Abnormal EEG results can show up in two ways. First, normal brain activity may be suddenly interrupted and changed. This happens in epileptic seizures. The other way an EEG can show abnormal results is called non-epileptiform changes..
Furthermore, what are the possible causes for an abnormal EEG?
Abnormal results on an EEG test may be due to:
- Abnormal bleeding (hemorrhage)
- An abnormal structure in the brain (such as a brain tumor)
- Tissue death due to a blockage in blood flow (cerebral infarction)
- Drug or alcohol abuse.
- Head injury.
- Migraines (in some cases)
- Seizure disorder (such as epilepsy)
what does a spike on an EEG mean? Epileptiform transients such as spikes and sharp waves are the interictal marker of a patient with epilepsy and are the EEG signature of a seizure focus. Nonepileptiform abnormalities are characterized by alterations in normal rhythms or by the appearance of abnormal ones.
Likewise, can an abnormal EEG be wrong?
Yes, EEG can be bad for you. The consequences of being misdiagnosed with epilepsy are obvious and serious [9]. When the diagnosis is based largely on an abnormal EEG, no amount of subsequent normal EEGs will 'cancel' the previous abnormal one, and the wrong diagnosis is very difficult to undo.
What can affect EEG results?
When epilepsy is present, seizure activity will appear as rapid spiking waves on the EEG. People with lesions of their brain, which can result from tumors or stroke, may have unusually slow EEG waves, depending on the size and the location of the lesion.
Related Question Answers
Does an EEG show brain damage?
What does an EEG show? EEG can also detect abnormal brain waves after a head injury, stroke, or brain tumor. Other conditions such as dizziness, headache, dementia, and sleeping problems may show abnormal brain patterns. It can also be used to confirm brain death.Can EEG detect mental illness?
Electroencephalography (EEG) is primarily of use in diagnosing epilepsy and other brain diseases (1), but there are other reasons why EEG is also an important diagnostic test in psychiatric practice. Epileptic seizures can also mimic psychiatric disorders or trigger episodes with psychiatric symptoms.What does a bad EEG look like?
The other way an EEG can show abnormal results is called non-epileptiform changes. This can be a general change in the way a normal brain wave looks. It may have an abnormal frequency, height or shape. It can also be a brain wave showing up that should not.Does epilepsy show up on MRI?
MRI scans (magnetic resonance imaging) It can show if there's a structural cause for someone's epilepsy. The MRI scan isn't painful, but it can be very noisy.Can EEG show anxiety?
We see anxiety as one manifestation of diminished self-regulation by the brain. The condition is often quite obvious in the EEG. During EEG training for anxiety, the person is shown information derived from his or her EEG in real time, and is asked to bring certain aspects of it under control.Can EEG show dementia?
An electroencephalogram (EEG) may be done to detect abnormal brain-wave activity. Although the EEG is usually normal in people with mild Alzheimer's disease and many other types of dementia, EEG abnormalities do occur in delirium and Creutzfeldt-Jakob disease, which is a cause of dementia.What does an EEG tell you?
An electroencephalogram (EEG) is a test used to evaluate the electrical activity in the brain. An EEG can be used to help detect potential problems associated with this activity. An EEG tracks and records brain wave patterns. Small flat metal discs called electrodes are attached to the scalp with wires.What causes abnormal electrical activity in the brain?
Abnormal electrical activity in the brain triggers seizure activity. A person may have a seizure disorder (epilepsy) and require medications. Other factors such as hypoglycemia (low blood sugar), which is a diabetic reaction, may cause seizures. Meningitis or a head injury may also cause a seizure.How long does it take to read an EEG?
The test itself will take about 30-60 minutes. Placing the electrodes usually takes 20 minutes, but can take up to an hour, so the entire procedure may take about one to 2 hours. If you have an ambulatory EEG, brain activity is recorded for 24 hours or more.Can stress cause seizure like symptoms?
Pseudoseizures, also called psychogenic nonepileptic seizures (PNES), are seizures that occur as a result of psychological causes, such as severe mental stress. It is easy to misdiagnose the condition as the symptoms are very similar to those of epilepsy, but this will result in the wrong treatment approach.Can an EEG miss a brain tumor?
The low specificity and sensitivity of EEG (even in patients with clinical seizures as primary symptom of a brain tumor) underline that EEG does not contribute to diagnosis and a normal EEG might even delay correct diagnosis.What does a normal EEG look like?
Most waves of 8 Hz and higher frequencies are normal findings in the EEG of an awake adult. The morphology of a wave may resemble specific shapes, such as vertex (V) waves seen over the vertex of the scalp in stage 2 sleep or triphasic waves that occur in the setting of various encephalopathies.What should you not do before an EEG test?
Your doctor may ask you to stop taking certain medicines before the test. These include sedatives and tranquilizers, muscle relaxants, sleeping aids and seizure medicines. Do not eat or drink anything with caffeine in it for 12 hours before the test. This includes cola, energy drinks, and chocolate.Is EEG better than MRI?
In contrast to MEG, which detects magnetic fields related to neuron activity, EEG detects electric fields produced by neurons in your brain. MRI (magnetic resonance imaging) – Epilepsy treatment is most effective when the onset of the seizure can be specifically localized to one or more origins within the brain.What is a sleep deprived EEG?
A sleep-deprived EEG test is done when you have had less sleep than usual. A sleep-deprived EEG can show up subtle seizures, including absence, myoclonic or focal (partial) seizures. Before you have a sleep-deprived EEG test, your doctor may ask you not to go to sleep at all the night before.Does a migraine show up on an EEG?
But your doctor may order one to look for signs of seizures, which can cause symptoms similar to those associated with migraine or other types of headaches. An EEG can show that something's not right in the brain, but it doesn't pinpoint the exact problem that might be causing a headache.Are EEG accurate?
This test can record brain activity over several days, which increases the chances of catching seizure activity. However, compared to inpatient video-EEG monitoring, an ambulatory EEG is not as good at determining the difference between epileptic seizures and nonepileptic seizures.Can EEG show past seizure activity?
A normal EEG does not mean that you did not have a seizure. The likelihood of recording a seizure during a routine EEG is small. The EEG generally records brain waves between seizures, called interictal brain waves. These waves may or may not show evidence of seizure activity.What are brain spikes?
Spikes are very fast waves and are called spikes because of their shape on the EEG. Each lasts less than 80 milliseconds (less than 1/12th of a second) and may be followed by slow delta waves. Spikes clearly stand out from other brain activity on the EEG. Polyspikes are a series of spikes that happen quickly. 
