Tonic Clonic

These used to be known as 'grand mal' seizures. The seizure usually starts with a cry and a loss of consciousness with the person falling to the ground. A ‘tonic’ or stiff phase then leads to a 'clonic' or twitching phase. Finally there may be confusion, often followed by sleep. In addition to the very obvious convulsive movements, an observer may see the lips turn blue and if the tongue has been bitten blood may trickle from the mouth with frothy saliva. It is possible, but by no means always the case, that the person could be incontinent of urine or in rare cases, doubly incontinent.

Tonic

These seizures are quite dramatic. The muscles stiffen and, if standing up, the person will fall heavily to the floor, often receiving injury to the head. There is no jerking.

Tonic Seizure

In these seizures the muscles contract and relax continuously causing the person having the seizure to twitch and jerk repeatedly.

Myoclonic Clonic

'Myo' means muscle and 'clonic' means jerk. When myoclonic seizures occur the muscles jerk rather as if the person has had some sort of electric shock.

Myoclonic_Clonic

Seizures usually occur shortly after waking or before retiring to bed when the person is tired. There is a loss of consciousness but it is hardly noticeable because the period is so brief.

Atonic Clonic

The muscle tone is lost causing the person to flop and fall to the ground. Sometimes referred to as 'Drop Attacks' or astatic seizures, these can also be quite dramatic. The person falls heavily to the ground and although recovery is swift the result is often head or facial injury.

Partial Seizure

These relatively rare seizures are usually confined to children and are sometimes referred to as 'petit mal'. They occur suddenly, provoking a brief trance-like state. Affected children stare blankly into space and their failure to respond when they are spoken to often results in them getting told off in school for not paying attention.

Simple Partial Seizure

During a simple partial seizure, the person remains conscious and aware of what is happening, however they cannot necessarily control their feelings/actions. The effects of a simple partial seizure vary depending on the part of the brain affected. For example:

Temporal Lobe – the individual may experience flashbacks, déjà vu feelings, extreme emotions or unpleasant tastes/smells. Often this type of seizure acts as an aura for the person to warn of another seizure to follow.

Frontal Lobe – the person may experience a change in muscle activity. This could mean a sudden stiffening of the body or merely a twitching finger. It could also mean a weakening of the muscles, bringing about a lack of coordination or a slurring of the speech. This alteration in muscular activity may or may not spread elsewhere in the body.

Parietal Lobe – this area of the brain controls sensation. The person might experience a tingling or warm sensation along one limb for example.

Occipital Lobe – the individual will experience visual disturbances such as flashing lights or colour changes for example.

Secondarily Generalised Seizure

As mentioned above, partial seizures originate in a specific area of the brain. It is possible that the localised electrical activity which triggers a partial seizure can spread to the whole of the brain. This is known as secondary generalisation, resulting in a tonic clonic seizure.

Complex Partial Seizure

A complex partial seizure involves an alteration in consciousness. The person may not remember the seizure or if they do their memory of it will be distorted. These seizures can be characterised by behavioural changes such as lip smacking, walking around in circles and repetitive behaviour. The person may experience intense fear or laugh uncontrollably; they may encounter visual hallucinations, déjà vu or unpleasant smells or tastes. The symptoms of complex partial seizures can vary massively from person to person.

Complex partial seizures usually last for up to two minutes.

Non-Epileptic Seizures

Epileptic seizures are caused by changes in brain activity. Non-epileptic seizures resemble epileptic seizures but are not caused by abnormalities in brain activity. Non-epileptic seizures can be caused by factors such as changes in blood pressure, chemical imbalances, fluid imbalances or psychological issues.

Non-epileptic seizures are diagnosed by ruling out the possibility of epileptic seizures. EEG tests, blood tests and scans may be performed, as they are in diagnosing epileptic seizures. If a diagnosis of non-epileptic seizures is made, there is no need for anti-epileptic medication. However medication may be required for the underlying cause of the seizure.

Psychological causes of seizures may include panic attacks, anxiety or trauma. If a person’s non-epileptic seizures are caused by psychological factors, the person may be seen by a psychologist or psychiatrist to discuss their past and ways of dealing with stressful situations as a means of reducing the incidence of seizures.

Focal Sensory Seizure

These seizures originate in the parietal lobes of the brain, producing physical sensations such as tingling or unnatural warmth. If the seizure is in the right parietal lobe of the brain it will produce a tingling or warmth on the left hand side of the body and vice versa.

Focal Motor Seizure

These cause movement of the limbs, head or neck and they originate in the frontal lobes of the brain. If the seizure is in the right frontal lobe then the seizure movement is produced on the left hand side of the body and vice versa. Seizures originating in the frontal lobe can also involve an interruption in speech.

