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What is Epilepsy: A complete guide to this chronic disorder

We’ve all heard of people who can’t be around flashing lights because of their epilepsy, but what is epilepsy? In this article, we will look at what is epilepsy, the symptoms, causes, types, and treatments of epilepsy as well as how it affects our body.

What is Epilepsy

What is epilepsy?

Epilepsy is a chronic disorder that means the same thing as seizure disorders. It’s known for its unpredictable and unprovoked seizures. It comes in a wide range of types and varies from person to person. The word epilepsy itself doesn’t indicate anything about the cause or severity of someone’s seizures. Epilepsy is found in more than 50 million people worldwide. Of those 50 million, 80% live in developing countries and 6-10 million with epilepsy live in India.

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Epilepsy can be traced back to Assyrian texts in 2,000 B.C. However, there are multiple references to epileptic-like happenings throughout many ancient texts, especially in ancient Greek medical texts. Hippocrates, a famous Greek physician, includes tons of neurological things within his book On Sacred Disease. For example, he included the first known neurosurgery procedure that refers that the craniotomy should be performed on the opposite side of the brain as the seizures in order to spare the patients from the “phlegma” that in theory caused the disease.

In the 18th and 19th centuries is when medicine began to make important advances and did more research on epilepsy. At the beginning of the 18th century, the belief that epilepsy was an idiopathic disease that derived from the brain and other organs became to come into view. William Cullen and Samuel A Tissot set out to accurately describe the various types of epilepsies. However, many people from The Church had religious superstitions and believed that epilepsy was a divine punishment or possession- the Grand Mal Seizures are the classic example of “possession”. The 19th century carries with it many advances in epilepsy form the French medical school. The 20th century is marked by the inventions of electroencephalography (EEG) and anti-epileptic drugs, advancement in neurosurgery, and the outline of underlying pathophysiological mechanisms. The most recent epileptic advances involve advanced imaging techniques, the development of microsurgery, and research connecting the genetic factors and epileptic seizures.

What is epilepsy: disease or disorder?

Epilepsy is a disorder due to the disturbance that is caused by neurons sending wrong messages to the brain. Unlike a disease, epilepsy can’t be caught.

What is epilepsy: symptoms

Epileptic seizures can affect any process your brain can coordinate and do. The symptoms will vary depending on the type of seizure. However, an epileptic person tends to have the same type of seizures every time so the symptoms will be similar to each epileptic episode. Some signs of seizures and symptoms can include:

  • Temporary confusión
  • Loss of consciousness and/or awareness
  • A staring spell
  • Psychic symptoms like anxiety, fear, or déjà vu
  • Uncontrollable and jerking movements in the arms and legs

What is epilepsy: causes

Epilepsy has no known cause for about half of the people who suffer from it. However, the other half of the people can trace their epilepsy to several factors, including:

  • Genetic influence. Sometimes epilepsy runs in the family. Researchers have linked some specific types of epilepsy to specific familiar genes. Other genes may make someone more sensitive to certain environmental conditions that can cause seizures.
  • Brain conditions. Conditions such as a brain tumor, dementia, or stroke can cause epilepsy. The leading cause of epilepsy in people over the age of 35 is a stroke.
  • Developmental disorders like autism or neurofibromatosis– a condition where tumors grow on the nervous system. About 3 in 10 kids with autism also have epilepsy.
  • Head trauma. Something like a traumatic brain injury can easily cause epilepsy.
  • Prenatal injury. Before we are born, we are incredibly sensitive to brain damage by things like infection, poor nutrition, or oxygen deficiencies. This brain damage may cause epilepsy or cerebral palsy.
  • Infectious diseases like meningitis, viral encephalitis, and AIDS can cause epilepsy.

What is epilepsy: types

Based on how the abnormal brain activity begins, doctors will classify the seizures into two groups: focal or generalized.

Focal seizures show up when there is just one area of your brain with abnormal activity. Sometimes they are called partial seizures. Without a thorough examination, sometimes the symptoms of focal seizures are confused with other neurological disorders like narcolepsy or migraines. There are two types of focal seizures:

  • Focal seizures without loss of consciousness, previously known as simple partial seizures, means that some senses are altered. For example, emotions and the way things look, smell, taste, sound, or feel may change. There can also be some involuntary jolting of a body part, like a leg or an arm, with sensory symptoms like tingling, flashing lights, or dizziness.
  • Focal seizures with impaired awareness, once known as complex partial seizures,  means that there is a change or loss of consciousness and/or awareness. Someone having a focal seizure with impaired awareness may stare into space and not respond normally to their environment. They may also use repetitive movements like chewing, swallowing, hand rubbing, or walking in circles.

