Types of Seizures
The modern system of seizure classification, the International Classifciation of Epileptic Seizures developed by the International League Against Epilepsy, categorizes and distinguishes different types of seizures. It draws an essential distinction between partial and generalized seizures. If the excessive electrical discharge is restricted to a given (localized) area in the brain, the seizure is termed partial. If the entire brain is involved, the seizure is generalized.
Partial Seizures are often characterized by abnormal brain activity that occurs in one area of the brain resulting in involuntary movement or unusual sensations, attention and behaviour changes. Partial Seizures can be further classified into either:
Simple Partial Seizures (formerly focal seizures)
Complex Partial Seizures (formerly psychomotor or temporal lobe seizures)
Generalized Seizures are characterized by abnormal brain activity in many areas of the brain. They may or may not include convulsions, but they usually involve a loss of consciousness. Generalized Seizures can be further classified into either:
Generalized Absence Seizures (formerly petit mal)
Tonic Clonic Seizures (formerly grand mal)
Simple Partial
When a person is conscious, muscle jerking may begin in one area of the body, then spread, may become a convulsive seizure; may involve sensory disturbance a person may hear, see or smell things that are not there; may experience emotions of joy, fear; anger, or a funny feeling in the stomach.
May look like the person is acting out, mental or psychosomatic illness or mystical experience.
Complex Partial
(Psychomotor or Temporal Lobe)(36%)
May start with a blank stare, chewing, then random activity, lasts a few minutes, may be unaware, unresponsive, dazed, mumbling, clumsy, may take off clothes, pick at clothing, pick up objects, run or be afraid; may struggle if restrained, the same set of actions will appear with each seizure, confusion afterwards and no memory of the seizure, no convulsions.
May look like the person is drunk or on drugs, mentally ill, or disorderly.
Common Types of Generalized Seizures
*An asterisk indicates old terminology
Tonic-clonic (Grand Mal)* (23%)
May start with a sudden cry and fall, progress from muscle rigidity to jerking, change breathing (may be temporarily suspended, skin bluish), bladder or bowel control may be lost, drooling, possible vomiting, loss of consciousness, duration of two to five minutes, fatigue and confusion before full recovery, 2 - 5 minutes in duration.
May look like a heart attack.
Absence (Petit Mal)* (6%)
Most often found in children, 2 - 10 seconds of staring, blinking, eyelids fluttering, rolling, chewing movements, unaware during the seizure, then a return to full awareness, fairly easy to control with medication.
May look like daydreaming; non-compliance to adult instructions; may result in learning difficulties if not detected and treated.
Atonic (Drop Attack)*
Person collapses and falls without warning, lasts 10 seconds with a quick recovery, then consciousness and is able to function again. Seizures may be drug-resistant and require a safety helmet.
Myoclonic (3%)
Abrupt muscle jerks in one part or all of the body, found in children, may be a single incident or a series of incidents, may fall off chair or spill things, may occur when going to sleep, or upon awakening.
May look like a nervous tic or startle response.
Tonic
Rigid muscle contraction.
Similar to tonic-clonic, but lacks the clonic (jerking) portion.
Clonic
Repetitive jerking.
May lead to a Tonic-clonic seizure.
Partial Seizures are often characterized by abnormal brain activity that occurs in one area of the brain resulting in involuntary movement or unusual sensations, attention and behaviour changes. Partial Seizures can be further classified into either:
Simple Partial Seizures (formerly focal seizures)
Complex Partial Seizures (formerly psychomotor or temporal lobe seizures)
Generalized Seizures are characterized by abnormal brain activity in many areas of the brain. They may or may not include convulsions, but they usually involve a loss of consciousness. Generalized Seizures can be further classified into either:
Generalized Absence Seizures (formerly petit mal)
Tonic Clonic Seizures (formerly grand mal)
Simple Partial
When a person is conscious, muscle jerking may begin in one area of the body, then spread, may become a convulsive seizure; may involve sensory disturbance a person may hear, see or smell things that are not there; may experience emotions of joy, fear; anger, or a funny feeling in the stomach.
May look like the person is acting out, mental or psychosomatic illness or mystical experience.
Complex Partial
(Psychomotor or Temporal Lobe)(36%)
May start with a blank stare, chewing, then random activity, lasts a few minutes, may be unaware, unresponsive, dazed, mumbling, clumsy, may take off clothes, pick at clothing, pick up objects, run or be afraid; may struggle if restrained, the same set of actions will appear with each seizure, confusion afterwards and no memory of the seizure, no convulsions.
May look like the person is drunk or on drugs, mentally ill, or disorderly.
Common Types of Generalized Seizures
*An asterisk indicates old terminology
Tonic-clonic (Grand Mal)* (23%)
May start with a sudden cry and fall, progress from muscle rigidity to jerking, change breathing (may be temporarily suspended, skin bluish), bladder or bowel control may be lost, drooling, possible vomiting, loss of consciousness, duration of two to five minutes, fatigue and confusion before full recovery, 2 - 5 minutes in duration.
May look like a heart attack.
Absence (Petit Mal)* (6%)
Most often found in children, 2 - 10 seconds of staring, blinking, eyelids fluttering, rolling, chewing movements, unaware during the seizure, then a return to full awareness, fairly easy to control with medication.
May look like daydreaming; non-compliance to adult instructions; may result in learning difficulties if not detected and treated.
Atonic (Drop Attack)*
Person collapses and falls without warning, lasts 10 seconds with a quick recovery, then consciousness and is able to function again. Seizures may be drug-resistant and require a safety helmet.
Myoclonic (3%)
Abrupt muscle jerks in one part or all of the body, found in children, may be a single incident or a series of incidents, may fall off chair or spill things, may occur when going to sleep, or upon awakening.
May look like a nervous tic or startle response.
Tonic
Rigid muscle contraction.
Similar to tonic-clonic, but lacks the clonic (jerking) portion.
Clonic
Repetitive jerking.
May lead to a Tonic-clonic seizure.