Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body. Your nerves take in information from your senses and send it to the brain to be processed. Your brain and nerves also communicate to help you move and to control your body's functions.

When the brain is healthy, it works quickly and automatically. But when you have a brain disease, it may affect how well you can function and do your daily activities. Some common brain diseases include:

• Brain tumors, which can press on nerves and affect brain function.
• Degenerative nerve diseases, which can affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Types include Alzheimer's disease and Parkinson's disease.
• Encephalitis (inflammation in the brain), which can lead to problems such as vision loss, weakness, and paralysis.
• Genetic brain disorders, which are caused by changes in genes (also called variants or mutations). These disorders can affect the development and function of the brain.
• Strokes, which can cause a loss of brain cells and can affect your ability to think clearly.
• Traumatic brain injuries (TBIs), which can affect brain function. They may range from mild to severe. The effects of a TBI may be temporary or permanent.

The symptoms of brain diseases vary widely, depending on the specific problem. In some cases, damage is permanent. In other cases, treatments such as surgery, medicines, or therapies such as physical, occupational, and speech therapies, may cure the disease or improve the symptoms.

Alzheimer's disease (AD) is the most common form of dementia among older people. Dementia is a brain disorder that seriously affects a person's ability to carry out daily activities.

AD begins slowly. It first involves the parts of the brain that control thought, memory and language. People with AD may have trouble remembering things that happened recently or names of people they know. A related problem, mild cognitive impairment (MCI), causes more memory problems than normal for people of the same age. Many, but not all, people with MCI will develop AD.

In AD, over time, symptoms get worse. People may not recognize family members. They may have trouble speaking, reading or writing. They may forget how to brush their teeth or comb their hair. Later on, they may become anxious or aggressive, or wander away from home. Eventually, they need total care. This can cause great stress for family members who must care for them.

AD usually begins after age 60. The risk goes up as you get older. Your risk is also higher if a family member has had the disease.

No treatment can stop the disease. However, some drugs may help keep symptoms from getting worse for a limited time.

Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it to develop abnormally. Sometimes it's a genetic problem. In other cases, exposure to certain medicines, infections, or radiation during pregnancy interferes with brain development. Parts of the brain may be missing, abnormally small or large, or not fully developed.

Treatment depends upon the problem. In many cases, treatment only helps with symptoms. It may include antiseizure medicines, shunts to drain fluid from the brain, and physical therapy.

There are head malformations that do not involve the brain. Craniofacial disorders are the result of abnormal growth of soft tissue and bones in the face and head. It's common for new babies to have slightly uneven heads, but parents should watch the shape of their baby's head for possible problems.

When you play the piano or hit a tennis ball you are activating the cerebellum. The cerebellum is the area of the brain that controls coordination and balance. Problems with the cerebellum include

• Cancer
• Genetic disorders
• Ataxias - failure of muscle control in the arms and legs that result in movement disorders
• Degeneration - disorders caused by brain cells decreasing in size or wasting away

Treatment of cerebellar disorders depends on the cause. In some cases, there is no cure but treatment may help with symptoms.

A genetic brain disorder is caused by a variation or a mutation in a gene. A variation is a different form of a gene. A mutation is a change in a gene. Genetic brain disorders affect the development and function of the brain.

Some genetic brain disorders are due to random gene mutations or mutations caused by environmental exposure, such as cigarette smoke. Other disorders are inherited, which means that a mutated gene or group of genes is passed down through a family. They can also be due to a combination of both genetic changes and other outside factors.

Some examples of genetic brain disorders include

• Leukodystrophies
• Phenylketonuria
• Tay-Sachs disease
• Wilson disease

Many people with genetic brain disorders fail to produce enough of certain proteins that influence brain development and function. These brain disorders can cause serious problems that affect the nervous system. Some have treatments to control symptoms. Some are life-threatening.

Friedreich's ataxia is an inherited disease that damages your nervous system. The damage affects your spinal cord and the nerves that control muscle movement in your arms and legs. Symptoms usually begin between the ages of 5 and 15. The main symptom is ataxia, which means trouble coordinating movements. Specific symptoms include

• Difficulty walking
• Muscle weakness
• Speech problems
• Involuntary eye movements
• Scoliosis (curving of the spine to one side)
• Heart palpitations, from the heart disease which can happen along with Friedreich's ataxia

People with Friedreich's ataxia usually need a wheelchair 15 to 20 years after symptoms first appear. In severe cases, people become incapacitated. There is no cure. You can treat symptoms with medicines, braces, surgery, and physical therapy.

