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Conditions of the nervous system are common in older adults and are a major source of disability. When nerve cells die, they are lost forever. However, remaining nerve cells tend to make up for the lost ones by growing new connections. Neurologic problems most commonly seen in older people can be grouped into three categories:
In addition, many medical conditions and medications can affect neurologic function. These changes in neurologic function are caused by disease and shouldn't be considered "normal aging." Neurologic problems can also cause dizziness or fainting (see Dizziness and Fainting).
StrokeA stroke results from loss of blood supply to the brain, usually because the arteries leading to the brain are damaged or obstructed. The part of the brain involved is unable to send signals to other parts of the nervous system, so any number of body functions can be affected (Figure: Brain Areas Affected By Strokes). Stroke is a leading cause of disability and death among older adults. The incidence of stroke increases with advancing age, doubling with each decade of life. Stroke is more common in men than in women, at least until the age of 85. On the bright side, the overall incidence of stroke has been going down in the United States since the middle of the 20th century, probably because of better control of the risk factors linked to stroke. The major risk factors for stroke include the following:
High blood pressure is the most common risk factor for stroke, with treatment decreasing the risk. Heart disease is also a common and important risk factor for stroke, especially when the arteries that supply blood to the heart are narrowed. The risk of stroke is increased 2-4 times in people with diabetes, but good management of blood glucose (sugar) levels seems to reduce this risk. Cigarette smoking increases the risk of stroke as much as three times. More importantly, the incidence of stroke greatly decreases 2 years after someone stops smoking. After 5 years, the risk of a former smoker is about the same as that of nonsmokers. A stroke occurs in one of three ways:
A stroke may happen when a large artery supplying blood to the brain becomes narrowed and then blocked. A major artery in the neck called the carotid artery is often the site of the blockage, although blockage to the circulation in the back of the head can also occur. Hardening of the arteries is the most common cause of a narrowed carotid artery. Blockage of small blood vessels The large arteries branch out to smaller blood vessels that penetrate deep within the brain. A blood clot (ie, thrombosis) in any of these small vessels can cause a small area of damaged brain tissue. In most cases, chronic high blood pressure is responsible for this condition, and controlling high blood pressure can prevent it. Functional problems from a "small" stroke usually develop over a period of hours. Over time, many of these small strokes can result in a decline in mental ability, a condition called multi-infarct dementia. The term infarct means tissue damage from blocked blood supply. Clots can break off from a larger clot in the heart, from a clot on the valves of the heart, or from plaque in large arteries. When a blood clot travels to the brain, the damage depends on the size of the clot. If the clot is small, the damage remains within the smaller blood vessels. Larger clots can block larger arteries, producing more severe damage. Strokes caused by embolism usually begin suddenly, and functional problems can result in only a few minutes. An irregular heartbeat called atrial fibrillation (see Heart Disease) increases the risk of an embolism followed by a stroke. Brain hemorrhages happen less often than other types of strokes. These strokes are often caused by chronic high blood pressure but can also be caused by head injury or blood vessel problems (eg, an aneurysm). The symptoms for this type of stroke can be very similar to symptoms from strokes due to blood clots. These two types of stroke can be distinguished only by specialized brain imaging tests that identify the hemorrhage. The signs and symptoms of stroke depend on the following:
Problems are often restricted to one side of the body, especially for strokes caused by blocked arteries. These problems may include weakness, numbness, paralysis, headaches, difficulty speaking, mental difficulties, vision problems, and coma. Strokes caused by blockage to small blood vessels usually have a distinct pattern. Most people have weakness or paralysis on one side of the body without any changes in body sensation. However, other symptoms may include changes in sensation, hand function, speaking ability, or coordination. Decreased alertness and vomiting are often seen with stroke due to brain hemorrhage. More serious symptoms include severe headache, dizziness, clumsiness, difficulty moving the eyes, paralysis of parts of the face, and coma. These latter symptoms should be viewed as an emergency, because of the risk of severe brain damage. If the blood clot in the brain is removed before the brain stem is compressed, recovery is more likely. Warning signs (transient ischemic attack) Before a stroke happens, there is often a period of reduced blood supply to the brain. This causes changes in function and sensation in the hands and face, which usually last less than 15 minutes. If the left side of the brain is affected, sudden difficulty in speaking may occur. This short-lived disability that completely resolves in minutes to hours is called a transient ischemic attack (TIA). A stroke caused by blockage of one of the main arteries to the brain is usually preceded by one or more TIA. However, these types of strokes can also happen suddenly without any warning. The number or severity of TIAs does not reliably predict the severity of a potential stroke. However, a TIA is a warning sign that a stroke may be coming. If you have had a TIA, you should be thoroughly evaluated to determine the source of the problem. Many tests are available to look for narrowed or damaged arteries in people with TIA or other symptoms. These tests include CT scans, MRI, ultrasound, and angiograms. In an angiogram, a special dye is injected into a blood vessel, and then x-rays are taken to see where the vessel is blocked or torn. This is the best method for examining the circulation within the brain and evaluating blood vessel changes. It is often a necessary procedure for people who are considering surgery. A stroke is an emergency, requiring a call to 911 and a trip to the hospital. Treatment for stroke involves general medical support (eg, IV fluids to control dehydration), as well as identification and treatment of underlying problems (eg, high blood pressure or heart disease). Blood thinners (ie, anticoagulants) are usually given to help prevent clots and improve blood flow, as long as there is no bleeding into the brain. Blood thinners are often given by injection immediately after a stroke and then continued (as oral pills) for several months. Common blood thinners include aspirin, heparin, warfarin, and coumadin. Aspirin is usually given at a dose of one third to one tablet daily. Surgery to remove plaque or to open a narrowed artery is an option for some healthy older adults. In any type of stroke, the outlook depends on the amount of damage and the location within the brain. Stupor, coma, severe weakness, and difficulty moving the eyes indicate major strokes with a poorer prognosis. People who are completely paralyzed on one half of the body or who have problems with vision or perceptions may not be able to function independently. Ability to function before a stroke is also a critical factor in determining level of independence after a stroke. Age by itself does not limit the possibility of a good outcome. However, older people tend to have other illnesses that can complicate recovery. Appropriate stroke rehabilitation is also important for the best recovery (see Rehabilitation). Referral for specialized stroke rehabilitation services appears to improve ability to function. Seizures (Epilepsy)A seizure is a sudden change in a person's movement or behavior that is caused by abnormal function of neurons (cells in the brain). It may be a single event that is caused by a specific problem, or seizures may be repeated at varying intervals. When seizures repeat or come back regularly, the condition is called epilepsy. Seizures can sometimes be continuous, consisting of several convulsions or "fits" one after the other separated by only minutes or seconds. This uncommon condition, which is called status epilepticus, is an emergency that requires immediate attention. Types of seizures are defined based on their characteristics and on the results of an electroencephalogram (EEG) test (sometimes called a brainwave test). Generalized seizures: In these seizures, the person loses consciousness and has convulsions ("fits") involving both sides of the body. Generalized seizures, also called grand mal seizures, are the ones most commonly seen in older adults. Petit mal seizures: This type of seizure is less common in older adults than grand mal seizures. Petit mal seizures cause a momentary loss of awareness without any major movement. Someone may stare off into space for a few seconds and then return to consciousness, sometimes completing the sentence started just before the seizure began. Focal or partial seizures: These seizures come from a particular part of the brain. They cause sudden change in movement, sensation, or behavior, often without loss of consciousness. One variation, called complex partial seizures, often involves psychiatric symptoms, such as hallucinations, illusions, panic states, and strange patterns of activity in the arms and legs. In younger people, epilepsy often has no known cause. In older people, most seizures are due to an underlying brain disease. Common causes include the following:
