Types of dementia explained

In Alzheimer’s, abnormal proteins called amyloid and tau build up in the brain. Over time, brain cells lose their connections and die.

Changes usually come on gradually. Early on, a person may repeat questions or lose track of dates. Later, language, planning, finding the way and daily care can be affected.

Alzheimer’s that affects someone under 65 is called younger-onset. It can come while a person is still working and raising a family.

Thinking can change suddenly after a stroke that blocks a large blood vessel in the brain.

Mild changes can slowly get worse over time from many minor strokes or disease in the brain’s small blood vessels.

Trouble with planning and judgment can be an early sign. Memory loss may or may not be a big symptom, depending on which brain areas are affected.

Risk factors overlap with heart disease and stroke. Not smoking, staying active, and managing blood pressure, cholesterol and blood sugar with your care team are recommended.

In dementia with Lewy bodies, thinking changes come first, and movement changes may come later or not at all. In Parkinson’s disease dementia, a person has Parkinson’s movement symptoms first, and thinking changes appear more than a year later.

Over time, people with either form develop similar symptoms, because the same brain changes cause both.

Attention and alertness can shift from day to day or even hour to hour. A person may stare into space, seem very drowsy, or seem much better one day and worse the next.

Most people with LBD see things that aren’t there, often early on. They are usually detailed and realistic, like children or animals.

What can help

• Stay calm and reassure, rather than arguing
• Check lighting and shadows that could be misread
• Tell the care team, especially if the person is frightened

In REM sleep behavior disorder, people seem to act out their dreams by talking, shouting or moving. It can appear years before other LBD symptoms. Daytime sleepiness is also common.

Changes can include

• Balance problems and falls
• Dizziness on standing
• Smaller handwriting
• Softer voice
• Slowness or stiffness
• Trouble swallowing

People may act out of character, seem to lack empathy, or have trouble reading social signals. Often they don’t realize their behavior has changed. Memory may stay fairly good at first.

PPA affects the ability to speak, read, write and understand words. In one type, people lose the meaning of words and may stop recognizing familiar faces or objects. In another, speaking gets harder and small linking words like “to” or “the” may drop out. There are three types in all.

What can help

• Speech-language therapy
• Picture boards, gestures and writing
• Giving extra time to answer

Some frontotemporal disorders mainly affect movement. Corticobasal syndrome makes it hard to use the hands for tasks like buttons. Progressive supranuclear palsy causes balance problems, falls and trouble moving the eyes, especially looking down. Some people have FTD together with ALS.

LATE (limbic-predominant age-related TDP-43 encephalopathy) causes Alzheimer’s-like problems with memory and thinking, but a different protein is involved. It tends to affect people over 80.

Right now LATE cannot be diagnosed in living people. Researchers are working on ways to do this.

If symptoms don’t match a single type, that doesn’t mean doctors got it wrong. More than one process may be involved. Good care focuses on the person’s needs, whatever the label.

NPH is a slow buildup of fluid in the brain. It causes problems with walking (feet can feel “stuck”), bladder control and thinking. It is most common in older adults.

NPH often improves with treatment, and early diagnosis improves the chance of a good recovery.

If mood or behavior has changed, a mental health evaluation may be suggested, to see whether depression or another condition is causing or adding to the symptoms.

Examples

• Chronic traumatic encephalopathy (CTE), from repeated head injuries
• Creutzfeldt-Jakob disease, a rare brain disorder
• HIV-associated dementia, when the virus affects the brain
• Huntington’s disease, an inherited brain disease

For head injuries, see the Concussion guide.

Doctors ask how and when symptoms began, about changes in behavior and personality, and about family history.

A physical exam and blood or other lab tests check hormones, vitamins and other levels that could explain symptoms. Tests of memory, problem solving, language and math look at thinking skills.

Scans can show strokes, tumors and other problems, and changes in the brain’s structure or activity. Patterns can point toward one type or another.

Measuring proteins in spinal fluid can help diagnose Alzheimer’s or other types. Some doctors can order a blood test for amyloid, but blood test results alone should not be used to diagnose dementia, and availability is still limited.

A primary care provider is often the first step. Neurologists, geriatric psychiatrists, neuropsychologists and geriatricians may help diagnose dementia. If there is no specialist nearby, a medical school neurology department can give a referral.

Free, confidential support for people living with dementia, caregivers and families, at 1-800-272-3900.

The Lewy Body Dementia Association’s Lewy Line (800-539-9767) offers information and support for people with LBD and their families.

The Association for Frontotemporal Degeneration (AFTD) HelpLine (866-507-7222) helps people with FTD, families and professionals with information, support and local resources.

Call or text 988 to reach the 988 Suicide & Crisis Lifeline.

Text HOME to 741741 to reach a trained Crisis Text Line counselor.

findahelpline.com lists free, confidential helplines by country. Many countries also have their own Alzheimer’s or dementia association. If you are in danger, call your local emergency number.