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses. Sometimes the cause is not known.

Degenerative nerve diseases include

• Alzheimer's disease
• Amyotrophic lateral sclerosis
• Friedreich's ataxia
• Huntington's disease
• Lewy body disease
• Parkinson's disease
• Spinal muscular atrophy

Degenerative nerve diseases can be serious or life-threatening. It depends on the type. Most of them have no cure. Treatments may help improve symptoms, relieve pain, and increase mobility.

Ataxia-telangiectasia (A-T) is a rare, inherited disease. It affects the nervous system, immune system, and other body systems. Symptoms appear in young children, usually before age 5. They include

• Ataxia - trouble coordinating movements
• Poor balance
• Slurred speech
• Tiny, red spider veins, called telangiectasias, on the skin and eyes
• Lung infections
• Delayed physical and sexual development

People with A-T have an increased risk of developing diabetes and cancers, especially lymphoma and leukemia. Although it affects the brain, people with A-T usually have normal or high intelligence.

A-T has no cure. Treatments might improve some symptoms. They include injections to strengthen the immune system, physical and speech therapy, and high-dose vitamins.

A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, or malignant, with cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are metastatic, and they start somewhere else in the body and move to the brain.

Brain tumors can cause many symptoms. Some of the most common are:

• Headaches, often in the morning
• Nausea and vomiting
• Changes in your ability to talk, hear, or see
• Problems with balance or walking
• Problems with thinking or memory
• Feeling weak or sleepy
• Changes in your mood or behavior
• Seizures

Doctors diagnose brain tumors by doing a neurologic exam and tests including an MRI, CT scan, and biopsy. Treatment options include watchful waiting, surgery, radiation therapy, chemotherapy, and targeted therapy. Targeted therapy uses drugs or other substances that attack cancer cells with less harm to normal cells. Many people get a combination of treatments.

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative brain disorder. Symptoms usually start around age 60. Memory problems, behavior changes, vision problems, and poor muscle coordination progress quickly to dementia, coma, and death. Most patients die within a year.

The three main categories of CJD are

• Sporadic CJD, which occurs for no known reason
• Hereditary CJD, which runs in families
• Acquired CJD, which occurs from contact with infected tissue, usually during a medical procedure

Cattle can get a disease related to CJD called bovine spongiform encephalopathy (BSE) or "mad cow disease." There is concern that people can get a variant of CJD from eating beef from an infected animal, but there is no direct proof to support this.

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, fatal brain disorder. It affects about one person in every one million per year worldwide; in the United States there are about 350 cases per year. CJD usually appears in later life and runs a rapid course. Typical onset of symptoms occurs at about age 60, and about 70 percent of individuals die within one year. In the early stages of the disease, people may have failing memory, behavioral changes, lack of coordination, and visual disturbances. As the illness progresses, mental deterioration becomes pronounced and involuntary movements, blindness, weakness of extremities, and coma may occur.

There are three major categories of CJD.

• In sporadic CJD, the disease appears even though the person has no known risk factors for the disease. This is by far the most common type of CJD and accounts for at least 85 percent of cases.
• In hereditary CJD, the person may have a family history of the disease and test positive for a genetic mutation associated with CJD. About 10 to 15 percent of cases of CJD in the United States are hereditary.
• In acquired CJD, the disease is transmitted by exposure to brain or nervous system tissue, usually through certain medical procedures. There is no evidence that CJD is contagious through casual contact with someone who has CJD. Since CJD was first described in 1920, fewer than one percent of cases have been acquired CJD. A type of CJD called variant CJD (or vCJD) can be acquired by eating meat from cattle affected by a disease similar to CJD called bovine spongiform encephalopathy (BSE) or, commonly, “mad cow” disease.

CJD belongs to a family of human and animal diseases known as the transmissible spongiform encephalopathies (TSEs) or prion diseases. A prion—derived from “protein” and “infectious”—causes CJD in people and TSEs in animals. Spongiform refers to the characteristic appearance of infected brains, which become filled with holes until they resemble sponges when examined under a microscope. CJD is the most common of the known human TSEs. Other human TSEs include kuru, fatal familial insomnia (FFI), and Gerstmann-Straussler-Scheinker disease (GSS). Kuru was identified in people of an isolated tribe who practiced ritual cannibalisms in Papua, New Guinea and has now almost disappeared. Kuru is considered an acquired prion disease. FFI and GSS are extremely rare hereditary diseases, found in just a few families around the world. To date, about 260 cases of vCJD, mostly in the United Kingdom, have been reported related to consuming beef but none in which the disease was acquired in the U.S. Other TSEs are found in specific kinds of animals. These include BSE, mink encephalopathy, feline encephalopathy, and scrapie, which affects sheep and goats. Chronic wasting disease (CWD) affects elk and deer and is increasingly prevalent in certain areas in the United States. To date no transmission of CWD to humans has been reported.

