What is dementia?

Dementia is not one specific disease. Rather, it is a cluster of symptoms. Generally, dementia is a broad term that describes a decline in cognitive functions, such as memory, language, and problem-solving skills.

In order to be diagnosed with dementia, this decline must interfere with a person’s functioning in daily life. People who show some signs of cognitive decline but who can continue to live life normally may instead be diagnosed with mild cognitive impairment.

There are a number of diseases¹ that can cause dementia, including Alzheimer’s, Lewy body disease, and Creutzfeldt-Jakob disease. Physical injuries or impairments, such as a stroke or head trauma (like those sustained in auto or construction accidents), can also cause the cognitive decline characteristic of dementia.

How common is dementia?

At least 5.7 million people in the United States are affected by dementia.² Of these cases, 60–70% are caused by Alzheimer’s disease. The second most common cause of dementia is vascular problems, such as strokes.

As our average life expectancy increases, so will the number of people affected by dementia. However, the frequency³ of the disease per capita is decreasing. In 2000, 12% of adults aged 65 and over were diagnosed with dementia in the U.S. By 2012, that number was down to 10.5%.

Dementia vs. Alzheimer’s

Many people believe dementia and Alzheimer’s disease (commonly referred to simply as “Alzheimer’s”) are synonymous. However, this is not exactly the case.

While dementia generally refers to a group of symptoms caused by cognitive decline, Alzheimer’s is a specific disease. Alzheimer’s can cause dementia⁴, but so can many other conditions. It may be helpful to think of it this way: Alzheimer’s can cause the symptoms of dementia, but not all cases of dementia are caused by Alzheimer’s.

Types of dementia

There are several types⁵ of dementia. Each is characterized by its particular symptoms and from where the decline originated in the brain.

A healthcare provider will work closely with a patient to determine and diagnose their type of dementia and the cause of their symptoms. Diagnosing the specific type of dementia a patient has can help them and their loved ones know what to expect and what treatment options might be the most effective.

Early onset dementia

Early onset dementia⁶ occurs in people younger than 65 years of age. This form of dementia is most commonly caused by Alzheimer’s disease, but it can also be caused by a stroke or an injury to the brain.

It can be more difficult to detect early onset dementia than it is to detect dementia in older patients. Because the condition is so rare, it isn’t frequently considered as a possible cause of a young patient’s symptoms.

Early onset dementia is generally treated with the same methods as those used to treat dementia in older patients.

Lewy body dementia

Lewy body dementia⁷, or LBD, occurs when abnormal deposits of a protein called alpha-synuclein, called Lewy bodies, form in the brain. These deposits change the brain chemicals act, leading to changes in mood, behavior, movement, and thinking.

There are two specific diagnoses of Lewy body dementia: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia. While both forms are caused by the same changes in the brain, their early signs and symptoms may differ. Over time, however, patients with either condition may begin to develop similar symptoms.

Diagnosing Lewy body dementia can be challenging, as its symptoms are often confused with those found in other brain diseases (such as Alzheimer’s) or psychiatric disorders (such as schizophrenia). Because of this, the only way to know for sure if Lewy bodies are the cause of a particular case of dementia is to detect them using a brain scan.

Lewy body dementia is a progressive disease: its symptoms are slow to develop and become more severe over time. The rate at which the signs and symptoms of LBD develop and worsen can vary greatly between patients, often depending on factors like age, overall health, and the severity of symptoms.

Vascular dementia

Vascular dementia⁸ occurs when blood flow is blocked from certain areas of the brain, depriving them of oxygen and key nutrients. This is most commonly caused by a stroke, but other types of vascular problems can also lead to widespread damage that results in cognitive difficulties.

The exact type of decline or symptoms experienced depends on where in the brain the stroke took place and which parts didn’t get the oxygen they needed. The decline in cognition caused by vascular dementia can range from mild to severe and can be caused by a single large stroke or a series of smaller ones.

Frontotemporal (frontal lobe) dementia

Frontotemporal dementia⁹, also known as frontal lobe dementia, occurs when nerve cells in the frontal lobe of the brain are destroyed. If a patient is undergoing regular brain scans, their provider will be able to see that the frontal lobe is shrinking over time.

