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Archive for the ‘Other Science’ Category

Thursday, October 31st 2013

The Falliability of Memory

I am fascinated by the faliability of memory. Especially episodic memory.

You and I really don’t remember what we think we remember. It is rarely accurate and yet people are utterly convinced of that their memory is accurate. There are obviously huge implications. Think criminal or civil law.

[Dr. Elizabeth] Loftus discovered that she could modify memories with startling ease. After showing a film of a crash, Loftus asked some volunteers if they “saw a broken headlight” and others if they “saw the broken headlight.” Those who got the latter question were twice as likely to say yes – though, in fact, the film showed no broken headlights.

Loftus was fascinated, and she soon turned her attention to criminal trials. Suspicious of the accuracy of eyewitness identifications, Loftus conducted an experiment in which volunteers looked at photographs of six faces while listening to a story of a crime.

One face was identified as the criminal, five as innocents. Three days later, Loftus showed the volunteers four photographs: one of an innocent character from the crime story, and three of new people. Sixty percent of volunteers identified the innocent character as the perpetrator from the story. They recognized a familiar face but muddled their associations with it.

[...]

One study in particular bolstered Loftus’ belief that much memory is malleable. In a now-famous experiment, Loftus told a volunteer that she had spoken with his mother and learned four things that happened to him as a 6-year-old.

She then ran through three real memories and one fake one. The volunteer sometimes claimed to remember the fake memory, which involved getting lost in a shopping mall then getting rescued by an elderly stranger. (Planting a more traumatic memory would be even more illuminating for psychologists, but researchers try to avoid permanently scarring their volunteers.)

Even odder, the volunteer would usually be happy to elaborate on this implanted memory. His panic, his confusion, his relief; it was all there, hidden away in his memory. Except that it wasn’t—it was all in his imagination. With just a small bit of coaxing, Loftus could insert this memory even into the most skeptical minds.

Or psychiatric illnesses.

Psychologists Miriam Lommen and colleagues studied 249 Dutch soldiers were deployed for a four month tour of duty in Afghanistan. As part of a study into PTSD, they were given an interview at the end of the deployment asking them about their exposure to various stressful events that had occurred. However, one of the things discussed was made up – a missile attack on their base on New Year’s Eve.

[...]

Eight of the soldiers reported remembering this event right there in the interview. The other 241 correctly said they didn’t recall it, but seven months later, when they did a follow-up questionnaire about their experiences in the field, 26% said they did remember the non-existent New Year’s Eve bombardment (this question had been added to an existing PTSD scale.)

Susceptibility to the misinformation was correlated with having a lower IQ, and with PTSD symptom severity.

I think this is one of the most fascinating parts of not just cognitive study but all of neuroscience.

Functional neurosurgery may hold promises to improve memory, not just in pathology (such as dementia), but in normal individuals. Initial studies show poor episodic improvement, but who knows what the future holds. And I wonder the implications of that for these “false” memories.

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Thursday, October 24th 2013

The Hands of Healthcare

I’ve previously written about how technology threatens physicians futures. There are some big proponents of computers doing what docs currently do and potentially doing it better. Whether its Watson dong oncology or a machine doing conscious sedation. This latter is the new thing,

Patients are hooked up to Sedasys and sedated intravenously. While connected, a patient’s condition is monitored by the machine. It measures oxygen levels, for instance. If there is a problem, the machine alerts the physician, and is supposed to take action, such as increasing the oxygen supply and stopping the anesthesia, and resumes only if the patient’s condition normalizes.

Patients also wear an earpiece, in case they drift into too deep a level of sedation and need to be awakened. As a doctor or nurse would do, the machine would, through the earpiece, tell the patient to wake up.

Its coming, even for surgeons eventually.

Saving grace might be the lack of a human touch.

Wednesday, May 22nd 2013

The Plate In The Head

Unfortunately sometimes in neurosurgery when you do a surgery you have to leave the part of the skull you remove to access the brain off. The most common situation is in neurotrauma.

A patient has had an extensive injury and perhaps there scalp has been opened and the underlying skull is exposed to the outside and poses a real infection risk.

Or their skull has been fractured so badly that it can’t cosmetically be put back together very well.

Or they have their skull put back on after surgery but it gets infected and then the infected piece of bone has to be removed and can’t be used again.

In these cases we sometimes use custom made implants which are built by biomedical firms off of a special CT scan. They are pretty amazing and can give great results. They’re also expensive and to be honest I’m not one hundred percent sure how they’re made.

But it comes as no surprise to me that the rise of commercial 3D printing might disrupt the, admittedly small, market for such cranioplasty implants and substantially lower costs.

Now replacing large portions of people’s skulls is not necessarily new. Back in 1997, Science Daily reported on advances in implants that involved using CT and MRI scans to create a model of the skull and then have a special implant manufactured from medical-grade plastic. What’s different about the 3D printed approach is that implants are lower cost and can be customized to specifically fit the patient. Additionally, if the implant doesn’t quite work out, replacements are readily available.

Other implants are coming, I would imagine. It is likely to be pretty impressive technology.

Friday, May 17th 2013

Biological Calculators

Biological computers are not new. There is continual work on creating circuits from cells. Now work out of MIT on an analog computational system. Big enough for MIT to issue a press release.

