite extensive diffuse brain damage. It is quite apparent that the liner material in children’s bicycle helmets is far too stiff …

rotational accelerations were found to be 30% higher than those found in similar tests using a full face polymer motorcycle helmet. More work needs to be done in this area as there would seem to be a deficiency in rotational acceleration attenuation that may be the result of insufficient shell stiffness “

A doctor from New Zealand reports:

“cycle helmets were turning what would have been focal head injuries, perhaps with an associated skull fracture, into much more debilitating global head injuries”

In Canada, the length of stay in hospital increased increased following helmet laws, from 4.3 days to 6.9 days. The number of serious head injury admissions increased by 46%.

A strange “study”

The Australian government introduced a policy of mandatory helmets. Many people wrote to the government about brain injury from rotational acceleration. The bureaucrats claimed:

“A 2009 study by the University of NSW confirmed the effectiveness of a bicycle helmet in reducing angular acceleration and subsequent brain injury in crashes”.

This study was commissioned by the government. It was not published. After much insistence, a copy was obtained from a government agency. The abstract states that the study’s aim is to

“investigate the ability of a bicycle helmet to reduce angular head acceleration“.

It seems to be a “study” with a pre-determined conclusion, like this one.

The study was set with unrealistic conditions, by

Using a type of hard-shell helmet not representative of the most common type of helmet used
Testing at unrealistically low speeds of 5 to 11 km/h
Testing on a non-abrasive surface not representing standard road conditions
Failing to test for oblique impacts (Oblique impacts generate high rotational acceleration)

Studies have reported high rotational acceleration with soft-shell helmets, at speeds above 30 km/h. This study fostered low rotational acceleration.

The study used a helmet with a ABS shell, like the one on the right. Then it generalised its results to all bicycle helmets.

The study conclusion makes no mention of the unrealistically low speeds (5 km/h to 11 km/h). How can accident protection research only do tests a low speed? Speed is a major factor affecting impact severity. Testing only a low speeds is almost useless.

The study tested a low speeds like 5 km/h, even though the risks they are “studying” have been reported at higher speeds like 30 km/h. The study then claimed that the risk doesn’t exist.

The conclusion fails to qualify the results by mentioning it was not using a realistic road surface. The flat surface used reduces the risk of the helmet sticking to the surface. Other studies have reported that helmets tend to stick to the road surface.

Despite the unrealistic conditions, the study claims are generalized without qualifications:

“At worst bicycle helmets do not appear to exacerbate head injury risks arising from angular acceleration.”

This is deceitful, as this claim is the result of the peculiar set up of the study. It cannot be generalised beyond the laboratory conditions.

Interview with an author of the study

CRAG has interviewed one of the study authors:

Why use hard-shell helmets?

“The helmets were supplied to us”

Why not use a soft-shell helmet, the most common type used today?

” the soft-shell helmet doesn’t do much – basically for cosmetic purposes – falls to pieces very easily – When touched can dent easily – Main function of soft shell helmets to ‘retain foam in semi-rigid format,’ not really for protection”

The tests were done at speed from 5 km/h to 11 km/h. Why not higher speeds like 20 km/h?

“We had borrowed the RTA’s crash dummy and didn’t want to damage it”

Do you believe that the conditions used in the study are realistic of real-world conditions?

“No “

Is this study comprehensive enough to assert that helmets do not increase rotational acceleration?

“the study does not address any oblique impact issues so therefore does not address potential increase in rotational acceleration of the brain

… current helmets on the market are limited in preventing rotational acceleration

… there is no rotational testing element in the helmet standard.”

In your opinion as an expert, do helmets do their job?

“As long as there is no oblique impact, yes

… But in an accident with any oblique impact, probably not

.. Current helmets do not appear to protect for brain injury such as concussion or haematoma“

Ethical issues

Between 2006 & 2009, the University of NSW earned $248,000 from helmet “studies” such as this one.

This study is still not published, escaping independent scrutiny. Its purpose seems to be to defend a controversial government policy.

The government is expected to fund research to improve helmets, like it did in 1987 (before the helmet law). Commissioning research to mask deficiencies of a government policy is unethical.