Generalized seizures appear in all area of the brain. There are six types known today: absence, tonic, tonic, clonic, myoclonic, and tonic-clonic.

  • Absence seizures, previously known as petit mal seizures, mean that the person stares into space or uses subtle movements like lip smacking and eye blinking. It can cause a brief loss of awareness. This type of seizure often occurs in children and can occur in clusters.
  • Tonic seizures affect the muscles in your back, arms, and legs and can cause you to fall to the ground due to the stiffening of your muscles.
  • Atonic seizures, also known as drop seizures, cause you to suddenly fall down due to a loss of muscle control.
  • Clonic seizures affect the arms, neck, and face. They show up by repeated jerking muscle movements.
  • Myoclonic seizures are little sudden twitches in your legs and arms.
  • Tonic-Clonic seizures, also known as grand mal seizures, are the most dramatic type of epileptic seizure a person can have. They can cause immediate and abrupt loss of consciousness, stiffening and shaking of the whole body, and sometimes a lack of bladder control and tongue biting.

What is epilepsy: how epilepsy affects the brain

Neurons are nerve cells that control the way we feel, think and move. Our neurons typically communicate using chemical and electrical signs, signals, and messages to each other that cause depolarization. When the signals are disrupted, damaged, or there are too many messages sent at once, is when a seizure begins.

Sometimes these neurons send out abnormal messages. If only a single neuron acts abnormal and sends out an unusual message, nothing will happen. But if lots of neurons, from the same area of the brain, being to send out unusual and abnormal messages together, for example, to have a seizure, then seizures can happen. There are three requirements for the unusual message to cause a seizure. First, each neuron has to be excited. Second, the message must be long enough to cause the other neurons to act in an identical way. Third, all of the neurons must be connected to other neurons within a few synapses. Once these conditions are met, the unusual seizure message spreads quickly. If the unusual message causes disrupted activity, this affects only a part of the brain which makes it a focal seizure. If the disrupted activity speaks to the whole brain, it becomes a generalized seizure. The part of the brain where the disruption (the neurons giving unusual messages) begins is known as the epileptic focus and is what doctors look for when finding out the causes of the seizures.

Because our brain has many different functions- such as memory, movement, moods, and all of our senses, a seizure can temporarily or seriously affect each and every one of these.

What is epilepsy: how epilepsy affects the body

Epilepsy doesn’t just affect our brain, but also our body and organs. Some examples include:

  • The heart is affected by an abnormal heartbeat. With enough seizures over time, people can develop regular abnormal heartbeats. Some doctors believe that sudden unexpected death in epilepsy (SUDEP)  is actually caused by an irregular heartbeat.
  • The lungs don’t always know how to keep rhythm and the breathing may become disrupted and labored. This is because the autonomic nervous system regulates our breathing. However, seizures disrupt this system and cause our breath to temporarily stop.
  • The reproductive system. Those with epilepsy commonly have up to two to three times more reproductive problems than those without epilepsy.
  • While epilepsy itself doesn’t weaken bones, the drugs many people take for epilepsy will weaken the skeletal system.
  • The effects seizures on the digestive system can involve abdominal pain or irritable bowels as well as loss of bowel control.
  • The entire muscular system can be affected because some seizures cause our muscles to tighten suddenly while others cause our muscles to go completely limp.

What is epilepsy: diagnosis of epilepsy

A person is diagnosed as epileptic when they have two unprovoked seizures that were not caused by a known and reversible medical condition like low blood sugar or alcohol withdrawal. Common ways a doctor diagnosis epilepsy after reviewing the symptoms and medical history is to run some tests. This may include:

  • Blood tests to check for infections and genetic conditions.
  • Lumbar puncture (spinal tap) is a needle that is placed into the lower back and spinal cord. The cerebral spinal fluid- the fluid that bathes the spinal cord and brain- that is removed is looked at for infections or any other problems.
  • A neurological exam to test behavior, mental function, motor skills, and be able to diagnose and determine the type of epilepsy.
  • Neuropsychological tests are tests given by doctors to look at your thinking, speech, and memory skills to see what areas of the brain are affected.
  • An electroencephalography (EEG) is the most common test for diagnosing epilepsy because it records the electrical activity in our brains. The EEG is able to see the changes in our normal brain wave pattern.
  • High-density EEG to see more precisely which areas of the brain are being affected by the seizures. A high-density EEG is the same as an EEG, but the electrodes are closer together, about half a centimeter apart than a normal EEG.
  • Computerized tomography scan (CT scan) which uses X-rays to look at the cross-sectional images of the brain. It can show brain abnormalities that could be causing the seizures like tumors or cysts.
  • Magnetic resonance imaging (MRI) uses powerful magnets and radio waves to show a highly detailed view of the brain. An MRI can detect brain lesions or abnormalities that could be the root cause of the seizures.
  • Functional MRI (fMRI) involves measuring the blood flow to specific parts of the brain when they are working. For example, looking at the areas of speech and movement before surgery so doctors can avoid injuring those places of the brain while operating.
  • Curry analysis takes the EEG data and puts it into an MRI of the brain to show where the seizures are taking place.
  • Positron emission tomography scan (PET Scan) injects a small amount of low-dose radioactive material into a vein to help see the active areas of the brain and be able to see abnormalities.
  • Single-photon emission computerized tomography scan (SPECT Scan) is used if the MRI and the EEG didn’t show the brain location where the seizures are originating. Like the PET Scan, it injects radioactive material into a vein to create a 3D map of the activity of the blood flow during seizures.
  • Statistical parametric mapping (SPM) compares the areas of the brain that have an increased metabolism during seizures. This can tell doctors where seizures began, in theory.
  • Magnetoencephalography (MEG) measures the magnetic fields that are produced by brain activity to help show possible areas of where the seizures start.

What is epilepsy: treatments

Typically, doctors begin to treat epilepsy with medication. If that doesn’t work, then they may try to fix epilepsy with surgery or therapy.

Many people can become one seizure-free by taking an anti-seizure/antiepileptic medication. Other people can have a decreased frequency or intensity of seizures by taking a combination of medications.

Epilepsy surgery involves removing the area of the brain that’s causing the seizures. Doctors will only perform the surgery if the area of the brain is small and well-defined, and if it doesn’t interfere with functions that we need every day like language, speech, motor, hearing, or vision. Even with surgery, many people will still need to take some sort of medication to prevent the seizures after a successful surgery.

There are some therapies that seem to work for some people, as well. The vagus nerve stimulation is like a little pacemaker that goes underneath the skin of the chest. The wires from the stimulator are connected to the vagus nerve in the neck. The idea is that it sends bursts of energy to our brain via the vagus nerve. Although it’s not clear how it stops seizures, it can usually reduce seizures by 20%-40%. Some younger people with epilepsy may be able to use the Ketogenic diet in order to reduce their seizures. It is a strict diet low in carbohydrates and high in fats.

What is epilepsy: Prognosis

Epilepsy is the fourth most common neurological disorder. However, the prognosis of it depends on each person and their seizures. Around 80% of people with epilepsy require ongoing treatment to prevent further seizures. Age, family history, infections, and other present disorders will affect how likely it is that the seizures will get better or even stop.

What is epilepsy: Social Stigma

What is the social stigma around epilepsy? Some people with epilepsy feel a social stigma, almost a shame, for having epilepsy because it leaves them out of certain things. Sometimes a child with epilepsy will be told they can’t participate in a school activity (which is illegal) or not invited to a birthday party. Furthermore, many healthcare and car insurance providers may not like to take on someone with epilepsy because they may not have the proper coverage, but they also pose a big risk factor. For example, there is a high risk of someone with epilepsy and frequent seizures crashing their car. However, that does not mean that they are a less safe driver than someone without epileptic seizures.

What is epilepsy

How to support someone with epilepsy

Make sure that someone with epilepsy:

  • Takes their medication correctly.
  • Getting enough sleep
  • Exercising
  • Wearing a medical alert bracelet in order to be treated correctly by medical personnel in case of emergency.
  • Let them live as independently as possible. For example, continuing to work.
  • Become educated about epilepsy!
  • Find a doctor that everyone likes
  • Find an epilepsy support group for both yourself and them.

Have you or anyone you know had epilepsy? How did they handle it? Let us know in the comments below!

Neuroimaging: What is it and how can it map the brain?

One of the ways psychology has progressed came from the use of various neuroimaging methods. In terms of experimental psychology history, neuroimaging started with the cognitive revolution. Many scientists realized that understanding the brain plays an enormous role in the external behavior.  Scientists also use neuroimaging methods and technique prevention, diagnosis and treatment for different neurological diseases.

Today we still do not have a clear cut picture of the whole brain in itself. Not every network has been mapped, but we have moved forward a substantial amount. The development of non-invasive and invasive neuroimaging methods and their use for research and medical purposes was a definite breakthrough.

Neuroimaging

Neuroimaging-What can we map?

