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Instituto Superior de Ciências da Informação e da Administração

Formação Especializada em Educação Especial

Cadeira:Neuropsicologia das Dificuldades de Aprendizagem

Professor:

Maria de Fátima Figueiredo

• Caderno V: DEMÊNCIAS



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Neurological Disorder Resources

Alzheimer's

Disease Aphasia Bell's Palsy

Creutzfeldt-Jakob

Disease

Epilepsy Encephalitis Huntington'sDisease

Neuromuscular Disorders

Neuro-oncology Neuro-immunology

Neuro-otology Pain

Pediatric Neurology Phobia Sleep Disorders Tourette Syndrome

Parkinson's Disease and other movement disorders

Alzheimer's Disease

• Alzheimer Association

• Alzheimer's Disease - Doctor's

Guide

• Alzheimer's Disease - Science-Week Focus Report

• Alzheimer's: Few Clues on the

Mysteries of Memory

• Alzheimer's Disease - American

Health Assistance Foundation• Alzheimer's Disease -

Unraveling the Mystery

• Alzheimer's Disease Fact Sheet

• Alzheimer's Disease - AmericanFederation for Aging Research

• Alzheimer's Disease Education

and Referral (ADEAR) Center

• Alzheimer's Disease

Bibliography for Children and Teens

• Alzheimer's Disease - Neuroscience for Kids

• Alzheimer's Diease and Plaques

- Soc. Neuroscience

Aphasia

• Aphasia - Nat. Inst. on Deafness and Other Communication Disorders

• Aphasia - Nat. Inst. of Neurological

Disorders and Stroke

• Aphasia - Amer. Speech-Language-

Hearing Assoc.

• National Aphasia Association

• Aphasia - eMedicine

Creutzfeldt-Jakob Disease

(CJD)

• Blood Recall/Withdrawal - CJD



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• BSE -- Bovine Spongiform

Encephalopathy ("Mad Cow Disease")

•

CJD - National Center for InfectiousDiseases

• CJD Voice

• Creutzfeldt-Jakob Disease Foundation,Inc.

• Official Mad Cow Disease Home Page

• Creutzfeldt-Jakob Disease - NINDS

• Creutzfeldt-Jakob Disease - Mayo

Clinic

Cerebrovascular Disease• Aneurysm Information Project

• National Stroke Association

• NINDS Stroke InformationGuide

• Stroke Diagnosis - Internet

Stroke Center

• Stroke - National Women'sHealth Information Center

• Preventing Stroke

Encephalitis• Encephalitis - eMedicine

• Encephalitis (Arbovirus) - CDC

• Encephalitis - Mayo Clinic

• Encephalitis (Nemours Foundation)

• Encephalitis Information Resource

Epilepsy

• Epilepsy - Neuroscience for

Kids

• EpiCentre

• Epilepsy.com • Epilepsy - World Health

Organization (WHO)

• Epilepsy Treatment - WHO

• Epilepsy History- WHO • Epilepsy - Social/Economic -

WHO

• Epilepsy Fact Sheet - NINDS,

NIH

• Epilepsy Foundation of America

• Frequently Asked Questionsabout Epilepsy

• Epilepsy - Genes may build the

Huntington's Disease

• Index - Internet Resources for

Huntington's Disease

• Huntington's Disease Resources

• Huntington's Disease Society of America

• Huntington's Disease - Nat. Inst. of Neurological Disorders and Stroke

• Huntington's Disease - Mayo Clinic• Huntington's Disease - WeMove

• Huntington's Disease - American

Speech-Language-Hearing Association

• Huntington's Disease Genetics - Soc.

Neuroscience



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road in treatment

Pain

• American Council for Headache

Education

• Migraine - Doctor's Guide to the

Internet

• Migraine Resource Center

• Trigeminal Neuralgia

Association Homepage

• Trigeminal Neuralgia -

International RadiosurgeryAssoc.

• Intern. Assoc. for the Study of

Pain

•

Parkinson's Disease and

Other Movement Disorders

• American Parkinson Disease

Association

• Michael J. Fox Foundation

• Dystonias - National Institutes of

Health

• National Parkinson Foundation

• Parkinson's Disease- Hope Through

Research (NINDS, NIH)

• Parkinson's Disease Foundation

• Biology of Parkinson's Disease -

Science-Week Focus Report

• The Parkinson Alliance

• Parkinson's Disease: New Treatments

Slow Onslaught of Symptoms

• Parkinson's Disease - Medline Plus

• Young Parkinson's Information and Referral Center - American Parkinson

Disease Association

• Restless Legs Syndrome Foundation

• We Move • Alpha-Synuclein and Parkinson's

Disease - Soc. for Neuroscience

• Dystonia - Soc. for Neuroscience

• Parkinson's and Dopamine - Soc.

Neuroscience

Tourette Syndrome

• Tourette Syndrome -

Neuroscience for Kids

• Tourette Syndrome Information- NINDS, NIH

• Tourette Syndrome Home Page

• Tourette's Syndrome and

Dopamine



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• Neuro-immunology

• Multiple Sclerosis - Neuroscience for Kids site

• Multiple Sclerosis Central

• Multiple Sclerosis Information for

Physician and Medical Students

• Multiple Sclerosis Society of America

• MS page by Aapo Halko

• Myelin Project



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Basic Information About Parkinson's DiseaseThe Disease

Parkinson's disease is a progressive disorder of the central nervous systemaffecting more than 1.5 million people in the United States. Clinically, thedisease is characterized by a decrease in spontaneous movements, gaitdifficulty, postural instability, rigidity and tremor. Parkinson's disease iscaused by the degeneration of the pigmented neurons in the SubstantiaNigra of the brain, resulting in decreased dopamine availability. The majorsymptoms of the disease were originally described in 1817 by an Englishphysician, Dr. James Parkinson, who called it "Shaking Palsy." Only in the1960's, however, pathological and biochemical changes in the brain of patients were identified, opening the way to the first effective medication for

the disease.

Incidence

Men and women alike are affected. The frequency of the disease isconsiderably higher in the over-60 age group, even though there is analarming increase of patients of younger age. In consideration of theincreased life expectancy in this country and worldwide, an increasingnumber of people will be victims of Parkinson's disease.

Treatment

Administration of the drug levodopa has been the standard treatment forParkinson's disease. Once it reaches the brain, levodopa is converted todopamine which replaces the same substance not present in sufficientamounts in Parkinson's patients. Treatment with levodopa does not,however, prevent the progressive changes of the brain typical of Parkinson'sdisease. The drug may also produce side effects in some people, due to itschange to dopamine before reaching the brain. The simultaneousadministration with levodopa of substances inhibiting this change allows ahigher concentration of levodopa to reach the brain and also considerablydecreases the side effects. Some new drugs have recently been approvedoffering a wider choice of medications for the patient, while others are underinvestigation in this country and overseas in an effort to obtain bettertherapeutic results with fewer side effects.