A concussion is a type of brain injury. It involves a short loss of normal brain function. It happens when a hit to the head or body causes your head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in your brain. Sometimes it can also stretch and damage your brain cells.

Sometimes people call a concussion a "mild" brain injury. It is important to understand that while concussions may not be life-threatening, they can still be serious.

Concussions are a common type of sports injury. Other causes of concussions include blows to the head, bumping your head when you fall, being violently shaken, and car accidents.

Symptoms of a concussion may not start right away; they may start days or weeks after the injury. Symptoms may include a headache or neck pain. You may also have nausea, ringing in your ears, dizziness, or tiredness. You may feel dazed or not your normal self for several days or weeks after the injury. Consult your health care professional if any of your symptoms get worse, or if you have more serious symptoms such as

• Convulsions or seizures
• Drowsiness or inability to wake up
• A headache that gets worse and does not go away
• Weakness, numbness, or decreased coordination
• Repeated vomiting or nausea
• Confusion
• Slurred speech
• Loss of consciousness

To diagnose a concussion, your health care provider will do a physical exam and will ask about your injury. You will most likely have a neurological exam, which checks your vision, balance, coordination, and reflexes. Your health care provider may also evaluate your memory and thinking. In some cases, you may also have a scan of the brain, such as a CT Scan or an MRI. A scan can check for bleeding or inflammation in the brain, as well as skull fractures.

Most people recover fully after a concussion, but it can take some time. Rest is very important after a concussion because it helps the brain to heal. In the very beginning, you may need to limit physical activities or activities that involve a lot of concentration, such as studying, working on the computer, or playing video games. Doing these may cause concussion symptoms (such as headache or tiredness) to come back or get worse. Then when your health care provider says that it is ok, you can start to return to your normal activities slowly.

Don’t get in over your head and ignore a concussion. A concussion is a type of traumatic brain injury (TBI) caused by a bump, blow, or jolt to the head. TBIs can also happen when a fall or blow to the body makes the head and brain move quickly back and forth. Even a “ding,” “getting your bell rung,” or a mild bump on the head can be serious. While most people with a concussion feel better within a couple of weeks, some will have symptoms that last for months or even longer. People with a concussion need to be seen by a medical professional. Getting help soon after the injury can help speed your recovery.

Key Facts & Prevention Tips

• Use safety gates at the top and bottom of stairs when young children are around.
• Athletes with a possible concussion should be immediately removed from play. They should not return to play the same day of the injury, and until cleared by an appropriate medical professional.
• Be sure the surface under your child’s playground is made of soft material, such as mulch or sand.

Contact Sports

Contact sports contributed to almost half (45%) of all emergency department visits for a sports- or recreation-related TBI in 2016.

Student Athletes

As many as 2.5 million high school students reported at least one concussion in the preceding 12 months while playing a sport or being physically active.

Back to School

Any student could take a spill, knock his/her head, and get a concussion in any number of school settings ranging from the hallway, the playground, the cafeteria, and beyond. Know your concussion ABC's; Assess the situation, Be alert for signs and symptoms, Contact a health care professional.

Child Safety Gate

Use safety gates at the top and bottom of stairs when young children are around.

Playground Safety

Be sure the surface on your child's playground is made of shock-absorbing material, such as hardwood mulch or sand.

Concussion Action Plan

Make sure your child's school and/or sports league has a concussion action plan.

Most TBIs that occur each year are mild TBIs or concussions. A mild TBI or concussion is caused by:

• A bump, blow, or jolt to the head, or
• By a hit to the body that causes the head and brain to move quickly back and forth

This sudden movement can cause:

• The brain to bounce around or twist in the skull
• Chemical changes in the brain
• Stretching and damaging brain cells

These changes in the brain lead to symptoms that may affect how a person thinks, learns, feels, acts, and sleeps.

Mild TBIs and concussions are serious

Healthcare providers may describe these injuries as mild because they are usually not life-threatening. Even so, the effects of a mild TBI or concussion can be serious.

Get medical care for a mild TBI or concussion

People with a mild TBI or concussion need to be seen by a healthcare provider. Contact your healthcare provider as soon as you can if you think you have a mild TBI or concussion.

