Magnets

Magnets in some Apple, Microsoft products may interfere with ICDs, pacemakers

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Strong magnets in newer portable electronic devices like the Apple AirPods Pro charging case or Microsoft Surface Pen can interfere with pacemakers and implantable cardioverter defibrillators, researchers reported.

Corentin Féry

“We show that there is a risk of deactivating the therapy of these medical devices if some electronic objects with magnets are placed near the chest of the patients,” Corentin Féry, MSc, a research engineer at the University of Applied Sciences and Arts Northwestern Switzerland, Institute for Medical Engineering and Medical Informatics in Muttenz, Switzerland, told Healio. “The key word is caution for wearers of ICDs and pacemakers. The risk for death is real for them since a tachycardia will not be detected if a device with a strong magnet is deactivating their implant. Our tests on some everyday objects, such as the iPhone 12 Pro Max or the Microsoft Surface Pen, lead us to say that it is necessary to keep a distance of at least 1 inch between the implants and these devices. We also recommend not to carry electronic objects in a pocket close to the chest, or to fall asleep with such devices.”

Phone

Investigating magnetic strength

The researchers investigated several portable electronic devices (PEDs), including the Apple AirPods Pro and its wireless charging case, the Microsoft Surface Pen and the Apple Pencil (second generation), comparing their magnetic field strength with the iPhone 12 Pro Max. Using a magnetic mapper with 64 magnetic sensors, researchers measured the magnetic field strength of the products at various distances. The PEDs were also placed incrementally closer to five defibrillators from two representative manufacturers (Boston Scientific: Inogen, Teligen and Cognis; Medtronic: Protecta and Viva Quad) until a therapy deactivation occurred. According to the FDA, a minimal field strength of 10 G is required for CV implantable devices to trigger to magnet mode.

The findings were published in Circulation: Arrhythmia and Electrophysiology.

The researchers found the farthest point where a 10 G intensity was measured is located about 2 cm (0.78 in) from the surface for the Apple products and at 2.9 cm (1.14 in) for the Microsoft Surface Pen. Magnet reversion mode was triggered at a distance between 8 mm and 18 mm for the tested PEDs.

“Our study found that PEDs other than the iPhone 12 have magnetic susceptibility and, thus, have the potential to inhibit lifesaving therapies,” the researchers wrote.

Although the test results showed the maximum distance for a possible ICD interaction, researchers said for safety, the minimal distance is between 0.8 cm (0.31 in) for the iPhone 12 Pro Max and the Apple Pencil (second generation) and 1.8 cm (0.71 in) for the Microsoft Surface Pen and the opened charging case of the Apple AirPods Pro.

“Clinicians should warn their patients to be cautious when using electronic devices,” Féry told Healio. “Since we have not tested all electronic devices on the market, we suggest caution with any device that has magnets.”

Sven Knecht

Sven Knecht, DSc, a research engineer at the Cardiovascular Research Institute Basel at University Hospital Basel, University of Basel in Switzerland, noted that the magnet mode does deactivate the therapy but not the detection of the tachycardia.

“Furthermore, the risk of death is theoretically possible if the deactivation of the ICD by the portable electronic device occurs during a lethal, hemodynamically relevant tachycardia,” Knecht told Healio. “This likelihood might, however, be relatively low.”

More research needed

A major limitation of the study was that it was not conducted on ICDs implanted in patients, Féry said, adding the researchers need to perform in vivo tests with the electronic devices, as well as highlight the potential risk with other classes of objects, such as watches or e-cigarettes.

As Healio previously reported, the FDA issued a warning in May that certain cellphones and smartwatches containing high field strength magnets may cause some implanted medical devices, particularly cardiac devices, to suspend normal operations when in proximity to the magnet. The FDA noted at the time that many implanted medical devices such as pacemakers and ICDs are designed with a “magnet mode” to allow safe operation during certain medical procedures such as MRI. Placing certain cellphones and smartwatches too close to the implanted device can cause the device to switch into magnet mode when it is not supposed to, suspending normal operations, the agency stated.

The American Heart Association recommends keeping cellphones at least 6 inches away from ICDs or pacemakers by using it on the ear opposite from the implantation and to avoid keeping the cellphone in a front chest pocket.

N.A. Mark A. Estes

“The current study extends observations on magnetic field interactions with even more devices containing magnets,” N.A. Mark A. Estes, MD, professor of medicine and director of the Clinical Cardiac Electrophysiology Fellowship Program at the Heart and Vascular Institute of the University of Pittsburgh School of Medicine, and an AHA volunteer, said in a press release. “Patients with cardiac electronic implantable devices should be instructed to keep all electronic devices that can generate a magnetic field several inches from their pacemakers or ICDs.”

Magnets are being used to retrieve patients’ lost, short-term memories.

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With almost perfect recall.

Scientists have found that dormant memories can be revived by delivering a pulse of magnetic stimulation to the brain, allowing people to retrieve forgotten information with almost perfect recall.

The results have revealed that a type of short-term memory called working memory could be far more complicated than we thought, and could answer some long-standing questions about what causes a number of mental illnesses.

“This changes how we think about the structure of working memory and the processes that support it,” one of the team, Nathan Rose from the University of Notre Dame in Australia, told NPR.

Working memory is the kind of short-term memory that gives you the ability to remember relevant information while in the middle of an activity.

It lets you memorise a new phone number long enough to make a call, or retain the names of two new people you meet at a party while you’re having a conversation.

For decades now, scientists have assumed that working memory retains information in the short-term through sustained brain activity.

