Autism Research

Autism Research

Learn more about CDC’s Study to Explore Early Development (also called SEED), the largest collaborative scientific study to date of the risk factors of autism.

SEED stands for the Study to Explore Early Development. It is a 5-year, multi-site collaborative study that will help identify what might put children at risk for autism spectrum disorders (ASDs) and other developmental disabilities. It is being conducted by six study sites and a data coordinating center called the Centers for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) Network.

SEED will:

• Be the largest collaborative scientific study to date of the possible risk factors of autism. It will include about 2,700 children, 2 through 5 years of age, as well as their parents.
• Include diverse groups from six areas across the county. This will give a more representative sample of all children with autism spectrum disorders in the United States.
• Use standard clinical procedures to classify children with and those without autism spectrum disorders.
• Give information on the many things that could lead to autism.

SEED is looking at risk factors for autism spectrum disorders by:

• Talking with mothers about pregnancy-related issues.
• Looking at the medical records of the mother and child.
• Asking the parents to fill out questionnaires at home.
• Taking cheek swabs from the mother, father, and child.
• Doing a developmental and physical evaluation of the child.
• Taking a small sample of blood from the mother, father, and child.

A number of factors are being studied for their potential link with autism spectrum disorders. These factors were picked after an in-depth look at existing studies. Each factor was chosen as high priority based on:

• How strongly it seemed to be linked with autism spectrum disorders.
• What new information was needed about it.
• How well it could be looked at using this study’s methods.

When the study is completed, will we know the causes of autism?

It is too soon to speculate on the results of the study. We hope the study will give us a better idea of which of the risk factors that we will be looking at seem to be the most important in causing autism. The causes may be related to genes, the environment, or a relationship between the two. For instance, some groups of children with certain genes may be more easily harmed by some types of environmental exposures.

Will this study find a prevention/cure for autism?

It is too soon to speculate on what we might find about the risk factors of autism. But, we are hopeful that the findings from SEED will help the development of future studies specifically designed to assess treatments among children with autism.

What is the CADDRE Network?

The CADDRE centers and Data Coordinating Center are:

• California CADDRE: Kaiser Permanente Division of Research and the California Department of Health Services
• Colorado CADDRE: Colorado Department of Public Health and Environment and the University of Colorado at Denver and Heath Sciences Center
• Georgia CADDRE: the National Center on Birth Defects and Developmental Disabilities
• Maryland CADDRE: Johns Hopkins University and Kennedy Krieger Institute
• North Carolina CADDRE: University of North Carolina at Chapel Hill
• Pennsylvania CADDRE: University of Pennsylvania School of Nursing and The Children’s Hospital of Pennsylvania
• Data Coordinating Center: Michigan State University

 CDC

Conversion Disorder

Conversion Disorder

What Is It?

A conversion disorder is a rare mental disorder in which a person has physical symptoms that no medical condition can explain. The person is not "faking." The symptoms do not appear to be under the person's conscious control and they can cause significant distress. Examples of symptoms are a loss of muscle control, blindness, deafness, seizures or even apparent unconsciousness.

Conversion disorder often appears after conflict or stress, though the person is not aware of this connection. The person believes the problem is physical. The name of the disorder comes from the idea that some sort of psychological distress is being converted into a physical symptom. Some experts believe that a conflict or painful thought is so unacceptable that it never reaches the person's awareness. In some cases, the person shows little concern about the physical symptom, a phenomenon sometimes called la belle indifference.

Conversion disorder is more common in women than in men. It occurs most frequently between adolescence and middle age. It appears more often in places where people know less about medicine and psychology, such as in developing countries. When the disorder occurs in a person who is knowledgeable about medical advancements, the symptoms tend to be subtler; symptoms are likely to be more severe in a person who doesn't know as much about medicine.

A very high percentage of people with conversion disorder have another psychiatric problem, such as generalized anxiety, obsessive-compulsive disorder or some form of depression. They also report a higher than average frequency of emotional or physical abuse during childhood.

Symptoms

Conversion disorder is characterized by one or more symptoms that suggest a neurological condition. Examples include:

• Poor coordination or balance
• Paralysis or weakness
• Difficulty speaking or swallowing
• Retention of urine
• Loss of touch or pain sense
• Blindness or other visual symptoms
• Deafness
• Seizures or convulsions

Psychological factors, such as stress or conflict, are associated with the appearance of the physical symptoms.