To create an analog adding or multiplying circuit that can calculate the total quantity of two or more compounds in a cell, the researchers combined two circuits, each of which responds to a different input. In one circuit, a sugar called arabinose turns on a transcription factor that activates the gene that codes for green fluorescent protein (GFP). In the second, a signaling molecule known as AHL also turns on a gene that produces GFP. By measuring the total amount of GFP, the total amount of both inputs can be calculated.

To subtract or divide, the researchers swapped one of the activator transcription factors with a repressor, which turns off production of GFP when the input molecule is present. The team also built an analog square root circuit that requires just two parts, while a recently reported digital synthetic circuit for performing square roots had more than 100.

Worth a look just as a matter of curiosity.

Friday, April 19th 2013

The Studies Are All Bad

One of my fellow residents might be a Ben Goldacre disciple except amongst all his citations in conversation I’ve never heard him reference the English Physician. I’ll call Dr. Goldacre the ‘Bill Nye’ or the ‘Neil Degrasse Tyson’ of the antagonistic medical epidemiology circle. But it’s a growing group. Amongst them as well the Greek epidemiologist, John Ioannidis.

There is a horrific set of facts about what we know in medicine.

1) Most medical research is so poorly designed that conclusions you can draw from it are…limited

2) The medical research we are conducting is low yield

3) Most medical research performed never comes to light because it fails to meet the hypothesis of those who conducted it

4) There is strong incentive to falsify results

Ioannidis has a famous paper entitled “Why Most Published Research Findings Are False,”

[T]he majority of modern biomedical research is operating in areas with very low pre- and post-study probability for true findings. Let us suppose that in a research field there are no true findings at all to be discovered.

A Huffington Post article by Dr. Ida Sim,

About 80 percent of clinical trials are funded by the commercial sector, but the commercial sector disproportionately studies drugs, and understudies behavioral treatments or older treatments that can’t be patented or profited from. When 75 percent of our medical costs are for chronic diseases that are largely due to poor lifestyle habits, where are the studies on prevention? On behavior? On effective patient-doctor or public health strategies? Where are the studies that examine the balance of benefits and harms, that guide patients and doctors on side effects and cost-effectiveness?

In England a researcher working for Aptuit is set to serve a prison sentence for falsifying lab results for a cancer drug.

Steven Eaton, from Cambridgeshire, has become the first person in the UK to be jailed under scientific safety laws.

[...]

Sheriff Michael O’Grady said: “I feel that my sentencing powers in this are wholly inadequate. You failed to test the drugs properly – you could have caused cancer patients unquestionable harm.

“Why someone who is as highly educated and as experienced as you would embark on such a course of conduct is inexplicable.”

Speaking after the case, Gerald Heddell, the Medicines and Healthcare Products Regulatory Agency’s director of inspection, enforcement and standards, said he welcomed the conviction.

He added: “This conviction sends a message that we will not hesitate to prosecute those whose actions have the potential to harm public health.”

Biomedical research is difficult to call science. What you can assume your doctor or surgeon knows about your condition is surprisingly less than you think. They will certainly act like they know and truly believe that they do but such knowledge is based on a limited amount of reliable data. In Dr. Ionnaidis’ essay there are some suggestions on making medical research better. And of course as Dr. Goldacre calls for all results of all medical research should be public. Even if that disincentivizes some research we may not be missing out on much.

Monday, October 29th 2012

Hackable Medical Devices

As we become more and more reliant on active, implanted biotechnology the opportunities for malicious manipulation of such rise. The hacking of medical devices isn’t a new threat. I’ve commented on it, as have publications more prominent than this blog. The issue has taken on enough of intellectual seriousness that it has prompted the creation of a multi-institutional center, the Medical Device Security Center. In 2008 that group published a method of wirelessly accessing information from some models of pacemakers and then injecting active attacks to change the performance of the pacemakers. After publication they presented the same at Defcon.

At the Black Hat Conference last year an independent researcher presented a theoretical method of wirelessly changing the serum glucose readings of an implanted diabetic pump.

An attacker could intercept wireless signals and then broadcast a stronger signal to change the blood-sugar level readout on an insulin pump so that the person wearing the pump would adjust their insulin dosage. If done repeatedly, it could kill a person. Radcliffe suggested scenarios where an attacker could be within a couple hundred feet of a victim, like being on the same airplane or on the same hospital floor, and then launch a wireless attack against the medical device. He added that with a powerful enough antenna, the malicious party could launch an attack from up to a half mile away.

The most recent, highly publicized hack devised by researchers is one concerning implantable cardiac defibrillators. At the Breakpoint conference in Australia this year,

In a video demonstration, [researcher Barnaby] Jack showed how he could remotely cause a pacemaker to suddenly deliver an 830-volt shock, which could be heard with a crisp audible pop.

[...]

In 2006, the U.S. Food and Drug Administration approved full radio-frequency based implantable devices operating in the 400MHz range, Jack said.

With that wide transmitting range, remote attacks against the software become more feasible, Jack said. Upon studying the transmitters, Jack found the devices would give up their serial number and model number after he wirelessly contacted one with a special command.

With the serial and model numbers, Jack could then reprogram the firmware of a transmitter, which would allow reprogramming of a pacemaker or ICD in a person’s body.

Any attacks on medical devices requires more than a common level of expertise but to one dedicated probably something within the ability to be self taught. There are much bigger public health issues, even within the biotechnology sphere, including the function and operating safety of such but this remains a scary prospect and one that deserves more attention. Medical device makers need to put more into the security of these devices and the FDA needs to place a focus on making sure device makers are doing such.