New research by the Human Brain Project finds that in the brains of patients with epilepsy, changes in neuronal activity can be detected as broadly as resting-state activity of the brain, even when the seizure is not continuing. A non-invasive approach could lead to a new way to help diagnose epilepsy.
Diagnosing epilepsy can be problematic for patients, who sometimes have to wear helmets and electrodes for long periods of time to wait for a seizure to occur, until doctors can document it with an EEG. Instead, the seizure is artificially induced, causing discomfort.
The new findings stem from a collaboration between the Institute of Neurosciences in Systeme (France), IRCCS E.Medea – La Nostra Famiglia (Italy) and the Department of General Psychology of the University of Padua (Italy). Published in the journal EpilepsyThe study compared the high-intensity electroencephalograms (EEG) of 37 patients with temporal lobe epilepsy with healthy controls.
While the brain is resting, spontaneous waves of neuronal activation are continuously generated. Their function is not fully understood, but they appear to play an important role in brain function. The researchers showed that even during the resting state it is possible to detect a change in the propagation patterns of so-called large-scale “nervous breakdowns”, indicating a possible diagnostic application in epilepsy. These neuronal avalanches are triggered by the spontaneous activation of a group of neurons which then spread across large regions of the brain, in a cascade effect.
“Our new method is able to detect relevant epilepsy features by taking into account the basic functional organization of the brain,” explain Gian Marco Dumas and Pierpaolo Sorrentino, respectively researchers at IRCCS E.Medea and the Institute of Neurosciences in Marseille, who collaborated on this study. “Even when a seizure does not occur, the brain of a patient with epilepsy presents some changes in the dynamics of its network on a whole-brain scale. So we thought it would be possible to examine the dynamics by looking at noncyclic spontaneous avalanches.”
We found that the change in the prevalence of neuronal avalanches in temporal lobe epilepsy clusters around regions of the brain that are central to seizure initiation and propagation. This opens up the potential for a new primary diagnostic method, particularly important for difficult cases where the scalp EEG fails to detect seizures, and additional investigations are necessary.”
Gian Marco Dumas and Pierpaolo Sorrentino
The results also revealed a link between the change in the prevalence of nervous breakdown and memory, which is often impaired in patients with epilepsy. The temporal lobe is specifically associated with memorization, and specific propagation patterns in the resting state can be altered by epilepsy. “This finding provides us with further evidence of the neuropsychological and neuropsychological relevance of nervous breakdowns,” the researchers suggested.
Duma, General Manager, et al. (2023). The variable prevalence of neuronal breakdowns in temporal lobe epilepsy relates to cognitive performance: a resting hdEEG case study. Epilepsy. doi.org/10.1111/epi.17551.