Disorders of Brain Function

Saturday, September 5, 2009

The underlying causes of certain neurological disorders such as Alzheimer’s disease are not yet known. However, much is known about other neurological disorders—such as Parkinson’s disease, multiple sclerosis, and migraines— although they are not yet fully understood. Research is ongoing to understand these disorders better and to develop effective treatments. Stimulate Your Mind Just as exercise strengthens your muscles, neurological research shows that “exercising” your brain may help keep it strong as you age.Engaging in intellectually stimulating activities such as reading, doing crossword puzzles, and learning new things increases the number of connections between the cells in your brain.Doctors now think that these extra connections may provide a buffer against the destructive effects of Alzheimer’s disease and, in some cases, postpone the onset of symptoms. Alzheimer’s Disease Alzheimer’s disease is a progressive disease in which brain cells degenerate and die, causing memory loss, confusion, loss of intellectual abilities (including thinking, reasoning, judgment, and memory), physical deterioration, and eventually death. It can also cause significant changes in mood, personality, and behavior. Alzheimer’s disease is the most common form of irreversible dementia (progressive deterioration of mental functioning). The disease usually occurs after age 65, and progresses over a course of about 8 to 10 years. However, it can take as few as 2 or as many as 20 years. The cause of Alzheimer’s disease is unknown. Most people who develop Alzheimer’s disease have no family history of it. Women are affected more often than men, but this may be related to the fact that women generally live longer and the disease occurs later in life. Alzheimer’s disease is not a normal part of aging. Symptoms of Alzheimer’s disease, which vary from person to person, appear gradually and worsen over time. Initial symptoms—such as inability to concentrate, forgetfulness, anxiety, and depression—often go unnoticed or may be mistakenly attributed to normal aging. Memory problems eventually worsen, and the person also experiences impaired intellectual skills. He or she becomes apathetic and withdrawn. In later stages of the disease the person becomes severely confused and disoriented and also may become irritable, fearful, suspicious, delusional, agitated, and even violent. Eventually the person will be unable to perform daily activities (such as bathing, dressing, eating, and using the toilet) and will need total care. Diagnosis of Alzheimer’s disease is based on symptoms (as described by the person or his or her family members) and tests that evaluate various aspects of mental functioning (such as short-term memory). To make a diagnosis of Alzheimer’s disease, the doctor needs to rule out other possible causes of the person’s symptoms, such as depression, kidney failure, liver disease, thyroid disorders, excessive alcohol intake, side effects of medication, drug interactions, fatigue, poor diet, vision problems, and hearing problems. Parkinson’s disease, stroke, and other neurological disorders, such as meningitis or encephalitis, also can cause similar symptoms. Computed tomography (CT) scanning and magnetic resonance imaging are not performed to diagnose Alzheimer’s disease but often are used to rule out other possible causes of dementia, such as a brain tumor or a stroke. Although there is no cure for Alzheimer’s disease, some people in the early to middle stages of the disease may benefit from medications (such as donepezil or tacrine) that help improve memory and manage some of the behavior problems caused by the disease. Other medications to treat or cure Alzheimer’s disease are currently under investigation. Caring for a Person Who Has Alzheimer’s Disease Caregiving can be demanding, stressful, and exhausting. If you are caring for a loved one who has Alzheimer’s disease, learn all you can about the disease so you can be adequately prepared to deal with this challenging situation. Here are some useful recommendations for caregivers: • Watch for warning signs of Alzheimer’s disease such as forgetfulness, confusion, or withdrawal. Some symptoms may be due to another underlying disease or condition—such as depression —that can be treated and cured. • Gather useful information (such as educational materials and referrals to support groups) from reliable sources such as your doctor, your local library, your local hospital, and your local chapter of the Alzheimer’s Association. • Make all necessary legal and financial arrangements (including advance directives, durable power of attorney, and payment of healthcare costs) as soon as possible. This will help prevent potential legal and financial problems in the future. Contact a lawyer for additional information and assistance. • Take all necessary precautions to protect your loved one from potential dangers such as falls, burns, poisoning, and wandering away from home. Taking steps such as locking away hazardous objects and materials (including medications, cleaning fluids, matches, lighters, and firearms), installing special locks on doors and windows, and placing night-lights along the route from the bedroom to the bathroom and in the bathroom itself