During a seizure, some brain cells send abnormal signals, which stop other cells from working properly. This abnormality may cause temporary changes in sensation, behavior, movement or consciousness. The onset of epilepsy is most common during childhood and after the age of 65, but the condition can occur at any age. Some people with epilepsy have seizures only when they are awake, some while asleep and some people have a mixture of both. There are over two million people in the U.S. with diagnosed epilepsy. Although it is relatively common, the disease is widely misunderstood.
Possible causes of epilepsy
Not all the causes of epilepsy are known, but many predisposing factors have been identified, including:
- brain damage resulting from malformations during brain development,
- head trauma,
- neurosurgical operations,
- penetrating wounds of the brain,
- brain tumor, high fever,
- bacterial or viral encephalitis,
- stroke,
- intoxication,
- acute or inborn disturbances of metabolism,
- chemical disturbances of the brain - drugs or poisons or organs that don't work properly.
- an inherited tendency to seizures.
- sleep loss.
- sudden stopping of drugs
Hereditary or genetic factors also play a role - mutations in several genes have been linked to some types of epilepsy. Some genes that code for protein subunits of voltage-gated and ligand-gated ion channels have been associated with forms of generalized epilepsy and infantile seizure syndromes.
Incidence
The most common ages of incidence are under the age of 18 and over the age of 65. It has been estimated that about 1% of the population meets the diagnostic criteria for epilepsy at any given time, but some theorize that the prevalence might in fact be much higher.
What provokes the seizure usually?
Some people with epilepsy have certain triggers that will undoubtedly produce a seizure.
If the trigger is considered to be part of the daily life and yet it causes a seizure, the seizures are considered as unprovoked. Examples of these normal provocants include:
- reading,
- hot water on the head,
- hyperventilation and
- flashing or flickering lights.
Types of seizures
Seizures may be described as
- partial (focal) - only involve a localized part of the brain
- generalized - involve the entire cortex.
The term secondary generalization is used to describe a partial seizure that later spreads to the whole of the cortex and becomes generalized.
Partial seizures
These seizures may further be subdivided into:
- Simple seizures - Simple seizures cause no interruption to consciousness, although they may cause sensory distortions or other sensations.
- Complex seizures - These seizures interrupt consciousness to varying degrees, although this does not necessarily mean that the person experiencing this sort of seizure will fall unconscious.
The effects of partial seizures can be quite dependent on the area of the brain which they are affected. Some of the most common effects are:
- particular sensory experience,
- movement in particular groups of muscles,
- particular thoughts or internal visual images
- mystical or ecstatic experiences
When the effects of a partial seizure appear as a 'warning sign' before a more serious seizure, they are known as an aura.
Generalized seizures
Generalized seizures can be sub-classified into a number of categories
- Absence seizures – This type of seizure involves an interruption to consciousness where the person that is experiencing the seizure seems to become vacant and unresponsive for a short period of time
- Tonic-clonic seizures – This type of seizure involves an initial contraction of the muscles which may involve
- tongue biting,
- urinary incontinence and
- the absence of breathing,
- rhythmic muscle contractions.
- Myoclonic seizures involve sporadic muscle contraction and can result in spontaneous and quick movements of muscles or muscle groups.
- Atonic seizures involve the loss of muscle tone, causing the person to fall to the ground. These are sometimes called 'drop attacks' but should be distinguished from similar looking attacks that may occur in narcolepsy or cataplexy.
Epilepsy syndromes
Febrile seizures
Convulsion triggered by a high fever that occurs in young children.
Benign rolandic epilepsy
It characterized by seizures that begin as partial and then progress to tonic-clonic convulsions.
Absence epilepsy
It characterized with momentary lapses of consciousness, often accompanied by jerking arms, lip-smacking and rapidly blinking eyes.
Juvenile myoclonic epilepsy
It is characterized by seizures involving sudden jerking of the arms and legs.
Infantile spasms
This syndrome usually involves seizures in which a baby twiches its arms forward. Babies usually cry after a spasm, and this condition is often mistaken for colic.
