A normal EEG does not rule out the possibility of epilepsy
. In fact, since the EEG records only a 30-minute snapshot of the brain’s activity, many EEGs are normal. The sensitivity of the EEG—that is, the likelihood that the test will pick up abnormality—increases each time the test is run.
How do you trigger a seizure?
Triggers are situations that can bring on a seizure in some people with epilepsy. Some people’s seizures are brought on by certain situations. Triggers can differ from person to person, but common triggers include
tiredness and lack of sleep, stress, alcohol
, and not taking medication.
Can an EEG induce a seizure?
In rare instances,
an EEG can cause seizures in a person with a seizure disorder
. This is due to the flashing lights or the deep breathing that may be involved during the test. If you do get a seizure, your healthcare provider will treat it immediately.
What does a spike on an EEG mean?
Spikes or sharp waves are terms commonly seen in EEG reports. If these happen only once in a while or at certain times of day, they may not mean anything. If they happen frequently or are found in specific areas of the brain, it could mean
there is potentially an area of seizure activity nearby
.
Does an abnormal EEG always mean epilepsy?
To complicate this further, some people have
‘abnormal’ EEGs but do not have epilepsy
. Also, many people who do have epilepsy will only have ‘abnormal’ activity on the EEG if they have a seizure at the time the test is happening.
What are the 3 types of seizures?
- Generalized onset seizures:
- Focal onset seizures:
- Unknown onset seizures:
Can you feel a seizure coming on?
Some people may experience feelings, sensations, or changes in behavior hours or days before a seizure. These feelings are generally not part of the seizure, but may
warn a person that a
seizure may come.
What are common seizure triggers?
Missed medication, lack of sleep, stress, alcohol, and menstruation
are some of the most common triggers, but there are many more. Flashing lights can cause seizures in some people, but it’s much less frequent than you might imagine.
What are warning signs of a seizure?
- Staring.
- Jerking movements of the arms and legs.
- Stiffening of the body.
- Loss of consciousness.
- Breathing problems or stopping breathing.
- Loss of bowel or bladder control.
- Falling suddenly for no apparent reason, especially when associated with loss of consciousness.
How long does an EEG take for seizures?
Routine outpatient EEG recordings usually take
20 to 40 minutes
, although a typical appointment will last about an hour, including some preparation time at the beginning and some time at the end. Other types of EEG recording may take longer. You can go home as soon as the test has been done.
What can a EEG reveal?
An EEG can determine
changes in brain activity
that might be useful in diagnosing brain disorders, especially epilepsy or another seizure disorder. An EEG might also be helpful for diagnosing or treating the following disorders: Brain tumor. Brain damage from head injury.
What is a normal EEG result?
Most waves of 8 Hz and higher frequencies
are normal findings in the EEG of an awake adult. Waves with a frequency of 7 Hz or less often are classified as abnormal in awake adults, although they normally can be seen in children or in adults who are asleep.
Why do they flash lights during EEG?
In some cases, a strobe light may be used during an EEG test. This aims
to detect if this alters the electrical pattern in the brain
. (Usually it does not. However, a small number of people have seizures triggered by flickering or strobe lights and so this may help to identify these people.)
What does an EEG look like with seizures?
Your doctor may refer to these waves as “epileptiform abnormalities” or “epilepsy waves.” They can look like
spikes, sharp waves, and spike-and-wave discharges
.
What does a neurologist do for seizures?
If you have spells that may be seizures, your primary doctor probably will send you to see a neurologist, a doctor who specializes in the brain and nervous system. The neurologist will
perform a complete neurological exam
to find out whether an area of your brain is functioning abnormally.
What can an EEG tell you about seizures?
It is most often used to determine the type and origin of seizures. For example, if you have a seizure disorder, the EEG can
show where abnormal activity in your brain comes from
and can help distinguish between generalized or focal seizures.
