Posts Tagged focal seizures

[Abstract] Focal onset seizure prediction using convolutional networks


Objective: This work investigates the hypothesis that focal seizures can be predicted using scalp electroencephalogram (EEG) data. Our first aim is to learn features that distinguish between the interictal and preictal regions. The second aim is to define a prediction horizon in which the prediction is as accurate and as early as possible, clearly two competing objectives.
Methods: Convolutional filters on the wavelet transformation of the EEG signal are used to define and learn quantitative signatures for each period: interictal, preictal, and ictal. The optimal seizure prediction horizon is also learned from the data as opposed to making an a priori assumption.
Results: Computational solutions to the optimization problem indicate a ten-minute seizure prediction horizon. This result is verified by measuring Kullback-Leibler divergence on the distributions of the automatically extracted features.
Conclusions: The results on the EEG database of 204 recordings demonstrate that
  1. the preictal phase transition occurs approximately ten minutes before seizure onset, and
  2. (the prediction results on the test set are promising, with a sensitivity of 87.8% and a low false prediction rate of 0.142 FP/h.
Our results significantly outperform a random predictor and other seizure prediction algorithms.
Significance: We demonstrate that a robust set of features can be learned from scalp EEG that characterize the preictal state of focal seizures.

via Focal onset seizure prediction using convolutional networks – IEEE Journals & Magazine

, , , , , , , , , , , , ,

Leave a comment

[WEB SITE] What should you do if a friend has a seizure?

Seizures are a fairly common occurrence, but would you know what to do – and what not to do – if you witnessed one?

Ten percent of people are expected to experience a seizure at some point during their lifetime, but would you know what to do if someone was having a seizure right next to you? Would you recognize it for what it was? Here, we give you an overview of different types of seizures and offer some helpful first aid tips.

Seizures normally take place when there is an abnormal “spike” of electrical activity in the brain. More often than not, seizures are associated with brain conditions (usually epilepsy) but can sometimes also be experienced by people without an epilepsy diagnosis.

In the United States, 3 million adults and 470,000 children have epilepsy, according to estimatesfrom the Centers for Disease Control and Prevention (CDC). This means that 1 in 10 people may experience a seizure in their lifetime.

Epileptic seizures fall under two categories: generalized seizures (in which the whole brain is affected), and focal, or partial, seizures (which are localized and only affect one part of the brain).

All types of seizures usually happen suddenly, and most people who experience them cannot tell that they are coming, so they will be unable to give any warning. Also, typically, an individual experiencing a seizure will not remember what happened during that episode.

One person prone to seizures due to her epilepsy describes her experiences.

A seizure feels like being dragged deep under water. I feel like I can’t catch my breath. For me, [it] feels like electricity stuns and weakens every nerve ending in my body. It feels as though black ink is bleeding inward from every which way, causing my vision to slowly fade out. My verbal communication is a pile of babbling gravel.”

Seizures can last from a few seconds to a few minutes (usually under 5), depending on the type and severity of the event.

Seizure do’s and don’ts

People who have epilepsy may experience one or several kinds of seizure. Below, we look at the different kinds of generalized and focal seizures and give you tips on how to recognize them, as well as how best to support someone who is experiencing them.

Generalized seizures

1. Absence seizures. Also referred to as “petit mal,” meaning “small harm” or “little illness” in French, these are unlikely to look like seizures to the unsuspecting external observer.

The person having an absence seizure will appear to be distracted or absent (hence its name), staring blankly into the distance and blinking rapidly. This kind of seizure will only last a few seconds, and the person experiencing it will typically not realize that they even had it.

Absence seizures do not require any intervention. Just stay calm, and once the seizure is over, treat the person as you normally would.

2. Tonic-clonic seizures. These seizures are the ones that you will likely have seen depicted in television shows and movies.

They do not manifest in the exact same way in all individuals but usually involve the individual crying out, falling down, losing awareness, experiencing muscle spasms (hence “tonic,” which refers to shaking and jerking) and stiffening (hence “clonic,” which refers to muscular stiffness), and breathing rapidly and with difficulty.