Many seizures in older adults are related to a stroke, and happen during the stroke, during rehabilitation, or even later. Often, seizures are caused by small strokes that happened earlier in someone's life. These earlier episodes may have been forgotten or never recognized as strokes. About 10% of people who have had a stroke develop a seizure disorder that requires treatment with medications. Older adults may sometimes develop a mild paralysis (called Todd's paralysis) at the end of a seizure. This paralysis can sometimes last as long as a day or so, creating the misleading impression of a stroke. Fortunately, Todd's paralysis usually disappears with no lasting effects. Because seizures in older adults usually have an underlying cause, a comprehensive examination and blood tests are in order. In addition, brain imaging (eg, a CT scan or an MRI) is usually done to look for tumors, abscesses, or blood clots in the brain. If meningitis is suspected, a spinal tap may be necessary. In this procedure, a small amount of the fluid that surrounds the brain and spinal cord is removed for analysis. Signs of meningitis include fever, changes in mental function, or severe or persistent headaches. An EEG can sometimes help identify the specific location in the brain of seizure activity. An EEG is not needed to diagnose a grand mal seizure, because this type of seizure is dramatic and unmistakable. However, the EEG can help identify abnormal brain waves that may have caused a more subtle seizure, such as a petit mal, partial, or complex-partial seizure. The EEG can also help distinguish between a recurrent seizure disorder and a single seizure due to medication or a change in body chemistry. The first step is to correct or manage any underlying disease process that might be causing the seizures. The next step is usually drug treatment, which is done slowly and cautiously, with close attention to possible adverse side effects. For example, some medications used to control seizures may decrease mental function or cause changes in behavior. Other medications can worsen liver problems. These side effects generally develop at much lower dosages in older adults than in younger ones. Usually, drug treatment is started at low dosages, and the dosage is increased gradually until the seizures are controlled. The medication should be taken for a reasonable amount of time before switching to or adding another medication. Do not stop taking your medication just because it doesn't seem to be working right away. In rare instances, surgery is needed to control seizures that are not helped by any medication. Seizure that continue coming back caused by problems in the brain, such as strokes or brain tumors, are more difficult to control than those seizures that happen in the late stage of Alzheimer's disease. There is no need to treat a single seizure from Alzheimer's disease, unless seizures begin happening often. Subdural Hematoma (Blood Clot on the Brain)The brain has two coverings. When a blood clot forms between the outer (dura) and inner covering of the brain, the condition is called a subdural hematoma, and it may cause a seizure. A subdural hematoma is usually caused by head trauma, even relatively minor head trauma in older adults. People with Alzheimer's disease also have a greater risk of developing a subdural hematoma. A subdural hematoma can become a chronic condition. About half the time, the cause is a head injury. Other risk factors include clotting problems, certain brain surgeries, and seizures. The symptoms of chronic subdural hematoma are usually headaches, mental difficulty, and paralysis on one side. Some people may develop seizures, weakness, or changes in sensation. Treatment Treatment for subdural hematoma varies depending on whether or not it is causing problems. If the symptoms keep worsening, surgery to remove the clot may be needed. If there are no symptoms or the symptoms are getting better, then a wait and see approach may be appropriate. In this case, the blood clot may shrink and disappear without surgery. HeadachesUnlike many problems that increase with age, headaches actually seem to decrease as we get older. In addition, very few people who suffer with migraines start getting them after the age of 50. Headaches can be classified into two types:
In contrast to migraines, tension-type headaches usually involve both sides of the head. Tension headaches often have a pressing or a tight quality. They are less severe than migraines and are not linked to nausea, vomiting, or auras. Persistent headaches in older adults are often a warning sign of an underlying medical problem. These problems can include brain tumors, subdural hematoma, neck problems, chronic lung disease, carbon monoxide poisoning, and inflammation of the blood vessels. In addition, many commonly used medications can cause headaches that are dull and nondescript. Medications linked to headaches include drugs for high blood pressure, drugs for Parkinson's diseases, and stimulants (eg, caffeine or nicotine). One cause of headache that is seen specifically in older adults is called "giant cell arteritis," which is a type of artery inflammation. Giant cell arteritis develops most commonly between the ages of 70 and 80. Women are affected twice as often as men. Pain may be centered at the temples or in the back of the head, and there may be tenderness and bumpiness around the blood vessels in the scalp. Common symptoms include vision problems, low-grade fever, and muscle aches. Blood tests often show