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Cognitive Decline vs. Dementia: Common Misconceptions

January 21, 2023Neelem Sheikh

For healthcare providers, being able to explain the difference between terms like cognitive decline, dementia, Alzheimer’s disease, and cognitive impairment in a simple, easy-to-understand way is important to their ability to properly support their patients. Raising awareness and providing education are essential steps in the movement towards early intervention and better health outcomes.

For patients who may be experiencing age-related cognitive changes, this can help them better understand what’s normal and what may be a sign for concern. For patients diagnosed with Alzheimer’s, other dementias, or Mild Cognitive Impairment, this can help them gain a greater understanding of their diagnosis and what to expect in the coming years.

In this article, we will break down the difference between cognitive decline vs. dementia and provide simple explanations for other commonly used terms that are frequently used synonymously with one another.

Cognitive Decline vs. Dementia

Although cognitive decline and dementia both represent general terms that relate to a decline in memory and other thinking abilities, there are several differences. 

Cognitive decline is a general term that refers to a decline in one or more cognitive abilities (cognitive domains). When this decline is reported by patients, it is called subjective cognitive decline, or SCI. SCI is the self-reported experience of worsening or more frequent confusion or memory loss. Throughout the aging process, some degree of cognitive decline is expected. 

While cognitive decline can be a sign of dementia, this is not always the case. Dementia refers to a decline in cognitive abilities that is significant enough to interfere with an individual’s ability to complete basic day-to-day activities, or Activities of Daily Living (ADLs). While a small degree of cognitive decline can be a normal part of the aging process, dementia is not. Dementia is caused by damage to brain cells. Depending on which parts of the brain are affected, different cognitive abilities are affected. Depending on the degree of damage, dementia can be mild, moderate, severe, or anywhere in between. 

Dementia vs. Alzheimer’s Disease 

Dementia is a general term and is not a specific disease. However, dementia is caused by several diseases and conditions, including Alzheimer’s disease. Alzheimer’s disease is the leading cause of dementia, accounting for approximately 60-80% of all dementia cases. In other words, not everyone with dementia has Alzheimer’s disease, but everyone with Alzheimer’s disease has dementia.

Alzheimer’s disease is a degenerative neurological disease that causes dementia symptoms which gradually get worse over time. Because of the areas of the brain that are damaged throughout the course of the disease, many people with Alzheimer’s disease also experience problems with movement (usually later in the disease course).

Other causes of dementia include: 

  • Lewy Body dementia
  • Vascular dementia
  • Frontotemporal dementia
  • Mixed dementia
  • Huntington’s disease
  • Parkinson’s disease dementia
  • Creutzfeldt-Jakob disease
  • Posterior cortical atrophy

Dementia vs. Mild Cognitive Impairment

Similar to how dementia can be caused by several different conditions, Mild Cognitive Impairment, or MCI, can be caused by several conditions, including Alzheimer’s disease. Similar to dementia, Mild Cognitive Impairment is a general term used to describe issues with cognitive functioning but is less severe than full-blown dementia. 

Alzheimer’s disease continuum diagram.

Mild Cognitive Impairment refers to a decline in cognitive abilities that are not severe enough to interfere with an individual’s ability to complete everyday tasks. It is considered the stage between expected cognitive decline and dementia; however, not all cases of Mild Cognitive Impairment will progress to dementia. An estimated 10-15% of people with Mild Cognitive Impairment go on to develop dementia each year.

Cognitive Decline vs. Dementia vs. Alzheimer’s vs. Mild Cognitive Impairment

To summarize, here are the primary differences between cognitive decline, dementia, Alzheimer’s disease, and Mild Cognitive Impairment.

Cognitive Decline vs. Dementia vs. Alzheimer’s vs. Mild Cognitive Impairment

Terminology Indicates Severity Clinical Diagnosis Specific Disease Impacts Daily Activities
Cognitive Decline No No No Depends on severity
Dementia Yes Yes No Yes
Alzheimer’s Disease Yes (staging further indicates severity) Yes Yes Yes
Mild Cognitive Impairment Yes Yes No No

Being able to break down complex terminology to patients is important for healthcare providers. It is an important step that is often needed to get patients more involved with their brain health. Encouraging patients to better understand their brain health and monitor changes as they age is also a key effort in promoting early intervention and, consequently, better health outcomes.

Altoida’s mission is to accelerate and improve drug development, neurological disease research, and patient care. To learn more about our precision neurology platform and app-based medical device,

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