The only symptom of epilepsy is the recurrence of seizures, but not all epileptic seizures are the same. Some seizures cause obvious physical movements or loss of consciousness, but in other cases a seizure might not be visible to a bystander – not even a health professional. Some people with undiagnosed epilepsy may not even realize that the strange sensations or emotions they’re experiencing are due to a seizure.
Symptoms experienced by seizures vary based on the area of the brain that is involved in abnormal electrical activity. Focal epilepsy causes seizures that originate in a specific part of the brain, but these seizures can spread across the brain to become generalized seizures.
FOCAL ONSET EPILEPSY has a few subcategories to better define the observed symptoms:
• Aware: The patient remains awake during the seizure
• Impaired Awareness: The patient loses consciousness during the seizure.
• Motor Onset: This categorization indicates that the symptoms observed involve abnormal movements
◦ Automatism (can involve stereotyped limb or face movements)
◦ Atonic (involves loss of motor tone or “drop attacks”)
◦ Clonic (fast jerking movements, stiffening and relaxing, of the limbs)
◦ Hyperkinetic (involves complex movements of the trunk and proximal limb ie. “pedaling”)
◦ Myoclonic (involves short muscle contractions)
◦ Tonic (involves sustained muscular contractions)
• Nonmotor Onset: This categorization indicates the the symptoms observed involve abnormal sensations and functions that do not produce abnormal movements
◦ Autonomic (changes in heart rate, blood pressure, or a sense of gastric rising and nausea)
◦ Behavior arrest
GENERALIZED ONSET EPILEPSY is described as motor or non-motor.
◦ Tonic-Clonic (“Grand Mal”)*
◦ Atonic (characterized by a sudden loss of muscle tone that causes an individual to collapse)
• Non-Motor (also known as Absence): Absence seizures are common in children. They last only a few seconds and have only mild outward signs, such as twitching facial muscles, or no outward manifestations. They may result in your child’s simply appearing to not be paying attention. Some children may have these seizures hundreds of times a day.
◦ Eyelid myoclonia
*Grand mal seizures are the most severe, and most dangerous, type of seizures. Grand mal seizures have two phases. In the first phase, called the tonic phase, the individual loses consciousness and becomes stiff; in the next phase, called the clonic phase, the individual begins to jerk, sometimes violently. Grand mal seizures usually stop on their own, but when the seizing continues uncontrollably the condition is known as status epilepticus. Status epilepticus is an emergency that requires immediate treatment to prevent brain damage or even death.
Although some seizures are mild, anyone with a seizure disorder should be treated to control them. Repeated seizures can cause brain damage over time, and there is a risk of sudden death (SUDEP) in patients with certain types of epilepsy. Medications can be effective in treating most cases of epilepsy, but surgery is the only known cure in appropriate cases (see Surgery for Epilepsy in Children).
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Reviewed by: Caitlin Hoffman, M.D.
Last reviewed/last updated: January 2021
Our Care Team
- Victor and Tara Menezes Clinical Scholar in Neuroscience
- Associate Professor of Neurological Surgery in Pediatrics
- Associate Professor of Neuropsychology in Neurological Surgery
- Director of Neuropsychology Services
- Vice Chair for Clinical Research
- David and Ursel Barnes Professor in Minimally Invasive Surgery
- Professor of Neurosurgery, Neurology, and Otolaryngology
- Director, Center for Epilepsy and Pituitary Surgery
- Co-Director, Surgical Neuro-oncology
- Child Neurologist Director, Pediatric Epilepsy
- Pediatric Epileptologist