Biofeedback

Biofeedback, a technique by which patients monitor their own bodily functions in an attempt to alter those functions. Primarily used in treating painful or stress-related conditions, biofeedback helps a patient control physiological processes that are normally considered involuntary.

In biofeedback training, electronic or mechanical instruments attached to the patient measure physical functioning, such as the degree of muscle tension. The machines then transform this information into amplified signals that the patient can hear or see—for example, a beep or a flashing light—thus enabling the patient to know when internal responses are abnormal. This feedback information (see Automation) can then guide the patient in trying to gain control over the internal condition.

Biofeedback learning has been likened to that involved in mastering an athletic skill. Although this kind of learning may occur in biofeedback, its benefits often are largely the result of relaxation induced by the procedure. Most treatments include training in formal relaxation techniques, which when used alone, often produce benefits equal to the biofeedback-assisted relaxation.

Biofeedback was developed in the late 1960s by scientists studying learning and the control of neuromuscular disorders, the autonomic nervous system, and mental states. Their work led to exaggerated claims that biofeedback would enable people to alter states of consciousness, lower blood pressure, and regulate heart functioning at will. Research has shown that although some degree of control is possible, it can be too limited to correct abnormal conditions.

Biofeedback is used to treat many disorders brought on or aggravated by stress, such as tension and migraine headaches, Raynaud's disease (abnormally cold hands and feet), tics, and muscle tension. It has shown particular promise in helping patients to recover the use of paralyzed limbs.

Fatigue

Fatigue (physiology), exhaustion of mind or body resulting from labor or exertion. Certain diseases, such as diabetes, cancer, and heart ailments, can also cause fatigue. Fatigue is characterized by the inability to perform physical tasks at one's usual pace or strength, and by a slowing of the thinking processes that may involve failure of memory.

The term fatigue is also used to denote a decreased susceptibility of a sensory receptor, such as the eye, to sensation. A red surface seems to become gray when it is stared at continuously, and the retina is said to be fatigued by long exposure to the color red. The same is true of hearing. A prolonged noise that is heard continuously becomes less intense due to fatigue of the processes of the inner ear. Continued mental exertion, as in a protracted working over of a problem, causes the condition known as mental fatigue.

Alzheimer’s Disease

Alzheimer’s Disease, progressive brain disorder that causes a gradual and irreversible decline in memory, language skills, perception of time and space, and, eventually, the ability to care for oneself. First described by German psychiatrist Alois Alzheimer in 1906, Alzheimer’s disease was initially thought to be a rare condition affecting only young people, and was referred to as presenile dementia.

Although Alzheimer’s disease is not a normal part of the aging process, the risk of developing the disease increases as people grow older. About 10 percent of the United States population over the age of 65 is affected by Alzheimer’s disease, and nearly 50 percent of those over age 85 may have the disease.

Alzheimer’s disease takes a devastating toll, not only on the patients, but also on those who love and care for them. Some patients experience immense fear and frustration as they struggle with once commonplace tasks and slowly lose their independence. Family, friends, and especially those who provide daily care suffer immeasurable pain and stress as they witness Alzheimer’s disease slowly take their loved one from them.

The causes of Alzheimer’s disease remain a mystery, but researchers have found that particular groups of people have risk factors that make them more likely to develop the disease than the general population. For example, people with a family history of Alzheimer’s are more likely to develop Alzheimer’s disease.

DIAGNOSIS

Alzheimer’s disease is only positively diagnosed by examining brain tissue under a microscope to see the hallmark plaques and tangles, and this is only possible after a patient dies. As a result, physicians rely on a series of other techniques to diagnose probable Alzheimer’s disease in living patients. Diagnosis begins by ruling out other problems that cause memory loss, such as stroke, depression, alcoholism, and the use of certain prescription drugs. The patient undergoes a thorough examination, including specialized brain scans, to eliminate other disorders. The patient may be given a detailed evaluation called a neuropsychological examination, which is designed to evaluate a patient’s ability to perform specific mental tasks. This helps the physician determine whether the patient is showing the characteristic symptoms of Alzheimer’s disease—progressively worsening memory problems, language difficulties, and trouble with spatial direction and time. The physician also asks about the patient’s family medical history to learn about any past serious illnesses, which may give a hint about the patient’s current symptoms.

TREATMENT

There is no known cure for Alzheimer’s disease, and treatment focuses on lessening symptoms and attempting to slow the course of the disease. Drugs that increase or improve the function of brain acetylcholine, the neurotransmitter that affects memory, have been approved by the United States Food and Drug Administration (FDA) for the treatment of Alzheimer’s disease. Called acetylcholinesterase inhibitors, these drugs have had modest but clearly positive effects on the symptoms of the disease. These drugs can benefit patients at all stages of illness, but they are particularly effective in the middle stage. This finding corresponds with new evidence that low acetylcholine levels in patients with Alzheimer’s disease may not be present in the earliest stage of the illness.

