Narcolepsy is a neurological sleep disorder characterized by chronic, excessive attacks of drowsiness during the day, sometimes called excessive daytime sleepiness (EDS). Attacks of drowsiness may persist for only a few seconds or several minutes. These episodes vary in frequency from a few incidents to several during a single day. Nighttime (nocturnal) sleep patterns may also be disrupted. Three additional symptoms often associated with narcolepsy are sudden extreme muscle weakness (cataplexy), a specific type of hallucination that occurs just before falling asleep or upon awakening, and brief episodes of paralysis while waking up. Narcolepsy also may be associated with "automatic behavior", i.e. doing something automatically without any memory afterward. The incidence of narcolepsy is approximately 1 in 2,000 and most researchers believe that the disorder remains undiagnosed or misdiagnosed in many cases.

There is increasing evidence that narcolepsy is an autoimmune disorder. Autoimmune disorders are caused when the body's immune system mistakenly attacks healthy tissue or cells. In narcolepsy, the immune system destroys certain brain cells that produce a peptide called hypocretin. Hypocretin impacts on many brain functions, but the details of its actions are not yet understood. Why the immune system attacks healthy cells in narcolepsy is unknown and additional environmental and genetic factors may play a role in the development of the disorder.

Symptoms vary depending on the type of seizure. In most cases, a person with epilepsy will tend to have the same type of seizure each time, so the symptoms will be similar from episode to episode.

Doctors generally classify Seizures as either focal or generalized, based on how and where the abnormal brain activity begins.

Focal seizures

When Seizures appear to result from abnormal activity in just one area of your brain, they're called focal seizures. These Seizures fall into two categories:

• Focal Seizures without loss of consciousness. Once called simple partial seizures, these Seizures don't cause a loss of consciousness. They may alter emotions or change the way things look, smell, feel, taste or sound. Some people experience deja vu. This type of seizure may also result in involuntary jerking of one body part, such as an arm or leg, and spontaneous sensory symptoms such as tingling, Dizziness and flashing lights.
• Focal Seizures with impaired awareness. Once called complex partial seizures, these Seizures involve a change or loss of consciousness or awareness. This type of seizure may seem like being in a dream. During a focal seizure with impaired awareness, you may stare into space and not respond normally to your environment or perform repetitive movements, such as hand rubbing, chewing, swallowing or walking in circles.

Symptoms of focal Seizures may be confused with other neurological disorders, such as migraine, narcolepsy or mental illness. A thorough examination and testing are needed to distinguish epilepsy from other disorders.

Generalized seizures

Seizures that appear to involve all areas of the brain are called generalized seizures. Six types of generalized Seizures exist.

• Absence seizures. Absence seizures, previously known as petit mal seizures, typically occur in children. They're characterized by staring into space with or without subtle body movements such as eye blinking or lip smacking and only last between 5-10 seconds. These Seizures may occur in clusters, happening as often as 100 times per day, and cause a brief loss of awareness.
• Tonic seizures. Tonic Seizures cause stiff muscles and may affect consciousness. These Seizures usually affect muscles in your back, arms and legs and may cause you to fall to the ground.
• Atonic seizures. Atonic seizures, also known as drop seizures, cause a loss of muscle control. Since this most often affects the legs, it often causes you to suddenly collapse or fall down.
• Clonic seizures. Clonic Seizures are associated with repeated or rhythmic, jerking muscle movements. These Seizures usually affect the neck, face and arms.
• Myoclonic seizures. Myoclonic Seizures usually appear as sudden brief jerks or twitches and usually affect the upper body, arms and legs.
• Tonic-clonic seizures. Tonic-clonic seizures, previously known as grand mal seizures, are the most dramatic type of epileptic seizure. They can cause an abrupt loss of consciousness and body stiffening, twItching and shaking. They sometimes cause loss of bladder control or biting your tongue.

Epilepsy has no identifiable cause in about half the people with the condition. In the other half, the condition may be traced to various factors, including:

• Genetic influence. Some types of epilepsy, which are categorized by the type of seizure you experience or the part of the brain that is affected, run in families. In these cases, it's likely that there's a genetic influence.

  Researchers have linked some types of epilepsy to specific genes, but for most people, genes are only part of the cause of epilepsy. Certain genes may make a person more sensitive to environmental conditions that trigger seizures.