It was thought that the continuous activity of a certain set of neurons was required to retain the information, and if that activity ever faulted, that memory would be lost forever.

But Rose and his team wanted to investigate how the brain determines what information to retain at any given moment, and what it ends up filing away for quick access later on.

Because while it might feel like we’re able to take in a whole lot of new information at a time, our working memory is actually quite limited in what it ‘chooses’ to retain.

“The notion that you’re aware of everything all the time is a sort of illusion your consciousness creates. That is true for thinking, too,” said one of the researchers, Brad Postle from the University of Wisconsin-Madison, in a press release.

“You have the impression that you’re thinking of a lot of things at once, holding them all in your mind. But lots of research shows us you’re probably only actually attending to – are conscious of in any given moment – just a very small number of things.”

The researchers gathered 66 participants to observe how their working memory actually functioned.

Through a number of experiments, they tested how the participants would remember sets of two different things – a face and a word. They were shown the items, then told they needed to remember them later on, and MRI scans were taken to see how the brain reacted.

“That caused a distinct pattern of activity in two groups of brain cells: one that was keeping track of the face and another that was keeping track of the word,” Jon Hamilton reports for NPR.

“But then … the researchers had people focus on just one of the items they’d seen. And when they did that, the brain activity associated with the other item disappeared.”

“It was almost as if the item had been forgotten,” Rose said.

But when the participants were warned that they were about to be quizzed on the second item they were supposed to remember, their working memory suddenly kicked back into gear – disproving previous assumptions that the working memory had to be continuously activated.

“People have always thought neurons would have to keep firing to hold something in memory. Most models of the brain assume that,” Postle explains in the release.

“But we’re watching people remember things almost perfectly without showing any of the activity that would come with a neuron firing. The fact that you’re able to bring it back at all in this example proves it’s not gone. It’s just that we can’t see evidence for its active retention in the brain.”

Next, the team asked the participants to focus on remembering the face, which caused them to forget about the word.

They then used a technique called transcranial magnetic stimulation (TMS) to apply a focused electromagnetic field to the exact part of the brain involved in storing the word, causing the participants to incorrectly think they’d been asked to focus on the word – not the face.

“We think that memory is there, but not active,” says Postle. “More than just showing us it’s there, the TMS can actually make that memory temporarily active again.”

The experiments only featured a very small sample size, so it’s not enough to start dreaming of a future where we can start using magnetic stimulation to recall lost short-term memories.

But the researchers say their experiment could help further our understanding of mental illnesses such as schizophrenia and depression, because it’s revealing exactly how our brains decide what thoughts to focus on, and how this can be mitigated.

“A lot of mental illness is associated with the inability to choose what to think about,” says Postle. “What we’re taking are first steps toward looking at the mechanisms that give us control over what we think about.”

Magnets can help ‘reset’ depressed brains, study finds .

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Researchers have shown that non-invasive magnetic pulses can reset unhealthy activity in a region of the brain known to be overactive in patients with depression.

The technique is known as transcranial magnetic stimulation (TMS), and has been shown to treat persistent depression, as well as boost people’s memories, aid Parkinson’s sufferers, and help stroke patients to speak again. But this is the first time researchers have shown exactly how it works on a neurological level, and the results are pretty impressive.

“We found that one session of TMS modifies the connectivity of large-scale brain networks, particularly the right anterior insula, which is a key area in depression,” lead scientist Sarina Iwabuchi, from the University of Nottingham in the UK, told the European College of Neuropsychology at a conference in Amsterdam, where the research was presented.

The right anterior insula is part of the prefrontal cortex, and overactivity in the region is linked to excessive rumination, self-absorption and impaired attention in depressed patients. But after delivering powerful magnetic pulses directly to this area in 16 healthy controls and 16 patients with major depressive disorder, the study showed that TMS could slow the activity in this region down in those with depression.

Even better is the fact that TMS is drug-free and painless – the only known side effect is the occasional headache. The technique simply requires a device to be applied to a patient’s head. But even though TMS was approved for limited use in the treatment of depression by the US Food and Drug Administration (FDA) in 2008, it’s still not widely used.

This is the first study to guide TMS pulses with functional MRI scans, and then measure the changes it produced in the brain, and the results suggest that the treatment may offer a much-needed alternative for the one-third of patients who don’t respond to traditional medications such as Lexapro and Prozac.

Currently these patients are recommended to try electroconvulsive therapy (ECT), or electric shock therapy as it’s sometimes known, which can be effective but requires anaesthesia and has been associated with side effects such as memory loss. A more targeted form of short electric pulses has been shown to be far gentler, but still requires patients to go under general anaesthetic and several treatment sessions. Scientists also still don’t really quite understand how ECT works.

TMS on the other hand doesn’t require any medication and appears to begin working after just one session. Importantly, this new study outlines the neurological changes that appear to be driving the positive results.

Of course, there are some big limits to this research, not least of all its small sample size. It also doesn’t provide evidence on how long-lasting these neurological changes are. But it’s been 30 years since we had a truly new treatment for depression, and so the research provides some much-needed hope for patients and their families.

“These findings are an exciting step in understanding how targeting the brain activity with magnetic stimulation may exert beneficial effects in the treatment of depression,” Catherine Harmer, a neuroscientist from the University of Oxford who wasn’t involved in the study told Amy Ellis Nutt over at TheWashington Post on behalf of the European College of Neuropsychology. “TMS techniques are still evolving … This kind of experimental medicine study is therefore essential for the improved personalisation and treatment of depression in the future.”