Lennox-Gastaut syndrome
Patient with this type of epilepsy syndrome has a severe epilepsy involving several different types of seizures. Atonic seizures are common.
Reflex epilepsies
These seizures are triggered by certain stimuli, most often intense, flickering or flashing light. That’s why this type is also called photosensitive epilepsy.
Sleep and epilepsy
To understand the interactions between sleep and epilepsy, it is important to view the timing of seizures during the circadian sleep-wake cycle, that is, whether the seizures tend to occur during the day (diurnal), during the night (nocturnal) or during the day and the night (random).
Sleep-related epilepsy occurs in a minority of epilepsy patients, anywhere from 10 to 25 percent, although because the patient is asleep, seizure activity is difficult to recognize. The patient may feel tired and fatigued during the day and not know why. Or the physician may recognize a pattern of sleep deprivation symptoms occurring over weeks or months.
Latest researches are indicating that seizure occurrence does seem to have some relation to sleep. The fact is also that several kinds of seizures occur more while asleep than when awake, while others occur with the awakening process. All seizures are said to be uncommon during the REM stage of sleep.
Anyway, there is no doubt that there is a great correlation between epilepsy and sleep. This is mostly because seizures are often precipitated or triggered by the loss of sleep. Seizures can be precipitated in epileptic patients and also in some people, who do not have seizures but have an inherited tendency to seizures.
Sleeping much less than usual is a fairly common trigger for seizures and should be avoided by patients with seizures or a tendency to seizures wherever possible.
Mechanism
The exact mechanism is not understood well. The sleep-wake cycle is associated with prominent changes in brain electrical activity and hormonal activity, so seizures and the sleep-wake cycle are often clearly related. There are also some changes related to the stage of sleep. Some people with epilepsy have all of their seizures while sleeping and others have most of their seizures just as they are falling asleep or just after waking up.
Diagnosis of epilepsy related to sleep
It is known that this type of epilepsy can be very difficult to diagnose but there are a few techniques physicians and patients can use to diagnose the sleep-related epilepsy. The initial step in diagnosing seizures that are associated with sleep is in the doctor's office.
Patient’s history - The person experiencing the seizures will explain a pattern of seizures that may occur, but medical testing can help confirm this.
Video EEG monitoring, which combines video and brainwave testing and captures the person's seizures during sleep, is very helpful not only in establishing the diagnosis, but also in really focusing on the kind of seizure that the person is experiencing during sleep.
There are very specific kinds of epilepsy where the seizures are more likely to occur while the person is sleeping. For this reason, it is helpful for doctors to have as much information as possible from eye witnesses about the seizure symptoms and times they occur.
Differential diagnosis
There are a number of different conditions that can be confused with sleep seizures. These include:
- sleep walking,
- sleep terrors,
- bed-wetting,
- restless-leg syndrome,
- sleep apnea and
- narcolepsy
READ Epilepsy/Seizures: What to do when someone has a seizure?
Treatment
The usual way to treat epilepsy is with the anti-epileptic drugs which are being used to prevent seizures by controlingl the excitability in the brain. Patients usually need to take these medications at regular intervals throughout the day, to make sure that there is a steady supply in their blood stream.
Anti-seizure (anticonvulsant) medications include: phenytoin (Dilantin®, Phenytek®), carbamazepine (Carbatrol®, Tegretol®), valproic acid (Depakene®), Divalproex (Depakote®), levetiracetam (Keppra®), gabapentin (Neurontin®), Phenobarbital, ethosuximide (Zarontin®), clonazepam (Klonopin®), primidone (Mysoline®), oxcarbazepine (Trileptal®), lamotrigine (Lamictal®), topiramate (Topamax®), felbamate (Felbatol®), tiagabine (Gabitril®) and zonisamide (Zonegran®).
Strategies for getting a good night's sleep
- Make sure your sleeping environment is quiet and dark.
- Go to bed at least half an hour before trying to fall asleep.
- Read in bed instead of watching television (unless reading a good novel keeps you awake and TV puts you to sleep).
- Avoid caffeine for at least 6 hours before bedtime.
- Have no more than one alcoholic beverage a day.
- Exercise daily but do not exercise within a few hours before going to bed