general signs of inflammation. Occasional tension headaches can be treated with over-the-counter products, such as aspirin or acetaminophen. However, you should check with your healthcare provider before using these pain relievers. Some over-the-counter pain relievers can cause problems with underlying medical conditions (eg, stomach ulcer or liver disease) or can interact with other drugs that you may be taking. If headaches are severe or come back several times, steps should be taken to diagnose and manage the underlying problem. There are prescription medications that can be used for more severe headaches, but many of these drugs cause blood vessels to constrict and need to be used cautiously if you also have high blood pressure, stroke, or heart disease. In some circumstances, certain drugs for heart disease or depression can also be used to prevent headaches. Tremors and Other Disorders of MovementA tremor is an involuntary, vibrating movement caused by rapid muscle contractions. Tremors are described in terms of their speed, the amount of shaking, and whether they happen at rest or during movement. All tremors get worse when someone gets excited, and they all disappear while sleeping. Normal, healthy people have a very rapid vibration that is a very fine tremor. You can see this by placing a piece of paper on your outstretched fingers. The edge of the paper shows a very fine movement, which is normal tremor. This normal tremor may become more evident when taking caffeine or other stimulants or if you are anxious or not getting enough sleep. This is the tremor of nervousness or stage fright. Several disorders of older life are linked to more pronounced tremors. Some of these disorders are mild and benign, while others, eg, Parkinson's disease, are debilitating. (See also Parkinson's disease.) Essential tremor is the most common tremor disorder in older adults. It is probably the same condition that is called "palsy shake." Essential tremor is a tremor that is seen when the limbs are in motion (eg, while writing or holding a cup). The arms are involved most commonly, and often the head and voice also. The tremor may be slightly worse in one arm than in the other, but it disappears when the arms are relaxed (eg, sitting with hands in lap or standing with arms at sides). The chin, tongue, and legs are also sometimes involved. Essential tremor is slower and more pronounced than normal, physiologic tremor. One of the striking features of essential tremor is that sometimes the tremor is mild or even absent, and at other times, it is severe. When the tremor is severe, it can interfere with daily activities, such as eating, writing, or buttoning a shirt. Stress or anxiety can make the tremor worse. The only known risk factors for essential tremor are age and genetics. Many people with essential tremor have a relative who also has essential tremor, which suggests that one form of the condition may run in families. In some families, people in several generations are affected. The cause of the form of the illness that does not run in families is unknown. Diagnosis and treatment Distinguishing essential tremor from several other conditions can be difficult. For example, some people have a normal, physiologic tremor that is more pronounced than average. Physiologic tremor may also become more pronounced in certain situations, such as anxiety, low blood glucose (sugar), use of certain medications, and certain illnesses (eg, hyperthyroidism). The main reasons for treatment of essential tremor are disability and embarrassment. Performing certain activities (eg, eating or writing) may be difficult, or the activity may need to be done differently (eg, only drinking with a straw out of closed cups). A tremor can even make some activities impossible. The response to drug treatment is variable, with the tremor improving in some people but not at all in others. The tremor rarely disappears completely. Alcohol may improve the tremor initially, but the tremor becomes worse once the alcohol wears off. Huntington's disease is an inherited (ie, genetic) illness that affects the nervous system. It is characterized by both abnormal movements and psychiatric symptoms. Huntington's disease usually begins between the ages of 30 and 40, but about 25% of cases begin after age 50. Jerky, writhing movements typically begin in the hands and face and eventually involve the limbs, neck, and trunk. Abnormal movements of the eyes are common. Mental difficulties may begin before or after the movement problems. Individuals may become depressed, irritable, aggressive, or impulsive. A major psychiatric illness occasionally develops. As the disease progresses, thought processes slow, judgment becomes affected, and the person may not be able to organize thoughts or stay focused. Memory may also be affected, and someone may have difficulty remembering how to do something that they've done many times before. Unfortunately, there is no good treatment for Huntington's disease. However, genetic research holds considerable promise for a cure in the future. Chorea is a flowing, continuous, random movement that flits from one part of the body to