can help prevent serious injuries. The Alzheimer’s Association offers a nationwide program called Safe Return that registers people with memory problems and provides them with special identification. The program maintains a 24-hour, toll-free number to call when a registered person is either lost or found. Contact your doctor or the Alzheimer’s Association for additional information. • Seek help and support from others. Do not try to do everything yourself. Keep an updated list of things that need to be done, and ask reliable family members or friends for help whenever you need it. Contact your doctor, local hospitals, and volunteer, community, and health organizations for information and referrals. Join a support group to share information and experiences with others in a similar situation. Consider hiring a professional caregiver through a licensed home health agency. • Be realistic about the inevitable outcome of the disease. Prepare yourself to deal with the loss of your loved one. Talking things over with a close friend or relative or with members of a support group will help you come to terms with your grief. • Be prepared to make informed decisions about long-term care. A person with late-stage Alzheimer’s disease needs total care. As soon as you learn that your loved one has Alzheimer’s disease, begin gathering information about longterm- care facilities in your area so you will be able to make an informed decision when necessary. • Take care of yourself. Take regularly scheduled breaks; eat a nutritious, wellbalanced diet; exercise regularly ; do not smoke ; and get plenty of sleep. Limit your intake of caffeine and alcohol, and use relaxation techniques such as meditation and deepbreathing exercises to help relieve stress. Contact the Alzheimer’s Association (800-272-3900) for additional information and advice on caring for a person who has Alzheimer’s disease. Amyotrophic Lateral Sclerosis Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease, is a progressive motor neuron disease that has no known cause. In ALS, the motor neurons (nerve cells in the brain and spinal cord that control muscular activity) gradually degenerate, causing the muscles to weaken and waste away, eventually leading to paralysis. ALS occurs during middle age, and men are more likely to develop the disease than women. Symptoms of ALS include tripping and falling, weakness in the hands and arms, and twitching and cramping of the muscles. As the disease progresses, it can cause difficulty speaking, swallowing, and breathing. In the final stages, although the person is aware and his or her intellect is unimpaired, he or she is unable to speak or move. Diagnosis of ALS is based on the symptoms and on the results of various diagnostic procedures, including electromyography (an examination that measures the electrical activity of the muscles), blood tests, muscle biopsies (removal of small samples of muscle tissue for microscopic examination), and computed tomography (CT) scanning and magnetic resonance imaging. There is no way to prevent the disease or to reverse or slow its progression. Most people with ALS die within 5 years of diagnosis. Treatment focuses on relieving discomfort and helping the person stay independent for as long as possible. The person’s life may be prolonged through the use of a ventilator (a machine that takes over breathing when a person can no longer breathe on his or her own) and feeding through a tube when a person has difficulty swallowing. Epilepsy In a person who has epilepsy, abnormal electrical activity in the brain causes seizures (temporary loss of consciousness or memory, or uncontrolled movements or behaviors). Epilepsy refers to a pattern of repeated seizures. The disorder can result from a brain tumor, stroke, head injury, lead poisoning, alcohol or other drug withdrawal, metabolic imbalances, or brain infections (such as encephalitis or meningitis). There are two basic categories of seizures: generalized seizures, which affect the entire brain, and partial seizures, which affect only one area of the brain. The two most common types of generalized seizures are grand mal seizures and petit mal (or absence) seizures. During a grand mal seizure, the person experiences loss of balance and coordination, loss of consciousness, and uncontrollable jerking movements. In some cases the person may also experience loss of bladder or bowel control. A grand mal seizure can last for several minutes and leave the person disoriented and exhausted. The person usually does not remember the seizure. Petit mal seizures occur most often in children. During a petit mal seizure, the person experiences loss of awareness that may last from a few seconds to about half a minute. Some people also experience brief confusion, muscle twitching, or rapid eye movements. The person is not aware of the seizure, and the symptoms are often subtle and may go unnoticed; the person may appear to be inattentive or daydreaming. This type of seizure may occur hundreds of times per day, seriously impairing the ability to concentrate or complete even simple tasks. During a simple partial seizure, a person may experience sudden muscle twitches, tingling sensations, or hallucinations that affect smell, taste, or vision. This type of seizure lasts for several