Dementia symptoms vary depending on the cause, but common signs and symptoms include:
- Memory loss
- Difficulty communicating or finding words
- Difficulty with complex tasks
- Difficulty with planning and organizing
- Difficulty with coordination and motor functions
- Problems with disorientation, such as getting lost
- Personality changes
- Inability to reason
- Inappropriate behavior
When to see a doctor
See a doctor if you or a loved one experiences memory problems or other dementia symptoms. Some treatable medical conditions can cause dementia symptoms, so it's important that a doctor determine the underlying cause.
Alzheimer's disease and several other types of dementia worsen over time. Early diagnosis gives you time to plan for the future while you can participate in making decisions.
Dementia involves damage of nerve cells in the brain, which may occur in several areas of the brain. Dementia may affect people differently, depending on the area of the brain affected.
Dementias can be classified in a variety of ways and are often grouped by what they have in common, such as what part of the brain is affected, or whether they worsen over time (progressive dementias).
Some dementias, such as those caused by a reaction to medications or an infection, are reversible with treatment.
Types of dementias that are not reversible and worsen over time include:
Alzheimer's disease. In people age 65 and older, Alzheimer's disease is the most common cause of dementia. People generally may develop symptoms after age 60, but some people may have early-onset forms of the disease, often as the result of a defective gene.
Although in most cases the exact cause of Alzheimer's disease isn't known, plaques and tangles are often found in the brains of people with Alzheimer's. Plaques are clumps of a protein called beta-amyloid, and tangles are fibrous tangles made up of tau protein.
Certain genetic factors also may make it more likely that people will develop Alzheimer's.
Alzheimer's disease usually progresses slowly over about eight to 10 years. Your cognitive abilities slowly decline. Eventually, the affected areas of your brain don't work properly, including parts of your brain that control memory, language, judgment and spatial abilities.
Vascular dementia. Vascular dementia, the second most common type of dementia, occurs as a result of brain damage due to reduced or blocked blood flow in blood vessels leading to your brain.
Blood vessel problems may be caused by stroke, infection of a heart valve (endocarditis) or other blood vessel (vascular) conditions.
Symptoms usually start suddenly and often occur in people with high blood pressure or people who have had strokes or heart attacks in the past.
Several different types of vascular dementia exist, and the types have different causes and symptoms. Alzheimer's disease and other dementias also may be present at the same time as this dementia.
Lewy body dementia. Lewy body dementia affects approximately 10 percent of people with dementia, making it one of the most common types of dementia. Lewy body dementia becomes more common with age.
Lewy bodies are abnormal clumps of protein that have been found in the brains of people with Lewy body dementia, Alzheimer's disease and Parkinson's disease.
Lewy body dementia symptoms are similar to symptoms of Alzheimer's disease. Its unique features include fluctuations between confusion and clear thinking (lucidity), visual hallucinations, and tremor and rigidity (parkinsonism).
People with Lewy body dementia often have a condition called rapid eye movement (REM) sleep behavior disorder that involves acting out dreams.
Frontotemporal dementia. This type of dementia tends to occur at a younger age than does Alzheimer's disease, generally between the ages of 50 and 70.
This is a group of diseases characterized by the breakdown (degeneration) of nerve cells in the frontal and temporal lobes of the brain, the areas generally associated with personality, behavior and language.
Signs and symptoms of frontotemporal dementia can include inappropriate behaviors, language problems, difficulty with thinking and concentration, and movement problems.
As with other dementias, the cause isn't known, although in some cases this dementia is related to certain genetic mutations.
Other disorders linked to dementia
Huntington's disease. This inherited disease causes certain nerve cells in your brain and spinal cord to waste away.
Signs and symptoms usually appear during your 30s or 40s. People may experience personality changes, such as irritability or anxiety.
The condition causes a severe decline in thinking (cognitive) skills over time. Huntington's disease also causes weakness and difficulty with walking and movement.
Traumatic brain injury. This condition is caused by repetitive head trauma, such as experienced by boxers, football players or soldiers.
Depending on the part of the brain that's injured, this condition can cause dementia signs and symptoms such as uncoordinated movement and impaired speech, as well as slow movement, tremors and rigidity (parkinsonism). Symptoms may not appear until many years after the actual trauma.