Diagnosis

Usually, a doctor or a mental health professional makes a diagnosis of conversion disorder based on the person's health history and a neurological examination. In the most obvious cases, a neurologist makes this diagnosis when the physical symptoms are not part of any known disorder of the nervous system. Sometimes additional tests can clarify the diagnosis. These tests may include an electroencephalogram, which measures electrical activity in the brain, or an electromyogram, which measures how well nerve impulses are being conducted through muscle tissue.

The doctor also tries to determine if any stress or conflict is at the root of the symptoms.

Ultimately, conversion disorder can be very hard to detect, even with testing. Also, the person may have another psychiatric problem, such as a mood disorder or a personality disorder.

Expected Duration

The symptoms of conversion disorder usually do not last long. Generally, the more quickly the symptoms start, the more rapidly they go away. Symptoms are more likely to last only a short time if the stress is clearly defined. More severe symptoms, such as paralysis or blindness, are less likely to last a long time because it is harder to sustain symptoms that interfere significantly with daily activities. A less severe symptom (such as tremor) or a symptom that is repeated and limited (such as seizure) can continue or come and go, depending on the nature of the stress.

Prevention

There is no known way to prevent this disorder.

Treatment

Sometimes symptoms go away on their own after stress has been reduced, conflict has been resolved or the family or community has responded with a show of concern and support. If the person experiences anxiety (an alteration of mood or disordered thinking), medication may help.

If the source of conflict or stress can be determined, it may be possible to provide relief through psychotherapy. For example, the person may be in conflict about leaving home, starting a new job or having a first child. With the help of psychotherapy, the person may learn to deal with the conflict and go forward with the new experience or retreat from the dilemma. In either case, the physical symptoms may stop.

When To Call a Professional

The person should be evaluated as soon as physical symptoms emerge. If the person is indifferent to the symptoms, a supportive family member or friend may need to guide the person to seek treatment.

Prognosis

The outlook for conversion disorder varies. It depends on the nature of the stress and on the symptoms.

Most symptoms of conversion disorder last a relatively short time. The more severe the symptoms, the more quickly they tend to disappear. However, the disorder may indicate that the person has persistent trouble coping with stress and conflict and a need for ongoing support.

Medlineplus

Narcolepsy

What is Narcolepsy?

Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep-wake cycles normally. At various times throughout the day, people with narcolepsy experience irresistable bouts of sleep. If the urge becomes overwhelming, individuals will fall asleep for periods lasting from a few seconds to several minutes. In rare cases, some people may remain asleep for an hour or longer.  In addition to excessive daytime sleepiness (EDS), three other major symptoms frequently characterize narcolepsy: cataplexy, or the sudden loss of voluntary muscle tone; vivid hallucinations during sleep onset or upon awakening; and brief episodes of total paralysis at the beginning or end of sleep.  Narcolepsy is not definitively diagnosed in most patients until 10 to 15 years after the first symptoms appear. The cause of narcolepsy remains unknown.  It is likely that narcolepsy involves multiple factors interacting to cause neurological dysfunction and sleep disturbances.

Is there any treatment?

There is no cure for narcolepsy.  In 1999, after successful clinical trial results, the U.S. Food and Drug Administration (FDA) approved a drug called modafinil for the treatment of EDS. Two classes of antidepressant drugs have proved effective in controlling cataplexy in many patients: tricyclics (including imipramine, desipramine, clomipramine, and protriptyline) and selective serotonin reuptake inhibitors (including fluoxetine and sertraline).  Drug therapy should be supplemented by behavioral strategies.  For example, many people with narcolepsy take short, regularly scheduled naps at times when they tend to feel sleepiest.  Improving the quality of nighttime sleep can combat EDS and help relieve persistent feelings of fatigue. Among the most important common-sense measures people with narcolepsy can take to enhance sleep quality are actions such as maintaining a regular sleep schedule, and avoiding alcohol and caffeine-containing beverages before bedtime.

The drug Xyrem (sodium oxybate or gamma hydroxybutyrate, also known as GHB) was approved in July 2002 for treating cataplexy and in November 2005 for EDS in people who have narcolepsy.  Due to safety concerns associated with the use of this drug, the distribution of Xyrem is tightly restricted.

What is the prognosis?

None of the currently available medications enables people with narcolepsy to consistently maintain a fully normal state of alertness.  But EDS and cataplexy, the most disabling symptoms of the disorder, can be controlled in most patients with drug treatment. Often the treatment regimen is modified as symptoms change. Whatever the age of onset, patients find that the symptoms tend to get worse over the two to three decades after the first symptoms appear. Many older patients find that some daytime symptoms decrease in severity after age 60.

NINDS

Hypersomnia

What is Hypersomnia?

