Normal EEG vs Epileptic EEG: Understanding the Differences

The aim of this narrative review is to provide an overview of EEG-based biomarker candidates for epilepsy and the techniques employed for their identification.

In recent years, researchers have been working tirelessly to identify reliable biomarkers that can distinguish between epilepsy and other pathological conditions. To date, only a few EEG features other than interictal epileptiform discharges (IEDs) have shown promise in this regard, with the potential to accurately diagnose epilepsy even when IEDs are not present.

One of the main challenges in diagnosing epilepsy is that standard EEG tests may not always detect spikes or other abnormal activity. In fact, a 20-minute standard EEG may appear completely normal despite an underlying epileptic disorder. This can lead to difficulties in making an accurate diagnosis and delays in treatment.

IEDs are currently considered the most established biomarker of epilepsy, particularly when seizures are not recorded. These discharges can be identified on an EEG even between seizures, providing valuable information about the presence of an underlying epileptic condition.

However, there is a growing need for alternative biomarkers that can reliably predict whether an individual suffers from epilepsy, even in the absence of evident epileptic activity. Such biomarkers could significantly shorten the period of diagnostic uncertainty and reduce the risk of seizure.

To address this need, researchers have been exploring various EEG-based techniques to identify potential biomarkers. These include analyzing different frequencies, such as alpha, beta, and theta waves, as well as examining other features like asymmetry and coherence.

In addition to these techniques, the Epilepsy Monitoring Unit (EMU) is also used to record abnormal brain activity during seizures that could not be detected with a regular 20-minute EEG. This unit allows for longer recordings and more detailed analysis of seizure activity.

In conclusion, while IEDs remain an important biomarker in the diagnosis of epilepsy, there is a clear need for alternative biomarkers that can accurately predict whether an individual suffers from the condition. Further research into EEG-based techniques and biomarkers could lead to significant advances in our understanding and treatment of epilepsy.

Normal eeg vs epileptic eeg