A person who has experienced a single traumatic head injury could develop a similar condition called posttraumatic dementia, which may cause symptoms such as long-term memory problems.
Creutzfeldt-Jakob disease. This rare brain disorder usually occurs in people without risk factors. This condition may be due to an abnormal form of a protein. Creutzfeldt-Jakob disease sometimes may be inherited or caused by exposure to diseased brain or nervous system tissue.
Signs and symptoms of this fatal condition usually appear around age 60 and initially include problems with coordination, memory, thinking and vision. Symptoms worsen over time and may include the inability to move or talk, blindness, or infections.
- Parkinson's disease. Many people with Parkinson's disease eventually develop dementia symptoms (Parkinson's disease dementia).
Dementia-like conditions that may be reversed
Some causes of dementia or dementia-like symptoms can be reversed. Your doctor may identify and treat these causes:
Infections and immune disorders. Dementia-like symptoms can result from fever or other side effects of your body's attempt to fight off an infection.
People may develop thinking difficulties if they have brain infections like meningitis and encephalitis, untreated syphilis, Lyme disease, or conditions that cause a completely compromised immune system, such as leukemia.
Conditions such as multiple sclerosis that arise from the body's immune system attacking nerve cells also can cause dementia.
- Metabolic problems and endocrine abnormalities. People with thyroid problems, too little sugar in the bloodstream (hypoglycemia), too low or too high amounts of sodium or calcium, or an impaired ability to absorb vitamin B-12 may develop dementia-like symptoms or other personality changes.
- Nutritional deficiencies. Dementia-like symptoms can occur as a result of not drinking enough liquids (dehydration); not having enough thiamin (vitamin B-1), a condition common in people with chronic alcoholism; and not having enough vitamins B-6 and B-12 in your diet.
- Reactions to medications. Dementia-like symptoms may occur as a reaction to a single medication or because of an interaction of several medications.
- Subdural hematomas. Subdural hematomas are caused by bleeding between the surface of the brain and the covering over the brain. They can cause symptoms similar to dementia.
Poisoning. Dementia-like symptoms can occur as a result of exposure to heavy metals, such as lead, and other poisons, such as pesticides.
Dementia-like symptoms may also occur in some people who have abused alcohol or recreational drugs. Symptoms may disappear after treatment, but in some cases symptoms may still be present after treatment.
- Brain tumors. Dementia rarely can result from damage caused by a brain tumor.
Anoxia. This condition, also called hypoxia, occurs when organ tissues aren't getting enough oxygen. Anoxia may occur due to severe asthma, heart attack, carbon monoxide poisoning or other causes.
If you've experienced a severe lack of oxygen, recovery may take longer. Symptoms, such as memory problems or confusion, may occur during recovery.
Normal-pressure hydrocephalus. Sometimes people have a condition caused by enlarged ventricles in the brain (normal-pressure hydrocephalus). This condition can cause walking problems, urinary difficulty and memory loss.
Shunt surgery, which delivers cerebrospinal fluid from the head to the abdomen or heart, may help these symptoms.
Many factors can eventually lead to dementia. Some factors, such as age, can't be changed. Others can be addressed to reduce your risk.
Risk factors that can't be changed
- Age. As you age, the risk of Alzheimer's disease, vascular dementia and several other dementias greatly increases, especially after age 65. However, dementia isn't a normal part of aging, and dementia can occur in younger people.
Family history. If you have a family history of dementia, you're at greater risk of developing the condition. However, many people with a family history never develop symptoms, and many people without a family history do.
If you have specific genetic mutations, you're at significantly greater risk of developing certain types of dementia.
Tests to determine whether you have certain genetic mutations are available.
- Down syndrome. By middle age, many people with Down syndrome develop the plaques and tangles in the brain that are associated with Alzheimer's disease. Some may develop dementia.
Risk factors you can change
You may be able to take steps to control the following risk factors of dementia.
- Heavy alcohol use. People who consume large amounts of alcohol may have a higher risk of dementia. Although studies have shown that moderate amounts of alcohol may have a protective effect, abuse of alcohol increases your risk of developing dementia.
Atherosclerosis. This buildup of fats and other substances in and on your artery walls (plaques) can reduce the blood flow to your brain and lead to stroke. Reduced blood flow to your brain can also cause vascular dementia.