When one thinks about the brain and the nervous system, one can think of many things to map. Of course, we have the brain itself, its parts and the functions of the anatomical functions. We have neuroimaging techniques who deal exactly with that. Despite the anatomy, however, there are many neuroimaging methods that try to look at things on a more microscopic level.

We have methods that can view the cortical areas of the brain. Other techniques look at cortical columns and different layers. We have methods that can record a single cell by itself. Going even further, we can look at the soma of the neuron, the dendrite and, separately the axons. We can even look at the synaptic connections between the two neurons.

Neuroimaging- Method Classification

Neuroimaging methods also do not just encompass the spatial resolution. We try to look into proteins, organelles, bacteria, mammalian cells, the brain of various species and, finally, human brains. Many neuroimaging methods also differ by the temporal resolution. They differ by how quickly they are able to detect an event that happens in the brain. These neuroimaging methods differ by milliseconds, seconds, minutes, hours and days. They also differ by the spatial resolution. Some methods can show anatomical structures well, while others cannot. Apart from that, the variety of the neuroimaging methods differs by how non-invasive and invasive they are.

If one can imagine, scientists use a lot more non-invasive neuroimaging methods in research. Not many regular participants agree to something that can potentially alter their brain functions. Medical practitioners are a lot more likely to use invasive neuroimaging methods in an attempt to treat certain diseases. Various patients with neurological diseases benefit on a daily basis from the invasive neurological methods. In some cases, the patients themselves are able to control the stimulating method.

Electrophysiological techniques

For many years now we know that neurons are able to generate electric potentials. We also know that the synaptic activity of the nervous matter is similar to a battery. It acts as an electric generator.

If we recall the first class in physiology we took, we can roughly remember the structure of the neuron. Words like the cell body or the soma, dendrites and an axon come to mind. Dendrites seem to be able to receive electrical signals. Axon sends electrical signals to the dendrite of the next neuron. The cell body combines the signals from the previous neurons. Then it sends another signal along the axon for the next neuron.

Within the neurons themselves, we are able to distinguish two different types of electrical activity.

1-Action potentials

The action potential is a very common concept that many students learn in their first class on the nervous system. The entire process happens for about 1 ms and culminates with the release of neurotransmitters in the end of the axons.

  • The stimulus from a previous neuron activates the voltage gates on sodium channels which will cause the influx of positively charged sodium to the cell.
  • This depolarizes the membrane. Sometimes the depolarization of the membrane is able to reach the threshold.
  • If that happens, a series of events happen in order to send the signal along the axon to the next neuron. This is what we call an action potential.
  • The potassium channels are still closed and since we have an influx of sodium, the membrane becomes more positive on the inside then it does on the outside.
  • After that, the channels for sodium close and, therefore, the influx of sodium stops as well.
  • That’s when the potassium channels stay open and the potassium comes out of the cell and makes the inside of the cell negative one more time. This repolarization of the neuron can lead to the overall voltage to be below the original resting potential
  • This happens due to the fact that the potassium channels stay open a little longer. This ends in hyperpolarization. During this period a new action potential cannot happen and this is what we call a refractory period of the neuron.
    • Scientists cannot record action potentials via surface electrodes. As of today, we are not able to record potentials from a single neuron. What we can record is the second type of electrical activity. We can, however, use intracranial electroencephalography (EEG) to measure them which happens to be an invasive technique.

2- Post-synaptic potentials

They last for hundreds of milliseconds and it is the addition of the potential from various neurons that happen at the same time. We are able to record the potentials together. Researchers can easily record these potentials from surface electrodes. Electroencephalography (EEG) can measure these types of potentials.

So, in the end, we are able to distinguish two principal types of neuroimaging methods that measure the electrical activity of the neuron.

Two principal types of electrophysiological techniques

  • Single-cell recordings
    • These recordings are able to measure a number of different action potentials every second. The electrodes will be place inside a single cell or nearby a neuron which makes the technique invasive.
    • This technique can be useful for researchers who want to understand how single cells work.
    • Due to the fact that this technique allows measuring single neurons, we are able to see how specific these cells are.
    • A paper published saying that single neurons were firing to Jennifer’s Aniston’s face and nobody else’s. This level of object recognition falls under very high-level vision neurons and the paper gained a lot of attention due to such a strange working of a single neuron. (1)
  • Event-related potentials (ERP)
    • These recordings get the summation of different electrical potentials for a variety of neurons (millions of them). This technique places electrodes on the skull, therefore, they are surface electrodes.

