Are there links between epilepsy and sleep?
The links between epilepsy and sleep are very complex. During sleep the brain is active, processing information to help us learn. Brain activity changes during the different stages of sleep.
Different stages of sleep
Sleep happens in an alternating pattern, over periods of about 90 minutes and is divided into two categories.
- non-rapid eye movement (NREM), light and deep sleep split into stages
- rapid eye movement (REM) sleep
Non-rapid eye movement sleep
- Stage one lasts about 10 minutes. Our muscles start to relax, we are half awake and half asleep and can easily be woken up.
- Stage two lasts about 20 minutes. Our heart rate and breathing slows down and seizures can be more likely to happen for some people with epilepsy as we go from this stage to stage three, deep sleep.
- Stage three is deep sleep (sometimes called slow-wave sleep). Our breathing and heart rate slows and our brain begins to produce ‘delta waves’, a type of brainwave associated with deep sleep. Delta waves increase as sleep gets deeper and it is difficult to be woken. If we are woken during this stage we will often be confused. Sleep walking and night terrors are more likely to happen during deep sleep than during light sleep.
Scientists believe that NREM sleep is important for strengthening connections between our brain cells and stabilising long-term memories. Deep sleep also helps the brain to recover from the day's events so that it can function well the next day.
Rapid eye movement sleep
The next stage of deep sleep is when most dreaming occurs. During REM sleep the brain tries to organise the information we have received throughout the day.
The purpose of REM sleep and dreaming is unclear. However some theories suggest it may be important for making sense of our thoughts, ideas and experiences, and the emotions and memories attached to them.
A lack of sleep can affect our memories and judgement. It can also affect our mood and how well our immune system works.
Are there links between seizures and sleep?
Some people have specific triggers for their seizures, for example a lack of sleep. In some types of epilepsy seizures can happen as someone is waking up and within the next few hours. People with epilepsy may have an irregular sleep pattern, as seizures at any time of the night can disrupt sleep and seizures during the day can affect the next night’s sleep. For some people the effects of having a seizure can upset their sleep pattern for several days afterwards.