These seizures are also called “grand mal,” meaning “great harm” or “great illness” in French. They may last up to a few minutes, and they leave the person dazed and physically exhausted.

If you witness someone experiencing a tonic-clonic seizure, your main priority should be to ensure that they are safe and do not get hurt. Make sure to:

  • cluttered room

    If someone is having a tonic-clonic seizure, your top priority should be to make sure that they do not get injured. Move them away from any heavy furniture and remove any potentially dangerous objects from their vicinity.

    Ease them to the ground if possible, to avoid a severe fall that may hurt them.

  • Put something soft (such as a folded jacket or sweater) under their head, to avoid head injuries.
  • Move them away (if possible) from large objects, including hard furniture, sharp edges, or hot surfaces (such as heaters), that may injure them.
  • Remove any small, hard objects or sharp objects (such as knives) that may surround them, to make sure that they do not get hurt.
  • Loosen any tight clothing or accessories around their neck (including ties and scarves), to make sure that they can breathe properly. Also, remove eyeglasses or sunglasses.
  • Similarly, remove any clothing items that may surround them, and which may accidentally wind around their neck and suffocate them.
  • As soon as you can, roll them onto their side. This is the first aid recovery position, which will allow the person to breathe more easily.

You must absolutely not:

  • Hold the person down or attempt to restrain them in any way; this is very dangerous for everyone involved, as a person experiencing a seizure cannot control their movements.
  • Attempt to put anything in their mouth. A popular myth suggests that inserting a wooden spoon will prevent the individual from swallowing their tongue or from biting it. No one can swallow their own tongue, and while a person experiencing a seizure may bite theirs, trying to insert anything into their mouths will only succeed in hurting their gums and teeth or making them choke.
  • Attempt to perform cardiopulmonary resuscitation; the person will typically regain normal breathing patterns once the seizure subsides.

It is also very important that you stay calm throughout and do not forget to time the seizure. This is a crucial step because, according to CDC guidelines, you must call an ambulance if the seizure lasts for longer than 5 minutes.


Focal seizures

1. Simple focal seizures. A person experiencing one of these may exhibit twitchiness – particularly in the face muscles – and may think that they are smelling or tasting something strange. Similar to the absence seizure, the simple focal seizure does not require any special intervention and normally lasts between a few seconds and a couple of minutes.

2. Complex focal seizures. This seizure type will make the person feel confused and disorientated, and they may not be able to respond clearly to questions or sustain any kind of interaction.

If you notice that someone is experiencing a complex focal seizure, stay calm, try to direct them to someplace safe (for example, away from moving cars), and speak to them gently and reassuringly. Do not leave them until the seizure has subsided – usually after about 2 minutes – and they have regained full awareness.

3. Secondary generalized seizures. These will typically start out as a regular focal seizure, only to evolve into a generalized, tonic-clonic seizure. In this case, you should follow the same guidelines as those outlined above.

What about non-epileptic seizures?

Non-epileptic seizures (NES), or “psychogenic non-epileptic seizures,” are not linked to abnormal electrical activity in the brain in the same way that epileptic seizures are. Instead, these are often caused by psychological factors, such as exposure to extreme stress, or are linked to psychiatric disorders.

These types of seizure are normally of three kinds:

woman feeling anxious

Other conditions and disorders can cause non-epileptic seizures. A panic attack, for instance, can manifest in a similar way to a regular seizure.

  • dissociative, which means that the person experiencing them has no awareness of, or control over, the event
  • panic attacks, which can make the person feel faint and be unable to breathe, and which make their heart race
  • brought on by a psychiatric disorder that makes the person to want to “trigger” or “stage” a seizure because they want to attract a degree of medical or social attention

Dissociative seizures and panic attacks are the most common NES. The general first aid guidelines for NES are usually the same as for epileptic seizures, and they focus on keeping the person safe from injury as the seizure unfolds.

For more information on seizures in general, the people who experience them, and what you can do to help, you can visit the Epilepsy Foundation website.

Source: What should you do if a friend has a seizure?