The American Parkinson Disease Association, Inc., founded in 1961, hassought to "Ease the Burden and Find the Cure" for this disease throughresearch, patient and family support and education.

Education

Our education program provides information and resources to patients, theirfamilies, friends, doctors and other medical professionals and enhancespublic education and awareness of the disease.



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A set of nine manuals dealing with symptoms and medications, support,physiotherapy, speech problems and equipment to be used in the home isavailable free of charge. Some of the manuals have already been translated

or are being translated into other languages.

Educational supplements dealing with specific subjects related to Parkinson'sdisease are periodically issued.

A quarterly newsletter which focuses upon the latest developments inresearch and treatment of the disease is also mailed to more than 200,000addresses.

APDA also publishes an annual International Parkinson's Disease ResourceGuide with the purpose of providing a worldwide exchange of informationamong the people afflicted by this disease and their supporting

organizations.

Support

Recognizing the devastating effects of the illness upon the patient and thefamily, a support program was initiated to motivate the patients inmaximizing strengths, minimizing impediments and achieving andmaintaining full potential. The American Parkinson Disease Association, Inc.sponsors 65 chapters and more than 250 affiliated support groups whichprovide education, counseling, assistance and referrals throughout theUnited States.

The chapters also sponsor regional symposia and conferences in cooperationwith the Information and Referral Centers.

To provide professional support to the educational, counseling and referralneeds of the chapters, the support groups and the Parkinsonians at large,the American Parkinson Disease Association, Inc. funds 58 Information andReferral Centers from coast to coast. Their functions are to educate, counseland refer patients to medical professionals, increase awareness of theincidence of the disease and to establish Parkinson's disease chapters andsupport groups in their areas. More than $2 million is allocated annually tomaintain these centers.

Research

The research program funds five types of grants:

1. The Roger C. Duvoisin, MD Fellowship, established in 2002,carries a stipend of $80,000 for one year and is intended to supportestablished researchers in Parkinson's disease studies.

2. The Cotzias Fellowship, awarded to young neurologists for threeconsecutive years, with yearly stipends of $70,000.

3. Research Grants of up to $50,000 a year are awarded to scientistsworking on Parkinson's disease.

4. Post-Doctoral Research Fellowships of $35,000 a year.



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5. Medical Student Fellowships in the amount of $4,000 each peryear.

APDA is also funding eight Centers for Advanced Research in institutionsacross the country at a level of $100,000 a year for five consecutive years.More than 2.3 million dollars is allocated annually to support researchprojectsFund Raising and Public Relations

Fund raising is of paramount importance to support our ambitious programs.Proceeds from contributions, direct mail, special events sponsored by thenational office and chapters, along with a bequest program and gifts fromfoundations and corporations are used for funding our programs. A series of public service announcements by prominent individuals are distributedperiodically. Our awareness campaigns and symposia throughout the United

States have helped increase our visibility. Without public support we wouldnot be able to fund our outstanding research projects and unique educationprograms. Since APDA is a privately funded association, we would like tothank all who have invested in our cause and look forward to a continuedand growing relationship in our quest to "Ease the Burden and Find TheCure."



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Epilepsy

Contents of this Page

Types of Epilepsy

Causes

Diagnosis

Treatment

Famous

People

Organizations

Epilepsy is NOT contagious and people withepilepsy are NOT "crazy." The word "epilepsy"comes from a Greek word meaning "to possess,seize or hold." Because the brain useselectrochemical energy, any disruption of theelectrical processes in the brain may causeabnormal functioning. Unfortunately, this is what

happens during epilepsy: neurons in the cerebral hemispheresmisfire and create abnormal electrical activity. People withepilepsy have seizures that are a bit like an electrical brainstorm.The seizure prevents the brain from:

• interpreting and processing incoming sensory signals (likevisual, somatosensory and auditory information).

• controlling muscles. That is why people with epilepsy mayfall down and twitch.

Types of Epilepsy

There are many types of epilepsy. Each type of epilepsy has different behavioraleffects and is treated with different methods. In some cases, people know theyare about to have a seizure because they see or hear something, or feel dizzy,nauseous, or "strange." This is called an aura. An aura can act as an "earlywarning system" telling a person that a seizure is about to happen. The personcan therefore minimize a possible injury by taking precautionssuch as sitting down.

1. Generalized seizures - uncontrollable discharge of neurons on BOTH sides of the brain. This is the mostcommon type of epilepsy. The seizure starts in onearea of the brain and spreads across the brain. Theseseizures produce muscle twitches, convulsions and lossof consciousness. People with this type of epilepsy donot remember having a seizure.

There are several types of generalized seizures:



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o Tonic-clonic ("grand mal") seizure - This seizure occurs when thereis a massive discharge of neurons on both cerebral hemispheres.

The body becomes rigid and there is also jerking of the body."Tonic-clonic" means "stiffness-violent." "Grand mal" means "greatsickness."

o Absence ("petit mal") seizure - This seizure is nonconvulsive.However, a person may become unaware of his or her surroundings and may stare off in space or freeze. This seizurelasts only 5-30 seconds.

o Myoclonic seizure - This seizure involves the motor cortex andcauses twitching or jerking of certain parts of the body.

o Atonic seizure - This seizure is characterized by the loss of muscletone and causes a person to fall down.

o Status epilepticus - This seizure is characterized by frequent, long-lasting seizures without regaining consciousness between attacks.This condition requires immediate medical attention.

2. Partial Seizures - This type of seizure is characterized by abnormalelectrical activity involving only a small part of the brain. Sometimes apartial seizure can spread to the whole brain.

Two types of partial seizures are:

o Simple partial seizures (also called "Jacksonian" or "focal" seizures) - Short-lasting seizures without loss of consciousness. People with

these kinds of seizures often see, hear or smell something strange. Also, only part of the body may jerk.

o Complex partial (psychomotor) seizures - A seizure with a change,not a loss, in consciousness. People may hear or see things or memories may resurface. Feelings of deja vu may also occur.

Causes

Many (50-70%) cases of epilepsy have no known cause. For the

remaining cases, there are many other events that may cause epilepticseizures:

• Head injuries, such as a car accident or a fall.• Brain tumor • Stroke • Arteriosclerosis (fatty plaque build-up in arteries)• Brain injury before birth caused by infection or lack of oxygen to the brain• Infection, such as meningitis or encephalitis



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Brain damage resulting from these events may cause a "scar" on the brain. This is where

an epileptic seizure starts. At this time it is not known why a scar starts a seizure. There

may be a genetic link for some types of epilepsy, but this is usually NOT the case.Sometimes a seizure will be started ("triggered") by:

• stress• lack of sleep• flashing lights or sounds (like from a video game or TV)• low blood sugar

Diagnosis

A doctor will want to find out several things before adiagnosis of epilepsy is made. The doctor may want toknow the answers to the following questions:

• How often do the seizures occur?• When was the first seizure?• Was there a head injury?• What are the seizures like?• Were there any unusual sensations (smells, sounds, lights)?• Is there any memory of the seizures?