You may consider using telemedicine or telehealth services if you are unable to visit a healthcare provider in person. Telemedicine and telehealth services:

• Connect patients and their healthcare providers through a phone or video chat
• Allow patients to get checked for mild TBI or concussion symptoms and get recovery tips without needing to travel to a medical office or hospital

Your healthcare provider can identify whether these services are available to you.

Patients experiencing mild TBI or concussion danger signs should seek care right away at an emergency department.

Healthcare providers check for symptoms and help with recovery

Your healthcare provider may ask about symptoms and test you to see if you have any problems with:

• Learning
• Memory
• Concentration, and
• Problem solving

These tests are called “neuropsychological” or “neurocognitive” tests and can help your healthcare provider identify the effects of a mild TBI or concussion. Even if the injury doesn’t show up on these tests, you may still have a mild TBI or concussion.

A scan of your brain (such as a CT scan) is not needed to spot a mild TBI or concussion, but may sometimes be used for patients at risk for bleeding on the brain after a head or brain injury.

Ask your healthcare provider for instructions on how to safely return to activities following a mild TBI or concussion. Be sure to follow all of your healthcare provider’s instructions carefully.

Repeated mild TBIs or concussions may lead to a longer recovery

A person with a history of multiple or repeated mild TBIs or concussions may experience a longer recovery or more severe symptoms. They may also have long-term problems, including:

• Ongoing problems with concentration, memory, headache
• Physical problems, such as keeping one’s balance

Your brain is your body’s command center. Its soft, sensitive tissues float in a cushioning fluid within the hard and sturdy skull. But a swift blow to the head or violent shaking can override these protections and lead to a mild type of brain injury known as a concussion.

More than 1 million mild traumatic brain injuries occur nationwide each year. These injuries can be caused by falls, car crashes or recreational activities like bike riding, skateboarding, skiing or even playing at the playground. More than half of concussions occur in children—often when playing organized sports such as football and soccer.

“Although concussions are considered to be a mild brain injury, they need to be taken seriously. They should not be treated as minor injuries that quickly resolve,” says Dr. Beth Ansel, an expert on rehabilitation research at NIH. With proper care, most people recover fully from a concussion. “But in some cases, a concussion can have a lasting effect on thinking, attention, learning and memory,” Ansel adds.

A single concussion is also known to raise your risk for having another concussion—and a second concussion may be more severe. It’s important to learn to recognize the causes and symptoms of concussion so you can take steps to prevent or treat these head injuries.

“The skull is designed to prevent most traumas to the brain, but it doesn’t really prevent the brain from moving around inside the skull,” says Dr. Frederick Rivara, a specialist in pediatric injuries and prevention at the University of Washington in Seattle. “A concussion can arise from the brain moving either rapidly back and forth or banging against the side of the skull.” This sudden movement can stretch and damage brain tissue and trigger a chain of harmful changes within the brain that interfere with normal brain activities.

More serious brain injuries that involve skull fracture, bleeding in the brain or swelling of the brain can be detected with X-rays or other imaging methods. But concussions can be more difficult to identify.

“A concussion isn’t visible from the outside, and you can’t see it with standard imaging tools like MRI and CAT scans,” says Dr. Christopher Giza, a pediatric brain specialist at the University of California, Los Angeles. “Instead we look for the signs and symptoms of abnormal brain function to make a diagnosis.”

Common symptoms include nausea, headache, confusion, dizziness and memory problems. Loss of consciousness occurs in about 1 in 10 concussions. A person with a concussion might have trouble answering basic questions and move in an awkward, clumsy way.

“Symptoms can arise quickly, or they can be delayed and appear over the next day or two,” Rivara adds.

For about 9 in 10 people with concussions, symptoms disappear within 7 to 10 days. Scientists have been working to learn more about those who take longer to recover. In one NIH-funded study, Dr. Keith Yeates of Ohio State University looked at 8- to 15-year-olds treated in an emergency room for mild traumatic brain injury.

“We found that the majority of these kids recovered quite quickly or showed no increase in symptoms at all,” Yeates says. “But a subgroup of kids, about 10% or 20%, showed a dramatic onset of symptoms after their injury and persistent symptoms that in some cases remained even 12 months after the injury.”

Body-related symptoms, such as headache and dizziness, tended to fade fairly quickly, the researchers found. But thinking-related symptoms, including problems with memory and paying attention, tended to linger in some kids throughout the year-long study. Children who had lost consciousness or had some additional abnormality that showed up on MRI scans after the injury had an increased risk for lasting problems.