minutes. The person is aware of the seizure as it occurs and can recall what happened afterward. During a complex partial seizure, a person appears dazed and may perform involuntary actions such as walking in circles, laughing, speaking nonsensically, or smacking his or her lips. The person is not aware of his or her actions. Afterward the person is confused and does not remember the seizure. A diagnosis of epilepsy is based on the results of a thorough neurological examination and an evaluation of the type and pattern of the person’s seizures. Because most people do not remember their seizures, information about the seizures is usually obtained from witnesses. The person will probably undergo an electroencephalogram to examine the electrical activity of the brain. Computed tomography (CT) scanning or magnetic resonance imaging will probably be performed to rule out other possible causes of the seizures, such as a brain tumor or a stroke. The risk of having a seizure increases with stress, sleep deprivation, fatigue, inadequate food intake, or failure to take prescribed medications. Seizures often occur spontaneously, but they can also be triggered by certain stimuli such as flickering or flashing lights, loud noises, or monotonous sounds. If you have grand mal seizures, you may be able to sense an oncoming seizure through feelings of unease or a recognizable sensory change (such as a specific sound, smell, or visual disturbance) called an aura. Epilepsy is usually treated with anticonvulsant medications (such as primidone or diazepam) that prevent or control seizures. In rare cases, if medication does not control the seizures, surgery may be performed to remove the affected brain tissue. A special diet helps some people. Biofeedback also may be helpful. Most people with epilepsy live normal, productive lives with the help of medication. Multiple Sclerosis Multiple sclerosis (MS) is a progressive, disabling disease of the central nervous system (the brain and spinal cord). MS is an autoimmune disease, in which the body’s immune system mistakenly attacks and destroys its own tissue (in this case, the myelin that surrounds and protects nerve cells). Early in the disease, inflammation occurs at random sites in the brain or spinal cord, damaging myelin and causing scarring (sclerosis) that interferes with the transmission of messages between the brain and the body. The initial symptoms of MS may include blurred or double vision, red color distortion, or blindness in one eye. Muscle weakness, lack of coordination and balance, fatigue, partial or complete paralysis, and spasticity (stiffness) can occur in the early stages of the disease. Other symptoms include numbness, tingling, tremors, dizziness, and slurred speech. About half of all people with MS also experience problems with concentration, attention, memory, and judgment, although intellectual and language skills remain unchanged. Depression and paranoia can occur, as can inappropriate mood swings. Sexual dysfunction and loss of bowel and bladder control also can occur. The symptoms may worsen when the body heats up from high environmental temperature, exercise, taking a hot bath, or having a fever. Early in the disease, symptoms often come and go. Later they may gradually worsen. The symptoms of MS usually appear between ages 20 and 40, although a diagnosis may not be made immediately. A diagnosis is based on eliminating other possible causes of the symptoms, such as stroke or a brain tumor, and detecting characteristic features of MS. For example, certain changes in the brain can be observed with magnetic resonance imaging after sufficient damage has occurred, and sometimes increased inflammatory proteins (antibodies) can be found in cerebrospinal fluid (obtained during a lumbar puncture). These antibodies, which are produced for no known reason, are strongly associated with MS. In some cases the doctor may perform an evoked response test, in which electrodes are placed on the person’s head, and electrical activity in the brain is recorded as he or she is exposed to various sensory stimuli such as sound or light. The cause of MS is unknown. Evidence suggests that the disease may result from a combination of a person’s genetic susceptibility (the disease tends to run in families) and a viral infection early in life. Environment also appears to have a role in susceptibility to MS. People who spend the first 15 years of their lives in a temperate climate have a higher risk of developing the disease later in life than those who spend their first 15 years in a tropical climate. This is thought to be the period when the viral infection occurs in susceptible people. Whites are twice as likely as blacks to develop MS, and women are twice as likely to be affected as men (although, when the disease starts later in life, men are as likely as women to be affected). Most people with MS live a normal life span. There is no cure for MS, although new treatments, such as interferon beta and glatiramer acetate, can reduce the likelihood of episodes and can slow progression of symptoms. Treatment will depend on symptoms. Corticosteroids (such as dexamethasone, methylprednisolone, or prednisone) or adrenocorticotropic hormone are prescribed to control inflammation in the nervous system during acute