Hypersomnia is characterized by recurrent episodes of excessive daytime sleepiness or prolonged nighttime sleep. Different from feeling tired due to lack of or interrupted sleep at night, persons with hypersomnia are compelled to nap repeatedly during the day, often at inappropriate times such as at work, during a meal, or in conversation. These daytime naps usually provide no relief from symptoms. Patients often have difficulty waking from a long sleep, and may feel disoriented. Other symptoms may include anxiety, increased irritation, decreased energy, restlessness, slow thinking, slow speech, loss of appetite, hallucinations, and memory difficulty. Some patients lose the ability to function in family, social, occupational, or other settings. Hypersomnia may be caused by another sleep disorder (such as narcolepsy or sleep apnea), dysfunction of the autonomic nervous system, or drug or alcohol abuse. In some cases it results from a physical problem, such as a tumor, head trauma, or injury to the central nervous system. Certain medications, or medicine withdrawal, may also cause hypersomnia. Medical conditions including multiple sclerosis, depression, encephalitis, epilepsy, or obesity may contribute to the disorder. Some people appear to have a genetic predisposition to hypersomnia; in others, there is no known cause. Typically, hypersomnia is first recognized in adolescence or young adulthood.

Is there any treatment?

Treatment is symptomatic in nature. Stimulants, such as amphetamine, methylphenidate, and modafinil, may be prescribed. Other drugs used to treat hypersomnia include clonidine, levodopa, bromocriptine, antidepressants, and monoamine oxidase inhibitors. Changes in behavior (for example avoiding night work and social activities that delay bed time) and diet may offer some relief. Patients should avoid alcohol and caffeine.

What is the prognosis?

The prognosis for persons with hypersomnia depends on the cause of the disorder. While the disorder itself is not life threatening, it can have serious consequences, such as automobile accidents caused by falling asleep while driving. The attacks usually continue indefinitely.

NINDS

Dyslexia

What is Dyslexia?

Dyslexia is a brain-based type of learning disability that specifically impairs a person's ability to read. These individuals typically read at levels significantly lower than expected despite having normal intelligence. Although the disorder varies from person to person, common characteristics among people with dyslexia are difficulty with spelling, phonological processing (the manipulation of sounds), and/or rapid visual-verbal responding. In adults, dyslexia usually occurs after a brain injury or in the context of dementia. It can also be inherited in some families, and recent studies have identified a number of genes that may predispose an individual to developing dyslexia.

Is there any treatment?

The main focus of treatment should be on the specific learning problems of affected individuals. The usual course is to modify teaching methods and the educational environment to meet the specific needs of the individual with dyslexia.

What is the prognosis?

For those with dyslexia, the prognosis is mixed. The disability affects such a wide range of people and produces such different symptoms and varying degrees of severity that predictions are hard to make. The prognosis is generally good, however, for individuals whose dyslexia is identified early, who have supportive family and friends and a strong self-image, and who are involved in a proper remediation program.

NINDS

Dementia with Lewy Bodies

Synonym(s): Lewy Body Dementia

What is Dementia With Lewy Bodies?

Dementia with Lewy bodies (DLB) is one of the most common types of progressive dementia. The central feature of DLB is progressive cognitive decline, combined with three additional defining features:  (1) pronounced “fluctuations” in alertness and attention, such as frequent drowsiness, lethargy, lengthy periods of time spent staring into space, or disorganized speech; (2) recurrent visual hallucinations,  and (3) parkinsonian motor symptoms, such as rigidity and the loss of spontaneous movement.   People may also suffer from depression.  The symptoms of DLB are caused by the build-up of Lewy bodies – accumulated bits of alpha-synuclein protein — inside the nuclei of neurons in areas of the brain that control particular aspects of memory and motor control.  Researchers don’t know exactly why alpha-synuclein accumulates into Lewy bodies or how Lewy bodies cause the symptoms of DLB, but they do know that alpha-synuclein accumulation is also linked to Parkinson's disease, multiple system atrophy, and several other disorders, which are referred to as the "synucleinopathies." The similarity of symptoms between DLB and Parkinson’s disease, and between DLB and Alzheimer’s disease, can often make it difficult for a doctor to make a definitive diagnosis. In addition, Lewy bodies are often also found in the brains of people with Parkinson's and Alzheimer’s diseases.  These findings suggest that either DLB is related to these other causes of dementia or that an individual can have both diseases at the same time.  DLB usually occurs sporadically, in people with no known family history of the disease. However, rare familial cases have occasionally been reported.

Is there any treatment?