“These kids were also more likely to have what looked like significant reductions in overall quality of life. And there was some evidence they were more likely to have academic problems than the kids without persistent symptoms,” Yeates says.

Yeates and others continue to explore ways to predict a person’s response to concussion. Much remains unknown about the underlying biology and outcomes of mild head injuries. Some NIH-funded researchers are looking at how injury and recovery processes differ in immature and adult brains. Other scientists are examining the problems that can arise from repeated injuries to the brain.

Researchers know that immediately after a concussion, the brain is especially vulnerable to having a second, more serious injury. But it’s not clear why—or how long that vulnerable period lasts. Giza and his colleagues have found that a single mild injury reduces the brain’s use of the sugar glucose as a fuel, at least in rats. A second mild injury 24 hours later leads to an even steeper drop in glucose use and memory problems that last longer. But when the brain has several days to recover, and the use of glucose returns to normal, a second mild brain injury seems to be no worse than the first.

“The finding suggests that when you superimpose 2 injuries on top of each other, the consequences can be greater,” Giza says. The brain’s use of glucose might be a way to assess risk and recovery time. “But we don’t yet have a clear understanding of what happens in the human brain after first and second injuries,” Giza adds.

Studies have found that the risk for a second injury is greatest in the 10 days following an initial concussion. If you suspect that someone has a concussion, make sure they stop whatever activity they’re doing, especially if they’re involved in a sport. Their brain dysfunction might not only cloud their thinking. It can also slow reaction times and affect their balance so they become more likely to have another injury.

“If someone has symptoms of concussion, they shouldn’t try to finish the quarter or finish the game. They need to be taken out of play right away and be seen by a health care provider,” Rivara says. “The current recommendations are to avoid physical activity for a period of time until all the symptoms have resolved, and then have a gradual return to play.”

Take steps to avoid concussions. “Wear helmets when appropriate, such as if you’re bicycling, skate-boarding or riding a horse,” says Rivara. Athletes can decrease their risk of concussion by wearing proper headgear and following the rules of good sportsmanship. Make living areas safer for seniors by removing tripping hazards such as throw rugs and clutter in walkways, and install handrails on both sides of stairways.

“The bottom line is that we still need to determine the best ways to prevent, accurately diagnose, treat and assess outcomes after mild traumatic brain injury,” says Ansel.

While this research continues, do what you can to prevent concussions. Learn to recognize the symptoms. And make sure that people with signs of concussion stop their activities and seek medical attention.

Symptoms of Concussion

Stop activity if you have these symptoms. Athletes should not return to play until evaluated by a health care provider.

• Headache or “pressure” in head
• Nausea or vomiting
• Balance problems or dizziness
• Double or blurry vision
• Sensitivity to light or noise
• Feeling sluggish or groggy
• Concentration or memory problems
• Confusion
• Feeling “down” or “not right”
• Changes to sleep patterns

Adapted from the U.S. Centers for Disease Control and Prevention

Encephalitis is an inflammation of the brain. Usually the cause is a viral infection, but bacteria can also cause it. It can be mild or severe. Most cases are mild. You may have flu-like symptoms. With a mild case, you may just need rest, plenty of fluids, and a pain reliever.

Severe cases need immediate treatment. Symptoms of severe cases include:

• Severe headache
• Sudden fever
• Drowsiness
• Vomiting
• Confusion
• Seizures

In babies, additional symptoms may include constant crying, poor feeding, body stiffness, and bulging in the soft spots of the skull.

Severe cases may require a stay in the hospital. Treatments include oral and intravenous (IV) medicines to reduce inflammation and treat infection. Patients with breathing difficulties may need artificial respiration. Some people may need physical, speech, and occupational therapy once the illness is under control.

Encephalitis is inflammation of the brain. Myelitis refers to inflammation of the spinal cord. When both the brain and the spinal cord are involved, the condition is called encephalomyelitis.

Infections and other disorders affecting the brain and spinal cord can activate the immune system, which leads to inflammation. This inflammation can produce a wide range of symptoms and, in extreme cases, cause brain damage, stroke, or even death.

When you get sick, some germs can attack the brain or the protective lining that surrounds the brain. This can cause swelling and lead to severe illness, or even death. It’s important to recognize the symptoms so you can get medical help as quickly as possible.

When the brain swells, it’s called encephalitis. When the lining of the brain, or meninges, becomes inflamed, it’s called meningitis. The symptoms can be similar for both.

At first, you might get a fever, feel tired, and sometimes have a rash. “Those things can last a day or two, or a little bit longer,” explains Dr. Avindra Nath, a neurologist at NIH. “Then, you may have a headache, along with fever, neck stiffness, and you can get sensitivity to light.”