An electroencephalogram (EEG) is often used to help in the diagnosis of epilepsy. The EEG of people with epilepsy often shows large spikes.Sometimes the EEG must be recorded for a whole day in the hospital or at home because a short test does not always pick up the abnormalactivity. However, the EEG does not always work because about 5% of people without epilepsy have "abnormal" EEG activity and about 20% of people with epilepsy have normal EEG activity.

Brain imaging methods (magnetic resonance imaging [MRI] or computer tomography [CT] scanning) may also be used to find the location of a scar or

damaged brain tissue. Sometimes positron emission tomography [PET] is used

to examine brain blood flow.

Treatment for Epilepsy

Drugs



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Antiepi lept ic Drugs

ChemicalName

CommonTradeName

Carbamazepine Tegretol

Clobazam Frisium

Clonazepam Rivotril

Diazepam Valium

Divalproexsodium

Depakote

Ethosuximide Zarontin

Gabapentin Neurontin

Lamotrigine Lamictal

Phenobarbital

many

names

Phenytoin Dilantin

Valproic acid Depakene

Sometimes seizures stop

without treatment. Manypeople take antiepileptic(also called"anticonvulsant") drugs tocontrol seizures. Thesedrugs, however, do notcure the disorder. Rather,these drugs control thesymptoms and are effectivein 60-80% of the cases.

Antiepileptic drugs work by

reducing the abnormalfiring of cortical neurons.These drugs may changethe activity of neurotransmittersresponsible for seizures or alter the way ions flow inand out of neurons.Unfortunately, many of these drugs have sideeffects such as drowsiness,dizziness and nausea sodoctors must balance theseundesirable effects withseizure control. It is alsoimportant to remember thatdifferent drugs are used totreat different types of seizures.

Surgery

When medication fails and the area of the brainwhere the seizure occurs is known, surgery may beperformed to treat epilepsy. There are several typesof surgery that have been used:

• Temporal Lobe Surgery - This is performed toremove brain tissue where the epilepticseizure starts. This type of surgery oftenremoves part of the cortex of the temporal



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lobe, hippocampus and amygdala. [Brain

mapping during surgery] • Corpus Callosotomy ("Split Brain" operation) -

The corpus callosum is cut to separate theright and left cerebral hemispheres. Thisprocedure is done to prevent the spread of theseizure from one side of the brain to the other.

• Hemispherectomy - One cerebral hemisphereis removed. The procedure is not performedvery often. Children who have this surgeryCAN function quite well although they oftenhave trouble using their arm on the side of the

body opposite to the surgery. In somesurgeries, only specific lobes of the brain areremoved.

Hemispherectomy

Experimental TreatmentsSeveral treatments for epilepsy are still under investigation. How and if they workis still controversial.

• Ketogenic Diet - a high fat, low protein/carbohydrate diet• Biofeedback - people trained to control EEG patterns to shorten seizures• Counterstimulation• Exercise• Relaxation Techniques• Vagus Nerve Stimulation - an electrical stimulator is implanted to stimulate

the vagus nerve (cranial nerve X)• Vitamin and Mineral Supplements

Epilepsy is a fairly common neurological disorder. It occurs in about 1 in every100-200 people. Throughout history there have been many famous people who

have had epilepsy:

Famous People with Epilepsy

Julius Caesar - RomanStatesman (100-44 B.C.)

Napoleon Bonaparte -Emperor of France (1769-1821)

George Frederick Handel Vincent van Gogh - Painter



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- Composer (1685-1759) (1853-1890)

Fyodor Dostoevski -Writer (1821-1881)

Pius IX - Pope (1792-1878)

Peter the Great - RussianCzar (1682-1725)

Lord Byron - Poet (1788-1824)

Did you know?

Saint Valentine is the patron saint of epilepsy.

For more information on epilepsy, see:

• An Epilepsy Education • EpiCentre • Epilepsy and Everyone • Epilepsy and GABA • Epilepsy: Taming the Seizures, Dispelling the Myths - from the U.S. FDA• Epilepsy - World Health Organization (WHO) • Epilepsy Treatment - WHO • Epilepsy History- WHO • Epilepsy - Social/Economic - WHO

• Epilepsy Fact Sheet- from NINDS, NIH• Epilepsy Surgery - includes images of EEG and MRI; photographs during

surgery



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Introduction Huntington's disease

In 1872, the American physician George Huntington wrote about an illness thathe called "an heirloom from generations away back in the dim past." He was notthe first to describe the disorder, which has been traced back to the Middle Agesat least. One of its earliest names was chorea,* which, as in "choreography," isthe Greek word for dance. The term chorea describes how people affected withthe disorder writhe, twist, and turn in a constant, uncontrollable dance-likemotion. Later, other descriptive names evolved. "Hereditary chorea" emphasizeshow the disease is passed from parent to child. "Chronic progressive chorea"

stresses how symptoms of the disease worsen over time. Today, physicianscommonly use the simple term Huntington's disease (HD) to describe this highlycomplex disorder that causes untold suffering for thousands of families.

In the United States alone, about 30,000 people have HD; estimates of itsprevalence are about 1 in every 10,000 persons. At least 150,000 others have a50 percent risk of developing the disease and thousands more of their relativeslive with the possibility that they, too, might develop HD.

Until recently, scientists understood very little about HD and could only watch asthe disease continued to pass from generation to generation. Families saw the

disease destroy their loved ones' ability to feel, think, and move. In the lastseveral years, scientists working with support from the National Institute of Neurological Disorders and Stroke (NINDS) have made several breakthroughs inthe area of HD research. With these advances, our understanding of the diseasecontinues to improve.

This brochure presents information about HD, and about current researchprogress, to health professionals, scientists, caregivers, and, most important, tothose already too familiar with the disorder: the many families who are affectedby HD.

What Causes Huntington's disease?

HD results from genetically programmed degeneration of nerve cells, calledneurons,* in certain areas of the brain. This degeneration causes uncontrolledmovements, loss of intellectual faculties, and emotional disturbance. Specificallyaffected are cells of the basal ganglia, structures deep within the brain that havemany important functions, including coordinating movement. Within the basalganglia, HD especially targets neurons of the striatum, particularly those in the



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caudate nuclei and the pallidum. Also affected is the brain's outer surface, or cortex, which controls thought, perception, and memory.

How is HD Inherited?

HD is found in every country of the world. It is a familial disease, passed fromparent to child through a mutation or misspelling in the normal gene.

A single abnormal gene, the basic biological unit of heredity, produces HD.Genes are composed of deoxyribonucleic acid (DNA), a molecule shaped like aspiral ladder. Each rung of this ladder is composed of two paired chemicalscalled bases. There are four types of bases—adenine, thymine, cytosine, and

guanine—each abbreviated by the first letter of its name: A, T, C, and G. Certainbases always "pair" together, and different combinations of base pairs join toform coded messages. A gene is a long string of this DNA in variouscombinations of A, T, C, and G. These unique combinations determine thegene's function, much like letters join together to form words. Each person hasabout 30,000 genes—a billion base pairs of DNA or bits of information repeatedin the nuclei of human cells—which determine individual characteristics or traits.

