Dementia vs Alzheimer’s: the difference between the two

When someone shows signs of forgetfulness, it’s easy to jump to conclusions. Is it dementia? Alzheimer’s? And what’s the difference? We’ll help you unravel these similar, but different terms. There is often misunderstanding about the difference between Alzheimer’s and the many forms of dementia, but diagnosis and good care depend on having knowledge of these conditions.

Alzheimer’s Disease is a form of dementia

Dementia is not a specific disease. It’s an umbrella term, describing a wide range of symptoms. Alzheimer’s, by contrast, is a disease. It’s one type of dementia — in fact, it happens to be the most common one — but it’s not the only one. Not everyone with dementia has Alzheimer’s disease.

There are multiple types of dementia

The National Institutes on Aging estimates that four to five million Americans currently have some form of dementia, and those forms include:

• Alzheimer’s Disease – 70-80% of people who have dementia have Alzheimer’s. It’s a progressive condition that usually affects people older than 65. There’s currently no cure. It happens when proteins called plaques, and fibers called tangles, build up in the brain, block nerve signals and destroy brain cells. As brain cells degenerate and die, there’s a corresponding decline in memory and mental function.

• Vascular Dementia – 20-30% who have dementia have vascular dementia. It happens when there’s not enough blood going to the brain, caused by damage to blood vessels or blockages that lead to mini-strokes or brain bleeding. There are several forms of vascular dementia, so symptoms may vary. In general, people with vascular dementia may show more problems with attention, organization, processing speed.

• Lewy Body Dementia – Up to 10-20% of those with dementia have this form. Lewy bodies are abnormal clumps of a protein called alpha-synuclein which build up in the cortex of the brain (the part that handles learning and memory). It causes problems with attention, sleeping issues, hallucinations, and unbalanced movements, similar to Parkinson’s disease symptoms. Memory loss tends to show up later with this kind of dementia.

• Frontotemporal Dementia – Up to 10% of those with dementia have this form, which involves the loss of nerve cells in the front and side areas (frontal and temporal lobes) of the brain. Symptoms include personality and behavior changes, inattention, memory problems, executive functioning difficulties (for example, problems planning, sequencing steps, doing multiple things at once), and trouble with language. Some people also have a hard time with writing and comprehension. Symptoms usually show up around age 60—earlier than they usually start with Alzheimer’s disease.

• Creutzfeldt-Jakob Disease (CJD) – This rare form of dementia happens when proteins called prions fold into an abnormal shape, damaging brain cells and triggering quick mental decline. People with CJD may also have mood changes, jerky movements, and trouble walking.

• Huntington’s Disease Dementia – A genetic issue, it affects the central part of the brain—the area that helps us think, move and show emotion.

• Mixed Dementia – Sometimes, a person has brain impairments caused by more than one type of dementia. For example, they may have blocked or damaged blood vessels (vascular dementia) and brain plaques and tangles (Alzheimer’s disease) at the same time.

Diagnosing dementia

To diagnose dementia, physicians look for a person to be having a hard time with at least two of the following cognitive functions and behaviors:

1. Memory
2. Communication & speech
3. Focus & concentration
4. Reasoning & judgment
5. Visual perception

A deeper, clinical dive

Although younger people can and do get Alzheimer’s (known as early-onset Alzheimer’s disease), the symptoms generally begin after age 60. Scientists believe that for most people, Alzheimer’s is caused by a combination of genetics, lifestyle and environmental factors that affect the brain over time.

When Alzheimer’s brain tissue is examined under a microscope, two types of abnormalities emerge that are indications of the disease. These abnormalities aren’t seen in brains without the disease.

1. Plaques – clumps of a protein, called beta-amyloid, that may damage and destroy brain cells in several ways, including interfering with cell-to-cell communication. 
2. Tangles – twisted threads of a protein, called tau, that get into abnormal tangles inside brain cells leading to failure of the internal cell “transport system” that normally carries nutrients and other essential materials throughout the cells.

Symptoms specific to Alzheimer’s

While both dementia and Alzheimer’s have some common symptoms, including a decline in the ability to process information, memory and communication impairment, symptoms specific to Alzheimer’s include:

• Difficulty remembering recent events or conversations
• Apathy
• Depression
• Impaired judgment
• Disorientation
• Confusion
• Behavioral changes
• Difficulty speaking, swallowing, or walking (in advanced stages of the disease)

Diagnosing Alzheimer’s can feel like a guessing game

When it comes to diagnosing Alzheimer’s, a doctor can’t say that a person has Alzheimer’s with absolute certainty, but there are things to test to be reasonably sure. These include attention, memory, language, and vision tests, and typically an MRI to look for changes in brain tissue.

Alzheimer’s is not curable, but with early detection, patients can explore treatments that may provide some relief of symptoms and help maintain a level of independence longer. There may also be opportunities to participate in clinical drug trials that help advance research.

The long-term outlook for dementia & Alzheimer’s: what the latest research says

On the good news front, scientists are continually investigating ways to stave off and/or treat dementia including Alzheimer’s. In addition, there is a growing body of evidence supporting the efficacy of brain rehabilitation in slowing the progression of these diseases. For example, researchers recently completed a study that found that Constant Therapy is a manageable and effective intervention for people living with dementia. The study was conducted by researchers at the University of Central Florida’s Communication Sciences and Disorders Clinic, and published in Perspectives of the ASHA Special Interest Groups. It concluded that Constant Therapy can help people living with dementia to achieve significant gains in their cognitive and language abilities through a clinician-monitored program tailored to their needs. The app’s easy-to-use interface is manageable for patients and caregivers and allows people with dementia to complete up to 600 percent more exercises at home than in the clinic alone. Just as important, sustained Constant Therapy use can boost users’ sense of confidence and offer hope through the prospect of further improvement.

For more information

1. Alzheimer’s Association
2. National Institutes on Aging (part of NIH)
3. American Speech-Language-Hearing Association (ASHA)
4. American Psychiatric Association
5. Demystifying Dementia (with downloadable infographic)