Senile Dementia

Senile Dementia, form of general intellectual impairment observed in elderly people. Approximately 10 percent of all people more than 65 years of age have clinically important intellectual impairment. Although about 20 percent of these cases may be due to treatable causes such as toxic drug reactions, most cases are what is known as Alzheimer's disease.

Senile dementia begins with failing attention and memory, loss of mathematical ability, irritability and loss of sense of humor, and poor orientation in space and time. Alzheimer's disease is relentlessly progressive and leads to death in 5 to 15 years. Examinations of the brains of persons who have died of Alzheimer's disease show characteristic twisted fibers, called neurofibrillary tangles, in certain areas of the brain, and cores of abnormal protein, called neuritic plaques, interspersed among nerve cells. No cure is known for Alzheimer's disease. A form of this disease strikes younger persons, in whom it is known as presenile dementia.

See also Aging; Geriatrics.

Brain Diseases and Disorders

Brain disorders have a wide range of causes, including head injury, stroke, bacterial diseases, complex chemical imbalances, and changes associated with aging.

Head Injury

Head injury can initiate a cascade of damaging events. After a blow to the head, a person may be stunned or may become unconscious for a moment. This injury, called a concussion, usually leaves no permanent damage. If the blow is more severe and hemorrhage (excessive bleeding) and swelling occur, however, severe headache, dizziness, paralysis, a convulsion, or temporary blindness may result, depending on the area of the brain affected. Damage to the cerebrum can also result in profound personality changes.

Damage to Broca's area in the frontal lobe causes difficulty in speaking and writing, a problem known as Broca's aphasia. Injury to Wernicke's area in the left temporal lobe results in an inability to comprehend spoken language, called Wernicke's aphasia.

An injury or disturbance to a part of the hypothalamus may cause a variety of different symptoms, such as loss of appetite with an extreme drop in body weight; increase in appetite leading to obesity; diabetes insipidus; hypothermia or fever; excessive emotionality; and uncontrolled anger or aggression. If the relationship between the hypothalamus and the pituitary gland is damaged (see Endocrine System), other vital bodily functions may be disturbed, such as sexual function, metabolism, and cardiovascular activity.

Stoke

A stroke is damage to the brain due to an interruption in blood flow. The interruption may be caused by a blood clot (see Embolism; Thrombosis), constriction of a blood vessel, or rupture of a vessel accompanied by bleeding. A pouchlike expansion of the wall of a blood vessel, called an aneurysm, may weaken and burst, for example, because of high blood pressure.

Brain Diseases

Epilepsy is a broad term for a variety of brain disorders characterized by seizures, or convulsions. Epilepsy can result from a direct injury to the brain at birth or from a metabolic disturbance in the brain at any time later in life.

Some brain diseases, such as multiple sclerosis and Parkinson disease, are progressive, becoming worse over time. Multiple sclerosis damages the myelin sheath around axons in the brain and spinal cord. As a result, the affected axons cannot transmit nerve impulses properly. Parkinson disease destroys the cells of the substantia nigra in the midbrain, resulting in a deficiency in the neurotransmitter dopamine that affects motor functions.

Cerebral palsy is a broad term for brain damage sustained close to birth that permanently affects motor function. The damage may take place either in the developing fetus, during birth, or just after birth and is the result of the faulty development or breaking down of motor pathways. Cerebral palsy is nonprogressive—that is, it does not worsen with time.

A bacterial infection in the cerebrum (see Encephalitis) or in the coverings of the brain (see Meningitis), swelling of the brain (see Edema), or an abnormal growth of healthy brain tissue (see Tumor) can all cause an increase in intracranial pressure and result in serious damage to the brain.

Scientists are finding that certain brain chemical imbalances are associated with mental disorders such as schizophrenia and depression. Such findings have changed scientific understanding of mental health and have resulted in new treatments that chemically correct these imbalances.

During childhood development, the brain is particularly susceptible to damage because of the rapid growth and reorganization of nerve connections. Problems that originate in the immature brain can appear as epilepsy or other brain-function problems in adulthood.

Several neurological problems are common in aging. Alzheimer's disease damages many areas of the brain, including the frontal, temporal, and parietal lobes. The brain tissue of people with Alzheimer's disease shows characteristic patterns of damaged neurons, known as plaques and tangles. Alzheimer's disease produces a progressive dementia (see Senile Dementia), characterized by symptoms such as failing attention and memory, loss of mathematical ability, irritability, and poor orientation in space and time.