Other symptoms include nausea or vomiting, double vision, drowsiness, and confusion. More severe illnesses can cause speech, hearing, or vision problems. If it’s left untreated, you could develop cognitive difficulties with progressive loss of consciousness, seizures, or muscle weakness.

You need to get immediate medical help if you have symptoms of encephalitis or meningitis. Early treatment is important for the best recovery. Treatment will depend on the cause. Viruses, bacteria, parasites, and fungi can all cause encephalitis and meningitis. The most common causes can be different depending on where you live.

“Worldwide, the most common cause of meningitis is bacterial meningitis,” Nath explains. “Now in the United States, we don’t see a lot of bacterial meningitis because we have certain vaccines. So, the most common cause of meningitis is viral meningitis.”

Early treatment for bacterial causes may be antibiotics and other medicines to treat swelling and other symptoms of the illness. There aren’t any specific anti-viral treatments for most viral causes. But treating the symptoms can affect the course of the illness. More severe illnesses may require hospitalization.

Anyone can get these conditions. Protecting yourself and your family from germs and staying up-to-date on vaccines is the best way to guard against both encephalitis and meningitis. Vaccines are available to prevent some bacterial causes of meningitis, including Haemophilus influenzae, pneumococcal pneumonia, and meningococcal disease.

NIH-funded researchers are looking for other ways to prevent or treat encephalitis and meningitis. Some are studying how to stop germs from infecting the brain or its lining.

Nath’s team is testing compounds that may block Zika virus from getting into brain cells grown in the lab. His team hopes that these may block other viruses that are transmitted by insects and parasites, too.

Many scientists are trying to develop broad antivirals, Nath says. “Broad” means the antiviral would stop many viruses rather than just one. This would be helpful, since doctors wouldn’t have to know which virus is causing the problem before starting treatment.

Until we have better treatments, prevention is still the best medicine. Children, older adults, and those with weakened immune systems are most at risk for infections. See the Wise Choices box for tips on protecting yourself and your family.

Guard Against Meningitis and Encephalitis

• Wash your hands with soap and water often.
• Avoid people who are coughing or showing other signs of sickness.
• Stay up-to-date on your vaccines.
• Protect yourself from mosquito and tick bites. Use insect repellents and wear full-sleeve shirts and pants when you’re outside. Keep insects out of your home. Use screens on windows and doors or use air conditioning instead. Empty all standing water from your yard.

What is dementia?

Dementia is a loss of mental functions that is severe enough to affect your daily life and activities. These functions include

• Memory
• Language skills
• Visual perception (your ability to make sense of what you see)
• Problem solving
• Trouble with everyday tasks
• The ability to focus and pay attention

It is normal to become a bit more forgetful as you age. But dementia is not a normal part of aging. It is a serious disorder which interferes with your daily life.

What are the types of dementia?

The most common types of dementia are known as neurodegenerative disorders. These are diseases in which the cells of the brain stop working or die. They include

• Alzheimer's disease, which is the most common form of dementia among older people. People with Alzheimer's have plaques and tangles in their brain. These are abnormal buildups of different proteins. Beta-amyloid protein clumps up and forms plaques in between your brain cells. Tau protein builds up and forms tangles inside the nerve cells of your brain. There is also a loss of connection between nerve cells in the brain.
• Lewy body dementia, which causes movement symptoms along with dementia. Lewy bodies are abnormal deposits of a protein in the brain.
• Frontotemporal disorders, which cause changes to certain parts of the brain:
  • Changes in the frontal lobe lead to behavioral symptoms
  • Changes in the temporal lobe lead to language and emotional disorders
• Vascular dementia, which involves changes to the brain's blood supply. It is often caused by a stroke or atherosclerosis (hardening of the arteries) in the brain.
• Mixed dementia, which is a combination of two or more types of dementia. For example, some people have both Alzheimer's disease and vascular dementia.

Other conditions can cause dementia or dementia-like symptoms, including

• Creutzfeldt-Jakob disease, a rare brain disorder
• Huntington's disease, an inherited, progressive brain disease
• Chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury
• HIV-associated dementia (HAD)

Who is at risk for dementia?

Certain factors can raise your risk for developing dementia, including

• Aging. This is the biggest risk factor for dementia.
• Smoking
• Uncontrolled diabetes
• High blood pressure
• Drinking too much alcohol
• Having close family members who have dementia

What are the symptoms of dementia?

