What Is the Difference Between Dementia and Alzheimer’s Disease?

Most conditions that cause dementia have no cure. Alzheimer's dementia is the third leading cause of death in California and sixth leading cause of death in the U.S.

Some treatments can slow the progression of the disease and others can help reduce the symptoms. Research continues for a cure and better treatments.

“As the aging population increases and the disease becomes more common, we are learning more and more about diagnosis, symptoms and treatment,” says Gregory Sahagian, MD, a neurologist and medical director of Scripps neuroscience services. “We have greater understanding of how Alzheimer’s disease affects the brain, and this has resulted in promising new research.”

Dementia is not a normal part of aging. It is normal to occasionally forget something that occurred just earlier especially as we age. The symptoms of dementia are more pronounced. Repeated difficulty with memory is the most well-known first sign of dementia.

Some people may have dementia-like symptoms but not the actual disease. Symptoms may be caused by other factors, such as depression, untreated sleep apnea, delirium and side effects of medications. Other possible causes are thyroid problems, certain vitamin deficiencies and alcohol abuse. These conditions are often reversible with treatment.

The exact cause of Alzheimer’s disease is not clearly understood. Those who develop the disease may be affected by a variety of factors.

A key feature of the disease is the presence of amyloid plaques and tau tangles in the brain. They are believed to block communication among nerve cells. Most people develop some plaques and tangles as they age but those with Alzheimer’s tend to develop far more.

Alzheimer’s disease develops in stages and move from mild to moderate to severe. The initial cells to suffer damage are those in the areas of the brain that control memory, language, and cognition.

At first, someone may have trouble recalling recent occurrences or conversations. They may ask the same question over and over. As the disease advances, more serious symptoms follow.

The patient may become increasingly disoriented and confused, developing mistrust of people close to them and those providing care. There may be more serious memory loss, as well as issues with communication, mobility and swallowing.

Caregiving becomes more significant as the disease progresses. More than 16 million adult family caregivers provide care for someone with Alzheimer’s or another form of dementia.

Alzheimer’s disease most often happens in people 65 and older.

• By age 65, one in 10 people have it.
• By age 85, nearly half the people in this age group have it.

Early onset is seen in less than 10 percent of cases.

Genetic and environmental factors and traumatic brain injuries are other risk factors.

Nearly two-thirds of Americans with Alzheimer’s dementia are women. This may have more to do with women living longer than men and the age risk factor.

African-American and Hispanic older adults are more likely than White older adults to have Alzheimer’s and other dementias. This may be largely due to health and socioeconomic disparities.

Neurologists and other specialists diagnose and manage patients with Alzheimer’s or other types of dementias. It takes a series of tests to make a diagnosis.

“We can diagnose Alzheimer’s disease through clinical examination,” Dr. Sahagian says. “Careful evaluation of the patient’s mental state and a medical history will result in a highly accurate diagnosis.”

Physicians conduct a range of examinations and tests to help diagnose dementia. These may include memory and cognitive evaluations, physical and neurological tests, lab work, brain scans and genetic testing.

Types of brain scans include computerized tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET).

PET imaging and biomarker tests are becoming more common as the technology involved improves. PET can be used to measure the amount of amyloid plaques and tau tangles in the brain, which are hallmark features of Alzheimer’s disease. Biomarker tests measure the levels of certain proteins in the blood or cerebrospinal fluid and can be used to detect early signs of Alzheimer’s disease, even before symptoms appear.

There are two classes of common oral medicines to treat symptoms of Alzheimer’s. They help improve memory loss, confusion, and problems with thinking and reasoning related to the disease. 

Cholinesterase inhibitors are used for mild and moderate symptoms. Memantine is used for moderate to severe symptoms. Doctors sometimes prescribe both together.

Treatments can help patients stay in their own homes longer and delay the need for long-term care.

Cholinesterase inhibitors prevent the breakdown of acetylcholine, a neurotransmitter or chemical messenger that plays a key role in learning and memory.

Three types are commonly prescribed:

• Donepezil
• Rivastigmine
• Galantamine

Side effects may include nausea and upset stomach.

Memantime works by reducing the amount of the chemical glutamate in the brain. People with Alzheimer's may have too much of this chemical in their brain, which causes damage.

Side effects may include headaches, constipation, confusion and dizziness.

Other new drugs are on the horizon of being approved by the Food and Drug Administration.

It is important to identify people who are at high risk for Alzheimer’s as early as possible.

“The sooner we can diagnose and treat someone with Alzheimer’s disease, the better that person’s quality of life,” Dr. Sahagian says. “If you or a loved one is approaching the age where your risk for Alzheimer’s disease begins to increase, talk to your physician about screening.”

Scripps provides specialized care and support for people with Alzheimer's. This includes cognitive screens, memory testing, standard imaging tests, and advanced radiology studies. In addition, Scripps partners with other local agencies to offer guidance and support to patients and their families.