Summary: Researchers report amplified EEG can produce diagnostic results of brain waves associated with migraine and epilepsy non-invasively.
Source: University of British Columbia.
New UBC research has found that amplified electroencephalograms (EEGs) can produce diagnostic results of a brainwave associated with migraines and epilepsy that are comparable to the current, more invasive, standard–a discovery that could lead to better treatment and diagnosis of these conditions.
The low-frequency brainwave linked to migraines and epilepsy is known as cortical spreading depression (CSD) and is currently best studied by placing electrodes directly on the surface of the brain. But researchers from UBC, Germany and Iran have found that EEGs–produced by placing electrodes only on the scalp–can produce equally reliable data if a specially designed amplifier is used in tandem.
“Using this method, we found that the electrical signals acquired from the skin of the scalp were very similar to those acquired from the surface of the brain,” said lead researcher Zoya Bastany, a master’s student in the faculty of applied science at UBC.
Bastany designed an AC/DC amplifier to acquire electrical signals from scalp electrodes used on anesthetized rats. The amplifier detects signals in a much broader frequency range than the standard clinical EEG system. CSD was then induced in the rats, and the recordings from scalp electrodes were compared with recordings from electrodes placed on the rats’ brains.
Cortical spreading depression has never before been accurately measured using EEGs, according to UBC electrical and computer engineering professor Guy Dumont, Bastany’s supervisor and study co-author.
“The new method opens up uses for EEGs in studying cortical spreading depression in a non-invasive manner and without a significant increase in diagnostic costs compared to standard EEG,” said Dumont.
Ali Gorji, a professor of neuroscience at the University of Münster in Germany and a study co-author, said the new analysis technique could contribute to the development of migraine drugs that target CSD, and to better understanding of other neurological disorders.
“Research is still continuing to fully understand the clinical relevance of CSD. But ultimately, having this noninvasive way of studying this brainwave could lead to better understanding, diagnosis and treatment of migraine, epilepsy and other neurological conditions such as stroke and traumatic brain injury,” said Gorji.
The study is a joint research program between UBC, University of Münster, and Shefa Neuroscience Research Center and Mashhad University of Medical Sciences in Iran.
Source: Lou Corpuz-Bosshart – University of British Columbia
Image Source: This NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Non-invasive monitoring of spreading depression” by Zoya J.R. Bastany, Shahbaz Askari, Guy A. Dumont, Erwin-Josef Speckmann, and Ali Gorji in Neuroscience. Published online July 7 2016 doi:10.1016/j.neuroscience.2016.06.056
Non-invasive monitoring of spreading depression
Spreading depression (SD), a slow propagating depolarization wave, plays an important role in pathophysiology of different neurological disorders. Yet, research into SD-related disorders has been hampered by the lack of non-invasive recording techniques of SD. Here we compared the manifestations of SD in continuous non-invasive electroencephalogram (EEG) recordings to invasive electrocorticographic (ECoG) recordings in order to obtain further insights into generator structures and electrogenic mechanisms of surface recording of SD. SD was induced by KCl application and simultaneous SD recordings were performed by scalp EEG as well as ECoG electrodes of somatosensory neocortex of rats using a novel homemade EEG amplifier, AgCl recording electrodes, and high chloride conductive gel. Different methods were used to analyze the data; including the spectrogram, bi-spectrogram, pattern distribution, relative spectrum power, and multivariable Gaussian fit analysis. The negative direct current (DC) shifts recorded by scalp electrodes exhibited a high homogeneity to those recorded by ECoG electrodes. Furthermore, this novel method of recording and analysis was able to separate SD recorded by scalp electrodes from non-neuronal DC shifts induced by other potential generators, such as the skin, muscles, arteries, dura, etc. These data suggest a novel application for continuous non-invasive monitoring of DC potential changes, such as SD. Non-invasive monitoring of SD would allow early intervention and improve outcome in SD-related neurological disorders.
“Non-invasive monitoring of spreading depression” by Zoya J.R. Bastany, Shahbaz Askari, Guy A. Dumont, Erwin-Josef Speckmann, and Ali Gorji in Neuroscience. Published online July 7 2016 doi:10.1016/j.neuroscience.2016.06.056