Genes are arranged in precise locations along 23 rod-like pairs of chromosomes.One chromosome from each pair comes from an individual's mother, the other from the father. Each half of a chromosome pair is similar to the other, except for

one pair, which determines the sex of the individual. This pair has two Xchromosomes in females and one X and one Y chromosome in males. The genethat produces HD lies on chromosome 4, one of the 22 non-sex-linked, or "autosomal," pairs of chromosomes, placing men and women at equal risk of acquiring the disease.

The impact of a gene depends partly on whether it is dominant or recessive. If agene is dominant, then only one of the paired chromosomes is required toproduce its called-for effect. If the gene is recessive, both parents must providechromosomal copies for the trait to be present. HD is called an autosomaldominant disorder because only one copy of the defective gene, inherited from

one parent, is necessary to produce the disease.

The genetic defect responsible for HD is a small sequence of DNA onchromosome 4 in which several base pairs are repeated many, many times. Thenormal gene has three DNA bases, composed of the sequence CAG. In peoplewith HD, the sequence abnormally repeats itself dozens of times. Over time— and with each successive generation—the number of CAG repeats may expandfurther.



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Each parent has two copies of every chromosome but gives only one copy toeach child. Each child of an HD parent has a 50-50 chance of inheriting the HDgene. If a child does not inherit the HD gene, he or she will not develop thedisease and cannot pass it to subsequent generations. A person who inherits theHD gene, and survives long enough, will sooner or later develop the disease. Insome families, all the children may inherit the HD gene; in others, none do.Whether one child inherits the gene has no bearing on whether others will or willnot share the same fate.

A small number of cases of HD are sporadic, that is, they occur even thoughthere is no family history of the disorder. These cases are thought to be causedby a new genetic mutation-an alteration in the gene that occurs during spermdevelopment and that brings the number of CAG repeats into the range thatcauses disease.

What are the Major Effects of the Disease?

Early signs of the disease vary greatly from person to person. A commonobservation is that the earlier the symptoms appear, the faster the diseaseprogresses.

Family members may first notice that the individual experiences mood swings or becomes uncharacteristically irritable, apathetic, passive, depressed, or angry.

These symptoms may lessen as the disease progresses or, in some individuals,may continue and include hostile outbursts or deep bouts of depression.

HD may affect the individual's judgment, memory, and other cognitive functions.Early signs might include having trouble driving, learning new things,remembering a fact, answering a question, or making a decision. Some mayeven display changes in handwriting. As the disease progresses, concentrationon intellectual tasks becomes increasingly difficult.

In some individuals, the disease may begin with uncontrolled movements in thefingers, feet, face, or trunk. These movements—which are signs of chorea—often

intensify when the person is anxious. HD can also begin with mild clumsiness or problems with balance. Some people develop choreic movements later, after thedisease has progressed. They may stumble or appear uncoordinated. Choreaoften creates serious problems with walking, increasing the likelihood of falls.

The disease can reach the point where speech is slurred and vital functions,such as swallowing, eating, speaking, and especially walking, continue todecline. Some individuals cannot recognize other family members. Many,however, remain aware of their environment and are able to express emotions.



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Some physicians have employed a recently developed Unified HD Rating Scale,or UHDRS, to assess the clinical features, stages, and course of HD. In general,the duration of the illness ranges from 10 to 30 years. The most common causesof death are infection (most often pneumonia), injuries related to a fall, or other complications.

At What Age Does HD Appear?

The rate of disease progression and the age at onset vary from person to person. Adult-onset HD, with its disabling, uncontrolled movements, most often begins inmiddle age. There are, however, other variations of HD distinguished not just byage at onset but by a distinct array of symptoms. For example, some persons

develop the disease as adults, but without chorea. They may appear rigid andmove very little, or not at all, a condition called akinesia.

Some individuals develop symptoms of HD when they are very young—beforeage 20. The terms "early-onset" or "juvenile" HD are often used to describe HDthat appears in a young person. A common sign of HD in a younger individual isa rapid decline in school performance. Symptoms can also include subtlechanges in handwriting and slight problems with movement, such as slowness,rigidity, tremor, and rapid muscular twitching, called myoclonus. Several of thesesymptoms are similar to those seen in Parkinson's disease, and they differ fromthe chorea seen in individuals who develop the disease as adults. These young

individuals are said to have "akinetic-rigid" HD or the Westphal variant of HD.People with juvenile HD may also have seizures and mental disabilities. Theearlier the onset, the faster the disease seems to progress. The diseaseprogresses most rapidly in individuals with juvenile or early-onset HD, and deathoften follows within 10 years.

Individuals with juvenile HD usually inherit the disease from their fathers. Theseindividuals also tend to have the largest number of CAG repeats. The reason for this may be found in the process of sperm production. Unlike eggs, sperm areproduced in the millions. Because DNA is copied millions of times during thisprocess, there is an increased possibility for genetic mistakes to occur. To verify

the link between the number of CAG repeats in the HD gene and the age atonset of symptoms, scientists studied a boy who developed HD symptoms at theage of two, one of the youngest and most severe cases ever recorded. Theyfound that he had the largest number of CAG repeats of anyone studied so far— nearly 100. The boy's case was central to the identification of the HD gene and atthe same time helped confirm that juveniles with HD have the longest segmentsof CAG repeats, the only proven correlation between repeat length and age atonset.



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A few individuals develop HD after age 55. Diagnosis in these people can bevery difficult. The symptoms of HD may be masked by other health problems, or the person may not display the severity of symptoms seen in individuals with HDof earlier onset. These individuals may also show symptoms of depression rather than anger or irritability, or they may retain sharp control over their intellectualfunctions, such as memory, reasoning, and problem-solving.

There is also a related disorder called senile chorea. Some elderly individualsdisplay the symptoms of HD, especially choreic movements, but do not becomedemented, have a normal gene, and lack a family history of the disorder. Somescientists believe that a different gene mutation may account for this smallnumber of cases, bu this has not been proven.

How is HD Diagnosed?

The great American folk singer and composer Woody Guthrie died on October 3,1967, after suffering from HD for 13 years. He had been misdiagnosed,considered an alcoholic, and shuttled in and out of mental institutions andhospitals for years before being properly diagnosed. His case, sadly, is notextraordinary, although the diagnosis can be made easily by experiencedneurologists.

A neurologist will interview the individual intensively to obtain the medical history

and rule out other conditions. A tool used by physicians to diagnose HD is to takethe family history, sometimes called a pedigree or genealogy. It is extremelyimportant for family members to be candid and truthful with a doctor who is takinga family history.

The doctor will also ask about recent intellectual or emotional problems, whichmay be indications of HD, and will test the person's hearing, eye movements,strength, coordination, involuntary movements (chorea), sensation, reflexes,balance, movement, and mental status, and will probably order a number of laboratory tests as well.