The symptoms of dementia can vary, depending on which parts of the brain are affected. Often, forgetfulness is the first symptom. Dementia also causes problems with the ability to think, problem solve, and reason. For example, people with dementia may

• Get lost in a familiar neighborhood
• Use unusual words to refer to familiar objects
• Forget the name of a close family member or friend
• Forget old memories
• Need help doing tasks that they used to do by themselves

Some people with dementia cannot control their emotions and their personalities may change. They may become apathetic, meaning that they are no longer interested in normal daily activities or events. They may lose their inhibitions and stop caring about other peoples' feelings.

Certain types of dementia can also cause problems with balance and movement.

The stages of dementia range from mild to severe. In the mildest stage, it is just beginning to affect a person's functioning. In the most severe stage, the person is completely dependent on others for care.

How is dementia diagnosed?

To make a diagnosis, your health care provider

• Will ask about your medical history
• Will do a physical exam
• Will check your thinking, memory, and language abilities
• May do tests, such as blood tests, genetic tests, and brain scans
• May do a mental health evaluation to see whether a mental disorder is contributing to your symptoms

What are the treatments for dementia?

There is no cure for most types of dementia, including Alzheimer's disease and Lewy body dementia. Treatments may help to maintain mental function longer, manage behavioral symptoms, and slow down the symptoms of disease. They may include

• Medicines may temporarily improve memory and thinking or slow down their decline. They only work in some people. Other medicines can treat symptoms such as anxiety, depression, sleep problems, and muscle stiffness. Some of these medicines can cause strong side effects in people with dementia. It is important to talk to your health care provider about which medicines will be safe for you.
• Occupational therapy to help find ways to more easily do everyday activities
• Speech therapy to help with swallowing difficulties and trouble speaking loudly and clearly
• Mental health counseling to help people with dementia and their families learn how to manage difficult emotions and behaviors. It can also help them plan for the future.
• Music or art therapy to reduce anxiety and improve well-being

Can dementia be prevented?

Researchers have not found a proven way to prevent dementia. Living a healthy lifestyle might influence some of your risk factors for dementia.

Hydrocephalus is the buildup of too much cerebrospinal fluid in the brain. Normally, this fluid cushions your brain. When you have too much, though, it puts harmful pressure on your brain.

Hydrocephalus can be congenital, or present at birth. Causes include genetic problems and problems with how the fetus develops. An unusually large head is the main sign of congenital hydrocephalus.

Hydrocephalus can also happen after birth. This is called acquired hydrocephalus. It can occur at any age. Causes can include head injuries, strokes, infections, tumors, and bleeding in the brain. Symptoms include

• Headache
• Vomiting and nausea
• Blurry vision
• Balance problems
• Bladder control problems
• Thinking and memory problems

Hydrocephalus can permanently damage the brain, causing problems with physical and mental development. If untreated, it is usually fatal. With treatment, many people lead normal lives with few limitations. Treatment usually involves surgery to insert a shunt. A shunt is a flexible but sturdy plastic tube. The shunt moves the cerebrospinal fluid to another area of the body where it can be absorbed. Medicine and rehabilitation therapy can also help.

Hydrocephalus is an abnormal buildup of fluid in the ventricles (cavities) deep within the brain. This excess fluid causes the ventricles to widen, putting pressure on the brain’s tissues.

Cerebrospinal fluid (CSF) is the clear, colorless fluid that protects and cushions the brain and spine. Normally, cerebrospinal fluid flows through the ventricles and bathes the brain and spinal cord before being reabsorbed into the bloodstream. The body typically produces enough CSF each day and absorbs the same amount. However, when the normal flow or absorption of CSF is blocked it can result in a buildup of CSF. The pressure from too much CSF can keep the brain from functioning properly and cause brain damage and even death.

Fortunately, there are treatment options that can restore normal levels of CSF. Though treatment is often helpful, it may take multiple surgeries to treat hydrocephalus. (Hydrocephalus is the most common reason for brain surgery in young children.) With treatment many people lead normal and productive lives.

What is hydrocephalus?