, , , ,

Leave a comment

[WEB SITE] The epilepsy signs in children you need to watch out for

Mother and son smiling at each other, face to face

Epilepsy is a common condition affecting the brain, and almost one in every 100 people across all ages will have the condition. Irfan Malik, consultant neurosurgeon at the London Neurosurgery Partnership, part of The Harley Street Clinic, looks at some of the more obscure epilepsy symptoms to watch out for in children.

What is epilepsy?

Epilepsy is caused by a sudden burst of intense electrical activity in the brain. The resulting seizures can present themselves in various ways – it all depends on which part of the brain is affected. The most well-known type of epileptic seizure is the tonic-clonic, which affects the whole brain. It is probably the most noticeable form of epilepsy and is known as a generalised seizure. This is usually identified by involuntary jerking of the body and often results in the partial or total loss of consciousness or awareness.

Epilepsy also causes focal seizures which affect one particular part of the brain. The way these seizures present themselves can vary from person to person. This tends to be why diagnosis can be so tricky in children, as young people often present with a range of different symptoms. As a result, epilepsy in children is often picked up at a late stage.

What are the symptoms of focal seizures?

The brain is made up of four different lobes – the parietal, temporal, occipital and frontal. Each affects different aspects of your physical and mental function and, in turn, focal seizures located in one of these areas can result in rarer types of epileptic symptoms.

In most cases the following symptoms won’t be cause for concern, but given the variation in how focal seizures can present it’s important for parents and teachers to spot potential signs of epilepsy.

1. Absence

While children of all ages can have a tendency to stare off into the distance – or have short attention spans – in some young children this could be a symptom of Childhood Absence Epilepsy (CAE).

CAE syndrome triggers what are known as absence seizures. They usually last about 10 seconds and end abruptly, consisting of staring spells during where the child may not be aware or responsive. In many cases a child will then resume normal activity straight after the seizure and may not even be aware that it even happened, which can make it particularly hard to diagnose. Absence seizures can occur from anywhere between one to 100 times a day. If left undiagnosed they can go on to affect their performance at school, and cause tonic-clonic fits later on in life.

2. Deja-vu

Epilepsy located in the temporal lobes will affect your child’s functions, including things such as feelings, emotions, thoughts, and experiences. An example of this is seizures that appear as feelings of Deja-vu, and a sense that what’s happening has happened before. However in other cases some people can feel as if everything around them appears strange or foreign.

Father and daughter playing on swing

Epilepsy in the temporal part of the brain can also cause a strange taste in their mouth or to smell something that isn’t there. These seizures can vary in intensity and quality, with some being so mild that your child barely even notices.

3. Strange sensations

The Parietal lobe is known as the “association cortex” as it is responsible for connecting meaning to the brain’s functions, such as recognising sounds as words and what you see as visual images. Seizures in this part of the brain can result in strange sensations – known as sensory seizures – and can present in a number of ways. For example, some children often feel like a part of their body is missing, have difficulty understanding words, experience hallucinations and have feelings of numbness, heat, pressure or electricity. These can last anywhere from a few seconds to a few minutes.

4. Hallucinations

Epilepsy occurring in the occipital lobe – as the name suggests – will affect your child’s sight. This is usually hard to diagnose and tends to be rare. Symptoms can include seeing flashing lights or colours, patterns, or images that appear to repeat before the eyes. It can also affect vision, causing partial blindness.

5. Laughter

Perhaps one of the most surprising, signs of an epileptic seizure is laughter. Known as gelastic seizures – taken from the Greek word for laughter – this type of seizure will usually occur suddenly in your child, causing them to laugh, often hysterically for no obvious reason, and will seem completely out of place. It tends to be slightly more common in boys, however it’s very rare, affecting one of every 1,000 children with epilepsy.

Confirming diagnosis

Usually there’s nothing to worry about, however if you think your child might be exhibiting any symptoms of epilepsy then it’s best to visit a specialist epilepsy centre to confirm a diagnosis. A consultant will conduct an investigation which will usually involve a mixture of tests such as blood tests, an MRI scan, and an electroencephalogram (EEG) – a procedure which detects electrical activity in your child’s brain using small, flat metal discs (electrodes) attached to the scalp. Today, treatment is fairly straightforward and epilepsy can be managed with anti-epileptic drugs (AEDs) that help control seizures. Many children will even grow out of epilepsy as they get older.