This type of dementia occurs when something goes wrong with the protein tau or the protein TDP43. However, the exact mechanisms by which this cell destruction occurs aren’t known at this time. Patients with frontal lobe dementia may notice particular trouble with speech or with motor and/or limb control.

Dementia causes

Dementia symptoms are caused by conditions or accidents¹⁰ that damage the brain and prevent it from functioning normally. These causes include:

• Diseases: When a patient has a disease such as Alzheimer’s or Lewy body dementia, their symptoms will include the decline that we call dementia. There are a number of diseases that can result in dementia, all of which cause problems in the brain that decrease its ability to function as usual.
• Vascular damage to the brain: If parts of the brain are deprived of blood flow (and, therefore, denied oxygen and nutrients), the patient may experience symptoms of dementia. These symptoms will vary depending on which areas of the brain are affected.
• Traumatic brain injury: People who suffer from head injuries in traumatic accidents will often experience symptoms of dementia. The type and extent of these symptoms will depend on the severity of the injury and which part of the brain was affected. Some dementia symptoms caused by TBI may be reversible with ongoing therapy.

Risk factors for dementia

Some factors¹¹ that may increase your risk of developing dementia include:

• Age: The frequency of dementia-causing conditions, such as Alzheimer’s and vascular dementia, increases with age. Early-onset dementia is much less common than dementia that begins after the age of 65.
• Genetics: Several particular genes can increase a person’s risk of developing Alzheimer’s disease, Creutzfeldt-Jakob disease, Huntington’s disease, Parkinson’s disease, and other diseases that cause dementia. While many people with these genes do not develop these associated diseases, the presence of these genes puts one at higher risk than those without them.
• Smoking: People who smoke are more likely to get dementia. This may be because smoking causes a myriad of vascular problems that can lead to strokes (and, as a potential result, vascular dementia).
• Alcohol use: Drinking excessively can increase your risk of dementia.
• Atherosclerosis: This condition is caused by the buildup of deposits called plaque on the walls of the arteries. Plaque is made up of fatty particles, cholesterol, and other matter. It sticks to the sides of arteries, limiting or blocking the flow of blood and forcing the heart to work harder than it should. This condition can lead to vascular dementia.
• High levels of LDL cholesterol: Low-density lipoprotein (LDL) is also known as the “bad” form of cholesterol. This is because LDL is more likely than other cholesterol molecules to stick to the walls of your arteries. Having high levels of LDL cholesterol drastically increases your risk of both vascular dementia and Alzheimer’s disease.
• Diabetes: People with diabetes are more likely to have both vascular dementia and Alzheimer’s than those without the condition. This may be due in part to the fact that having diabetes puts a person at a higher risk for both atherosclerosis and strokes.
• Mild cognitive impairment: People diagnosed with mild cognitive impairment—cognitive struggles that don’t interfere with life to the extent that dementia does—often go on to develop full-blown dementia as they get older. However, a diagnosis of mild cognitive impairment does not necessarily mean that a person is guaranteed to develop dementia at any point in their life.

Dementia symptoms

The signs and symptoms¹² of dementia may come on quickly in some patients and develop so slowly that they are easily missed in others. Since treatments for some forms of dementia are most effective in the early stages of the disease, it’s important to keep an eye out for the early indicators of cognitive decline.

Some common signs and symptoms of dementia include:

• Memory loss, usually noted by someone close to the patient
• Difficulty problem-solving or coming to reasonable conclusions
• Difficulty completing complex or multi-step tasks
• Difficulty communicating or finding the right words
• Difficulty with spatial activities or visual processing, like getting lost in your own neighborhood
• Difficulty planning
• Difficulty organizing
• Difficulty with motor skills or coordination
• Confusion or disorientation

Dementia can also cause psychological changes, such as changes in personality. Some patients see drastic shifts in their demeanors, suddenly becoming angry, peaceful, kind, or high-strung when they never were before.

