Epilepsy is a disorder in which you have recurring seizures. Normally, nerve cells in the brain transmit electrical and chemical signals to other nerve cells, glands, and muscles. Seizures happen when too many of these nerve cells, or neurons, fire electrical signals at the same time at a much faster rate than they normally would. Usually, a seizure lasts a few seconds to several minutes. In some cases, they can last longer.

Not all seizures occur due to epilepsy. According to the Mayo Clinic, a person would usually have to have at least two unprovoked seizures for their doctor to diagnose them with epilepsy. An unprovoked seizure is one that happens without a clear cause.

Signs of a seizure can be subtle or dramatic. The affected person could:

  • simply stare at nothing for a few seconds
  • lose consciousness
  • exhibit strange behavior, such as saying nonsense
  • stiffen, shake, or have violent, jerking movements

Although they can vary widely, specific symptoms are often associated with specific kinds of seizures. An episode can start out as a simpler form of seizure, but it can become another type of seizure with more widespread or powerful effects.

The type of seizure depends on which part and how much of the brain is affected. The two main categories of epileptic seizures that exist are partial and generalized. Multiple types of seizures are in each category.

Also called a focal or local seizure, partial seizures result from abnormal activity in one part of the brain. The two kinds of partial seizures are simple partial seizures and complex partial seizures.

Simple partial seizures

People don’t usually lose consciousness with simple partial seizures, but other symptoms depend on what the malfunctioning part of the brain controls. These seizures usually last less than 2 minutes.

The symptoms may include:

  • twitching or stiffening of individual body parts, such as an arm or leg
  • a sudden change in emotions for no apparent reason
  • difficulty speaking or understanding speech
  • feelings of deja vu, or repeating an experience
  • unpleasant sensations, such as a rising feeling in the stomach, changes in heart rate, or goose bumps
  • hearing, smelling, tasting, or feeling things that aren’t there, or sensory hallucinations, such as flashing lights, tingling sensations, or thinking sounds are muffled when they’re clear

Complex partial seizures

The symptoms of complex partial seizures depend on which part of the brain the seizures affect. These seizures affect a larger region of the brain than simple partial seizures. These seizures cause a change in consciousness or awareness, which can include a loss of consciousness. These seizures usually last about 1 to 2 minutes.

The signs and symptoms of complex partial seizures may include:

  • an aura, or an unusual sensation that warns of the seizure
  • staring off at nothing
  • performing odd, meaningless behaviors that often repeat, or automatisms, which can include fumbling with clothes, walking in circles, and making chewing motions
  • word repetition, screaming, laughing, or crying, which are less common

After the seizure, the person may be disoriented or not remember what happened immediately before or after the seizure.

A person may start having a simple partial seizure that develops into a complex partial seizure. It may then develop into a generalized seizure.

Generalized seizures seem to involve all parts of the brain. Six kinds of generalized seizures exist. They include the following:

Tonic seizures

Tonic seizures are named for the way they affect muscle tone. These seizures cause muscles to stiffen. They most often affect muscles in the back, arms, and legs but don’t usually cause a loss of consciousness. Most often, tonic seizures occur during sleep and last less than 20 seconds. If a person is standing when they have a tonic seizure, they’ll likely fall.

Clonic seizures

These seizures are rare and involve the rapid contraction and relaxation of muscles. This leads to a rhythmic, jerking movement, most often in the neck, face, or arms. This movement cannot be stopped by holding down the affected body parts. These aren’t the same as tonic-clonic seizures, which are more common. Tonic-clonic seizures begin with muscle stiffening, which happens in tonic seizures, that’s followed by jerking movements, which happens in clonic seizures.

Tonic-clonic seizures

This type is also known as the grand mal seizure, from the French term for “great illness.” It’s this type of seizure that most people envision when they think of seizures. These seizures usually last 1 to 3 minutes. A tonic-clonic seizure that lasts more than 5 minutes is a medical emergency.

The initial warning sign of a tonic-clonic seizure may be a grunt or other sound due to muscles stiffening and forcing out air. The first phase is the tonic phase. In this phase, the person will lose consciousness and fall to the floor if they’re standing. Their body will then begin to convulse or move violently. This is known as the clonic phase. During the seizure, the twitching will appear rhythmic, as with clonic seizures.

During tonic-clonic seizures, the following may occur:

  • A person may bite their own tongue, resulting in bleeding from the mouth.
  • They may be unable to control secretions, leading to increased salivation, or foaming at the mouth.
  • a loss of bowel control or bladder function
  • They may become injured from the convulsions or from their body striking objects during the seizure.
  • They may also turn slightly blue.

A person who’s had a tonic-clonic seizure is often sore and tired afterward and has little or no memory of the experience.

The grand mal seizure can occur due to a more limited type of seizure, such as partial seizure, that’s worsening. This is called a secondary generalized seizure. The electrical misfire starts in a specific area of the brain, but the malfunction moves into larger areas of the brain. This can happen swiftly or slowly.

Read more: Seizure first aid: How to respond when someone has an episode »

Atonic seizures

Also known as astatic seizures or drop attacks, these seizures involve a brief loss of consciousness. These are called “atonic” because they involve a loss of muscle tone and, therefore, a loss of muscle strength. These seizures usually last less than 15 seconds.

A person experiencing an atonic seizure while sitting may only nod their head or slump over. If standing, they’ll fall to the ground. If their body is stiff when they fall, it’s likely a tonic seizure rather than an atonic seizure. Once an atonic seizure is over, the person is usually unaware of what happened. People who have atonic seizures may choose to wear a helmet, as these seizures often result in injury.

Myoclonic seizures

These seizures usually feature rapid jerking of specific portions of the body. They can feel like jumps inside the body and usually affect the arms, legs, and upper body. People without epilepsy can feel these types of jerks or twitches, especially when falling asleep or when waking in the morning. Hiccups are another example of what myoclonic seizures feel like. In people with epilepsy, these seizures often cause body parts on both sides of the body to move at the same time. These seizures usually last only a couple seconds and don’t cause a loss of consciousness.

Myoclonic seizures may be part of several different epilepsy syndromes, including:

  • juvenile myoclonic epilepsy
  • Lennox-Gastaut syndrome
  • progressive myoclonic epilepsy

Absence seizures

Also known as petit mal seizures, absence seizures occur more often in children. They usually include a brief loss of awareness in which the person stops what they’re doing, stares off into space, and becomes unresponsive. This can be confused with daydreaming.

If a child has complex absence seizures, they’ll also make some kind of muscle movements. These can include rapid blinking, chewing, or hand movements. Complex absence seizures can last up to 20 seconds. Absence seizures without muscle movement, called simple absence seizures, usually last less than 10 seconds.

Although they only last seconds, absence seizure can happen numerous times in one day. The possibility of absence seizures should be considered in kids who seem to space out or who have difficulty paying attention.