What are the Different Types of Dementias?
Dementia is a broad term that refers to any condition leading to a breakdown of the integrity of the brain, resulting in problems in cognitive abilities and day-to-day living skills. Depending on the type of dementia, symptoms at the onset of the condition may vary, and their course over time may also differ. Many individuals have cognitive problems due to a range of medical and psychiatric conditions, but unless they are severe enough to affect day-to-day functioning, a diagnosis of dementia would not be given.
Alzheimer’s disease (AD)
Alzheimer’s disease, the most common type of dementia, typically presents in the person’s 70s, though early-onset forms due to genetic mutations are known. An individual with AD usually complains of memory problems first and difficulty finding the right words. Over time, visuospatial problems begin to affect driving ability as well. As the disease progresses, the person’s ability to manage day-to-day affairs such as dressing, cooking, cleaning, driving, handling finances, shopping, toileting, etc. begin to decline. During the middle course of the condition, behavioral problems often emerge. These include false beliefs (delusions), hallucinations, paranoia, depression, anxiety, aggression, wandering, pacing, repetitive calling out, and so on. If no other medical condition takes the person’s life, individuals with AD often become mute and bedridden in the advanced stages. They typically die of complications of an infection such as pneumonia.
Lewy body dementia (LBD)
LBD is related to Parkinson’s disease. Individuals with LBD typically begin to experience problems during the late 60s or early 70s. The presenting problem, however, is often different from AD; instead of memory problems, the individual with LBD often begins to experience visual hallucinations and paranoid delusions (false beliefs that are firmly held). The psychosis is often accompanied by changes in motor function such as tremors, rigidity, slowing of movements, stooped posture, and falls. Not uncommonly, individuals with LBD have serious problems navigating directions, and their ability to manage daily affairs is quite impaired. A hallmark of LBD is that these individuals are extremely sensitive to medications often used to treat delusions and hallucinations (antipsychotics). In addition, persons with LBD do not uncommonly experience a sleep disorder in which they act out their dreams because the body paralysis that should be present during the dreaming phase of sleep is impaired. Memory and other cognitive problems emerge throughout the illness, but unlike AD, they are not typically the primary presenting problem.
Fronto-temporal dementia (FTD)
FTD is not a single condition; it’s a group of conditions with many different presentations. FTD typically has an onset earlier than AD and LBD, usually in the 60s. The most common form is characterized by significant changes in behavior and personality such as loss of social graces, lack of attention to hygiene, new dietary habits, acquiring new habits such as smoking that were not part of their lifelong behavior, and poor insight into their behavior. Other forms of FTD can present significant changes in the ability to understand language and concepts or express themselves. Prominent behavioral problems often emerge over the course of the condition, and their lifespan after diagnosis tends to be shorter than those with AD. Many known genetic mutations are associated with FTD.
Vascular Dementia (VD)
VD results either from major strokes or accumulation of damage from small strokes that did not result in any physical symptoms. Vascular brain damage is often found in AD, so a precise diagnosis can be challenging. Classically, VD displays a stepwise decline in which the person is doing well, then experiences a stroke, leading to further decline, and so on. Depression, apathy, and daily affairs problems can be quite prominent with VD. Not uncommonly, changes in motor function, such as tremors, or falls, may appear too. Treating vascular risk factors such as high blood pressure, diabetes, high cholesterol, smoking, sedentary lifestyle, etc. is very important to reduce the risk of VD and all dementias in general. A Mediterranean diet is often also recommended.
This is a very brief overview of the most common forms of dementia, but more detailed information can be found in the resources listed below.
Mace, Nancy L., and Peter V. Rabins. The 36-Hour Day: A Family Guide to Caring for People Who Have Alzheimer’s Disease, Other Dementias, and Memory Loss. Johns Hopkins UP, 2017.
Sifton, Carol Bowlby. Navigating the Alzheimer’s Journey. Health Professions, 2004.
Kertesz, A. The Banana Lady and Other Stories of Curious Behavior and Speech. Trafford, 2006.
U. S. Department of Health and Human Services. Lewy Body Dementia: Information for Patients, Families, and Professionals. CreateSpace Independent Publishing Platform, 2016.