Types of Epileptic Seizures – Epileptic Aura
Generalized vs. Focal Seizures – Epileptic Seizures Classification – Tonic – Clonic – Myoclonic – Atonic Seizures – Automatisms
Types of Epileptic Seizures
Epileptic seizures are classified based on their appearance, association with loss of consciousness, and presence of other associated symptoms.
Each particular epileptic syndrome has characteristic types of seizures.
Please don’t confuse a seizure type with an epilepsy type. Epilepsy is a disease that presents with seizures. Seizures are symptoms of epilepsy and there are different symptoms, or different seizures.
Simple and Unnatural Movements
Myoclonus is an involuntary sudden, brief, jerky, irregular movement. It can involve the whole body or a body part. Myoclonus can be single or come in series. The closest normal phenomenon is nocturnal myoclonus, which commonly occurs upon falling asleep. Sleep associated myoclonus is almost always normal. Myoclonus in awake state is almost always is not.
Clonic seizures are repetitive, more prolonged muscle contractions in the same muscle group. A typical frequency of contractions is about 1 to 3 per second.
Tonic seizures are prolonged stiffening of muscles that may last from seconds to minutes.
Tonic-clonic seizures, also known as grand mal seizures, characterized by an abrupt loss of consciousness followed by tonic muscle contractions. Air is forced out of the lungs leading to an “ictal cry”. Forceful mouth closure causes a tongue bite (usually on the side). Pupils are dilated and eyes roll up. Arms are flexed and legs extended with pointing toes. Clonic movements follow. Gasping respirations are produced by clonic contractions of the chest muscles. Urine incontinence may occur. Brief postictal unconsciousness is followed by confusion for at least a few minutes. Generalized body-ache is frequently reported after grand mal seizure.
Versive seizure is a prolonged forced turn of the head, eyes and sometimes the body to the side. Versive seizures are generated in the frontal lobe on the opposite side. “Fencing” position with head turned to the extended arm and the opposite arm elevated to the head level and flexed is not uncommon.
Spasm is a sudden posturing with head, trunk, and limbs flexed or extended for a few seconds. This posturing is often symmetrical and sometimes involves only the head. Spasm is a classical feature of West Syndrome.
Seizures with Lack of Movements or Loss of Muscle Tone
Absence seizure is characterized by sudden behavioral arrest, blank stare, unresponsiveness, and sometimes brief upward rotation of the eyes. It lasts for a few seconds and does not produce any confusion. Interrupted activity continues normally after the attack is over. This type of absence is called a simple absence. Simple absence seizures are typically provoked by hyperventilation and flickering light.
Association of absence seizure with myoclonus, loss of postural tone, lip smacking, grimacing, hands fumbling, aimless walking, or other automatic behavior is referred to as complex absence.
Atonic seizures present by sudden loss of muscle tone. Loss of tone may involve head, limb, or the whole body. A whole body muscle tone loss leads to so called drop attack. Face injuries are common in drop attacks. Atonic seizures last less than 5 seconds and are typically followed by brief confusion.
Negative myoclonus is brief (less than 1/2 a second) loss of muscle tone in the whole body or a body part.
Akinetic seizures are events of inability to start or continue movements in spite of normal level of awareness. Loss of speech could be an example.
Complex Automatic Behavior
Automatisms are complex repetitive movements or behaviors that resemble normal voluntary movements. Cognition is usually impaired and there is minimal recall about the events during the attack.
Automatisms in the face are common: chewing, lip smacking, swallowing, or teeth grinding. Other examples are bursts of crying, expression of fear on the face, repetitive phrases or words.
In the hands, automatic behaviors present as tapping, manipulating or exploratory movements, which may look pretty natural.
Some epilepsy sufferers experience auras prior to generalized seizures or independently of them. Auras present as variety of different sensations. The type of sensation depends on the brain area involved and it is usually unique for each person.
Here are a few examples: smell of burning rubber, numbness, nausea, butterflies in the stomach, Deja vu, Jamais vu, feeling of unreality, objects appear larger or smaller than usual, feeling like in a dream, hunger, pain and many others. Some auras might be quite bizarre, such as sensation of stranger behind the back.
All those symptoms may be experienced by absolutely healthy people, so circumstances, associated symptoms, and setting of these experiences have to be evaluated by professional.
Generalized vs. Focal Seizures
These terms reflect the extent of brain involvement in the seizure activity. In focal seizure, only a part of the body is involved. Generalized seizures spread to both sides during seizure activity. A focal seizure may turn into generalized one.
Focal Seizures may present as abnormal involuntary movements or auras described above. They used to be called simple partial seizures. Spreading of seizure activity to larger areas of the brain can lead to altered awareness or loss of conciseness, which is a complex partial seizure. Focal seizure may generalize into a full blown grand mal attack. Here are a few examples of simple partial seizures:
-clonic seizures in the hand, spreading to the arm, face and leg on the same side
-sensation of tingling or shaking spreading in a similar manner
-vomiting, pallor, flashing, chocking
-smells, metallic taste
Focal epilepsy might be confused with stroke and migraine aura. Even though focal seizures may last for days, the pattern of short (minutes) attacks is more common.
Generalized Seizures involve both sides of the body and/or produce loss of consciousness. A generalized seizure may evolve from a focal one or it may be generalized at onset. The most common generalized seizures are tonic-clonic (grand mal), myoclonic, and absences. Generalized body shaking is not essential for generalized seizure. Loss of consciousness is a cardinal feature of generalized epilepsy.
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Disclosure: This Web Site is intended for education purpose only. The information provided on this site must not be perceived as a guide for self-diagnosis or self-treatment. Every effort is made to keep the information current, but there are absolutely no guarantees of timely updates. By Andre Strizhak