People with HD commonly have impairments in the way the eye follows or fixeson a moving target. Abnormalities of eye movements vary from person to personand differ, depending on the stage and duration of the illness.

The discovery of the HD gene in 1993 resulted in a direct genetic test to make or confirm a diagnosis of HD in an individual who is exhibiting HD-like symptoms.Using a blood sample, the genetic test analyzes DNA for the HD mutation bycounting the number of repeats in the HD gene region. Individuals who do nothave HD usually have 28 or fewer CAG repeats. Individuals with HD usually have



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40 or more repeats. A small percentage of individuals, however, have a number of repeats that fall within a borderline region (see table 1).

Table 1

No. of CAG repeats Outcome

<

28

Normal range; individual will not develop HD

29-34 Individual will not develop HD but the next generation is at risk

35-39 Some, but not all, individuals in this range will develop HD; next generation

is also at risk

>

40

Individual will develop HD

The physician may ask the individual to undergo a brain imaging test. Computed tomography (CT) and magnetic

resonance imaging (MRI) provide excellent images of brain structures with little if any discomfort. Those with HD may show shrinkage of some parts of the brain— particularly two areas known as the caudate nuclei and putamen —andenlargement of fluid-filled cavities within the brain called ventricles. Thesechanges do not definitely indicate HD, however, because they can also occur in

other disorders. In addition, a person can have early symptoms of HD and stillhave a normal CT scan. When used in conjunction with a family history andrecord of clinical symptoms, however, CT can be an important diagnostic tool.

Another technology for brain imaging includes positron emission tomography(PET,) which is important in HD research efforts but is not often needed for diagnosis.

What is Presymptomatic Testing?

Presymptomatic testing is used for people who have a family history of HD buthave no symptoms themselves. If either parent had HD, the person's chancewould be 50-50. In the past, no laboratory test could positively identify peoplecarrying the HD gene—or those fated to develop HD—before the onset of symptoms. That situation changed in 1983, when a team of scientists supportedby the NINDS located the first genetic marker for HD—the initial step indeveloping a laboratory test for the disease.

A marker is a piece of DNA that lies near a gene and is usually inherited with it.Discovery of the first HD marker allowed scientists to locate the HD gene on



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chromosome 4. The marker discovery quickly led to the development of apresymptomatic test for some individuals, but this test required blood or tissuesamples from both affected and unaffected family members in order to identifymarkers unique to that particular family. For this reason, adopted individuals,orphans, and people who had few living family members were unable to use thetest.

Discovery of the HD gene has led to a less expensive, scientifically simpler, andfar more accurate presymptomatic test that is applicable to the majority of at-risk people. The new test uses CAG repeat length to detect the presence of the HDmutation in blood. This is discussed further in the next section.

There are many complicating factors that reflect the complexity of diagnosingHD. In a small number of individuals with HD—1 to 3 percent—no family history

of HD can be found. Some individuals may not be aware of their genetic legacy,or a family member may conceal a genetic disorder from fear of social stigma. Aparent may not want to worry children, scare them, or deter them from marrying.In other cases, a family member may die of another cause before he or shebegins to show signs of HD. Sometimes, the cause of death for a relative maynot be known, or the family is not aware of a relative's death. Adopted childrenmay not know their genetic heritage, or early symptoms in an individual may betoo slight to attract attention.

How is the Presymptomatic Test Conducted?

An individual who wishes to be tested should contact the nearest testing center.(A list of such centers can be obtained from the Huntington Disease Society of

America at 1-800-345-HDSA.) The testing process should include severalcomponents. Most testing programs include a neurological examination, pretestcounseling, and followup. The purpose of the neurological examination is todetermine whether or not the person requesting testing is showing any clinicalsymptoms of HD. It is important to remember that if an individual is showing evenslight symptoms of HD, he or she risks being diagnosed with the disease duringthe neurological examination, even before the genetic test. During pretest

counseling, the individual will learn about HD, and about his or her own level of risk, about the testing procedure. The person will be told about the test'slimitations, the accuracy of the test, and possible outcomes. He or she can thenweigh the risks and benefits of testing and may even decide at that time againstpursuing further testing.

If a person decides to be tested, a team of highly trained specialists will beinvolved, which may include neurologists, genetic counselors, social workers,psychiatrists, and psychologists. This team of professionals helps the at-risk



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person decide if testing is the right thing to do and carefully prepares the personfor a negative, positive, or inconclusive test result.

Individuals who decide to continue the testing process should be accompanied tocounseling sessions by a spouse, a friend, or a relative who is not at risk. Other interested family members may participate in the counseling sessions if theindividual being tested so desires.

The genetic testing itself involves donating a small sample of blood that isscreened in the laboratory for the presence or absence of the HD mutation.Testing may require a sample of DNA from a closely related affected relative,preferably a parent, for the purpose of confirming the diagnosis of HD in thefamily. This is especially important if the family history for HD is unclear or unusual in some way.

Results of the test should be given only in person and only to the individual beingtested. Test results are confidential. Regardless of test results, followup isrecommended.

In order to protect the interests of minors, including confidentiality, testing is notrecommended for those under the age of 18 unless there is a compelling medicalreason (for example, the child is exhibiting symptoms).

Testing of a fetus (prenatal testing) presents special challenges and risks; in factsome centers do not perform genetic testing on fetuses. Because a positive test

result using direct genetic testing means the at-risk parent is also a gene carrier,at-risk individuals who are considering a pregnancy are advised to seek geneticcounseling prior to conception.

Some at-risk parents may wish to know the risk to their fetus but not their own. Inthis situation, parents may opt for prenatal testing using linked DNA markersrather than direct gene testing. In this case, testing does not look for the HD geneitself but instead indicates whether or not the fetus has inherited a chromosome 4from the affected grandparent or from the unaffected grandparent on the side of the family with HD. If the test shows that the fetus has inherited a chromosome 4from the affected grandparent, the parents then learn that the fetus's risk is the

same as the parent (50-50), but they learn nothing new about the parent's risk. If the test shows that the fetus has inherited a chromosome 4 from the unaffectedgrandparent, the risk to the fetus is very low (less than 1%) in most cases.

Another option open to parents is in vitro fertilization with preimplantationscreening. In this procedure, embryos are screened to determine which onescarry the HD mutation. Embryos determined not to have the HD gene mutationare then implanted in the woman's uterus.



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In terms of emotional and practical consequences, not only for the individualtaking the test but for his or her entire family, testing is enormously complex andhas been surrounded by considerable controversy. For example, people with apositive test result may risk losing health and life insurance, suffer loss of employment, and other liabilities. People undergoing testing may wish to cover the cost themselves, since coverage by an insurer may lead to loss of healthinsurance in the event of a positive result, although this may change in the future.

With the participation of health professionals and people from families with HD,scientists have developed testing guidelines. All individuals seeking a genetictest should obtain a copy of these guidelines, either from their testing center or from the organizations listed on the card in the back of this brochure. Theseorganizations have information on sites that perform testing using the establishedprocedures and they strongly recommend that individuals avoid testing that does

not adhere to these guidelines.