There is no cure for DLB.  Treatments are aimed at controlling the cognitive, psychiatric, and motor symptoms of the disorder. Acetylcholinesterase inhibitors, such as donepezil and rivastigmine, are primarily used to treat the cognitive symptoms of DLB, but they may also be of some benefit in reducing the psychiatric and motor symptoms.  Doctors tend to avoid prescribing antipsychotics for hallucinatory symptoms of DLB because of the risk that neuroleptic sensitivity could worsen the motor symptoms.  Some individuals with DLB may benefit from the use of levodopa for their rigidity and loss of spontaneous movement.

What is the prognosis?

Like Alzheimer’s disease and Parkinson’s disease, DLB is a neurodegenerative disorder that results in progressive intellectual and functional deterioration.  There are no known therapies to stop or slow the progression of DLB.  Average survival after the time of diagnosis is similar to that in Alzheimer’s disease, about 8 years, with progressively increasing disability.

NINDS

Frontotemporal Dementia

Synonym(s): Pick's Disease, Primary Progressive Aphasia, Semantic Dementia, Dementia – Semantic

What is Frontotemporal Dementia?

Frontotemporal dementia (FTD) describes a clinical syndrome associated with shrinking of the frontal and temporal anterior lobes of the brain. Originally known as Pick’s disease, the name and classification of FTD has been a topic of discussion for over a century.  The current designation of the syndrome groups together Pick’s disease, primary progressive aphasia, and semantic dementia as FTD.  Some doctors propose adding corticobasal degeneration and progressive supranuclear palsy to FTD and calling the group Pick Complex.  These designations will continue to be debated.  As it is defined today, the symptoms of FTD fall into two clinical patterns that involve either (1) changes in behavior, or (2) problems with language.  The first type features behavior that can be either impulsive (disinhibited) or bored and listless (apathetic) and includes inappropriate social behavior; lack of social tact; lack of empathy; distractability; loss of insight into the behaviors of oneself and others; an increased interest in sex; changes in food preferences; agitation or, conversely, blunted emotions; neglect of personal hygiene; repetitive or compulsive behavior, and decreased energy and motivation.  The second type primarily features symptoms of language disturbance, including difficulty making or understanding speech, often in conjunction with the behavioral type’s symptoms.  Spatial skills and memory remain intact.  There is a strong genetic component to the disease; FTD often runs in families.

Is there any treatment?

No treatment has been shown to slow the progression of FTD. Behavior modification may help control unacceptable or dangerous behaviors.  Aggressive, agitated, or dangerous behaviors could require medication.  Anti-depressants have been shown to improve some symptoms.

What is the prognosis?

The outcome for people with FTD is poor.  The disease progresses steadily and often rapidly, ranging from less than 2 years in some individuals to more than 10 years in others.  Eventually some individuals with FTD will need 24-hour care and monitoring at home or in an institutionalized care setting.

NINDS

Multi-Infarct Dementia

Synonym(s): Dementia – Multi-Infarct

What is Multi-Infarct Dementia?

Multi-infarct dementia (MID) is a common cause of memory loss in the elderly.  MID is caused by multiple strokes (disruption of blood flow to the brain).  Disruption of blood flow leads to damaged brain tissue.  Some of these strokes may occur without noticeable clinical symptoms. Doctors refer to these as “silent strokes.”  An individual having a silent stroke may not even know it is happening, but over time, as more areas of the brain are damaged and more small blood vessels are blocked, the symptoms of MID begin to appear.  MID can be diagnosed by an MRI or CT of the brain, along with a neurological examination. Symptoms include confusion or problems with short-term memory; wandering, or getting lost in familiar places; walking with rapid, shuffling steps; losing bladder or bowel control; laughing or crying inappropriately; having difficulty following instructions; and having problems counting money and making monetary transactions.  MID, which typically begins between the ages of 60 and 75, affects men more often than women. Because the symptoms of MID are so similar to Alzheimer’s disease, it can be difficult for a doctor to make a firm diagnosis.  Since the diseases often occur together, making a single diagnosis of one or the other is even more problematic.

Is there any treatment?

There is no treatment available to reverse brain damage that has been caused by a stroke.  Treatment focuses on preventing future strokes by controlling or avoiding the diseases and medical conditions that put people at high risk for stroke:  high blood pressure, diabetes, high cholesterol, and cardiovascular disease.  The best treatment for MID is prevention early in life – eating a healthy diet, exercising, not smoking, moderately using alcohol, and maintaining a healthy weight.

What is the prognosis?

