Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sunny days pose risk of 'flicker illness' for a few airlifted patients

07.03.2007
A case report published in the current issue of the journal Prehospital Emergency Care suggests that light streaming through whirling helicopter rotor blades during medical air transport can cause symptoms ranging from nausea to full-blown seizures in a very small number of patients.

The report, published in the January/March volume, cites several studies, case reports and historical examples related to photosensitive epilepsy, suggesting that the phenomenon is an under-recognized but highly preventable complication of helicopter transport.

"This shouldn’t preclude transporting a patient from point A to point B in an aircraft," said Jeremy Cushman, M.D.,, an Emergency Medicine attending physician at the University of Rochester Medical Center and the report’s lead author. "But this concern does need to register as a legitimate risk for a small number of patients. Personnel ought to know how to guard against it."

The case report details an account of a patient who suffered a severe foot injury and required an airlift from a remote geographic location to a hospital in Baltimore, where Cushman worked at the time. Flight paramedics noted flickering bursts of sunlight cast across the patient’s face, to which the patient’s eyes soon began blinking, and then his facial muscles began jerking in coordinated rhythm. The patient, stable and displaying strong vital signs, immediately fell into a seizure, despite paramedics’ attempts to block the flashes from the patient’s face.

During the hospital examination, the patient reported no previous head injury or family history of seizures; he also had a normal EEG and CT scan, and, at a three-month follow-up visit, reported no recurrence of the seizure.

"He was not diagnosed with a seizure disorder," Cushman said. "But we never exposed him to flickering light again, either, giving us all the more reason to suspect that as the cause."

Giuseppe Erba, M.D., professor of Neurology and Pediatrics at the University of Rochester Medical Center, is a world expert on photosensitivity, including epileptic seizures caused by flashing lights of video games and television. Erba says that he also encounters patients affected by a similar flickering effect caused by sunlight filtering through a row of trees as the patients are riding in cars.

"Photosensitive patients may twitch, then jerk, and finally, if nothing is done to stop it, have a seizure," Erba said. "It’s a tricky business, this photosensitivity, because it can exist without a patient having spontaneous seizures, as the paper states. This makes prevention even more difficult, especially since routine EEG tests are not always carried out properly in the lab and too often, false negative results occur."

Cushman and co-author Douglas Floccare, M.D., M.P.H., of the Maryland State Police Aviation Command researched how often this sort of light-induced epilepsy occurs in patients, even pilots, with no history of seizures – especially in aircraft on sunny days. The team found several photosensitive epilepsy studies and various reports from over the course of decades, even centuries, both on ground and in flight. Together, these pieces create a picture that suggests the condition may be more common and difficult to diagnose than originally thought.

For instance, Cushman highlights second century writings from the Roman novelist and orator Apuleius, who noted that the spinning of a potter’s wheel could send onlookers into seizures. Cushman also describes an array of other non-whirling stimuli that have been documented over time to induce seizures, including music, hot water, working with fractions, and even tooth brushing.

The most common photosensitive stimulus is television, Cushman said, and resulting seizures are often dubbed instances of "video game" or "space invader" epilepsy, a condition that Erba studies and has made recommendations to help prevent.

"Almost 10 years ago in Japan, more than 700 children were hospitalized after watching a cartoon explosion on a show called Pokemon," Cushman said. "And with numbers like that, there’s more at play than the mere two in 10,000 patients that statistics show are vulnerable to light-induced epilepsy. We’ve begun to wonder if even people not diagnosed with epilepsy can also be affected, to some degree, by a flickering stimulus like the light in our report."

Cushman noted that other studies further underscore the more widespread photosensitivity evidenced by the Pokemon cartoon incident; one showed that even 28 percent of normal, non-epileptic control subjects exposed to light flashes can suffer symptoms such as nausea, headaches, fear and vomiting, if the flickering light is set to the right frequency. In that same study, as many as 5 percent of "normal" subjects experienced a loss of consciousness or seized.

Convinced that photosensitivity triggered by spinning rotors, though rare, is an under-recognized and preventable complication of medical air transport – one that can be produced even in some patients without previous seizure history – Cushman now instructs flight paramedics to routinely shield patients’ eyes while en route.

"More than 30 years ago, there was a case reported of a young soldier waiting to board a helicopter who began seizing without any previous medical history," Cushman said. "Other reports exist for incapacitation of Air Force pilots, with anything from simple spatial disorientation to serious seizures. What’s interesting is that these findings were reported for previously healthy individuals."

He and Floccare use the term "flicker illness" to refer to the whole continuum of complications, from wooziness to vomiting to all-out seizing, induced by quick-flashing light.

"Many aircraft commonly used for air medical transport have similar frequencies to the 24 flickers per second of the rotor blades in the helicopter used in the case we highlight," Cushman said. "And though this isn’t so common a complication – I’ve seen four total cases in the course of five years and thousands of transports – the more I dialogue with others, the more they recall having encountered something similar."

Cushman noted that the report may be more relevant in sunnier places like Phoenix, where colleagues have been very interested in the report. Baltimore and Rochester see some 105 and 61 sunny days per year on average, respectively, compared to aptly named Phoenix’s 211.

Becky Jones | EurekAlert!
Further information:
http://www.urmc.rochester.edu

More articles from Health and Medicine:

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>