How Does a Person Decide Whether to be Tested?

The anxiety that comes from living with a 50 percent risk for HD can beoverwhelming. How does a young person make important choices about long-term education, marriage, and children? How do older parents of adult childrencope with their fears about children and grandchildren? How do people come toterms with the ambiguity and uncertainty of living at risk?

Some individuals choose to undergo the test out of a desire for greater certaintyabout their genetic status. They believe the test will enable them to make moreinformed decisions about the future. Others choose not to take the test. They areable to make peace with the uncertainty of being at risk, preferring to forego theemotional consequences of a positive result, as well as possible losses of insurance and employment. There is no right or wrong decision, as each choiceis highly individual. The guidelines for genetic testing for HD, discussed in theprevious section, were developed to help people with this life-changing choice.

Whatever the results of genetic testing, the at-risk individual and family members

can expect powerful and complex emotional responses. The health andhappiness of spouses, brothers and sisters, children, parents, and grandparentsare affected by a positive test result, as are an individual's friends, workassociates, neighbors, and others. Because receiving test results may prove tobe devastating, testing guidelines call for continued counseling even after the testis complete and the results are known.

Is There a Treatment for HD?



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Physicians may prescribe a number of medications to help control emotional andmovement problems associated with HD. It is important to remember however,that while medicines may help keep these clinical symptoms under control, thereis no treatment to stop or reverse the course of the disease.

Antipsychotic drugs, such as haloperidol, or other drugs, such as clonazepam,may help to alleviate choreic movements and may also be used to help controlhallucinations, delusions, and violent outbursts. Antipsychotic drugs, however,are not prescribed for another form of muscle contraction associated with HD,called dystonia, and may in fact worsen the condition, causing stiffness andrigidity. These medications may also have severe side effects, includingsedation, and for that reason should be used in the lowest possible doses.

For depression, physicians may prescribe fluoxetine, sertraline, nortriptyline, or

other compounds. Tranquilizers can help control anxiety and lithium may beprescribed to combat pathological excitement and severe mood swings.Medications may also be needed to treat the severe obsessive-compulsive ritualsof some individuals with HD.

Most drugs used to treat the symptoms of HD have side effects such as fatigue,restlessness, or hyperexcitability. Sometimes it may be difficult to tell if aparticular symptom, such as apathy or incontinence, is a sign of the disease or areaction to medication.

What Kind of Care Does the Individual with HD Need?

Although a psychologist or psychiatrist, a genetic counselor, and other specialistsmay be needed at different stages of the illness, usually the first step in diagnosisand in finding treatment is to see a neurologist. While the family doctor may beable to diagnose HD, and may continue to monitor the individual's status, it isbetter to consult with a neurologist about management of the varied symptoms.

Problems may arise when individuals try to express complex thoughts in wordsthey can no longer pronounce intelligibly. It can be helpful to repeat words back

to the person with HD so that he or she knows that some thoughts areunderstood. Sometimes people mistakenly assume that if individuals do not talk,they also do not understand. Never isolate individuals by not talking, and try tokeep their environment as normal as possible. Speech therapy may improve theindividual's ability to communicate.

It is extremely important for the person with HD to maintain physical fitness asmuch as his or her condition and the course of the disease allows. Individualswho exercise and keep active tend to do better than those who do not. A dailyregimen of exercise can help the person feel better physically and mentally.



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Although their coordination may be poor, individuals should continue walking,with assistance if necessary. Those who want to walk independently should beallowed to do so as long as possible, and careful attention should be given tokeeping their environment free of hard, sharp objects. This will help ensuremaximal independence while minimizing the risk of injury from a fall. Individualscan also wear special padding during walks to help protect against injury fromfalls. Some people have found that small weights around the ankles can helpstability. Wearing sturdy shoes that fit well can help too, especially shoes withoutlaces that can be slipped on or off easily.

Impaired coordination may make it difficult for people with HD to feed themselvesand to swallow. As the disease progresses, persons with HD may even choke. Inhelping individuals to eat, caregivers should allow plenty of time for meals. Foodcan be cut into small pieces, softened, or pureed to ease swallowing and prevent

choking. While some foods may require the addition of thickeners, other foodsmay need to be thinned. Dairy products, in particular, tend to increase thesecretion of mucus, which in turn increases the risk of choking. Some individualsmay benefit from swallowing therapy, which is especially helpful if started beforeserious problems arise. Suction cups for plates, special tableware designed for people with disabilities, and plastic cups with tops can help prevent spilling. Theindividual's physician can offer additional advice about diet and about how tohandle swallowing difficulties or gastrointestinal problems that might arise, suchas incontinence or constipation.

Caregivers should pay attention to proper nutrition so that the individual with HD

takes in enough calories to maintain his or her body weight. Sometimes peoplewith HD, who may burn as many as 5,000 calories a day without gaining weight,require five meals a day to take in the necessary number of calories. Physiciansmay recommend vitamins or other nutritional supplements. In a long-term careinstitution, staff will need to assist with meals in order to ensure that theindividual's special caloric and nutritional requirements are met. Some individualsand their families choose to use a feeding tube; others choose not to.

Individuals with HD are at special risk for dehydration and therefore require largequantities of fluids, especially during hot weather. Bendable straws can makedrinking easier for the person. In some cases, water may have to be thickened

with commercial additives to give it the consistency of syrup or honey.



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Introduct ion Creutzfeldt - Jakob disease

Prion diseases are a group of rare, invariably fatal brain disorders which occur both in humans and certain animals. They first came to public attention in the mid1980s in the form of the BSE epidemic in the United Kingdom. BSE (bovinespongiform encephalopathy) is a prion disease in cattle. Tissue from infectedanimals may have contaminated cattle feed, leading to the silent spread of theBSE epidemic. There is also a theory that BSE came from feed contaminatedwith scrapie, the long established sheep prion disease. Inevitably, concern over whether BSE could pass to humans mounted.

In humans the best known of the prion diseases is Creutzfeldt-Jakob Disease(CJD), which reportedly affects around one person per million per year. In the

United States this translates to 250-300 new cases per year. It is well known thatCJD is very difficult to diagnose leading to speculation that the one case per million report may be incorrect. Most of the cases are "classical" or "sporadic"CJD (sCJD), occurring for no, as yet, known reason. The sporadic form accountsfor approximately 85% of the cases, the familial form approximately 15%. Therehave also been a few cases which have occurred from contamination via medicalprocedures; this type is known as iatrogenic or Acquired CJD. Finally over thelast few years, another type of Acquired CJD called variant (vCJD) has beenidentified in young people. vCJD has been linked to ingestion of beef tainted withBSE (bovine spongiform encephalopathy), most cases have occurred in theUnited Kingdom.



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Alzheimer's Disease

What is Alzheimer's Disease?In 1986, President Ronald Reagan's "I don't remember," "I don'trecall" responses seemed to many to be lame answers toquestions about political dealings. However, it turns out that theymay have been the truth. In 1994, former President RonaldReagan announced that he had Alzheimer's disease (AD).