• Head trauma. Head trauma as a result of a car accident or other traumatic injury can cause epilepsy.
• Brain abnormalities. Abnormalities in the brain, including brain tumors or vascular malformations such as arteriovenous malformations (AVMs) and cavernous malformations, can cause epilepsy. Stroke is a leading cause of epilepsy in adults older than age 35.
• Infections. Meningitis, HIV, viral encephalitis and some parasitic infections can cause epilepsy.
• Prenatal injury. Before birth, babies are sensitive to brain damage that could be caused by several factors, such as an infection in the mother, poor nutrition or oxygen deficiencies. This brain damage can result in epilepsy or cerebral palsy.
• Developmental disorders. Epilepsy can sometimes be associated with developmental disorders, such as autism.

Doctors generally begin by treating epilepsy with medication. If medications don't treat the condition, doctors may propose surgery or another type of treatment.

Medication

Most people with epilepsy can become seizure-free by taking one anti-seizure medication, which is also called anti-epileptic medication. Others may be able to decrease the frequency and intensity of their seizures by taking a combination of medications.

Many children with epilepsy who aren't experiencing epilepsy symptoms can eventually discontinue medications and live a seizure-free life. Many adults can discontinue medications after two or more years without seizures. Your doctor will advise you about the appropriate time to stop taking medications.

Finding the right medication and dosage can be complex. Your doctor will consider your condition, frequency of seizures, your age and other factors when choosing which medication to prescribe. Your doctor will also review any other medications you may be taking, to ensure the anti-epileptic medications won't interact with them.

Your doctor likely will first prescribe a single medication at a relatively low dosage and may increase the dosage gradually until your seizures are well controlled.

There are more than 20 different types of anti-seizure medications available. The medication that your doctor chooses to treat your epilepsy depends on the type of seizures you have, as well as other factors such as your age and other health conditions.

These medications may have some side effects. Mild side effects include:

• Fatigue
• Dizziness
• Weight gain
• Loss of bone density
• Skin rashes
• Loss of coordination
• Speech problems
• Memory and thinking problems

More-severe but rare side effects include:

• Depression
• Suicidal thoughts and behaviors
• Severe rash
• Inflammation of certain organs, such as your liver

To achieve the best seizure control possible with medication, follow these steps:

• Take medications exactly as prescribed.
• Always call your doctor before switching to a generic version of your medication or taking other prescription medications, over-the-counter drugs or herbal remedies.
• Never stop taking your medication without talking to your doctor.
• Notify your doctor immediately if you notice new or increased feelings of depression, suicidal thoughts, or unusual changes in your mood or behaviors.
• Tell your doctor if you have migraines. Doctors may prescribe one of the anti-epileptic medications that can prevent your migraines and treat epilepsy.

At least half the people newly diagnosed with epilepsy will become seizure-free with their first medication. If anti-epileptic medications don't provide satisfactory results, your doctor may suggest surgery or other therapies. You'll have regular follow-up appointments with your doctor to evaluate your condition and medications.

Surgery Epilepsy surgery

When medications fail to provide adequate control over seizures, surgery may be an option. With epilepsy surgery, a surgeon removes the area of your brain that's causing seizures.

Doctors usually perform surgery when tests show that:

• Your seizures originate in a small, well-defined area of your brain
• The area in your brain to be operated on doesn't interfere with vital functions such as speech, language, motor function, vision or hearing

For some types of epilepsy, minimally invasive approaches such as MRI-guided stereotactic laser ablation may provide effective treatment when an open procedure may be too risky. In these procedures, doctors direct a thermal laser probe at the specific area in the brain causing seizures to destroy that tissue in an effort to better control the seizures.

Although many people continue to need some medication to help prevent seizures after successful surgery, you may be able to take fewer drugs and reduce your dosages.

In a small number of cases, surgery for epilepsy can cause complications such as permanently altering your thinking (cognitive) abilities. Talk to your surgeon about his or her experience, success rates, and complication rates with the procedure you're considering.

Therapies Vagus nerve stimulation Open pop-up dialog box Close Vagus nerve stimulation Vagus nerve stimulation

In vagus nerve stimulation, an implanted pulse generator and lead wire stimulate the vagus nerve, which leads to stabilization of abnormal electrical activity in the brain.

Deep brain stimulation Open pop-up dialog box Close Deep brain stimulation Deep brain stimulation

Deep brain stimulation involves implanting an electrode deep within the brain. The amount of stimulation delivered by the electrode is controlled by a pacemaker-like device placed under the skin in your chest. A wire that travels under your skin connects the device to the electrode.

MRI of deep brain stimulation Open pop-up dialog box Close MRI of deep brain stimulation MRI of deep brain stimulation

A magnetic resonance imaging (MRI) scan of deep brain stimulation shows the location of electrodes placed in the brain.

