by A recent study conducted by researchers from the University of Birmingham has shed light on the relationship between sleep patterns, stress hormones, and epilepsy seizures. The researchers used mathematical modeling to analyze the impact of various physiological processes, including sleep and changes in the concentration of the stress hormone cortisol, on epileptiform discharges (ED) – key signatures of epilepsy.
Epilepsy is a neurological disorder characterized by recurrent and spontaneous seizures. Until now, seizures were believed to occur randomly. However, the discovery of ED activity with varying timescales ranging from hours and days to months has changed this understanding.
The team analyzed 24-hour EEG recordings from 107 individuals with idiopathic generalized epilepsy and identified two subgroups with distinct distributions of epileptiform discharges. One subgroup experienced the highest incidence of seizures during sleep, while the other experienced them during the daytime.
In their publication in PLOS Computational Biology, the international research team described how the dynamics of cortisol, sleep stage transition, or a combination of both factors accounted for most of the observed distributions of ED. Their mathematical model explained the activity of interconnected brain regions and how the excitability of these regions can be influenced by stimuli such as transitions between sleep stages or fluctuations in cortisol levels.
The frequency of epileptiform discharges tends to increase during the night, early in the morning, and in stressful situations. The researchers found that sleep explained 90% of the variation in one subgroup, whereas cortisol accounted for around 60% in the other subgroup.
Cortisol, which is one of the primary stress hormones in humans, is produced and secreted by the hypothalamic-pituitary-adrenal (HPA) axis. In stressful situations, HPA axis activity increases, leading to elevated cortisol levels.
Dr. Marinelli, one of the researchers involved in the study, explained that sleep alone could not explain the changes in the likelihood of epileptiform discharges during wakefulness observed in the first subgroup. There was a decrease in the likelihood of discharges during the later hours of sleep, following an initial sharp increase. This can be attributed to the fact that deep sleep, which is associated with an increase in epileptiform discharges, is more prominent during the first third of the sleep period. The researchers also observed an increase in discharges before waking, indicating a combined effect of sleep and cortisol due to the known increase in cortisol levels around waking.
These findings highlight the importance of considering sleep and stress hormones as factors that influence the occurrence of seizures in people with epilepsy. By understanding the relationship between sleep patterns, cortisol levels, and epileptiform discharges, researchers may be able to develop targeted interventions and treatment strategies to improve the management of epilepsy. Further studies are needed to validate these findings and explore potential therapeutic approaches based on these insights.
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1. Source: Coherent Market Insights, Public sources, Desk research
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