Dementia is a broad term referring to a decline in cognitive function (such as a loss of thinking, remembering, and reasoning skills)—to the extent that it interferes with a person’s daily life and activities. Not a disease itself, the term dementia is intended to describe the spectrum of severity, ranging from the mildest to the most severe stages—regardless of the cause.
The most common causes are Alzheimer’s disease and vascular dementia. However, there are many causes of dementia. Some forms are due to degeneration of neurons, while others are due to disturbances in other body systems that result in neuronal dysfunction.
Neurodegenerative means that neurons (which are brain cells) gradually degenerate (cease to function or function inappropriately, and, eventually die). This death of brain cells impairs the neuron-to-neuron connections, called synapses—which is where and how messages are passed along in your brain). This “disconnect” can results in a range of dysfunction.
While not an exhaustive list, here are some of the more common causes of dementia:
- Alzheimer’s disease
- Parkinson’s disease with dementia
- vascular dementia
- frontotemporal lobar degeneration, including: frontotemporal dementia; Pick’s disease; supranuclear palsy; corticobasal degeneration; medication side effects; depression; vitamin B12 deficiency; chronic alcoholism; certain tumors or infections of the brain; blood clots pressing on the brain; metabolic imbalances, including thyroid, kidney and liver disorders
Other Causes of Dementia
True dementia is irreversible. However, some problems have dementia-like symptoms, such as various metabolic disturbances, which can be reversible with appropriate and timely treatment—and without suffering permanent damage. This is one of the many reasons why seeing your doctor and getting a medical workup as soon as symptoms develop is so very important.
It’s absolutely normal to forget things once in a while. And, experiencing memory loss by itself does not mean an individual has dementia. However, there is a difference between occasional forgetfulness, and the kind of “forgetting” that may be cause for serious concern.
Forgetting who someone is; forgetting how to do common tasks (such as how to use the telephone or find your way home); or being unable to comprehend and/or retain information that has been clearly provided ––these are red flags that need to be evaluated by a medical professional. Getting lost in familiar settings (driving to the supermarket, for example), is often one of the first signs of dementia.
Up to 25 percent of people over the age of 75, and 40 percent of people older than 80 years of age have some form of dementia. Plus, with life expectancy improving—and the size of the population 65 years of age and older increasing from 37 million people (in 2006) to an estimated 71.5 million by the year 2030 (in the United States alone)—the number of people diagnosed with dementia, as well as the number of people living with dementia, is increasing.
Scientists all over the world are working hard to gain a better understanding of the many different aspects of dementia, so that we might develop preventative measures (such as a vaccine), improved early detection diagnostic tools, better and longer lasting treatments, and even cures.
For example, a vaccine known as a bapineuzumab jab is currently in its final phase of testing. While not a cure, this vaccine has been shown to prevent, and in some cases reverse, the buildup of amyloid plaques in the brain. Amyloid plaques—which are the hallmarks of Alzheimer’s disease—are dense, mostly insoluble (not dissolvable) clumps of protein fragments that deposit a highly damaging gunky substance outside and around the brain’s nerve cells.
There is also increasing evidence that lifestyle factors, such as getting regular exercise and maintaining social connections may be effective ways to decrease the risk of developing dementia.
Scientists are also investigating avenues including: genetic factors, various neurotransmitters, the role of inflammation, factors that influence programmed cell death in the brain, the roles of tau, as well as the possible roles of oxidative stress (i.e., chemical reactions that can damage proteins, DNA, and lipids/fats inside cells).
Written by: Wendy Leonard, MPH
Published on May 11, 2011
Updated on Mar 05, 2013
Medically reviewed by Jennifer Monti, MPH, MD