How are non-epileptic attacks diagnosed?

NEAs often look like epileptic attacks or fainting spells. It is important to know what type of attacks you have, as they need different treatment. Better knowledge of NEAs means they can now be identified more easily.

It is important to realise that the diagnosis of NEAD and other seizure disorders is often a gradual process rather than a single event. The information available to the doctor about a first blackout is often limited. The diagnosis may become clearer as more events are observed and described. Most patients with NEAD are initially misdiagnosed as having epilepsy.

Specialists in treating attacks (such as neurologists) can sometimes tell what type of attacks you have when you or someone who has seen them describe the attacks in detail. Although NEAs resemble epileptic seizures, there are small but important differences in how patients and witnesses describe these different seizure types. Experts can make a correct diagnosis on the things you or others may say about your attacks in eight of ten cases. Video recordings (for instance on a mobile phone) or even photos of a typical attack can be very helpful to the doctor to make the correct diagnosis. Seizure experts can accurately diagnose nine out of ten seizures if they have access to a video recording of a seizure. The doctor would also be more likely to be able to diagnose NEAD if they had observed a seizure directly and examined you during the seizure.

Depending on the nature of your attacks other tests can be helpful, including brain scans, blood tests and heart recordings. These tests may be carried out to look for other causes of blackouts. However, in some cases no further investigations are necessary when a seizure expert has heard a description of your attacks.

The kind of tests often carried out can include:

Electrocardiogram (ECG or EKG)

This is a test which measures the electrical activity produced by the heart. The test is useful if your doctor thinks that your blackouts could be caused by an abnormal heart rhythm. Having an ECG involves wires being attached to the chest, arms and legs. A brief ECG can be recorded in less than 15 minutes.

However, the ECG can also be recorded for longer periods of time with portable ECG devices. There are even small ECG recorders which can be implanted under the skin and which can record the ECG for many months.

Electroencephalogram (EEG)

This is a test which measures the electrical activity produced by the brain. It can show abnormal patterns of electrical activity or epileptic activity. Epileptic activity is seen during epileptic seizures but can sometimes also be seen in between seizures (without causing any symptoms). The EEG is recorded using small metal plates which are stuck to the head.

A typical EEG recording involves recording the electrical activity of the brain at rest but also when the brain is stimulated, for instance by deliberate over breathing or with flashing lights. A brief recording can be completed in about 30 minutes.

However, EEG recordings with portable machines over one or two days are also possible. It is important to realise that subtle EEG abnormalities without symptoms are common in healthy individuals and do not prove a diagnosis of epilepsy.

Computed Tomography (CT) of the head

This is a test which produces a series of two dimensional pictures of the brain using X-rays. It can show up abnormalities of the shape or structure of the brain which could give rise to epileptic seizures. Having a CT involves lying down on a bench and putting your head into a large, open ring. It takes less than 15 minutes to take the pictures. It is important to realise that an abnormality on a CT scan does not prove a diagnosis of epilepsy.

Magnetic Resonance Imaging (MRI) of the head

This is a test which produces very detailed pictures of the brain using radio waves. An MRI scan may be carried out to look for changes in the brain which can cause epilepsy. To obtain an MRI scan, the whole body has to go into a big machine (which looks and sounds a bit like an oversized washing machine). It takes about 40 minutes to acquire the pictures. Some people who get anxious in confined spaces struggle with MRI scans. Looking at the scanner first, listening to music over headphones, or taking tablets to help with anxiety just before the test can help. An abnormal MRI scan does not prove the diagnosis of epilepsy.

Blood tests (prolactin, creatine kinase)

If blood can be taken soon after a seizure some constituents of the blood sometimes gives doctors a better idea whether a blackout was cause by an epileptic seizure or a non-epileptic attack. However, the intepretation of blood tests depends a lot on when exactly the blood was taken and what was happening at this time.

Tilt table test

This test can be useful if your doctor suspects that your attacks could be due to a sudden drop of blood pressure. The test involves people lying on a couch whilst their heart rate and blood pressure are constantly monitored. People who are prone to fainting may experience a drop in their blood pressure when the couch is tilted up 45 degrees. Unfortunately, a normal tilt table test does not rule out a diagnosis of fainting.

Video-EEG monitoring

The most reliable test is video-EEG monitoring. It usually involves an admission to hospital. During this test people are constantly monitored with a video camera whilst their EEG is recorded. The aim of this test is to record a typical attack and the electrical brain activity during the attack. This test shows your doctor what exactly your attacks look like and whether the attacks are caused by epileptic activity in the brain. If you have NEAD, your attacks will not be associated by epileptic activity.

Using this test, your doctor can make a diagnosis of NEA with almost complete certainty. However, sometimes NEAs cannot be proven by video-EEG because seizures are too infrequent or fail to occur in hospital. Also, even if a NEA has been recorded by video-EEG, this does not prove that all previous seizures were also NEAs. Having said that, studies using prolonged video-EEG monitoring have found that only one in twenty people with NEAD has additional epileptic seizures.

Although it is relatively straightforward for experts to make the diagnosis of NEAD, most people initially see doctors with their blackouts who do not specialise in this area. This is one reason why many patients receive an inaccurate diagnosis of epilepsy in the first place.

Read more about why many people are initially misdiagnosed with epilepsy