Psychological changes can also include the sometimes-sudden development or demonstration of:

• Depression
• Anxiety
• Paranoia
• Hallucinations
• Agitation
• Inappropriate behavior

Early signs of dementia

Early-stage dementia can look very different from the disease in its later stages. Because its symptoms worsen over time, dementia can remain undetectable in some patients until it worsens to the point that people close to the patient begin to take notice. Those with early-stage dementia often show the following symptoms¹³:

• Memory loss: This includes forgetting recently learned information, forgetting dates and events that have always been important, and asking the same questions over and over. This often starts out like the normal cognitive decline that can come with old age, then quickly worsens.
• Difficulty with familiar tasks: People with dementia may forget how to drive to a location they’ve driven to all their lives or struggle with the rules to their favorite game. When a person cannot do something they have always done with ease, it is often a sign of dementia.
• Struggles with problem-solving or organizing: People may begin to struggle with things like making a favorite recipe or keeping track of their monthly expenses. If a person has always kept their own budget and suddenly forgets to pay the bills, it may be a sign of dementia.
• Visual or spatial cognition trouble: Those with dementia may struggle with reading, lose their balance easily, or forget where they are and/or how to get home.
• Misplacing or losing things: The symptoms of dementia can make it hard for someone to keep track of things like their keys, eyeglasses, and other frequently used objects. Some people struggle with this throughout their lives, but if this has never been a problem in the past, it may be a good idea to have the person evaluated for dementia.
• Social withdrawal: People with dementia often struggle to follow or contribute to conversations. Because of this, they may begin to withdraw socially. They may do this in an attempt to hide their cognitive decline, or they may simply forget to spend time with the people they love. This can make it difficult for friends and family to accurately evaluate the degree of an individual’s cognitive decline.

Dementia stages

There are seven identified stages¹⁴ of dementia. They are ranked according to the severity of symptoms and impact, ranging from nearly undetectable to debilitating. These states are as follows:

• No visible impairment: Even though cognitive changes may be occurring, the patient can live normally and care for themselves. Brain scans may show damage, but it has not yet begun to impair the patient’s functioning.
• Very mild: The patient shows symptoms similar to those of normal aging. They may forget the date of an appointment they’ve scheduled, but remember it later. They might also start misplacing things more often but without becoming bewildered or disoriented. Brain images may show mild damage, plaque deposits, or degeneration.
• Mild: A patient has begun to show mild cognitive problems. They may seem more forgetful than usual or become disoriented. Occasionally, they may struggle to find the right words to express themselves. People near the patient often begin to notice their decline during this stage.
• Moderate: The patient begins to forget recent events and struggles to manage their personal affairs. They are not able to complete complex or multi-step tasks. When approached about the problem, they may deny it and withdraw from those closest to them. Their healthcare providers, as well as their close friends, will notice their symptoms.
• Moderately severe: Memory lapses become major, including forgetting significant life events. The patient may forget that they were ever married or be unable to recall a story they used to tell frequently. They need help with daily tasks, like getting dressed or making food. It is usually necessary to have someone take over handling the patient’s personal affairs.
• Severe: At this stage, the patient can no longer care for themselves. They may forget the names of their loved ones and stop finishing tasks only part of the way through. Their speech may become slow or slurred, and incontinence, depression, and delusions may become apparent. Agitation and frustration are also common during this stage.
• Very severe: Patients with very severe dementia require full-time care. They gradually lose the ability to speak and will need help with all of their daily activities, such as bathing, washing, and using the toilet. They may lose motor functioning to the point of experiencing difficulty chewing food and even losing the ability to walk.

Complications from dementia

Dementia causes many changes in the body. These changes can affect the body’s ability to function as normal, which can lead to complications¹⁵, including:

• Poor nutrition: People with dementia may forget how to eat or prepare their own food. Patients may also lose the ability to chew and/or swallow as the condition progresses, which can lead to malnutrition.
• Low self-care: Patients with dementia often forget about basic self-care, like showering, brushing their teeth, using the toilet, and taking necessary medications.
• Safety issues: Because of cognitive and motor decline, everyday tasks like driving, cooking, or walking can become dangerous for people with dementia.
• Pneumonia: Because dementia leads to problems with chewing and swallowing, patients often aspirate food or drink into their lungs. This can cause choking and lead to pneumonia.
• Infection: People with dementia often fail to notice infections in their early stages. These can become severe very quickly, especially if caregivers are not around to watch for these problems.