The fundamental role of science is to serve the truth. It is NOT to serve the interests of the state.

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July 2013 update

The same team of researchers published a related study in 2013. It is called: “Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests“.

Like the “study” described above, this study sets up unrealistic conditions. Nothing can be concluded about real life accidents from unrealistic conditions.

Bureaucrats have peddled this study as “proof” that helmets reduce rotational acceleration.
Public money well spent?

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Challenging a helmet fine through the courts

Abstract

The defence of necessity allows people to ignore a law to avoid even more dire consequences. Bicycle helmets increase the risk of accident and can cause brain injury. To avoid these dire consequences, cyclists can ignore the helmet law.

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Sue Abbott challenged a helmet fine in New South Wales (NSW), Australia. She argued that wearing a helmet was more dangerous than not wearing one. District Court Judge Ellis concluded:

“Having read all the material, … I frankly don’t think there is anything advantageous and there may well be a disadvantage in situations to have a helmet and it seems to me that it’s one of those areas where it ought to be a matter of choice.”

The defence of necessity states that people can break a law to avoid even more dire consequences. The test has 3 parts:

1. You must have an honest belief that complying with the law puts you at increased risk of injury

For example:

Helmets increase the risk of accidents
Helmets increase the risk of brain injury

2. It was necessary to do the activity that led to the breach (ie., to cycle)

This is a personal issue. For example combining regular exercise with transport is necessary to stay in good health.

3. You must show that no harm was caused by breaking the law.

No harm was caused from riding on that specific occasion. Cycling provides health benefits while reducing traffic congestion and pollution. Wearing a hat instead of a helmet reduces the risk of skin cancer.

More details from Sue Abbott court case.

Sue Abbott has challenged other helmet fines for herself and for her daughter.

Others have challenged helmet fines, like Dan. His defence ends with the following observation:

“Finally, I will leave it to your Honour to ponder the following absurdity. Riding a bicycle without a helmet is activity that delivers health benefits to the individual, reduces the healthcare tax burden on society, delivers economic benefits in terms of reduced road congestion, reduces the risks to other road users and benefits both the local and the wider environment. It is safe, has no appreciable negative consequences, and is considered entirely normal everywhere in the world where bicycle use is widespread. Yet this safe, fun, and beneficial activity is considered a criminal offence in New South Wales.”

Dan challenged four helmet fines in another court case. The magistrate recognised the risk of brain injury from wearing a helmet. He let him off with a token fine. Sue Abbott described the trial. An extract from the verdict:

“[The magistrate] reviewed all the evidence presented, and basically accepted all of it as factually correct; he also made some comments about the bicycle helmet law not being ‘helpful’ …

It also highlighted the absurdity of the bicycle helmet law to the point where he was prepared to criticise it on the record.”

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The emergence of policy-driven studies

Abstract

In the mid 1990’s, evidence emerged that the bicycle helmet law had failed to reduce the risk of cycling injuries. Governments responded by commissioning “studies” exaggerating the benefits of helmets while ignoring their tendency to increase accidents. Such policy-driven studies are quoted in official government communications to justify its controversial policy.

These deceitful practices waste precious resources while real cycling safety is neglected. This might explain why Australia has one of the worst cycling safety record among developed countries, with a fatality rate 5 times greater and a serious injury rate 22 TIMES higher than best practice.

The hidden side of scientific research

Generally, research is conducted with scientific discipline, with a purpose to further scientific knowledge. However, sometimes the entity funding the research has a vested interest in a certain outcome, compromising the independence of the research.

This has been the case for some research funded by drug companies for example, where the research results are used to sell or promote drugs. Powerful government and corporate interests are increasingly influencing scientific research through controlling its funding, as reported by Brian Martin from the University of Wollongong:

“In the routine practice of scientific research, there are many types of misrepresentation and bias which could be considered dubious. However, only a few narrowly defined behaviours are singled out and castigated as scientific fraud. A narrow definition of scientific fraud is convenient to the groups in society — scientific elites, and powerful government and corporate interests — that have the dominant influence on priorities in science. Several prominent Australian cases illustrate how the denunciation of fraud helps to paint the rest of scientific behaviour as blameless”

Government is a large source of research funding. In the mid 1990s, evidence emerged that the helmet law had failed to improve safety. Several researchers reported this. A bicycle activist who promoted helmet wearing and initially believed in the helmet law looked at the data and concluded:

“It is fair to say that, so far, there is no convincing evidence that Australian helmet legislation has reduced the risk of head injury in bicycle crashes.”