another. Several conditions are linked to chorea in older adults. Chorea without symptoms of other conditions in people 60 years and older is called senile chorea. Involuntary, complex movements of the face, mouth, and tongue may be seen alone or with limb movements. Senile chorea is not linked to with mental disturbance or a family history of Huntington's disease. Chorea can be effectively treated with some antipsychotic drugs, but serious side effects (see Psychoses) are possible. Other medications with less severe side effects are also available. All of the medications for treating chorea can cause symptoms similar to those of Parkinson's disease, but these symptoms usually depend on dose and disappear when the medication is stopped. Parkinson's DiseaseParkinson's disease is a slowly progressive degenerative disease of the nervous system. It is fairly common in people 60-65 years old, but it is most common in people 75 years old and older. In Parkinson's disease, nerve cells in the brain that produce a substance called dopamine are lost. The cause is unknown but it appears to run in families in some cases. Long-term exposure to high levels of manganese or certain pesticides has been linked to Parkinson's disease in some studies. Parkinson's disease begins subtly. The principal feature of the disease is slowing of movement that includes hesitating at the start of movement and slowing during the movement itself. An early sign is that the arm doesn't swing normally when walking. Slowing usually starts on one side of the body but typically ends up involving both sides. The problem progresses from the hands toward the body. Late in the disease, there is almost no movement at all in the body, including the face. The face may lack expression, and eye blinking is reduced. Another classic feature of Parkinson's disease is a distinctive tremor at rest that decreases with active, purposeful movement. The tremor begins at the fingers (usually in one hand) and over time tends to involve both hands and then the arms. Fine movements of the hands, such as those needed to button a shirt or tie shoelaces, may be difficult. In addition to slowed movement and tremor, people with Parkinson's disease have a type of muscle stiffness in which there is resistance to movement when their arm or leg is moved passively by another person. This resistance has been compared to moving through a pool of cold molasses. Problems with posture are also common, and people tend to slump forward, rather than standing or sitting straight up. The combination of resting tremor, muscle stiffness, and lack of movement interfere with walking, resulting in a characteristic bent-over shuffling gait. In some cases, steps become smaller and faster, which are less stable. The tendency to fall becomes a serious problem as the disease progresses. Loss of the reflexes involved with posture causes someone to lean forward and start to fall. The slowed movement makes it difficult to stop the fall, either by taking a step or moving the arms. Mood changes and mental problems (eg, dementia) are often seen in Parkinson's disease, with many sufferers having some type of depression. This depression may be due to changes in the way certain brain chemicals are broken down, rather than simply despair over the loss of function. Other features of Parkinson's disease may include the following:
Parkinson's disease is generally diagnosed based on the developing clinical signs. Occasionally, sophisticated tests are needed to differentiate Parkinson's disease from other conditions of the nervous system. In addition, signs of mild early Parkinson's can look like changes that can happen in normal aging (eg, slowing down, some loss of balance, stiffness, difficulty walking, and stooped posture). However, unlike in normal aging, the slowing and muscle stiffness of Parkinson's disease usually begin on one side of the body. Tremor at rest is also not a feature of normal aging. The mainstay of treatment is a drug called levodopa (L-dopa) that is usually combined with another drug called carbidopa. Other drugs are available, but the combination of L-dopa and carbidopa usually help the most with the least side effects. These drugs provide dopamine to replace the neurotransmitter that is no longer produced in Parkinson's disease. These drugs are usually started at small doses that are increased gradually over several weeks until the symptoms decrease or until side effects appear. Common side effects include nausea, abdominal cramps, drop in blood pressure, and confusion. Some older adults develop serious mental disturbances, such as sudden psychosis and hallucinations.Surgery may help some people with symptoms that are not controlled with drug treatment. Supportive therapy, such as diet, exercise, and fecal softeners for constipation, are also important. Disorders Similar to Parkinson's Disease (Parkinsonism)Several disorders are similar to Parkinson's disease, including the following: These conditions are generally termed "parkinsonism."Progressive supranuclear palsy Progressive supranuclear palsy causes slow movements and sometimes a tremor. However, it usually progresses much