episodes, especially when the symptoms affect movement rather than sensation. To relieve fatigue, your doctor may prescribe amantadine or modafinil. He or she also will advise you to help prevent fatigue by staying cool (such as with air conditioning). The doctor may prescribe muscle relaxants to relieve muscle spasms and also may recommend that you swim or participate in a water therapy program. Physical therapy can help maintain muscle strength and improve your balance and coordination. Occupational therapy can help you learn easier ways to perform daily tasks. For urinary incontinence, your doctor may prescribe an antispasmodic medication (such as dicyclomine or hyoscyamine) to relax the bladder and control muscle contractions. Parkinson’s Disease Parkinson’s disease is a progressive degenerative disease like amyotrophic lateral sclerosis, though it has a much slower course. Researchers believe that a combination of factors—including environmental toxins, genetic predisposition, accelerated aging, or damage to cells from free radicals—may bring about the disease. The average age of onset is 60, but many younger adults have early symptoms. Men and women are affected equally by Parkinson’s disease. In Parkinson’s disease, the neurons in the basal ganglia (clusters of paired nerve cells deep inside the brain) that control muscular activity become damaged or die. These nerve cells produce an important neurotransmitter (chemical messenger) called dopamine, which has an essential role in controlling muscle actions. Without sufficient dopamine, the nerve impulses are disrupted, causing the primary symptoms of the disease: tremor (trembling) in the hands, feet, arms, legs, and head; stiffness and weakness; slow movement; and impaired balance and coordination. The early symptoms of Parkinson’s disease are subtle and appear gradually. The hands and feet may tremble slightly. Eventually the person’s speech may become slow and halting, and his or her handwriting will become very small. Some people may have a flat facial expression and become stiff and unsteady. As the disease progresses, they may experience problems with memory and thought processes. The skin may become oily (especially on the forehead, nose, and scalp) or very dry, or excessive sweating may occur. People with Parkinson’s disease often have difficulty sleeping. Depression also is common. A diagnosis of Parkinson’s disease is based on the symptoms. There is no cure for the disease, but medication can relieve the symptoms for most people in less severe stages of the disease. The most common medication is levodopa (also called L-dopa), which the body converts to dopamine. Not all symptoms respond well to levodopa, and those that do will return if the medication is stopped. Anticholinergic drugs such as benztropine may be prescribed to relieve tremor. Brain surgery to reduce tremor and rigidity may be performed on some people for whom medication has not been effective. Although the progression of Parkinson’s disease cannot be slowed, treatment to relieve symptoms can help people continue to lead active lives. Tourette’s Syndrome Tourette’s syndrome is a rare inherited disorder characterized by involuntary movements and nasal and vocal sounds. Researchers believe that the abnormality in the gene or genes responsible for the disease affects the way the brain controls neurotransmitters (chemical messengers such as serotonin and dopamine). Symptoms usually begin before age 18, and men are up to four times more likely to have the disease than women. In some cases the symptoms are not noticeable or do not continue into adulthood. Early symptoms of the disease include facial tics such as eye blinking, nose twitching, or grimaces. (Note that most such tics are not due to Tourette’s syndrome.) Over time the tics may become more noticeable and may include head jerking, neck stretching, foot stamping, and body twisting or bending. The person also may make strange noises, such as coughing, sniffing, grunting, yelping, barking, or shouting. More disturbing symptoms, such as involuntary shouting of obscenities, constantly echoing words of others, touching others excessively, or repeating actions obsessively, also may occur. In severe cases people with Tourette’s syndrome may harm themselves by biting their lips and cheeks and banging their heads against hard objects. Tics periodically change in number, frequency, type, and location. They also may disappear for a time and then reappear. If a person tries to suppress a tic, tension will build until the tic occurs, often in a more dramatic manner. Tics tend to worsen in stressful situations and improve during periods of relaxation or when the person concentrates on another activity. Tourette’s syndrome is diagnosed through monitoring of symptoms (the tics must be present for at least 1 year) and confirmation of a family history of the disease. In some cases neurological tests may reveal another cause of the symptoms. There is no cure for Tourette’s syndrome, although symptoms tend to decrease with age. The disorder does not affect the intellect. The person may not require any treatment, but the doctor may prescribe medications to reduce specific symptoms that interfere with daily routine. Relaxation techniques and biofeedback can help prevent tics.