Some research shows there may be an association between blood vessel (vascular) conditions and Alzheimer's disease.
- Blood pressure. Several studies show high or low blood pressure may increase your risk of developing dementia.
- Cholesterol. If you have high levels of low-density lipoprotein (LDL) cholesterol, you may have an increased risk of developing vascular dementia or Alzheimer's disease. Researchers continue to study how cholesterol may affect dementia.
- Depression. Although not yet well understood, late-life depression, especially in men, may be an indication of the development of dementia.
- Diabetes. If you have diabetes, you may have an increased risk of developing Alzheimer's disease and vascular dementia.
- High estrogen levels. Women taking estrogen and progesterone years after menopause may be at greater risk of developing dementia.
- Homocysteine blood levels. Elevated blood levels of homocysteine, a type of amino acid produced by your body, may increase your risk of developing vascular dementia.
- Obesity. Being overweight or obese during the middle of your life may increase your risk of developing dementia when you're older.
- Smoking. Smoking may increase your risk of developing dementia and blood vessel (vascular) diseases.
Dementia can affect the functioning of many body systems and, therefore, the ability to carry out day-to-day tasks. Dementia may lead to several problems, including:
Inadequate nutrition. Many people with dementia will eventually reduce or stop eating and drinking. They may forget to eat or think they've already eaten. Changes in meal times or noise distractions in their environment may affect whether they eat.
Often, advanced dementia causes you to lose control of the muscles used to chew and swallow. This may put you at risk of choking or aspirating food in your lungs. If this happens, it can block breathing and cause pneumonia.
You also lose the feeling of hunger and, with it, the desire to eat. Depression, side effects of medications, constipation and other conditions also can decrease your interest in food.
- Reduced hygiene. In moderate to severe stages of dementia, you'll eventually lose the ability to independently complete daily living tasks. You may no longer be able to bathe, dress, brush your hair or teeth, or use the toilet on your own.
- Difficulty taking medications. Because your memory is affected, remembering to take the correct amount of medications at the right time can be challenging.
Deterioration of emotional health. Dementia changes behaviors and personality. Some of the changes may be caused by the actual deterioration happening in your brain, while other behavioral and personality changes may be emotional reactions to coping with the changes in your brain.
Dementia may lead to depression, aggression, confusion, frustration, anxiety, a lack of inhibition and disorientation.
Difficulty communicating. As dementia progresses, you may lose the ability to remember the names of people and things. You may have trouble communicating with others or understanding others.
Difficulty communicating can lead to feelings of agitation, isolation and depression.
- Delusions and hallucinations. You may experience delusions in which you have false ideas about another person or situation. Some people, especially those with Lewy body dementia, may have visual hallucinations.
- Sleep difficulties. You may experience sleep difficulties, such as waking up very early in the morning. Some people with dementia may have restless legs syndrome or rapid eye movement (REM) sleep behavior disorder, which also can interfere with sleep.
- Personal safety challenges. Because of a reduced capacity for decision-making and problem-solving, some day-to-day situations can present safety issues for people with dementia. These include driving, cooking, falling, getting lost and negotiating obstacles.
There's no sure way to prevent dementia, but there are steps you can take that might help. More research is needed, but it may be beneficial to do the following:
- Keep your mind active. Mentally stimulating activities, such as puzzles and word games, and memory training may delay the onset of dementia and help decrease its effects.
- Be physically and socially active. Physical activity and social interaction may delay the onset of dementia and reduce its symptoms.
- Quit smoking. Some studies have shown smoking in middle age and older may increase your risk of dementia and blood vessel (vascular) conditions. Quitting smoking may reduce your risk.
- Lower your blood pressure. High blood pressure may lead to a higher risk of some types of dementia. More research is needed to determine whether treating high blood pressure may reduce the risk of dementia.
Pursue education. People who have spent more time in formal education appear to have a lower incidence of mental decline, even when they have brain abnormalities.
Researchers believe that education may help your brain develop a strong nerve cell network that compensates for nerve cell damage caused by Alzheimer's disease.
- Maintain a healthy diet. Eating a healthy diet is important for many reasons, but a diet rich in fruits, vegetables and omega-3 fatty acids, commonly found in certain fish and nuts, may promote overall health and lower your risk of developing dementia.