What is dementia?

It’s estimated that more than 5 million Americans suffer from dementia. While not a specific disease, dementia is the general term used to describe the mental decline of an individual that causes interference in their daily life. When there has definitely been abnormal decline, but the individual can continue to function normally in day-to-day activities, that person’s condition may be called mild cognitive impairment (MCI).

At a high level, dementia can be explained simply as the result of brain cells that have been damaged. When brain cells become damaged, it impairs the body’s natural functions and affects how we think, behave, and feel. The human brain has different regions, each responsible for specific cognitive functions. Damaged cells in these different regions of the brain lead to the wide variety of symptoms someone with dementia may experience.

Signs of Dementia

The symptoms associated with dementia vary, but may affect normal core mental functions in various ways:

• Memory loss
• Language (commonly the ability to find words)
• Motor skills, particularly fine motor skills
• Motivation, planning, and organizational skills
• Trouble with calculations
• Visual perception
• Behavior or personality (paranoia, anxiety, depression, and agitation)

The signs of dementia typically don’t appear all at once but emerge gradually and worsen slowly over time. Note this may not always be the case, and sometimes mental symptoms may appear to start abruptly in the setting of another medical illness (e.g. hip surgery) or psychological stressor (e.g. death of a spouse). 

People with dementia may start experiencing higher frequencies of misplacing items, having trouble keeping up with appointments, or even paying bills. Depending on the type of dementia, behavioral changes may also be noticed. Difficulty in managing challenges in daily life could indicate a cognitive disorder and should be addressed by a professional.

Types of Dementia

As noted earlier, dementia is not a specific disease, but a general term used to describe cognitive disorders. The most common cause of dementia in the United States is Alzheimer’s disease, which accounts for 60-80 percent of cases. Other forms of dementia include vascular dementia, Lewy body dementia, and frontotemporal dementia (FTD). 

Vascular Dementia

Vascular dementia occurs when the brain does not receive adequate blood flow, causing the cells in the brain to become damaged and eventually die. The rate in which symptoms appear can be rapid or gradually worsen over time. For example, a stroke caused by a major blood vessel becoming blocked can cause sudden onset of severe problems. Numerous small strokes may cause cognitive decline over a longer period of time. 

Because different areas of the brain may be affected, memory loss is not the only indication of vascular dementia. The symptoms may be most noticeable immediately following a major stroke and include confusion, disorientation, trouble speaking, and vision loss. Conditions affecting blood vessels within the brain may also lead to other symptoms and changes in thinking. 

Common early signs of blood vessel associated damage include forgetfulness, trouble finding the right words, impaired judgement, and emotional and behavioral changes. High blood pressure, high cholesterol, and generally poor vascular health can put an individual at a higher risk of developing vascular dementia. Working with your primary care provider to manage these risk factors may markedly reduce your risk of developing vascular dementia.

Lewy Body Dementia

Lewy Body Dementia, LBD for short, is a progressive brain disorder with symptoms that can resemble Alzheimer’s disease. Lewy bodies are named after the scientist, Friedrich H. Lewy, who discovered the abnormal protein deposits while studying Parkinson’s disease in the early 1900’s. It is the second most common form of progressive dementia after Alzheimer’s. 

Where Alzheimer’s disease is often attributed to the build up of plaques containing beta amyloid proteins, Lewy Body dementia is associated with abnormal deposits of the alpha-synuclein proteins in nerve cells. These Lewy bodies affect chemical processes in the brain’s nerve cells and can lead to problems with movement, coordination, thinking, and mood. Other symptoms can include visual hallucinations, sleep difficulties, and depression. 

There are currently two diagnoses of Lewy Body dementia – dementia with Lewy bodies, which is the same as Lewy Body dementia, and Parkinson’s disease dementia. Parkinson’s disease dementia occurs when someone who is diagnosed with Parkinson’s begins to experience cognitive decline. This decline normally happens at least a year after the person is diagnosed with Parkinson’s disease. 

