An EEG gives information about the electrical activity of the brain during the time the test is happening. When someone has an epileptic seizure their brain activity changes. This change, known as
epileptiform brain activity
, can sometimes be seen on an EEG recording.
What can an EEG tell you about 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. An EEG is of value for diagnosing epilepsy only if it detects patterns typical of epilepsy.
How does an EEG diagnose epilepsy?
Electroencephalography (EEG)
Clinicians can find evidence of abnormal electrical activity in the brain and figure out the type or types of seizures a patient is having, as well as the origin(s), by
measuring brain waves over minutes to a couple of hours
.
What happens if EEG is abnormal?
Abnormal EEG results can show up in two ways. First,
normal brain activity may be suddenly interrupted and changed
. This happens in epileptic seizures. In partial seizures, only part of the brain shows the sudden interruption.
Does an abnormal EEG confirm 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. This is why
having an EEG cannot diagnose epilepsy
, and why EEGs are used alongside other tests and investigations.
Can a EEG show past seizures?
An EEG can usually show if you are having a seizure at the time of the test
, but it can’t show what happens to your brain at any other time. So even though your test results might not show any unusual activity it does not rule out having epilepsy.
What are the 3 types of seizures?
- absence seizures (formerly known as petit mal)
- tonic-clonic or convulsive seizures (formerly known as grand mal)
- atonic seizures (also known as drop attacks)
- clonic seizures.
- tonic seizures.
- myoclonic seizures.
Can an EEG detect anxiety?
EEG has also been used in the diagnosis of
mental disorders
, such as anxiety [28–30], psychosis [31–34], and depression [35–38].
Do all seizures show up on MRI?
MRI Scans. A doctor may order an MRI scan—in which a magnetic field and radio waves create computerized two- or three-dimensional images—to better view the structure of the brain. The
scans may show any problems that may be causing the seizures
. MRIs provide the most detailed and accurate images of the brain.
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 Disorders Can an EEG detect?
- Sleep disorders (such as narcolepsy)
- Head injuries.
- Brain infection.
- Brain haemorrhage.
- Alzheimer’s disease.
- Degeneration of brain tissue.
- Metabolic conditions that affect brain tissue.
- Hormonal conditions that affect brain tissue.
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
.
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.
What does a neurologist do for seizures?
Your regular doctor will probably refer you to a neurologist or an epileptologist, a doctor with specific training
in diagnosing and treating epilepsy
. The specialist will typically order more tests to find the cause of your epilepsy, and they will prescribe medicine to prevent more seizures.
How does a neurologist check for epilepsy?
Electroencephalogram (EEG)
.
This is the most common test used to diagnose epilepsy. In this test, electrodes are attached to your scalp with a paste-like substance or cap. The electrodes record the electrical activity of your brain.
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.