Governments responded by commissioning “studies” defending its policy, then quoting such policy-driven studies to justify its policy.

The Henderson report: a policy-driven study

In 1995, the Motor Accidents Authority of New South Wales (Australia) commissioned a policy-driven study that became known as the Henderson Report. Written in an authoritative style, it pretends to be scientific. That illusion breaks down when one notices two unusual features for a scientific report:

It contains many strongly worded, unqualified assertions. Researchers with scientific integrity tend to be very careful with their assertions, making sure they are backed up by sufficient evidence and qualified by their context. You rarely see unsupported or unqualified assertions in a scientific report.
Assertions are not annotated, making it impossible to verify the data source.

This is not a scientific report. It is unsubstantiated opinions presented as facts. Here are a few of them (From the Executive Summary, under “The effectiveness of head protection”):

“Helmet design and construction is based on known mechanism of head and brain injury”. Not true. This ignores rotational acceleration, the main cause of brain injury.
“At the very minimum helmets halves the risk of head injury”. Not true. Helmets can aggravate brain injury through rotational acceleration.
“Those who do not wear helmets are several times more likely to sustain injury to the brain tissue”. Not true. Ignores that helmet wearers are more likely to have accidents.
“in Victoria, the number of bicyclists with head injuries decreased by 48 per cent”. Misleading. Ignores the decline in cycling and head injury reduction for pedestrians.
“The vast majority of head impacts occurring … are easily survivable if a Standards-approved helmet is worn”. Not true. Helmets are not designed to protect in a serious accident.
“No studies have come to conclusions contrary to the above”. Not true. The Hillman report (1992), one of the most comprehensive and famous review of helmet research at the time, is ignored.

Many assertions in this report are false or misleading. The report ignores evidence that does not support helmets.

This “study” has received much criticism, notably in the vehicular cyclist:

“Individuals and organizations zealously pushing mandatory helmet use for cyclists are continuing to churn out reams of propaganda. One of the more voluminous efforts is Michael Henderson’s “The Effectiveness of Bicycle helmets: A Review” 1995, a politically motivated paper prepared on behalf of the Motor Accidents Authority of New South Wales, Australia apparently in a desperate effort to justify the State’s botched law outlawing cyclists who ride without a helmet.

Henderson’s report recycles much of the same old material that’s been cited by others over the years. The studies he references fail to provide a real world context, and to show any particular understanding of cycling. Although presenting bicycle head injuries as a worldwide problem, Henderson neglects to provide us with any sense of the size or scope of it.”

Contrast the bold narrow claims from this report with the more comprehensive approach from the Hillman report:

“By wearing helmets, cyclists are at best only marginally reducing their chances of being fatally or seriously injured in a collision with a motor vehicle which is the predominant cause of these injuries. Even the most expensive ones provide little protection in these circumstances. Moreover, the argument in favour of helmets would have validity if there were proof that behaviour does not change in response to perceived risk. But there is no such proof. Safety devices encourage higher levels of risk-taking. As a result, cyclists are likely to ride less cautiously when wearing a helmet owing to their feeling of increased security. After all, the message of the advocates of helmet wearing is that such a practice will protect the cyclist’s head adequately in the event of any accident, not just a minor one when cyclists are hit by very slow-moving vehicles or fall off and hit their heads on the ground. Cyclists may be less likely to have an accident if they are not wearing a helmet, and are therefore riding with greater care owing to an enhanced sense of their vulnerability.”

Subsequent policy-driven studies

Official evaluations of the helmet laws commonly employ biased selection of research and statistics, resulting in benefits being unduly attributed to them and adverse effects (like an increase in the risk of accidents) ignored. Despite data showing that cycling safety has lagged pedestrian safety since the helmet law, policy-driven studies found a way to claim that the helmet law was a success. For example, a 1997 report from a government agency made two misleading claims:

“Cycling casualties decreased after the helmet law”. This ignored the decrease in the cycling. Per cyclists, cycling casualties increased.
“A ‘strong correlation’ between higher helmet wearing rates and lower casualties”. The underlying data indicates the opposite.