RonaldReagan

Alzheimer's disease attacks the brain; it is not a normal part of aging. People with AD have a gradual memory loss anddifficulties with language and emotions. The progressive loss of intellectual abilities is termed dementia. As the diseaseadvances, the person may need help in all aspects of life:bathing, eating, and using the restroom. Because of this round-the-clock care, families and friends of people with AD aregreatly affected. The disease is irreversible and there iscurrently no cure.

Who Gets AD? About 5-6% of the US population has AD or a relateddementia. This means that approximately four million

Americans have AD. As the population ages, theburden to caregivers and cost to society will grow. It isestimated that by 2050, 14 million people in the USwill suffer from AD.

Alzheimer's disease ranks fourth in the cause of deathamong adults. About 100,000 people die per year as a result

of AD. Five to 10 percent of the population over age 65

have AD. At the age of 85 and older, about 50% have AD.Although age is a factor, research has shown that genetics

also play a role. Because women tend to live longer than

men, more women are affected by AD than men.

Furthermore, 80% of caregivers are women, so they arealso secondarily affected by the disease.

Estimated Number of Cases

of AD in the U.S.(millions)



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Symptoms

Memory loss, especially of recent events and newlyacquired information, is perhaps the most noticeable traitof AD. The first symptoms have a gradual, subtle onset,and can be a sign of many dementias, not just AD. For example, a person may become lost in familiar surroundings, forget whether a task was done, repeat thesame story, or is unable to learn new things. As thedisease worsens, the person may be unable to find theright word or to make responsible decisions.

One of the most painful aspects of the disease is

that the person sometimes will not recognizefriends or family members. Personality changescan occur, such as unusual agitation, paranoia,depression, and social withdrawal. Later, peoplewith AD may wander, or be unable to find their way home. New research, however, has shownthat a part of the brain that processes visual andspatial information may be damaged in peoplewith AD. This may account for the problems ADpatients have with orienting themselves.) Patientsmay also become inattentive, thus unable to care

for their day-to-day bodily needs. Other parts of the brain including the basal forebrain andhippocampus, areas important for memory, arealso affected by AD. Many AD sufferers die fromother causes such as pneumonia. From the timeof diagnosis, AD patients generally live 6-8 years,although many live for as long as 20 year after thediagnosis.

The symptoms of AD vary tremendously from personto person, but in time, each person who has AD will

experience worsening symptoms. Many of the behavioral changes associated with AD - depression, paranoia, and delusions - can be helped with

medication. However, there is no cure for AD,

although some treatments hold promise.

Areas of the brainaffected by AD

A = Cerebral CortexB = Basal ForebrainC = Hippocampus

Image courtesy of the NIA

Illustrator: Lydia Kibiuk



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A Closer Look at an AD Brain

The microscopic changes that occur in thebrain of a person with AD were first noted byGerman neurologist Alois Alzheimer in 1906.He performed an autopsy on a woman whohad become more and more confused in theyears preceding her death. He called thechanges he observed in her brain plaques andtangles. These features can only be seen uponautopsy. Tangles and plaques interfere withneuronal functions, such as communicatingwith each other and sending messages to other

parts of the body.

Research suggests that the formation of tangles inthe brain may be a part of the normal aging process.

Dr. John Morris of Washington University School

of Medicine in St. Louis, Missouri, published areport titled "Tangles and plaques in nondemented

aging and preclinical Alzheimer's disease" in the

March 1999 issue of Annals of Neurology, Volume

45 Number 3, pages 358-368. This study showed that of the 39 nondemented people (people with no

behavioral evidence of Alzheimer's disease), all had tangles in their brains. So perhaps developing

tangles is an inevitable part of growing old. "This isfurther evidence that there is such a thing as truly

healthy aging and that Alzheimer's disease is not

inevitable," states Morris. More research is needed

to figure out what role tangles and plaques play inAD. Are only plaques responsible, or do tangles and

plaques interact?

Other observed changes in the brain affected by AD

include:

• neuronal degeneration in a part of thebrain called the nucleus basalis of Meynert.

• decreased brain levels of theneurotransmitter acetylcholine.

Image courtesy of the NIA Illustrator: Lydia Kibiuk



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Neurofibrillary Tangles

It is unclear how neurofibrillary tangles (NFT)form. NFTs are found inside of the neuron: theneurons themselves become deformed and clumptogether. NFTs have been described as lookinglike a rope tied in knots. A protein named tau hasbeen shown to be involved in forming NFTs, butmore research is needed to solve the mystery of how and why NFTs form, and how exactly theyaffect the brain.

Plaques

Unlike tangles, plaques occur outside the neuron.Plaques are mainly composed of a protein calledbeta amyloid, although other proteins contribute toplaque formation. Research has shown that aprotein in our bodies called amyloid plays asignificant role in AD. Proteins are vital moleculesthat control all sorts of processes in our body. Theamyloid protein occurs naturally in our brains, butas we age, too much of it (in a form called betaamyloid) accumulates in the brain, formingplaques. Beta amyloid is formed when an enzyme

clips the amyloid precursor protein; beta amyloid,a fragment from this process then aggregates indeposits. It is unknown whether these depositsare due to excess production or whether theenzymes that usually break it down are notfunctioning properly. This situation is similar thatof cholesterol in our bodies. Some cholesterol isneeded to keep our cells healthy, but too muchcholesterol can block arteries and lead to heartattacks and other problems.

Image courtesy of the NIA Illustrator: Lydia Kibiuk



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Drug Therapies

Only two drugs for treating AD have beenapproved by the US Food and Drug

Administration (FDA): Cognex and Aricept.These drugs are cholinesterase inhibitors (generic names tacrineand donepezil, respectively). These drugs inhibit the breakdown of acetylcholine by blocking the action of cholinesterase, the key

enzyme in the breakdown of acetylcholine. Both drugs increase the level of theacetylcholine in the brain. Both drugs also slow memory loss and help the personperform daily tasks. It is important to note that these drugs are not a cure, theyonly lessen the symptoms of AD.

Tacrine has side effects on liver enzymes, so a new experimental drug, rivastigmine, maysoon be approved for AD. It is "brain selective" and does not affect liver enzymes.

At least 17 other drugs for treating AD are awaiting approval from the US FDA.

Other Therapies

• Vitamin E (an antioxidant) and aspirin (an anti-inflammatory) are beingconsidered as treatments. How each works to lessen the symptoms of ADis not clear. It has been suggested that Vitamin E protects the nerve cellmembranes from damage by a harmful chemical process called oxidation.

• Studies have shown that some architectural designs help AD patients. For example, buildings with circular floor plans allow AD patients to wander until they find their room. Signs reminding AD patients to do certain taskscan help focus attention. Having the same schedule each day can also aidthe AD patient's memory.

• Some studies have shown modest effects of the plant Ginkgo biloba onthe symptoms associated with AD.

