What is the difference between dementia and Alzheimer’s disease?

Navigating through the various types and stages of cognitive disorders can be confusing, especially because terms like dementia and Alzheimer’s are often used interchangeably. The question “what is the difference between dementia and Alzheimer’s?” comes up a lot, especially when people are first diagnosed. Dementia and Alzheimer’s disease are actually distinct concepts. Dementia is an overall term for any one of the over 100 conditions (such as Alzheimer’s disease) that impact memory, thinking, or social abilities severely enough to interfere with day-to-day functioning.

You can think of dementia as an umbrella term: it’s the overall term for any condition that can impact cognitive functioning–for example, memory, problem solving, decision making, or social abilities–severely enough to interfere with daily functioning. We aren’t talking about occasionally forgetting a phone number or where you left your keys. We are talking about changes in cognition like consistently forgetting to turn the stove off when you cook, getting lost in familiar places and finding yourself unable to travel from point A to point B, and other issues that impact your ability to live safely independently.

If your loved one has an Alzheimer’s diagnosis or is showing any symptoms that fall within the greater umbrella of dementia, it is important to have a personalized Alzheimer’s and dementia care in place. There are also practical steps for dementia caregivers to help them prepare to support their loved one. Starting with the basic understanding of dementia, and more specifically, Alzheimer’s disease and other causes of dementia, is a great first step.

Alzheimer’s disease is one of the many conditions that can cause dementia. Alzheimer’s disease is the most common type of dementia, accounting for 60-80% of dementia cases. However, there are many other types of dementia as well. In this way, “dementia” functions like the overall term “cancer” while “Alzheimer’s” functions like any of the types of cancer, like breast cancer or prostate cancer. Dementia is not a specific disease but rather a set of symptoms (e.g., memory decline, communication difficulties) caused by different conditions, including Alzheimer’s disease, vascular dementia, Lewy body dementia, and frontotemporal dementia. Although these four types of dementia account for about 90% of all dementias, there are many other more rare causes of dementia as well. These include Creutzfeldt-Jakob disease, Huntington’s disease, and normal pressure hydrocephalus.

The different types of dementia all have different causes and commonly present with different symptoms. While the exact cause of Alzheimer’s disease is not fully understood, it is believed to be due to a combination of genetic, environmental, and lifestyle factors.

Brain Changes

1. Amyloid Plaques: There are clumps of a protein called beta-amyloid that accumulate between nerve cells, believed to disrupt cell function and trigger inflammation.
2. Neurofibrillary Tangles: There are also twisted fibers of a protein called tau that build up inside cells, disrupting communication between neurons.
3. Loss of Neuronal Connections and Cell Death: Alzheimer’s disease affects the synapses (connections between neurons) and leads to cell death and associated brain shrinkage. For example, the hippocampus (essential for forming memories) shrinks.
   

Genetic Factors

1. Risk Genes: These are genes that increase the risk that someone will develop Alzheimer’s disease. For example, people with APOE-e4 have a higher risk of developing Alzheimer’s disease compared to those who don’t.
2. Deterministic Genes: These are genes that directly cause Alzheimer’s. It is important to note that these genes are rare, accounting for less than 1% of all Alzheimer’s cases. They are typically associated with hereditary forms of Alzheimer’s disease that tend to have a younger onset and be more aggressive.

Environmental and Lifestyle Factors:

Certain environmental exposures and lifestyle factors do increase the risk of developing Alzheimer’s disease. These include the following:

• Lack of exercise
• Poor diet
• Lack of social engagement
• Hearing impairment
• Hypertension
• Diabetes
  

A Deeper Look into Alzheimer’s Disease Symptoms

Many people associate dementia with memory loss, but for many people living with different types of dementia, memory loss isn’t even a symptom. Memory loss is however a symptom often seen in the most common type of dementia, Alzheimer’s disease. Some of the other symptoms include the following:

• Challenges in Planning or Solving Problems: Difficulties in developing and following plans.
  
  • Example: Difficulty following a familiar recipe
• Difficulty with Familiar Tasks: Struggling to complete routine tasks that were previously not a challenge
  
  • Example: Unable to manage a household budget that was previously an easy-to-maintain monthly task
• Confusion with Time and Place: Losing track of dates, seasons, or the passage of time
  
  • Example: Thinking New Year’s is coming up when it’s actually summer
• Trouble with Visual and Spatial Relationships: Visual problems, such as difficulty reading, judging distance, or being unable to determine color or contrast
  
  • Example: Difficulty driving because of an inability to correctly judge the distance between your car and other vehicles and objects
• New Problems with Communication: Challenges in receptive (understanding what others are saying or writing) or expressive (being able to express thoughts verbally or in writing) speech
  
  • Example: Word finding difficulties and consistently being unable to recall the name of common objects
• Decreased Judgment: Showing poor or risky decision making
  
  • Example: Giving away large amounts of money to scams
• Withdrawal from Social Activities: Withdrawing from social connections, hobbies, or other previously enjoyed activities
  
  • Example: Avoiding seeing friends
• Changes in Personality and Mood: Being fearful, depressed, anxious, or suspicious
  
  • Example: Big mood swings in a previously more even keeled individual

And of course, memory loss is also a major symptom of Alzheimer’s disease. People often have difficulty remembering recent conversations, names, or events and find themselves unable to learn new information. The different types of memory can be impacted differently, especially in the earlier stages. For example, short-term memory, The ability to hold small amounts of information in mind for a short amount of time and learn new information, is often impacted early on. A person may forget the name of someone they just met or not be able to recall what they had for breakfast. Episodic memory, or memory of specific events or episodes,is also commonly impacted, especially for recent events, so a person may forget that they just went to a gathering with friends a few days prior. However, long-term memory is often preserved in the earlier stages of Alzheimer’s, so a person may be able to remember a childhood address or the name of their grade three teacher. Procedural memory, or knowing how to perform different actions and skills, is also often preserved in earlier stages, for example knowing how to tie shoes or how to play a favourite song on the piano. To learn more, read about the seven primary stages of Alzheimer’s. These can also help you distinguish between Alzheimer’s, dementia as the umbrella term, and normal aging.

In Conclusion

In sum, the question “what is the difference between Alzheimer’s and dementia?” is a very common one. Alzheimer’s is a type of dementia, which is an umbrella term describing a set of cognitive symptoms, such as memory loss and communication difficulties that lead to functional impairment. So, while all individuals with Alzheimer’s have dementia, not everyone with dementia has Alzheimer’s disease because there are many other causes of dementia, such as vascular dementia and Lewy-body dementia. Proper diagnosis is important because it ensures that people receive the right treatments, resources, and support to manage their condition.