Hydrocephalus is a condition in which the primary characteristic is excessive accumulation of cerebrospinal fluid (CSF) -- the clear fluid that surrounds the brain and spinal cord. This excessive accumulation results in an abnormal dilation of the spaces in the brain called ventricles. This dilation causes potentially harmful pressure on the tissues of the brain. Hydrocephalus may be congenital or acquired. Congenital hydrocephalus is present at birth and may be caused by genetic abnormalities or developmental disorders such as spina bifida and encephalocele. Acquired hydrocephalus develops at the time of birth or at some point afterward and can affect individuals of all ages. For example, hydrocephalus ex-vacuo occurs when there is damage to the brain caused by stroke or traumatic injury. Normal pressure hydrocephalus occurs most often among the elderly. It may result from a subarachnoid hemorrhage, head trauma, infection, tumor, or complications of surgery, although many people develop normal pressure hydrocephalus without an obvious cause. Symptoms of hydrocephalus vary with age, disease progression, and individual differences in tolerance to CSF. In infancy, the most obvious indication of hydrocephalus is often the rapid increase in head circumference or an unusually large head size. In older children and adults, symptoms may include headache followed by vomiting, nausea, papilledema (swelling of the optic disk, which is part of the optic nerve), downward deviation of the eyes (called "sunsetting"), problems with balance, poor coordination, gait disturbance, urinary incontinence, slowing or loss of development (in children), lethargy, drowsiness, irritability, or other changes in personality or cognition, including memory loss. Hydrocephalus is diagnosed through clinical neurological evaluation and by using cranial imaging techniques such as ultrasonography, computer tomography (CT), magnetic resonance imaging (MRI), or pressure-monitoring techniques.

Is there any treatment?

Hydrocephalus is most often treated with the surgical placement of a shunt system. This system diverts the flow of CSF from a site within the central nervous system to another area of the body where it can be absorbed as part of the circulatory process. A limited number of individuals can be treated with an alternative procedure called third ventriculostomy. In this procedure, a small hole is made in the floor of the third ventricle, allowing the CSF to bypass the obstruction and flow toward the site of resorption around the surface of the brain.

What is the prognosis?

The prognosis for individuals diagnosed with hydrocephalus is difficult to predict, although there is some correlation between the specific cause of hydrocephalus and the patient's outcome. Prognosis is further complicated by the presence of associated disorders, the timeliness of diagnosis, and the success of treatment. The symptoms of normal pressure hydrocephalus usually get worse over time if the condition is not treated, although some people may experience temporary improvements. If left untreated, progressive hydrocephalus is fatal, with rare exceptions. The parents of children with hydrocephalus should be aware that hydrocephalus poses risks to both cognitive and physical development. Treatment by an interdisciplinary team of medical professionals, rehabilitation specialists, and educational experts is critical to a positive outcome. Many children diagnosed with the disorder benefit from rehabilitation therapies and educational interventions, and go on to lead normal lives with few limitations.

What is normal pressure hydrocephalus?

Normal pressure hydrocephalus (NPH) is an abnormal buildup of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. It occurs if the normal flow of CSF throughout the brain and spinal cord is blocked in some way. This causes the ventricles to enlarge, putting pressure on the brain. Normal pressure hydrocephalus can occur in people of any age, but it is most common in the elderly. It may result from a subarachnoid hemorrhage, head trauma, infection, tumor, or complications of surgery. However, many people develop NPH even when none of these factors are present. In these cases the cause of the disorder is unknown.

Symptoms of NPH include progressive mental impairment and dementia, problems with walking, and impaired bladder control. The person also may have a general slowing of movements or may complain that his or her feet feel "stuck." Because these symptoms are similar to those of other disorders such as Alzheimer's disease, Parkinson's disease, and Creutzfeldt-Jakob disease, the disorder is often misdiagnosed. Many cases go unrecognized and are never properly treated. Doctors may use a variety of tests, including brain scans (CT and/or MRI), a spinal tap or lumbar catheter, intracranial pressure monitoring, and neuropsychological tests, to help them diagnose NPH and rule out other conditions.

Is there any treatment?

Treatment for NPH involves surgical placement of a shunt in the brain to drain excess CSF into the abdomen where it can be absorbed as part of the normal circulatory process. This allows the brain ventricles to return to their normal size. Regular follow-up care by a physician is important in order to identify subtle changes that might indicate problems with the shunt.

What is the prognosis?

The symptoms of NPH usually get worse over time if the condition is not treated, although some people may experience temporary improvements. While the success of treatment with shunts varies from person to person, some people recover almost completely after treatment and have a good quality of life. Early diagnosis and treatment improves the chance of a good recovery. Without treatment, symptoms may worsen and cause death.

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Epilepsy has many possible causes, including illness, brain injury, and abnormal brain development. In many cases, the cause is unknown.

Doctors use brain scans and other tests to diagnose epilepsy. It is important to start treatment right away. There is no cure for epilepsy, but medicines can control seizures for most people. When medicines are not working well, surgery or implanted devices such as vagus nerve stimulators may help. Special diets can help some children with epilepsy.