7.12 Dementia and Alzheimer’s: Differences & Impact on Aging

Jan 14, 2020 | Cognitive Psychology, Courses, ch7 Memory Models & Disorders

In this lesson, you will learn what dementia is and is not through definitions and examples. You will also examine Alzheimer’s disease, the leading cause of dementia and memory loss in the elderly.

Dementia and Alzheimer’s

You are volunteering at a nursing home, and you find a little girl crying in the lobby. You stop, and you ask her, ‘What’s wrong?’

She says she’s visiting her grandpa, and she got upset because he didn’t remember her name or who she was. As you try to comfort her, you are wondering, ‘Why did her grandpa forget her?’

Dementia Defined

Memory loss is the most common symptom of a cognitive disorder called dementia. Dementia is the gradual loss of mental functions, such as reasoning and memory, that’s severe enough to interfere with a person’s daily life. Unpredictable changes in personality can also occur. Dementia is considered a late-life disorder because it develops most frequently in the elderly.

Dementia is not actually a disease itself; it is a group of symptoms that are caused by other conditions. Dementia can be caused by substance abuse, hypothyroidism, vitamin deficiencies, head injury, Parkinson’s disease, and many other disorders. Some causes, such as vitamin deficiencies, can be treated and cured. However, only about 20% of dementia is treatable, and in most cases dementia cannot be cured.


How do you know if a decline in mental functioning is due to the normal aging process or dementia? This is usually determined by two factors. The first factor is the discovery of an underlying medical condition that could cause dementia. The second factor is how great of an impact the symptoms have on a person’s daily life.

Let’s look at the following examples and discuss how likely they are to be a result of dementia.

Your 84-year-old grandfather frequently forgets where he put his glasses. This level of forgetfulness is most likely due to the normal aging process. If he eventually finds his glasses and it doesn’t interfere with his daily activities to a large degree, then there is no real cause for concern.

However, let’s say your grandfather often forgets that he wears glasses, and he panics when he can’t see the newspaper print. It takes a while for his disorientation to go away when this happens. In this scenario, your grandfather would be experiencing the effects of dementia.

Your neighbor is 68 years old. She lives alone, but is often visited by her children and grandchildren who live nearby. Yesterday, her 10-year-old granddaughter came to your house and asked to use the phone. She told you that her grandmother had been forgetting things a lot and that she wouldn’t open the door for her because she didn’t recognize her. The girl’s mother had asked her to call from your house if something like this happened. Your neighbor is suffering from dementia. Her forgetfulness has her family concerned, and it’s interfering with her normal activities.

However, let’s say your neighbor does not see her grandchildren very often and doesn’t expect them to visit. She looks through the peephole in the door and doesn’t recognize the girl who is knocking, so she doesn’t answer the door. The girl comes to your house and asks to call her mother. She complains that her grandmother would not open the door for her, but she seems more angry than concerned. It is unlikely that this is a result of your neighbor suffering from dementia.

Alzheimer’s Disease

The most common cause of dementia is Alzheimer’s disease. Alzheimer’s disease is a progressive neurological disease evidenced by a gradual decline in cognitive functioning, memory loss, and a loss of ability to perform tasks.

Alzheimer’s disease develops after the age of 65 in most cases. However, this isn’t always the case. Early-onset Alzheimer’s occurs when Alzheimer’s disease affects people at an age younger than 65.

In Alzheimer’s disease, nerve cells in the brain die gradually. The process occurs over a period of several years and is different from one individual to the next. At first, symptoms may be occasional forgetfulness or other normal signs of aging. However, as the disease progresses, the symptoms become more serious. A person may become very confused, and their personality can even change. When symptoms become more severe, Alzheimer’s disease can be frightening for the person suffering from it as well as for their loved ones.

Lesson Summary

Remember the little girl you met at the nursing home in the beginning of this lesson? You now know that the most likely reason her grandpa cannot remember her is because he’s suffering from dementia.

Dementia is the gradual loss of cognitive functions such as memory and reasoning. This loss of cognitive function interferes with daily activities. It usually develops in late-life and cannot be cured in most cases.

Alzheimer’s disease is the most common cause of dementia, but there are many potential causes. Alzheimer’s disease is a progressive neurological disease that causes a mental decline to occur over a period of years. Alzheimer’s disease typically occurs in people over the age of 65. If someone is diagnosed with Alzheimer’s before the age of 65, it is called early-onset Alzheimer’s. Conditions such as Alzheimer’s disease that cause dementia can be difficult for both the individual and for their family members.

Learning Outcomes

Following this video lesson, you’ll be able to:

  • Distinguish between dementia and normal aging
  • Define dementia, Alzheimer’s disease, and early-onset Alzheimer’s, and understand the difference between dementia and Alzheimer’s
8.1 What is Metacognition in Psychology? - Definition & Examples
7.11 Amnestic Disorder: Definition, Causes and Treatment for Amnesia