When we hear the word “dementia,” most of us think of Alzheimer’s ­disease. But the two terms aren’t interchangeable, and in fact, some forms of dementia look quite different from Alzheimer’s in terms of symptoms, disease progression and brain changes.

Bottom Line Personal asked Zaldy Tan, MD, director of the Bernard & Maxine Platzer Lynn Family Memory and Healthy Aging Program at Cedars-Sinai Medical Center, to explain non-Alzheimer’s dementia and how to reduce your risk for all kinds…

Types of dementia. Defined broadly, dementia is a condition affecting the brain that causes difficulty thinking and remembering, and that increasingly affects the performance of day-to-day functions. Saying someone “has dementia” is like saying they “have cancer”—we know what cancer is, but we acknowledge that there are differences among the various types.

Determining what type of dementia a person has can drive decisions about which treatments to try and provide a set of expectations about how the disease will progress and what the overall prognosis will be.

The four main forms of dementia…

Alzheimer’s disease: The reason Alzheimer’s commands so much attention is that it’s the most common type of dementia, accounting for 50% to 75% of cases. While the ultimate cause of Alzheimer’s is unknown, its hallmark is the accumulation of a protein called amyloid, which forms plaques, and “­neurofibrillary tangles” of tau protein within healthy neurons in the brain. It first affects the hippocampus, the area of the brain responsible for short-term memory. Later, it spreads to other regions affecting attention, concentration, sequencing, motor skills and long-term memory.

Vascular dementia: This type of dementia is related to tissue damage following loss of blood flow to the brain, usually from a stroke or brain hemorrhages. Its symptoms can resemble those of Alzheimer’s but depend on which brain region is impaired. Generally, vascular dementia affects the ability to retrieve new memory, but other symptoms can include apathy, disorganization, confusion and inability to concentrate. Vascular dementia may come on suddenly, as after a severe stroke, or gradually over the course of years. About 20% to 30% of dementia cases are attributed to vascular dementia.

Lewy body dementia (LBD): Actor Robin Williams, who passed away in 2014, had this form of dementia. Like Alzheimer’s, LBD is marked by an excess of a protein in the brain, but in this case the protein is alpha-synuclein, not amyloid. As alpha-synuclein accumulates, amassing deposits known as Lewy bodies, brain function deteriorates. Besides disrupted thinking and attention, patients can experience hallucinations, delusions and Parkinson’s-like motor problems. In fact, because the loss of motor control looks so similar to Parkinson’s, and because there is no blood test that reveals LBD, cases often are misdiagnosed as “Parkinson’s dementia,” with the Lewy bodies discovered only upon autopsy. From 10% to 25% of dementia patients have LBD.

Frontotemporal dementia (FTD): Roughly 10% to 15% of dementia cases fall under this umbrella term, which refers to deterioration of the brain’s frontal and temporal lobes, responsible for personality, language and behavior. As the disease sets in, the lobes shrink, diminishing their function. Patients can undergo drastic personality changes and begin to engage in inappropriate behaviors. Some experience reduced ability to use language. Onset of FTD tends to occur earlier than Alzheimer’s, between ages 40 and 65. Its cause is unknown.

Risk factors

Various characteristics and behaviors have been associated with increased or decreased risk for dementia. but keep in mind three things when assessing such studies…

They almost always express associations (and not causation) between certain factors and the likelihood of dementia diagnosis. Example: A recent study by researchers at University of Plymouth in the UK found that being simultaneously prescribed three or more medications—especially for urinary and respiratory infections—was associated with increased dementia risk. But that doesn’t mean those medications cause dementia. It could be that the infections themselves drive a later dementia diagnosis…or some underlying condition could make a person prone both to the infections and dementia. Don’t draw simple conclusions from such studies.

These findings tend to have small effects. Example: A study from Southern Medical University in Guangzhou, China, on fish oil and dementia found that people taking supplements were about 9% less likely to develop dementia. That’s intriguing enough to warrant further investigation, but not a reason to start gobbling fish-oil pills—especially when there are other factors whose significance dwarfs that of fish oil.

Risk factors for dementia tend to fall into one of two categories. In the first category are well-established factors including age, history of head trauma to the point of losing consciousness, family history (dementia in a first-degree relative), stroke, cerebrovascular disease, high blood pressure, African-American race and Hispanic heritage. Enough research has been done on these factors that little debate remains (although even these still are just associations, not causes). The other category contains less defined or less established factors including poor sleep, smoking, ­diabetes, high body mass index (BMI) and high triglycerides. These haven’t been investigated enough to be considered well-established. Bearing in mind what’s established versus what is only associated should help you decide where to focus your efforts to reduce risk.


Because many well-established risk factors for dementia are beyond an individual’s control, taking steps to prevent the condition means making choices within a limited sphere of influence. You can’t control your age, your heritage or whether a parent had dementia—but you can lower your risk for cerebro-
vascular disease and high blood pressure.

One thing the science makes clear: What is good for your heart is good for your brain. Diet, exercise and blood pressure control are the likeliest ways to counteract underlying risk for dementia.

That’s especially important given what researchers call the “multiple-hit” hypothesis of dementia risk. Imagine that, thanks to an underlying genetic predisposition, Person A’s brain is cluttered with abnormal proteins, and he develops dementia regardless of the lifestyle choices he makes. Meanwhile, most people are more like Person B, who has some accumulation of abnormal proteins but still, in her 80s and 90s, continues to function adequately and live independently. Yet even Person B could develop dementia and lose her independence if she were to suffer a series of small strokes. At that point, the abnormal proteins coupled with the tissue damage from blood deprivation could tip her over the edge.

Getting 150 minutes of moderate to vigorous physical activity each week, plus two days of strength training, is recommended for cardio and brain health. So is following a Mediterranean-style or MIND diet. Both these diets emphasize complex carbohydrates, vegetables, fish, olive oil and beans, and both are low in salt, red meat and sweets.

Those two major lifestyle factors will have a greater impact on whether you develop dementia than scrambling after some new behavior (coffee drinking, crossword puzzles) each time a new study comes out.             


There’s no cure for dementia, but today’s medications lessen the disease’s severity, slow its progression and can help manage its symptoms. The FDA has approved three classes of drugs…

Acetylcholinesterase inhibitors such as donepezil (Aricept) and rivastigmine (Exelon) improve function by increasing the neurotransmitter protein acetylcholine in the junctions that brain cells use to communicate with each other. Although designed for Alzheimer’s patients, physicians often try them in LBD and vascular dementia cases, since those patients often have an acetylcholine deficit similar to that seen in Alzheimer’s.

NMDA receptor antagonists such as memantine (Namenda) help with cognition by blocking the brain receptor NMDA, which becomes overstimulated in dementia cases. These drugs are approved for only moderate- to late-stage Alzheimer’s-type dementia, but evidence suggests they can help some vascular dementia patients.

Neither of those classes modifies the disease. They help only with symptoms. But the FDA has approved one monoclonal antibody, aducanumab, and two others are in trials. These drugs clear the amyloid plaques that cause Alzheimer’s. Unfortunately, while they appear effective at removing plaques, their impact on the disease is less impressive.

Early diagnosis: If you notice cognitive problems in yourself or a loved one beyond normal age-related changes, get tested. Today’s therapies and the ones coming, are promising. And an early diagnosis allows you to plan ahead while you’re still able to make decisions about personal goals, money, family and health care.

Related Articles