Sleep is important for migraine patients’ brain function

Migraine patients have a greater vulnerability to reduced sleep than others and thus an increased need for sleep after an attack to restore normal brain function.

The norwegian studies shows that reduced sleep affects different mechanisms in the brain depending on whether you usually have migraine attacks related to sleep or not related to sleep. The results also show that the migraine group had a greater vulnerability to reduced sleep after a migraine attack, and thus an increased need for sleep during and after an attack to maintain normal brain function. The researchers also discovered new mechanisms, which can help explain what changes in the brain before a migraine attack starts.

– We have known for hundreds of years that there is a connection between sleep and migraines. Many people find that either too little or too much sleep can

increase the risk of developing a migraine attack. Some people also experience sleep changes before a seizure and an increased need for sleep during a seizure. For some, sleep can also help to interrupt the attack itself. Despite the fact that these factors are well known, people have not yet understood why this connection occurs or been able to use this information to understand more about the mechanisms that cause migraines, says first author Martin Syvertsen Mykland, doctor and researcher at the Department of neuromedicine and movement science at NTNU.

Sleep reduction during seizures
The researchers have found that certain inhibitory mechanisms in the brain that are controlled by GABA-B receptors change gradually until a migraine attack. These inhibitory mechanisms change differently in response to reduced sleep both between seizures and gradually until seizure onset.

– The degree of changes after sleep and between seizures also corresponds to the degree to which one experiences increased sensitivity to light, sound and smell during seizures, and dopamine-controlled symptoms before seizures such as increased yawning. This has given us indications of how certain deep structures in the brain help to initiate the development of a seizure and to change how inhibitory systems in the cerebral cortex work, says Martin Syvertsen Mykland.
These systems also responded differently to reduced sleep depending on whether one usually has migraine attacks in connection with sleep or not. This may indicate that these two phenotypes of migraine represent different subgroups with somewhat different pathophysiology. Furthermore, the researchers want to find out if this means that sleep-related subgroups should be treated differently.

– We have also seen that when you sleep half as much during a migraine attack, you get reduced brain function compared to a corresponding reduction in sleep outside of an attack. This reduced brain function is similar to what healthy people get from one day of total sleep deprivation. This indicates that the migraine brain becomes more vulnerable to lack of sleep during attacks and can help to show which mechanisms explain the experience of an increased need for sleep that many people with migraine themselves describe during attacks, says Martin Syvertsen Mykland.
The results may indicate that there are better grounds for recommending sleep during migraine attacks for them, where this is possible. The researchers also believe that one should further explore subgroups of migraine with different distribution of attacks related to sleep and whether these should be handled in different ways.

– At the same time, we will use the results for further investigations with the aim of uncovering more detailed mechanisms that can be used for diagnostics and targeted treatment of migraines, says Martin Syvertsen Mykland.

Sleep resets the brain after a seizure
Marte-Helene Bjørk, senior physician at Haukeland University Hospital and professor at the University of Bergen, is co-author of one study. She says that many migraine patients find that sleep is linked to their migraines.
– Some have discovered that too little or too much sleep causes them to have seizures. Some treat their attacks by sleeping, which is particularly common for children with migraines. It is common to feel tired both before and after a migraine attack, and some people notice that they yawn more right before an attack, she says.

However, it has been unknown which functions and structures in the brain explain the connection between migraine and sleep. This study has, in a very systematic way, investigated brain function before and after a migraine attack in patients with and without sleep-related migraine, as well as after normal and too little sleep.

– The study finds neurophysiological findings that support that there is a pathophysiological connection between migraine and sleep. Several of the articles from this project point to the fact that sleep is particularly important for restoring brain function after a migraine attack, Marte-Helene Bjørk.
The authors point to dysfunction in the regulation of the hypothalamus as a possible cause.

– The study has to some extent changed my practice towards migraine patients, as I am more careful about going through the connection between migraine and sleep with them. I remind them that it is important to have a regular circadian rhythm to prevent attacks, and that some people with migraines need more sleep than others, says Marte-Helene Bjørk.

Some people are in a hurry in their everyday life, and with a migraine attack they take painkillers and continue with everything they have to do without resting or sleeping. Some people find that they cannot get the seizure to go away completely, or that the seizure comes back again. This study finds evidence that it is important to sleep in order to reset the brain after a seizure.

The article was written by Marit Aaby Vebenstad and first published in Migrene/hodepine March 21, 2023.