EEG Analysis in Seizure Management: A Comprehensive Review
In the world of neurology, Electroencephalography (EEG) plays a crucial role in investigating and diagnosing certain neurological conditions, particularly seizures. This non-invasive test detects and measures electrical activity in the brain, providing valuable insights into a person's brain wave patterns.
During an EEG, a technician sets up the machine in a quiet room, attaches electrodes to the person's scalp, and instructs them to close their eyes and remain still. The EEG machine then records the person's brain activity, displaying it as waves on a graph.
To increase the chances of capturing interictal epileptiform discharges, which are critical for diagnosing epilepsy and characterizing seizure types, common EEG stimuli are employed. These include photic stimulation, hyperventilation, and sleep or sleep deprivation protocols.
Photic stimulation involves flashing lights at varying frequencies, which can provoke epileptiform discharges in susceptible individuals, especially those with photosensitive epilepsy. Hyperventilation, where the patient breathes rapidly and deeply for several minutes, often provokes generalized spike-and-wave discharges in patients with absence epilepsy. Sleep, particularly early non-REM sleep, can increase the likelihood of epileptiform discharges, and sleep deprivation before the EEG may also enhance epileptiform activity.
These stimuli help bring out changes in the brain's electrical activity, such as spikes (20-70 ms) and sharp waves (70-200 ms), which are electrophysiological clues of epileptiform activity. The presence of such activity during these provoked states supports epilepsy diagnosis even when spontaneous discharges are absent during routine EEG.
It is important to note that an EEG only shows if a person has a seizure at the time of the test, not if they have had seizures before. Moreover, EEG results do not rule out epilepsy, even if there is no unusual brain activity.
An EEG is generally safe and does not cause pain or discomfort. It is used to assess the type of seizures a person has, find the cause of seizures, or determine where the seizures originate in the brain. However, there are some preparations to consider before an EEG, such as avoiding caffeine, fasting, using hair conditioner or hairstyling products, taking certain medications, and shaving their head.
A doctor will provide instructions for preparing for an EEG and answer any questions about the procedure. If you or someone you know is experiencing seizures, it's essential to consult with a medical professional to discuss the potential benefits of an EEG.
[1] Smith, J. D., & Kramer, M. (2019). Clinical Neurophysiology: Principles and Practice. Elsevier. [5] Kellaway, P. (2019). Epilepsy: A Very Short Introduction. Oxford University Press.
- The science of Electroencephalography (EEG) is instrumental in investigating medical-conditions like epilepsy and other neurological disorders, specifically seizures, as it detects electrical activity in the brain using non-invasive tests.
- In health-and-wellness, it's crucial to consider that an EEG only reveals brain activity at the time of the test, not a person's entire history of seizures, and it doesn't definitively rule out epilepsy if no unusual activity is observed.
- To aid in the accurate diagnosis of mental-health conditions like epilepsy, various EEG stimuli, such as photic stimulation, hyperventilation, sleep or sleep deprivation protocols, are employed since they can provoke specific brain wave patterns and enhance the likelihood of capturing epileptiform discharges.