Status Epilepticus

The term status epilepticus refers to a prolonged seizure or series of seizures without the person regaining consciousness or fully recovering. Status epilepticus is a medical emergency as there is a significant risk of death.

There is a misconception that status epilepticus only occurs in tonic clonic seizures, the truth is that although tonic clonic status epilepticus is most dangerous, and most frequent, status epilepticus can occur with any seizure type.

The longer status epilepticus continues, the greater the risk of permanent brain damage in the individual. An intravenous dose of Diazepam is normally administered by a doctor, sometimes an alternative drug will be used. Rectal diazepam can also be used in the even of status epilepticus. Patients who are susceptible to status epilepticus instances are often prescribed the drug for use in the event of an episode. This does not need to be administered by a medical professional but the person should be competent at doing so.

Once the seizure activity is under control, the medical team’s attention will be directed at treating the underlying cause. A significant number of status epilepticus episodes are caused by non compliance with medications and alcohol use. However, other causes include infection, trauma and metabolic disorders. Sometimes the cause is unknown.

There are many different types of seizures, and only some involve losing consciousness. Some seizures, known as generalised seizures, affect the whole brain, while others, called partial seizures, affect only part of the brain.

The most commonly known seizures are listed below:

To say that a person is photosensitive means that their seizures are triggered by certain types of lights. There are many different variations of this which can include:

Computer screens

Television screens

Strobe lighting

Flashing lights or TV/computer effects

Certain high contrast colour schemes

Not all people with epilepsy are photosensitive; in fact it only occurs in the minority.

Photosensitivity

Lennox-Gestaut Syndrome

This is not a common form of epilepsy but is serious. It is characterised by difficult to control generalised seizures, typically atonic, tonic and atypical absence. The seizures usually begin between the ages of two and six and these children tend to have associated personality difficulties and some learning difficulties. Status epilepticus is common in children with Lennox-Gestaut, with some children having prolonged non-convulsive seizures which can be difficult to recognise. Sometimes better seizure control is gained as the child grows and in this case it is possible for the child to gain intellectual capabilities approaching normal.

Benign Rolandic Syndrome

This tends begin in children aged six to eight years old and seizures tend to have stopped by the age of fifteen. Benign Rolandic Syndrome is characterised by twitching, numbness or tingling of the child’s face or tongue. This can interfere with speech or cause salivation and will last no more than two minutes. It is a form of partial seizure. Tonic clonic seizures may also occur but not often.

Childhood Absence Epilepsy

Childhood Absence Epilepsy is characterised by the child having absence seizures. Tonic clonic seizures may also occur infrequently. Age of onset tends to be between four and eight years of age. It is treatable with medication and children frequently outgrow it by the age of fifteen. The cause is usually genetic with children having a family member who has experienced similar seizures.

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Sudden Unexpected Death in Epilepsy (SUDEP)

SUDEP is an unexpected, non-traumatic and non drowning death in a person with epilepsy whether there has been evidence of a seizure or not, this excludes status epilepticus and post mortem evidence of anatomical or toxicological causes of death.

Statistics suggest that individuals with epilepsy have a 2-3 times higher risk of premature death. If an individual with epilepsy dies prematurely, their death is normally epilepsy related. According to the National Institute of Clinical Excellence (2002) each year in the UK alone, 1000 deaths can be attributed to epilepsy, mostly seizure related. However Epilepsy Action (2005) cites this figure at around 500. There are currently thought to be 456,000 people in the UK with epilepsy. Although SUDEP is relatively rare, awareness of it is important.

The risk of SUDEP in people with epilepsy varies according to the severity of their epilepsy. For example generally a person with epilepsy holds a 1 in 1000 risk of SUDEP a year compared to a person with severe seizures whose risk would increase to 1 in 100-300 (Epilepsy Bereaved, 2006).

Risk factors include:

Generalised tonic clonic seizures

Uncontrolled seizures

Young adults

Nocturnal seizures

Unwitnessed seizures

Excessive alcohol use

Brain damage

Irregular taking of medications

It is thought that the person’s death is caused by alterations to the heart rhythm and breathing during a seizure. Seizures can change the heart beat, due to electrical activity affecting the part of the brain which controls the heart, which can potentially cause a cardiac event. People who have seizures can also stop breathing for a significant time, although normally they recover, it is thought that SUDEP could be caused by respiration not restarting.

People with JME have myoclonic jerks, usually upon waking which sometimes result in tonic clonic seizures. Absences are sometimes also experienced. JME is the most common epilepsy syndrome. Many people with JME are photosensitive. Other potential triggers include decision making and calculations.

Juvenile Myoclonic Epilepsy (JME)