The helmet law was introduced as a part of a package of road safety measures including a crackdown on speeding and drink driving. The number of cyclists reduced significantly. Any assessment of the helmet law must take into account these confounding factors. Yet many government-funded “studies” like this one did NOT adjust for this, attributing all apparent improvements to the helmet law. Such negligence is difficult to comprehend. How could the “researchers” miss such basic adjustments? It is odd that these mistakes favor the legislation while the government funds the “research”.

Most medical case-studies, claiming that the helmet law has been effective, are also riddled with errors. They typically start from the assumption that helmets save lives and attempt to “prove” it by selectively fishing for data that supports their predetermined conclusion.

Some government studies not only contain false claims, but fail to rectify them after being corrected.

In 2000, the Australian Transport Safety Bureau (ATSB), a federal government agency, released a meta-analysis, that claimed to provide

“overwhelming evidence in support of helmets for preventing head injury and fatal injury“.

This claim was rebutted in 2003, highlighting that:

“the meta-analysis … take no account of scientiﬁc knowledge of [brain injury] mechanisms”

The ATSB did not reply to the rebuttal, thus giving up on its claim. Despite being discredited, this analysis is still used by the government to defend the helmet law, claiming that helmets reduce the risk of head injury by 60%.

In 2011, a meta-analysis re-assessed this ATSB meta-analysis. It concluded:

“This paper … was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets …

According to the new studies, no overall effect of bicycle helmets could be found when injuries to head, face or neck are considered as a whole.“

Publication bias is the tendency of contradictory or inconclusive results not to be published, resulting in a literature formed of apparently consistent findings that exaggerate the actual effect. Time-trend bias is the tendency to pick a specific time period that exaggerates the actual effect.

Since then, various government agencies have wasted more taxpayers money by commissioning policy-driven “studies”, attempting to obfuscate the failure of the helmet law.

A prominent university seems to be moving away from policy-driven studies, as reported here:

“the faculty wished to move away from conducting sponsored policy studies for government because this did not generate valuable intellectual property“

The dire consequences of this dishonest behavior

Independent researchers who have studied the result of the helmet law have come to different conclusions.

Dorothy Robinson, a researcher from the University of Armidale, said:

“mandatory bicycle helmet laws increase rather than decrease the likelihood of injuries to cyclists …

Having more cyclists on the road is far more important than having a helmet law, for many reasons …

[the] governments [which introduced the helmet laws] do not like to admit they’ve made mistakes”.

Bill Curnow, once a scientist from the CSIRO, wrote as a conclusion in a scientific article:

“Compulsion to wear a bicycle helmet is detrimental to public health in Australia but, to maintain the status quo, authorities have obfuscated evidence that shows this.”

An independent group of public health and transport practitioners and researchers wrote in their report:

“The failure of mass helmet use to affect serious head injuries, be it in falls or collisions, has been ignored by the medical world, by civil servants, by the media, and by cyclists themselves. A collective willingness to believe appears to explain why the population-level studies are so little appreciated. …. The disconnect between received wisdom and the facts is stark.“

These are strong words from independent researchers, revealing frustration at the government unwillingness to admit they made a mistake.

For how long can policy-driven studies sustain failed policies?

In what way can this be justified as good use of taxpayers money?

Such deceptive studies add little to scientific knowledge. They exaggerate the reduction of minor injuries while ignoring the increased risk of serious injuries. Such deceitful practices have dire consequences. They tend to mislead policy makers towards false “solutions” to cycling safety, while neglecting more effective measures, like reducing the risk of accidents.

This might explain why Australia has one of the worst cycling safety record among developed countries, with a fatality rate 5 times greater and a serious injury rate 22 TIMES greater than best practice.

The practice of commissioning dubious studies to defend its failed policy while neglecting more effective safety measures constitutes an abuse of public trust among the bureaucrats entrusted with cycling safety.

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