Further information on epilepsy can be found at Epilepsy ActionThe London Neurosurgery Partnership at The Harley Street Clinic can provide an initial assessment service and offers support for children and their families who are looking for an epilepsy diagnosis.

Source: The epilepsy signs in children you need to watch out for

, , , , , , ,

Leave a comment

[WEB SITE] A Look at Epilepsy – Electrical Outbursts in the Brain

Illustration of a man holding a child; a doctor and patient; and a brain.When you hear the word epilepsy, you might think of intense seizures with muscle spasms and loss of consciousness. But most epilepsy seizures are surprisingly subtle and may be hard to recognize. These little spells can be an early warning sign of epilepsy, a brain disorder that strikes an estimated 1 in 26 Americans at some point in their lives. The sooner epilepsy is recognized, the sooner it can be treated and seizures prevented.

Most people know surprisingly little about epilepsy, even though it’s the nation’s 4th most common neurological disorder, after migraine, stroke, and Alzheimer’s disease. Epilepsy is marked by repeated, unpredictable seizures that may last for seconds or minutes. Seizures arise from abnormal bursts of electrical activity in the brain that trigger jerky movements, strange emotions or sensations, falls, or passing out.

“Epilepsy can strike people of all ages, from the moment of birth—even in the delivery room—up to older ages,” says Dr. Jeffrey Noebels, an epilepsy expert at Baylor College of Medicine. The condition is most likely to first arise in children and in adults over age 60. “Most types of epilepsy last a lifetime, but some are self-limited, meaning they can go away on their own,” Noebels adds.

The causes of epilepsy are varied. “Defects in genes are probably responsible for the largest fraction of epilepsy cases,” Noebels says. Scientists so far have linked more than 150 genes to epilepsy. “Other types of epilepsy can be acquired through trauma (such as head injury or stroke), infections, brain tumors, or other factors.”

Anything that disrupts the normal pattern of brain activity—from illness to brain damage to faulty brain development—can lead to seizures. But for up to half of people with epilepsy, the underlying cause is simply not known.

Types of seizures can also vary widely, which is why epilepsy is sometimes called a “spectrum disorder.” In some people, seizures may appear only occasionally. At the other end of the spectrum, a person may have hundreds of seizures a day. The seizures can be severe, with convulsions, loss of consciousness, or even sudden death in rare cases. Or seizures may be barely noticeable.

Such subtle seizures—sometimes called partial or focal seizures—can cause feelings of déjà vu (feeling that something has happened before); hallucinations (seeing, smelling, or hearing things that aren’t there); or other seemingly mild symptoms. During some seizures, a person may stop what they’re doing and stare off into space for a few seconds without being aware of it.

“These little spells or seizures can sometimes occur for years before they’re recognized as a problem and diagnosed as epilepsy,” says Dr. Jacqueline French, who specializes in epilepsy treatment at the New York University Langone Medical Center. “They can be little spells of confusion, little spells of panic, or feeling like the world doesn’t look real to you.”

The symptoms of these small seizures generally depend on which brain regions are affected. Over time, these types of seizures can give rise to more severe seizures that affect the whole brain. That’s why it’s important to get diagnosed and begin epilepsy treatment as soon as possible. “If you notice a repeating pattern of unusual behaviors or strange sensations that last anywhere from a few seconds to a few minutes, be sure to mention it to your doctor or pediatrician,” French says.

Over the past few decades, NIH-funded scientists have been working to develop better approaches for diagnosing, treating, and understanding epilepsy. The condition can now be diagnosed through imaging tools like MRI or CT scans, by testing blood for defective genes, or by measuring the brain’s electrical activity. Seizures can often be controlled with medications, special diets, surgery, or implanted devices. But there’s still a need for improved care.

