Epilepsy

Epilepsy is a chronic neurological condition characterized by recurrent unprovoked seizures. The condition is named from the Greek epilepsia ("a taking hold of or seizing"), and has in the past been associated with religious experiences and even demonic possession. Many neurologists prefer the less stigmatized term seizure disorder as a description of the condition.

Table of contents

1 Type of Epileptic Seizure 2 Causes 3 Treatment 4 Controversy 5 Famous People with Epilepsy 6 See also 7 External links

Type of Epileptic Seizure

Epileptic seizures are classified both by their patterns of activity in the brain and their effects on behaviour.

In terms of their pattern of activity, seizures may be described as either partial or generalised. Partial seizures only involve a localised part of the brain, whereas generalised seizures involve the whole of the cortex. The term 'secondary generalisation' may be used to describe a partial seizure that later spreads to the whole of the cortex and becomes generalised.

Partial seizures may be further subdivided into simple and complex seizures. This refers to the effect of such a seizure on consciousness; simple seizures cause no interuption to consciousness (although they may cause sensory distortions or other sensations) whereas complex seizures interupt conscious experience. This does not necessarily mean that the person experiencing this sort of seizure will fall unconcious (like a faint). For example, complex partial seizures may involve the unconscious repetition of simple actions, gestures or verbal utterances.

The effects of partial seizures can be quite dependent on the area of the brain in which they are active. For example, a partial seizure in areas involved in perception may cause a particular sensory experience (for example, the perception of a scent, music or flashes of light) whereas when centred in the motor cortex a partial seizure might cause movement in particular groups of muscles. This type of seizure may also produce particular thoughts or internal visual images or even experiences which may be distinct but not easily described. Seizures centred on the temporal lobes are known to produce mystical or ecstatic experiences in some people.

When these effects appear as a 'warning sign' before a more serious seizure they are known as an aura and may be the result of a partial seizure which later becomes generalised.

Generalised seizures can be sub-classified into a number of categories, depending on their behavioural effects:

• Absence seizures (sometimes referred to as petit mal seizures) involve an interruption to consciousness where the person experiencing the seizure seems to become vacant and unresponsive for a short period of time (usually upto 30 seconds). Slight muscle twitching may occur.
• Tonic-clonic seizures (sometimes referred to as grand mal seizures), involve an initial contraction of the muscles (tonic phase) which may involve tongue biting, urinary incontinence and the absence of breathing. This is followed by rhythmic muscle contractions (clonic phase). This type of seizure is usually what is referred to when the term 'epileptic fit' is used colloquially.
• Myclonic seizures involve sporadic muscle contraction and can result in jerky movements of muscles or muscle groups.
• Atonic seizures involve the loss of muscle tone, causing the person to fall to the ground. These are somtimes called 'drop attacks' but should be distinguished from similar looking attacks that may occur in narcolepsy or cataplexy.
• Status epilepticus refers to continuous seizure activity with no recovery between successive tonic-clonic seizures. This is a life threatening condition and emergency medical assitance should be called immediately if this is suspected. A tonic-clonic seizure lasting longer than 5 minutes (or two minutes longer than is usual in a person with epilepsy) is usually considered grounds for calling the emergency services.

Causes

Seizures can result from a number of unrelated conditions, including residual scarring from stroke, toxicity, electrolyte imbalances, brain diseases and head trauma. Generalized tonic/clonic seizures may occur in any person under certain circumstances, including fevers and drug overdoses, but these patients are not typically classified as epileptics. Epilepsy connotes that an individual has seizures which recur over time in an unpredictable fashion. In 70% of all cases, there is no definable cause for epilepsy. It can occur in anyone at any age with no apparent etiological basis. In the other 30% of cases, an injury or disease of the brain is present, and the abnormal electrical activity can be traced to this region.

The most common ages of onset for epilepsy are for those under the age of 18 and those over the age of 65. About 4% of the population has some form of epilepsy.

A small but detectable decline in cognitive function is known to be associated with epilepsy although it has not been entirely clear to what extent this is due to the epilepsy itself or to the drugs used to treat it. Newer anti-epileptic drugs are considered to have less cognitive effects than older drugs. On an individual level, a person's reaction to epileptic seizures and / or anti-epileptic drugs may be idiosyncratic so it is difficult to predict how a particular person might be affected. However, except in rare cases, cognitive impairment is not considered a major feature of epilepsy.

Treatment

Epilepsy is often treated with medication, Neurocybernetic Prostheses (similar to a heart pacemaker) and occasionally via surgery or specialized diet. In most cases, the proper emergency response to a Generalized Tonic/Clonic epileptic seizure is simply to prevent the patient from injuring themselves, by moving him or her away from sharp edges, placing something soft beneath the head, and carefully moving them onto their side to avoid asphyxiation. If the seizure lasts longer than 3-4 minutes, contact Emergency Medical Services immediately, as this may indicate the presence of Status Epilepticus, a potentially fatal condition. One should never place any object in a person's mouth during a seizure as this could result in injury to the victim's mouth. It is not possible (despite folklore to the contrary) for a person to swallow the tongue during a seizure.

Various drugs have been discovered that serve to control or limit seizures, including carbamazepine (brand name Tegretol), oxcarbazepine (Trileptal), clonazepam (Klonopin), ethosuximide (Zarontin), felbamate (Felbatol), fosphenytoin (Cerebyx), gabapentin (Neurontin), lamotrigine (Lamictal), phenobarbital (Luminal), phenytoin (Dilantin), primidone (Mysoline), tiagabine (Gabitril), topiramate (Topamax), valproate, sodium divalproex (Depakene, Depakote) and vigabatrin (Sabril).

Ketogenic diets have also been found to be effective in controlling some types of epilepsy, although the mechanism behind the effect is not fully understood. Ketogenic diets are high in fat and extremely low in carbohydrates, with intake of fluids often limited. This treatment, originated as early as the 1920s, was largely abandoned with the discovery of modern anti-epileptic drugs, but has enjoyed a return to popularity in recent times. Ketogenic diets are sometimes prescribed in severe cases where drugs have proven ineffective.

Controversy

There has been some controversy – although very little – over the standards for diagnosis for partial-complex seizures and how these standards are applied in practice, both among some surrealists and in particular as regards Mary Baker Eddy, founder of Christian Science.

In April 2003, the BBC TV science programme "Horizon" featured discussion of research by American neurologist Gregory Holmes indicating that Ellen G. White, spiritual founder of the Seventh-day Adventist Church, may have suffered from temporal lobe epilepsy triggered by a head injury at age nine – the epilepsy supposedly being responsible for her powerful religious visions.

There has also been serious speculation that science fiction author Philip K. Dick suffered from similar seizures; he experienced visions on several occations, that, among other effects, reportedly helped him save his infant son from an undiagnosed life-threatening medical condition.

Famous People with Epilepsy

• Ian Curtis of Joy Division
• Julius Caesar
• Napoleon Bonaparte
• Alexander the Great
• Mohammed
• George Gordon Byron, 6th Baron Byron
• Fyodor Dostoevsky
• Vincent van Gogh
• Danny Glover
• Edward Lear
• Abraham Lincoln

See also

• seizure
• Jacksonian seizure

External links

• What to do when someone has a seizure - Information from Epilepsy Action
• Non-profit Epilepsy organization website
• God on the Brain, from BBC's "Horizon"
• The Epilepsy Foundation, a non profit organization to help peaple learn, understand, and live with epilepsy.