The prognosis for individuals with MID is generally poor.  The symptoms of the disorder may begin suddenly, often in a step-wise pattern after each small stroke.  Some people with MID may even appear to improve for short periods of time, then decline after having more silent strokes.  The disorder generally takes a downward course with intermittent periods of rapid deterioration.  Death may occur from stroke, heart disease, pneumonia, or other infection.

NINDS

Dementia

What is Dementia?

Dementia is not a specific disease. It is a descriptive term for a collection of symptoms that can be caused by a number of disorders that affect the brain. People with dementia have significantly impaired intellectual functioning that interferes with normal activities and relationships. They also lose their ability to solve problems and maintain emotional control, and they may experience personality changes and behavioral problems, such as agitation, delusions, and hallucinations. While memory loss is a common symptom of dementia, memory loss by itself does not mean that a person has dementia. Doctors diagnose dementia only if two or more brain functions – such as memory and language skills — are significantly impaired without loss of consciousness.  Some of the diseases that can cause symptoms of dementia are Alzheimer’s disease, vascular dementia, Lewy body dementia, frontotemporal dementia, Huntington’s disease, and Creutzfeldt-Jakob disease.  Doctors have identified other conditions that can cause dementia or dementia-like symptoms including reactions to medications, metabolic problems and endocrine abnormalities, nutritional deficiencies, infections, poisoning, brain tumors, anoxia or hypoxia (conditions in which the brain’s oxygen supply is either reduced or cut off entirely), and heart and lung problems.  Although it is common in very elderly individuals, dementia is not a normal part of the aging process.

Is there any treatment?

Drugs to specifically treat Alzheimer’s disease and some other progressive dementias are now available.  Although these drugs do not halt the disease or reverse existing brain damage, they can improve symptoms and slow the progression of the disease. This may improve an individual’s quality of life, ease the burden on caregivers, or delay admission to a nursing home. Many researchers are also examining whether these drugs may be useful for treating other types of dementia.  Many people with dementia, particularly those in the early stages, may benefit from practicing tasks designed to improve performance in specific aspects of cognitive functioning. For example, people can sometimes be taught to use memory aids, such as mnemonics, computerized recall devices, or note taking.

What is the prognosis?

There are many disorders that can cause dementia. Some, such as Alzheimer’s disease or Huntington’s disease, lead to a progressive loss of mental functions. But other types of dementia can be halted or reversed with appropriate treatment. People with moderate or advanced dementia typically need round-the-clock care and supervision to prevent them from harming themselves or others. They also may need assistance with daily activities such as eating, bathing, and dressing.

NINDS

Bulimia Nervosa

Bulimia nervosa is characterized by recurrent and frequent episodes of eating unusually large amounts of food (e.g., binge-eating), and feeling a lack of control over the eating. This binge-eating is followed by a type of behavior that compensates for the binge, such as purging (e.g., vomiting, excessive use of laxatives or diuretics), fasting and/or excessive exercise.

Unlike anorexia, people with bulimia can fall within the normal range for their age and weight. But like people with anorexia, they often fear gaining weight, want desperately to lose weight, and are intensely unhappy with their body size and shape. Usually, bulimic behavior is done secretly, because it is often accompanied by feelings of disgust or shame. The binging and purging cycle usually repeats several times a week. Similar to anorexia, people with bulimia often have coexisting psychological illnesses, such as depression, anxiety and/or substance abuse problems. Many physical conditions result from the purging aspect of the illness, including electrolyte imbalances, gastrointestinal problems, and oral and tooth-related problems.

Other symptoms include:

• 
  chronically inflamed and sore throat
• 
  swollen glands in the neck and below the jaw
• 
  worn tooth enamel and increasingly sensitive and decaying teeth as a result of exposure to stomach acids
• 
  gastroesophageal reflux disorder
• 
  intestinal distress and irritation from laxative abuse
• 
  kidney problems from diuretic abuse
• 
  severe dehydration from purging of fluids

As with anorexia, TREATMENT FOR BULIMIA often involves a combination of options and depends on the needs of the individual.

To reduce or eliminate binge and purge behavior, a patient may undergo nutritional counseling and psychotherapy, especially cognitive behavioral therapy (CBT), or be prescribed medication. Some antidepressants, such as fluoxetine (Prozac), which is the only medication approved by the U.S. Food and Drug Administration for treating bulimia, may help patients who also have depression and/or anxiety. It also appears to help reduce binge-eating and purging behavior, reduces the chance of relapse, and improves eating attitudes.

CBT that has been tailored to treat bulimia also has shown to be effective in changing binging and purging behavior, and eating attitudes. Therapy may be individually oriented or group-based.

NIH

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