Like Alzheimer’s, the symptoms worsen over time and can be hard to diagnose due to the similarities with other diseases affecting cognitive function. According to the National Institute of Health, LBD typically lasts 5-8 years from diagnosis to death, but can be as little as 2 years and as much as 20 years. There is currently no cure for Lewy Body Dementia.

Frontotemporal Dementia

Frontotemporal dementia (FTD) is used to describe a group of disorders that tend to affect the frontal and temporal lobes in the brain. Depending on which portions of these lobes are damaged on which side of the brain, frontotemporal dementia can affect behavior, language, or movement. It’s possible for someone to experience more than one group of symptoms. 

Frontotemporal dementia is like other forms of dementia in that it is a progressive condition that worsens over time. It is the most common form of dementia for people under the age of 60 and can affect individuals as early as their 40’s. Unlike Alzheimer’s disease, behavioral and personality changes rather than decline in memory and thinking abilities may be the dominant symptom in some individuals with frontotemporal dementia. These changes include loss of empathy or other interpersonal skills, lack of judgment, repetitive compulsive behavior, and increasingly inappropriate actions. 

Other individuals with FTD may experience profound difficulties with aphasia, the loss of ability to understand or express oral or written language. Some may have difficulty naming things and replace the words they’re trying to use with simpler words or words that sound similar to the one they want. Others’ speech can become more hesitant and have trouble constructing sentences. 

In rarer instances, some experience movement problems similar to those associated with Parkinson’s disease and can include tremors, poor coordination, and rigidity. While the symptoms are sometimes indistinguishable, when examined after death, brains of individuals with frontotemporal dementia can be associated with two very distinct abnormalities. In some individuals, brain cells show accumulation of a protein called Tau while in others abnormal collection of protein called TDP-43 is seen in neurons.

Mild Cognitive Impairment (MCI)

Although technically not a form of dementia, Mild Cognitive Impairment (MCI) is used to describe cognitive decline that is clearly abnormal, but not severe enough to disrupt daily life and keep individuals from living independently. It is considered the bridge between normal cognitive changes caused by aging and the more serious decline associated with dementia. 

Mild cognitive impairment can also affect different functions of the brain memory, language, thinking, and judgement. It’s also possible for those suffering from MCI to experience depression, anxiety, and anger. Changes may be less noticeable at first and gradually become more severe. In some instances, the individual may not be aware of the changes, only to have them recognized by a close friend or family member. 

Recognizing MCI typically requires some formal (paper and pencil) cognitive testing. While people with mild cognitive impairment are at risk for developing dementia, there are instances when it does not worsen. The course of someone with MCI depends on the underlying cause, and it is earliest stage at which diseases like Alzheimer’s disease might be recognized based on memory loss or other symptoms. Because it represents a very early, pre-dementia stage of degenerative brain diseases, recognition of MCI represents an important goal for early intervention in these conditions.

Causes of Dementia and What to Look For

Dementia has a mix of causes, but the most common causes include degenerative neurological diseases like Alzheimer’s disease, vascular disorders, Lewy body dementia, and frontotemporal dementia.  Usually dementia will go through several stages of increasing severity but can vary depending on the area of the brain that is affected. Early signs of dementia include memory loss, trouble performing familiar tasks, and being confused about time or place. 

Some individuals may experience personality or behavior changes, apathy, and depression. It’s important to speak with your physician if you feel you are experiencing signs of dementia. There is currently no one test for diagnosing dementia. Diagnosis involves reviewing medical history, physical exams, lab testing, and identifying the characteristic changes in thinking, day-to-day function and behavior.

Want to know more about how you can help fight Alzheimer’s and dementia? Consider joining the Emory Healthy Brain Study, a unique clinical research study aimed at finding the biomarkers that will allow us to predict the development of neurodegenerative diseases.

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