Profile of Epilepsy as a Disability
Contributor: Elson L. So, MD, Mayo Clinic, Rochester, MN
This module presents a current profile of epilepsy as a disability. It can be a helpful update for
physicians who are not epilepsy specialists and employers with minimal knowledge about epilepsy.
What is an epileptic seizure?
Transient disruption of brain functions due to abnormal and excessive electrical discharges in
This disruptive event must be distinguished from events that are non-epileptic and not due to abnormal and excessive electrical discharges in brain cells, such as syncope and psychogenic events (events mimicking seizures that have an emotional basis). Non-epileptic events may require further neurological investigations to include 24-hour video-EEG monitoring. Events with an emotional causality would require psychiatric intervention.
What is epilepsy?
Epilepsy is a condition that predisposes to recurrent unprovoked seizures.
It is diagnosed when two or more unprovoked seizures have occurred. The occurrence of only
one seizure is not epilepsy and often will not be treated with medication.
Are all seizures epilepsy?
Some seizures are not really epilepsy, but are specifically provoked:
Seizures are provoked by acute brain disturbance (e.g., head trauma, drug or alcohol intoxication, metabolic disturbance, stroke, fever, hyperglycemia, or hypoglycemia, etc.). Many acute brain disturbances are treatable or reversible, so that the risk of seizure recurrence can be satisfactorily reduced by appropriate treatment of the brain disturbance.
Unprovoked Seizures, when two or more being epilepsy, occur when an acute brain disturbance cannot be identified as the cause of seizure, in spite of neurological evaluation.
How are types of seizures diagnosed?
According to how the seizure begins:
The following are localized beginning in one area of the brain:
- Simple Partial Seizure - no mental confusion during or after the seizure. About 14% of
persons with epilepsy have this type of seizure and may involve simple motor movement or a sensation in one part of the body (e.g., a brief arm tremor). This type of seizure is often easily accommodated at work – often does not affect driving, etc.
- Complex Partial Seizure - brief mental confusion which sometimes goes unnoticed; loss of posture and falling are rare. After the seizure has ended, confusion steadily reduces over a few
seconds to a few minutes. About 36% of persons with epilepsy have this type of seizure. These
seizures by themselves do not involve convulsions, but can involve odd motor movements,
lip smacking, or odd sensations.
The following seizure types involve general epileptiform activity:
Generalized Seizure - further divided into:
- Primary Generalized Seizure - seizure begins diffusely from both cerebral hemispheres without
any determinable area of onset. Examples are generalized tonic-clonic seizures, (formerly called
"grand mal") absence seizures, myoclonic seizures (formerly called "petit mal"), and atonic seizures. About 25% of persons with epilepsy have generalized tonic-clonic or "grand mal" seizures, 5% or less have either absence ("petit mal") seizures or myoclonic seizures, with less than 1% for atonic seizures. Falls may sometimes occur with generalized tonic-clonic seizures, and more commonly with atonic seizures.
- Secondary Generalized Tonic Clonic Seizure - seizure begins as either simple or complex partial
seizure, which then spreads diffusely to involve both hemispheres and results in convulsive activity.
According to etiology:
Symptomatic seizure - cause of seizure is known and is non-genetic.
Idiopathic seizure - cause of seizure is unknown, or genetic factors are present or suspected.
Cryptogenic seizure - probably a symptomatic seizure, but the exact cause could not be definitely
What are the symptoms and signs of an epileptic seizure?
Symptoms and signs may vary from person to person, but are usually consistent and predictable for each indivicual.
Examples of symptoms are loss of awareness, mental confusion, speech impairment, paresthesias (abnormal sensations such as numbness or tingling),an olfactory or visual hallucination, and abdominal discomfort.
Examples of external signs are mental confusion, staring, muscle twitches, oral or manual automatic
behavior, unsteadiness, and convulsions.
How often does epilepsy occur?
Prevalence in the U.S. is about 1% of the population.
Approximately 2 to 3 million Americans have epilepsy.
It affects all ages, socioeconomic, and racial groups.
Incidence is highest in the young infants and in the elderly.
What causes epilepsy?
When the cause is determined, the four most common are head trauma, stroke, brain tumor,
and brain infection.
Other causes include drug effects or intoxication, genetics, metabolic disturbances.
Cause is "unknown" in 60% of cases (i.e. idiopathic / cryptogenic).
How is epilepsy diagnosed?
- Accurate history and seizure description are most important;
- Blood tests: Complete Blood Count (CBC), electrolytes, liver and renal function tests
- Computerized Tomography Scanning (CT) is preferred for emergent evaluation of acute
- Magnetic Resonance Imaging (MRI) is preferred for further evaluation or in non-emergent
- Electroencephalograms (EEG), preferably wake and sleep (in order not to miss aberrant
- In more complex cases, 24-hour video-EEG can be utilized to help make the diagnosis.
What are the treatments for epilepsy
Anti-epileptic medication (AED) is the primary treatment.
Epilepsy in some patients does not require AED treatment because of the benign nature and
prognosis of the epilepsy.
Epilepsy surgery should be considered when medications fail to satisfactorily control seizures
and the seizure origin in the brain can be well localized and safely removed.
When epilepsy surgery is not an option, ketogenic diet and vagus nerve stimulation are
palliative treatment options.
What is the prognosis of epilepsy?
60% to 70% will respond satisfactorily to the first AED used.
Prognosis is highly dependent on the cause of epilepsy.
Satisfactory response within a few months to the first AED used is predictive of favorable
long-term seizure control.
In the long-term, most patients achieve satisfactory seizure control, about 50% of whom
can successfully discontinue AED treatment.
What contributes to breakthrough seizure or treatment failure?
- Poor compliance
- Sleep deprivation
- Active medical illness
- Major emotional stress
- Medication adjustments
- Fever related to flu / other sickness
- Substance abuse