“Traditional medications for treating epilepsy are effective but problematic,” says Dr. Ivan Soltesz, who studies epilepsy at Stanford University. “About 1 in 3 patients has drug-resistant epilepsy, meaning that available drugs can’t control the seizures. In these cases, surgical removal of brain tissue may be the best option.” When the drugs do work, he explains, they can also cause numerous side effects, including fatigue, abnormal liver function, and thinking problems.

One issue with today’s medicines is they aren’t targeted to the malfunctioning brain cells. Rather, they tend to affect the whole brain. “The drugs are also not specific in terms of the timing of treatment,” Soltesz says. “The medications are always in the body, even when the seizures are not occurring.”

He and other researchers are working to create highly targeted epilepsy therapies that are delivered only to malfunctioning brain regions and only when needed to block a seizure. So far, they’ve developed an experimental approach that can stop epilepsy-like seizures as they begin to occur in a mouse. The scientists hope to eventually translate those findings for use in people who have epilepsy.

In another line of NIH-funded research, a team of scientists is studying a deadly and poorly understood condition called SUDEP (for sudden unexpected death in epilepsy). “Most people with epilepsy live long and happy lives. But SUDEP is the most common cause of the shorter lifespan that can occur with epilepsy,” says Noebels. “It’s been a real mystery. We haven’t known who’s at greatest risk for this premature death. It can happen to different people who have epilepsy, from all walks of life.”

Noebels and his colleagues have identified several mouse genes that seem related to both sudden-death seizures and heart rhythm problems. The researchers are now searching for similar human genes that may help predict who’s most at risk for SUDEP. “We believe that SUDEP doesn’t have to happen—that we can learn about it, predict it, and eventually find better ways to prevent it in every patient,” Noebels says.

You can take steps to reduce some risk factors for epilepsy. Prevent head injuries by wearing seatbelts and bicycle helmets, and make sure kids are properly secured in car seats. Get proper treatment for disorders that can affect the brain as you age, such as cardiovascular disease or high blood pressure. And during pregnancy, good prenatal care can help prevent brain problems in the developing fetus that could lead to epilepsy and other problems later in life.

“We’ve made exciting advances to date in our understanding of epilepsy, its prevention, and treatment,” says French. “But there’s still much we have to learn, and much we’re actively working to improve.”

The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia. Jehi L, Friedman D, Carlson C, Cascino G, et al. Epilepsia. 2015 Oct;56(10):1526-33. doi: 10.1111/epi.13116. Epub 2015 Aug 7. PMID: 26250432.

On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy. Krook-Magnuson E, Armstrong C, Oijala M, Soltesz I. Nat Commun. 2013;4:1376. doi: 10.1038/ncomms2376. PMID: 23340416.

Sudden unexpected death in epilepsy: Identifying risk and preventing mortality. Lhatoo S, Noebels J, Whittemore V; NINDS Center for SUDEP Research. Epilepsia. 2015 Nov;56(11):1700-6. doi: 10.1111/epi.13134. Epub 2015 Oct 23. PMID: 26494436.

NIH News in Health, November 2015

, , , ,

Leave a comment

[WEB SITE] Epilepsy with Partial Seizures – Leaflet

About 1 in 30 people in the UK develop epilepsy at some stage. It most commonly starts in childhood and in people aged over 60. However, epilepsy can begin at any age. Seizures are well controlled by treatment in about 4 in 5 cases. There are different types of epilepsy. This leaflet is about epilepsy with partial seizures. Partial seizures are also called focal seizures. Other leaflets in this series include:

  • Epilepsy – A General Introduction
  • Epilepsy – Childhood Absence Seizures
  • Epilepsy – Could It Be?
  • Epilepsy – Living With Epilepsy
  • Epilepsy – Treatments
  • Epilepsy – Tonic-clonic Seizures
  • Epilepsy – Dealing With a Seizure
  • Epilepsy – Contraception/Pregnancy Issues
  • Epilepsy and Sudden Unexpected Death

Continue –> Epilepsy with Partial Seizures | Health |

, , ,

Leave a comment

%d bloggers like this: