Epilepsy 101

Epilepsy is a condition that affects millions of people worldwide, often causing unprovoked seizures due to irregular brain activity. But what exactly happens in the brain when someone has epilepsy?

It is important to establish that not everyone with seizures has Epilepsy. While epilepsy can

start at any age, it often begins in childhood, or in people over the age of 60.

Epilepsy can be due to genetic factors - 1 in 3 people with epilepsy have family history- or

brain damage from causes like stroke, infection, severe head injury or a brain tumour.

However, around half of epilepsy cases have an unknown cause.

Now, imagine your brain as a big city with lots of lights. Each light represents a part of your

brain that controls things like movement, feelings, and thoughts. Epilepsy is like when the

lights in the city start flickering or shut completely. There are three main types of epilepsy,

and each affects the lights in different ways:

1) Generalized epilepsy: when all the lights in the city flicker or go out at once, affecting the whole brain. There are two main kinds:

• Generalized Motor (Grand Mal) Seizures: Imagine the lights in the city going wild,

  making everything shake. This is like the shaking or jerking movements during myoclonic or tonic-clonic seizures.

• Generalized Non-Motor (Absence) Seizures: Picture the lights suddenly pausing, making everything freeze. During these seizures, a person might stare into space or make small, repeated movements, like lip-smacking.

  
  

2) Focal epilepsy: when only the lights in one part of the city flicker or go out. This means

only one part of the brain is affected:

• Focal Aware Seizures: The lights flicker, but people in that part of the city know what’s happening. The person stays aware during the seizure.

• Focal Impaired Awareness Seizures: The lights flicker, and people lose track of what’s going on. The person might not remember the seizure.

• Focal Motor Seizures: Some lights flicker, causing strange movements, like twitching, rubbing hands, or walking around.

• Focal Non-Motor Seizures: The lights stay on, but everything feels strange, like

  sudden change in mood or temperature. The person might feel odd sensations

  without moving in unusual ways.

3) ‘Unknown’ epilepsy: ‘Unknown’ epilepsy is like a power outage where no one knows where it happened because the person was alone or asleep during the seizure. Doctors might later figure out if it's more like generalized or focal epilepsy. Some people can even have both types.

But how do doctors find out if someone has epilepsy? A range of tests could be used to look at the brain’s activity and structure, including:

• Electroencephalogram (EEG): detects abnormal electrical activities in the brain using electrodes. This procedure can be utilised in Stereoelectroencephalography (SEEG), a more invasive method where the electrodes are placed directly on or within the brain to locate the abnormal electrical activities more precisely.

  
  

• Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI): form

  images of the brain to detect abnormal brain structures such as brain scarring, tumours or damage that may cause seizures.

  
  

• Blood tests: test for genetic or metabolic disorders, or health conditions such as

  anaemia, infections or diabetes that can trigger seizures.

  
  

• Magnetoencephalogram (MEG): measures magnetic signals generated by nerve

  cells to identify the specific area where seizures are starting, to diagnose focal

  epilepsy.

  
  

• Positron emission tomography (PET): detects biochemical changes in the brain,

  detecting regions of the brain with lower-than-normal metabolism linked to seizures.

  
  

• Single-photon emission computed tomography (SPECT): identifies seizure focus by measuring changes in blood flow in the brain during or between seizures, using a tracer injected into the patient. The seizure focus in this scan is seen by an increase in blood flow to that region.

So, how does epilepsy affect the brain? For most people, especially those with infrequent or primarily generalised seizures, cognitive issues are less likely compared to those with focal seizures, particularly in the temporal lobe. The following cognitive functions can be affected:

• Memory: seizures can disrupt the hippocampus in the temporal lobe, responsible for storing and receiving new information. This can lead to difficulties in remembering words, concepts, names and other information.

  
  

• Language: seizures can affect areas of the brain responsible for speaking,

  understanding and storing words, which can lead to difficulties in finding familiar

  words.

  
  

• Executive function: seizures can impact the frontal lobe of the brain which is

  responsible for planning, decision making and social behaviour, leading to challenges in interacting, organising thoughts and controlling unwanted behaviour.

  
  

While epilepsy itself cannot be cured, treatments exist to control seizures including:

• Anti-Epileptic Drugs (AEDs): suppress the brain’s ability of sending abnormal electrical signals - effective in 70% of patients.

  
  

• Diet: ketogenic diets can reduce seizures in some medication- resistant epilepsies

  and in children as they alter the chemical activity in the brain.

• Surgery:

1) Resective Surgery: removal of the part of the brain causing the seizures, such as temporal lobe resection, mainly for focal epilepsy.

2) Disconnective Surgery: cutting the connections between the nerves through which the seizure signals travel in the brain, such as in corpus callosotomy, mainly for generalised epilepsy.

3) Neurostimulation device implantation (NDI): insertion of devices in the body to control seizures by stimulating brain regions to control the electrical impulses causing the seizures. This includes vagus nerve stimulation and Deep Brain Stimulation (DBS).

Even though epilepsy can be challenging, many people manage it successfully with the right treatment. Continued research offers hope for even better, long lasting treatments in the future.

Written by Hanin Salem

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REFERENCES

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Epilepsy Foundation. (n.d.). Thinking and Memory. [online] Available at: https://www.epilepsy.com/complications-risks/thinking-and-memory [Accessed 10

Aug. 2024].

GOSH Hospital site. (n.d.). Invasive EEG monitoring. [online] Available at: https://www.gosh.nhs.uk/conditions-and-treatments/procedures-and-

treatments/invasive-monitoring/ [Accessed 9 Aug. 2024].

My Epilepsy Team.com. (2016). Epilepsy: What People Don’t See (Infographic) | MyEpilepsyTeam. [online] Available at: https://www.myepilepsyteam.com/resources/epilepsy-what-people-dont-see-

infographic [Accessed 29 Aug. 2024].

National institute of Neurological Disorders and stroke (2023). Epilepsy and Seizures

| National Institute of Neurological Disorders and Stroke. [online] www.ninds.nih.gov. Available at: https://www.ninds.nih.gov/health-

information/disorders/epilepsy-and-seizures [Accessed 10 Aug. 2024].

NHS (2020). Epilepsy. [online] NHS. Available at: https://www.nhs.uk/conditions/epilepsy/ [Accessed 10 Aug. 2024].