Apart from medications and surgery, these potential therapies offer an alternative for treating epilepsy:

• Vagus nerve stimulation. In vagus nerve stimulation, doctors implant a device called a vagus nerve stimulator underneath the skin of your chest, similar to a heart pacemaker. Wires from the stimulator are connected to the vagus nerve in your neck.

  The battery-powered device sends bursts of electrical energy through the vagus nerve and to your brain. It's not clear how this inhibits seizures, but the device can usually reduce seizures by 20-40%.

  Most people still need to take anti-epileptic medication, although some people may be able to lower their medication dose. You may experience side effects from vagus nerve stimulation, such as throat pain, hoarse voice, shortness of breath or coughing.

• Ketogenic diet. Some children with epilepsy have been able to reduce their seizures by following a strict diet that's high in fats and low in carbohydrates.

  In this diet, called a ketogenic diet, the body breaks down fats instead of carbohydrates for energy. After a few years, some children may be able to stop the ketogenic diet — under close supervision of their doctors — and remain seizure-free.

  Consult a doctor if you or your child is considering a ketogenic diet. It's important to make sure that your child doesn't become malnourished when following the diet.

  Side effects of a ketogenic diet may include dehydration, constipation, slowed growth because of nutritional deficiencies and a buildup of uric acid in the blood, which can cause kidney stones. These side effects are uncommon if the diet is properly and medically supervised.

  Following a ketogenic diet can be a challenge. Low-glycemic index and modified Atkins diets offer less restrictive alternatives that may still provide some benefit for seizure control.

• Deep brain stimulation. In deep brain stimulation, surgeons implant electrodes into a specific part of your brain, typically your thalamus. The electrodes are connected to a generator implanted in your chest. The generator regularly sends electrical pulses to your brain at timed intervals, and may reduce your seizures. Deep brain stimulation is often used for people whose seizures don't get better with medication.
• Responsive neurostimulation. These implantable, pacemaker-like devices can help significantly reduce how often seizures occur. These responsive stimulation devices analyze brain activity patterns to detect seizures as they start and deliver an electrical charge or drug to stop the seizure before it causes impairment. Research shows that this therapy has few side effects and can provide long-term seizure relief.

Potential future treatments

Researchers are studying many potential new treatments for epilepsy, including:

• Continuous stimulation of the seizure onset zone (subthreshold stimulation). Subthreshold stimulation — continuous stimulation to an area of your brain below a level that's physically noticeable — appears to improve seizure outcomes and quality of life for some people with seizures. Subthreshold stimulation helps stop a seizure before it happens. This treatment approach may work in people who have seizures that start in an area of the brain that can't be removed because it would affect speech and motor functions (eloquent area). Or it might benefit people whose seizure characteristics mean their chances of successful treatment with responsive neurostimulation are low.
• Minimally invasive surgery. New minimally invasive surgical techniques, such as MRI-guided focused ultrasound, show promise at treating seizures with fewer risks than traditional open-brain surgery for epilepsy.
• Transcranial magnetic stimulation (TMS). TMS applies focused magnetic fields on areas of the brain where seizures occur to treat seizures without the need for surgery. It may be used for patients whose seizures occur close to the surface of the brain and are not candidates for surgery.
• External trigeminal nerve stimulation. Similar to vagus nerve stimulation, this device would stimulate specific nerves to reduce frequency of seizures. But unlike vagus nerve stimulation, this device would be worn externally so that no surgery to implant the device is needed. In studies, external trigeminal nerve stimulation provided improvements in both seizure control and mood.

Certain factors may increase your risk of epilepsy:

• Age. The onset of epilepsy is most common in children and older adults, but the condition can occur at any age.
• Family history. If you have a family history of epilepsy, you may be at an increased risk of developing a seizure disorder.
• Head injuries. Head injuries are responsible for some cases of epilepsy. You can reduce your risk by wearing a seat belt while riding in a car and by wearing a helmet while bicycling, skiing, riding a motorcycle or engaging in other activities with a high risk of head injury.
• Stroke and other vascular diseases. Stroke and other blood vessel (vascular) diseases can lead to brain damage that may trigger epilepsy. You can take a number of steps to reduce your risk of these diseases, including limiting your intake of alcohol and avoiding cigarettes, eating a healthy diet, and exercising regularly.
• Dementia. Dementia can increase the risk of epilepsy in older adults.
• Brain infections. Infections such as meningitis, which causes inflammation in your brain or spinal cord, can increase your risk.
• Seizures in childhood. High fevers in childhood can sometimes be associated with seizures. Children who have seizures due to high fevers generally won't develop epilepsy. The risk of epilepsy increases if a child has a long fever-associated seizure, another nervous system condition or a family history of epilepsy.