• A controversial surgical treatment for AD has been reported by Dr. HarryS. Goldsmith at the University of Nevada School of Medicine. He placespart of the omentum, a fatty membrane in the abdomen which holdsorgans in, on the brain. This has been shown to improve short-term

memory in AD patients, perhaps because of a chemical in the omentum.Further research is warranted to explain how (and if) this surgery works.



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Expanding Diagnostic Tools

Because a definitive diagnosis of AD can only be made byexamining the brain after a person dies, AD diagnosis in theliving must be made by exclusion. This means that other diseases must be ruled out as a cause of the dementia. There isno single test to show that a person has AD, but several testscan suggest the presence of AD.

• When analyzing cerebrospinal fluid, an elevated level of certain proteins,including amyloid beta protein, may indicate that a person is likely to have

AD.• As imaging technology becomes more sophisticated and accessible,

health professionals can use CAT scans to visualize brain shrinkage. Abrain with widened sulci (the indentations on the surface of the brain), andenlarged cerebral ventricles (the spaces in the brain which are filled withCSF) - all characteristics of AD (and other neurological disorders).

• Brain imaging methods can also be used to gain information about bloodflow and metabolic activity in various parts of the brain.

PET Scans



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Risk Factors

First and foremost, the chance of developing AD increases with age. Witheach additional year of life, there is increased likelihood that one willdisplay symptoms of AD. Alzheimer's disease affects men and womenabout equally, and strikes all ethnic groups.

There are actually two types of AD: familial (early onset) and sporadic (late

onset). Familial AD is a rare form of AD that affects a small subset of people at ayounger age, usually before their fifties. It has a strong genetic component:

mutations on genes 21, 14, and 1 cause a predisposition to AD.(Reported in

Neurology, July 1998.)

Sporadic (late-onset) AD is the type most people are familiar with. It affects people most often after they reach 65 years of age. A gene called ApoE onchromosome 19 has been pinpointed as being a risk factor for AD.

What Can You Do to Protect Your Brain As You Age? As you age, some connections in your brain may fail dueto tangles or plaques, so it makes sense that the moreneural connections you have overall, the more you willbe able to compensate for the damaged connections. It's

like a sports team. If one player gets injured and there isa qualified player on the bench who can substitute, theteam will still function well. The more players available toplay for injured team members, the better the team willfare.

How do you get and maintain neural connections? It is thought

that staying active, both mentally and physically, will help.

Challenge your mind. Remember people's names. Work crossword puzzles. Do math. Read. Learn new words.



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Future Research

Understanding Alzheimer's disease is one of the mostactive areas in neuroscience research. In 1998,scientists took a big step forward by breeding mice thatdevelop the symptoms of AD. These mice will helpresearchers unravel the mysteries of AD. Researchinto future treatments can be divided into severalcategories.

Chemical Theories

1. Biochemical Changes in the Brain

Brain cells need certain nutrients to grow. Oneof these nutrients is called NGF, for nervegrowth factor. A decrease in NGF couldcontribute to AD. Experiments on rats haveshown that NGF promoted growth of newsynaptic connections in a part of the brain calledthe hippocampus. This new growth, in theory,could help restore memory loss. The flip side tochemicals which help neurons grow are thechemicals which kill neurons. These chemicalsare neurotoxic. Perhaps an increased level of

neurotoxins contributes to the disease. If levelsof these neurotoxic substances could beregulated, fewer neurons would die, thuslessening the symptoms of AD.

2. Neurotransmitter Deficiencies in the Brain Neurons use neurotransmitters to communicate.

As mentioned previously, acetylcholine levelsare lower in AD brains compared to non-ADbrains. It has been shown that drugs with theside effect of lowering acetylcholine can causetemporary memory loss. Thus, drugs which

promote increased levels of acetylcholine in thebrain may slow the dementia.

3. Toxic Chemical Excesses in the Brain In the past, aluminum, mercury and other metalsfound in the brain tissue of AD patients causedspeculation that these compounds contributedto the disease. Most scientists agree thataluminum and other metals probably do notcause AD, although they result from the diseaseprocess. Further research is needed to clarify



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these metals' role in AD.

The Genetic TheoryThe genetics of AD are confusing atbest. Some families may have manymembers affected, but becausefamily members may be exposed tothe same environment, it is

impossible to say how much heredity is to blame.Several genes have been identified on chromosomes21 and 14 in the familial type of AD. In the morecommon sporadic type, people with a gene for aprotein called apolipoprotein E on chromosome 19

tend to have a higher incidence of AD than the generalpopulation. Much more work needs to be done to fullyunderstand how genetics influences the incidence of

AD.

The Autoimmune TheoryYour immune system fights off infection from bacteria,viruses, and other threats to your well-being. If thissystem goes awry, your immune system can attack itsown tissue. Scientists hypothesize that if your immunesystem attacks your brain as you age, AD symptoms

could result. However, it is unclear whether this leadsto AD, because signs of this type of attack have beenseen in non-AD brains.

The Slow Virus TheorySome brain disorders which cause symptoms similar to

AD are caused by slow viruses. However, no one hasidentified a virus specific for AD.

They saidit !

"Alzheimer's can be called the long good-bye. Yougrieve about the loved one from the moment youbegin to observe the gradual loss of memory and thespeech and personality changes, because they areincurable. The person you love is gradually changingbefore your eyes. You say good-bye many times untilthe final good-bye at death."--- Norma Wylie, 1996 (in Sharing the Final Journey:Walking with the Dying)



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References and further information

1. Alzheimer's: Few Clues on the Mysteries of Memory 2. Alzheimer's Disease - American Health Assistance Foundation3. Alzheimer's Disease - Unraveling the Mystery4. Alzheimer's Disease Fact Sheet 5. Alzheimer's Disease - American Federation for Aging Research6. Alzheimer's Disease - NINDS7. Alzheimer's Disease Education and Referral (ADEAR) Center 8. The Alzheimer's Association information on issues relating to AD9. Alzheimer's Disease Bibliography for Children and Teens



Introduction Dyslexia

What is Dyslexia? Dyslexia is a brain-based type of learning disability that specifically impairs aperson's ability to read. These individuals typically read at levels significantlylower than expected despite having normal intelligence. Although the disorder varies from person to person, common characteristics among people withdyslexia are difficulty with phonological processing (the manipulation of sounds)

and/or rapid visual-verbal responding.

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 theeducational environment to meet the specific needs of the individual withdyslexia.

What is the prognosis?

For those with dyslexia, the prognosis is mixed. The disability affects such a widerange of people, producing 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 andfriends and a strong self-image, and who are involved in a proper remediationprogram.

What research is being done?

The NINDS and other institutes of the National Institutes of Health, including theNational Institute of Child Health and Human Development and the NationalInstitute of Mental Health, conduct research on dyslexia. Current researchavenues focus on developing techniques to diagnose and treat dyslexia andother learning disabilities, increasing the understanding of the biological basis of learning disabilities, and exploring the relationship between neurophysiologicalprocesses and cognitive functions with regard to reading ability.

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