Electroencephalography & Event-Related Potentials (ERP)

Since we now know that the brain produces electrical potentials, we are able to measure them. Electroencephalography helps us do that. Scientists can place various electrodes on the surface of the scalp and then measure the bio-electrical activity that the brain produces. Event-related potentials (ERP) are the potentials from various neurons that happen as a result of different stimuli given by the scientist to the participant. Stimuli and the tasks that the researchers assign can range from motor, to sensory and cognitive.

So the scientists are able to measure where and when the neurons will spike as a result of a certain assigned stimuli. Researchers have been able to find various ERP components or similarly distributed neurons that fire at the same time. They found various ERP components related to language, visual attention, auditory components (famous concepts like the mismatch negativity) and many others.

Other neuroimaging methods

Magnetoencephalography (MEG)

Neuroimaging methods don’t just stop at measuring the electrical activity of the neurons. Another famous brain imaging technique is MEG – it records magnetic fields. Electrical currents that already occur in the brain generate magnetic fields. MEG is able to directly measure the brain function which is a huge advantage when comparing it with other techniques. Apart from that, it has very high temporal resolution and high spatial resolution which is one of the rarest things when it comes to brain research. Usually, neuroimaging methods are either higher in spatial resolution or in temporal resolution, not both.

MEG is non-invasive. Scientists are able to use it with other neuroimaging methods at the same time – like EEG. One big disadvantage of MEG comes from the fact that in order to get the magnetic fields, a special room that gets rid of other types of magnetic interference needs to be built. Due to this, the machine is quite costly, but one of the best methods for measuring brain activity as of today.

Other famous types of brain imaging do not measure direct brain activity, however, they have quite good spatial resolution and are often used for clinical and diagnostic purposes.

Positron Emission Tomography (PET)

This technique gives an image of brain activity, however, in order to produce that image radioactive material needs to be either inhaled or injected by the participant. The image will then be produced due to this radioactive material going to the areas of the brain that are active.

Computed Tomography Scan (CT Scan)

This technique is able to produce brain images as well. It is able to show the anatomy of the brain, however, not the functions themselves which are a serious drawback especially if we consider the fact that X-ray lights need to go through the head to produce the image.

Magnetic Resonance Imaging (MRI)

MRI – Neuroimaging

One of the most common techniques nowadays. It gives an image of anatomical structures in the brain. It is non-invasive, but the patient must remain still in the MRI chamber which could prove to be quite painful for those suffering from claustrophobia. Apart from that, any type of metallic devices cannot be put in the chamber so many patients and subjects are not able to get a scan.

Functional Magnetic Resonance Imaging (fMRI)

An upgrade from the MRI – this technique detects the blood-oxygen-level dependent contrast imaging (BOLD) levels in the brain which are the changes in the blood flow and it not only gives the anatomical structures but the functions as well. Various colors will change depending on which part of the brain is active. The big drawback with this technique is the fact that it does not directly measure brain activity, but BOLD signal so we cannot for sure say that the activity that we find via fMRI studies is fully accurate and is produced by neurons.

Diffusion Tensor Imaging (DTI)

A technique based on MRI and it measures the way the water can travel through the white matter in the brain. It can show the activity as the colored area on the image. It’s very good in detecting concussions so can be used in clinical applications which is a huge advantage. Again, it does not measure direct brain activity which is a huge disadvantage and sometimes it also distorts the images. DTI has a quite low spatial resolution.

Transcranial Magnetic Stimulation (TMS)

The electric field that TMS is able to generate is able to interfere with the action potentials that are happening in the brain. It’s a highly invasive technique and is able to be used in research applications for the workings of many diseases and pathologies. What we do know is that repetitive TMS is able to produce seizures so, obviously, it has some sort of side effects and needs to be used with caution.

Neuroimaging- New Developments in Neuroscience

New neuroimaging methods and brain imaging techniques are being developed nowadays and, perhaps, soon enough we will be able to not only map the entire anatomical structures of the brain but functions as well. As of right now, these are the majority of the neuroimaging methods that are used in cognitive neuroscience. Maybe, in a few years, we will be able to develop a low-cost neuroimaging technique that has both high spatial and temporal resolution and is non-invasive to the participants!

References

Quiroga RQ, Reddy L, Kreiman G, Koch C, Fried I. Invariant visual representation by single neurons in the human brain. Nature [Internet]. 2005;435(7045):1102–7. Available from: http://www.nature.com.zorac.aub.aau.dk/nature/journal/v435/n7045/abs/nature03687.html%5Cnhttp://www.nature.com.zorac.aub.aau.dk/nature/journal/v435/n7045/pdf/nature03687.pdf