more rapidly than Parkinson's, with marked disability within a few years. A person with progressive supranuclear palsy falls early in the course of the disease and develops difficulty with the tongue, mouth, and other facial muscles. Difficulty speaking and swallowing are early findings. In addition, stiffness usually begins in the body and then spreads to the arms and legs, rather than starting in the arms and legs and spreading to the body, as in Parkinson's disease. A distinctive feature of progressive supranuclear palsy is difficulty in moving the eyes up and down, and later from side to side. People with Parkinson's disease may have some mild limitations of eye movements but to a much lesser degree. Another group of disorders have been grouped together under the term "Parkinson's plus," because these conditions often have symptoms in addition to those of Parkinson's disease, such as dizziness, fainting, and orthostatic hypotension (see also Fainting). One of these conditions is Shy-Drager syndrome, which causes a combination of slow movements, significant nervous system problems, and clumsiness. Movement problems caused by drugs Several drugs used to treat psychiatric diseases are among the major causes of movement disorders in older adults. The severity of the movement disorder is determined by the dosage of the drug, the length of time the person has been on it, and age. Parkinsonism commonly develops after long-term treatment with antipsychotic drugs. The symptoms usually disappear when the drugs are stopped, although they may persist or even increase for a short time. However, years of treatment at high dosages may result in parkinsonism that is irreversible. In addition, long-term treatment with antipsychotic drugs can sometimes cause extreme restlessness, an inability to remain still, and sudden muscle reactions in any part of the body. The person usually complains of cramps and other pains as well as severe stiffness. "Tardive dyskinesia" is a very severe movement disorder that can develop after months or years of taking antipsychotic drugs. It causes rapid, irregular muscle contractions that cause the person's lips, tongue, face, and neck to move constantly. The lips may smack and form many odd facial expressions. Unusual tongue movement, such as the tongue protruding from the mouth is also seen. People with tardive dyskinesia seldom complain of the mouth and tongue movements, although these can be quite disfiguring. In managing tardive dyskinesia, older adults and their heathcare providers should discuss the benefits and risks of antipsychotic medicine. Drugs used to treat tardive dyskinesia should be administered cautiously because of the danger of additional side effects. MeningitisMeningitis is a bacterial or viral infection of the covering (ie, the meninges) around the brain and spinal cord. Bacterial meningitis is more common than viral meningitis in older adults. Generally, the organisms that cause meningitis in older people are the same as those in younger people. Typical symptoms of bacterial meningitis include high fever, major changes in mental function, headache, and a stiff neck. In other cases, people may show only an unexplained low-grade fever, changes in mental function, or seizures. Meningitis is a serious medical problem that requires prompt medical attention. A spinal tap is usually needed to diagnose meningitis. Spinal fluid typically contains increased white blood cells as well as bacterial organisms. Antibiotics given IV are always necessary. People usually recover from meningitis if appropriate treatment is given promptly. Amyotrophic Lateral Sclerosis (Lou Gehrig's Disease)Amyotrophic lateral sclerosis (ALS) is a rare degenerative and fatal condition characterized by a progressive weakness and wasting of skeletal muscles. Often, there is also paralysis of the mouth and face. Eventually there is respiratory failure. People with ALS commonly have problems walking, falls, less hand strength, difficulty eating, and difficulty speaking. The prognosis is poor, with average survival only about 2-3 years. Peripheral Nerve Problems (Peripheral Neuropathy)Peripheral nerves control our body movements and sense of feel. Peripheral nerve function probably decreases mildly in all healthy, older adults. When peripheral neuropathy becomes more serious, it often leads to difficulty walking and a tendency to fall. The most common cause of peripheral neuropathy in the United States is diabetes. Other common causes in older adults include certain medications, alcohol abuse, kidney disease, vitamin or mineral deficiencies (eg, vitamin B6 or B12 deficiency), and some types of cancer. Treatment for neuropathy depends on the cause. It can range from withdrawal of alcohol or medications, to nutritional supplements, to treatment of an underlying disease (eg, cancer). Research suggests that good control of blood glucose (sugar) lessens the severity of neuropathy in people with diabetes. Treatments for nerve pain include creams applied to the skin and some types of antidepressant or anticonvulsant medications. |
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Published: 10/27/2005