Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Show EEG's Potential to Reveal Depolarizations Following TBI

01.10.2014

The potential for doctors to measure damaging "brain tsunamis” in injured patients without opening the skull has moved a step closer to reality, thanks to pioneering research at the University of Cincinnati (UC) Neuroscience Institute.

The potential for doctors to measure damaging "brain tsunamis” in injured patients without opening the skull has moved a step closer to reality, thanks to pioneering research at the University of Cincinnati (UC) Neuroscience Institute.


Jed Hartings, PhD, research associate professor in the department of neurosurgery at the University of Cincinnati College of Medicine.

The research team, led by Jed Hartings, PhD, research associate professor in the department of neurosurgery at the UC College of Medicine, has shown that spreading depolarizations—electrical disturbances that spread through an injured brain like tsunami waves—can be measured by the placement of electroencephalograph (EEG) electrodes on the scalp. The team demonstrated the effectiveness of the noninvasive technique by making simultaneous invasive recordings from electrodes that were placed directly on the surface of the brain in 18 patients who had undergone surgery following a traumatic brain injury (TBI).
  
"We can see clearly when spreading depolarizations occur with invasive recordings,” Hartings says. "And when we looked at this data side by side with the non-invasive EEG recordings, it just jumped out at us. When you look at the scalp EEG the right way, evidence of the spreading depolarization could be seen.”
 
The discovery has the potential to revolutionize bedside neuro-monitoring by enabling doctors to measure spreading depolarizations, which lead to worse outcomes, in patients who do not require surgery. At present, only about 10 to 15 percent of patients with TBI undergo surgery and are candidates for intracranial monitoring.
 
"This landmark observation broadens the spectrum of patients and conditions that can be monitored for the occurrence of spreading depolarizations,” says co-investigator Norberto Andaluz, MD, associate professor of neurosurgery and director of the UC Neurotrauma Center at the UC Neuroscience Institute. Until now, spreading depolarizations could only be detected through the insertion of surgical leads into the patient's brain. Thanks to this discovery, we will acquire a better understanding of the role that depolarizations play in virtually every neurological condition, thus opening new opportunities for therapeutic interventions.”


The research was published online in the journal Annals of Neurology earlier this month and highlighted online in the journal Nature Reviews. The research was funded by the U.S. Army’s Psychological Health and Traumatic Brain Injury (PH/TBI) Research Program and the Mayfield Education & Research Foundation.


The discovery was not made sooner because of historical conventions in how scalp EEG data is reviewed, Hartings says. Continuous EEG is typically studied in small 10-second segments, which allows detection of abnormal brain waves, such as epileptic spikes, which last fractions of a second.  The changes associated with spreading depolarizations, on the other hand, develop over tens of minutes.
 
When the data is time-compressed so that hours of EEG recordings are presented on a single screen, the picture comes into focus. "The pattern jumps out at you,” Hartings says. "Suddenly, what you see developing over a course of 45 minutes is a depression of the amplitude of the brainwaves. It takes maybe 15 minutes for that to develop to its minimum, and then it will slowly recover again over another 15 to 20 minutes. So you can only see the depolarization when you are looking at long epochs of data.


"This is something that people have probably been recording for 50 years,” Hartings adds, "but they weren’t looking at the data in the right way to be able to recognize it.”
 
Hartings likened the phenomenon to the Nazca Lines, the famous geoglyphs in the desert of southern Peru. The Nazca Lines suggest nothing up close, but when seen at a distance from surrounding foothills or an airplane, images of artistry emerge.


In the Annals of Neurology study, the researchers reported on spreading depolarizations that lasted from 10 minutes to several hours. More than 80 percent of the depolarizations could be detected with scalp EEG.
 
Bringing the "Nazca Lines of the brain” into focus from the patient’s bedside is a primary objective of Hartings’ research, which has played a leading role worldwide in the understanding of spreading depolarizations in acute neurologic injury. Hartings’ team characterized the phenomenon in TBI and laid the foundation for understanding its destructive nature in research published in Lancet Neurology and Brain in 2011.
 
"One of our main objectives going forward is to develop techniques for measuring spreading depolarizations non-invasively, using a more traditional EEG,” Hartings says.
  
Because the spreading depolarizations range from subtle to obvious, more research is needed. "If the activity is subtle, perhaps we can we use digital signal processing techniques to make the signal more obvious,” Hartings says. "Can we define data processing procedures that will clean up the signal and maybe even establish criteria that will set off an automatic alarm to alert bedside physicians?”


Translating and refining this knowledge into a broadly applicable methodology with a refined user-friendly bedside display, Hartings says, is perhaps five years away.


Additional co-investigators of the study included J. Adam Wilson, PhD, Jason Hinzman, PhD, Sebastian Pollandt, MD, Vince DiNapoli, MD, PhD, and David Ficker, MD. 


Andaluz is a neurosurgeon with the Mayfield Clinic, and Ficker is a UC Health neurologist and director of the EEG Laboratory and the Epilepsy Monitoring Unit at the UC Neuroscience Institute. 

Cindy Starr | Eurek Alert!
Further information:
http://healthnews.uc.edu/news/?/25230/

More articles from Health and Medicine:

nachricht Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>