What Is Cognitive Decline and How to Prevent It

Cognitive DeclineEach of us has been in a situation where we notice cognitive change in ourselves or someone we know.

Maybe it’s a parent who has difficulty using their smartphone, a friend who frequently asks, “Did I tell you this already?” or a spouse who takes longer than usual to read their GPS on a road trip.

These types of things happen all the time. But how do we know if the behaviors are normal? Are they due to stress and fatigue, normal cognitive aging, or could they be signs of something outside the norm?

Educating ourselves on the risks of cognitive decline and the preventive steps we can take right now, regardless of age, to protect our brain is a powerful step.

To help arm you with this powerful knowledge, we will briefly discuss symptoms, signs, and risk factors of cognitive decline, and look into what can be done to prevent it.

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What Is Cognitive Decline? 7 Symptoms and Signs

Cognitive decline is part of the normal aging process. Accelerated cognitive decline, however, is pathological. The boundary between normal and accelerated cognitive decline can be difficult to determine because the strengths and weaknesses of our cognition are highly personal. Dementia is not part of the normal aging process (National Institute on Aging, 2020).

Pathological age-related cognitive decline

Neurodegenerative disorders at any age that involve cognitive decline and dementia are pathological and classified as mild neurocognitive disorder and major neurocognitive disorder in the Diagnostic and Statistical Manual (fifth edition, text revision).

Mild neurocognitive disorder is not dementia. Major neurocognitive disorder is dementia. The term “dementia” has been replaced with major neurocognitive disorder as a diagnosis. The term mild cognitive impairment (MCI) is used clinically and in research to describe mild neurocognitive disorder.

Mild cognitive impairment

Mild cognitive impairment is a state between normal cognitive functioning and dementia, but dementia is not present. Cognitive symptoms of MCI are noticeable by the individual or family members and can be objectively measured as impairment in one or more areas of cognition. Symptoms are minimal and do not necessarily affect basic daily functioning (Petersen et al., 2018).

A diagnosis of MCI does not always lead to dementia. In some cases, symptoms may never progress and may even improve (Li et al., 2014). A diagnosis of MCI increases the risk of dementia at a rate of approximately 10% to 15% of cases per year compared to about 1% to 2% per year in individuals without MCI (Li et. al., 2004).

Signs of MCI can include:

  1. Increase in forgetfulness (Mayo Clinic, 2023); for example, forgetting a regular lunch date with a neighbor.
  2. Increased difficulties managing medication (Weir, 2019); for example, with diabetes management, remembering to test blood sugar before eating and calculating insulin dosage using a sliding scale
  3. Increased difficulties managing money (Bangen et al., 2010); for example, difficulty counting money, performing calculations with money, and taking precautions with financial decisions
  4. Daily activities taking longer or requiring considerably more effort or accommodations to complete (Hugo & Ganguli, 2014); for example, planning out meals to prepare for the week and making a grocery list taking more time and effort than usual
  5. Increased difficulties navigating familiar places (Mayo Clinic, 2023); for example, navigating inside the grocery store or way-finding in the city
  6. Increased difficulties with goal-directed behavior (Hugo & Ganguli, 2014); for example, difficulties finishing the laundry when distracted and keeping up with conversations at the dinner table
  7. Noticeable changes in mood (Mayo Clinic, 2023); for example, increased feelings of sadness or loss of interest in activities typically enjoyed, increased anxiety, or difficulty controlling temper

A good way to evaluate whether a change in cognition is significant is to ask:

  • Does the change go beyond what is expected compared to typical day-to-day functioning?
  • Is the change more compared to people of the same age?

Major neurocognitive disorder

Major neurocognitive disorder is diagnosed when cognitive decline is severe enough to interfere with a person’s ability to function in their social or work life. The decline is persistent and progressive over time. This is a diagnosis of dementia.

There are four causes of dementia that account for the majority of cases, and each reflects specific changes in the brain (National Institute on Aging, 2022).

  1. Alzheimer’s dementia
    The most common form of dementia caused by a buildup of amyloid protein outside the neuron and accumulation of the tau protein (tangles) inside the neuron that interfere with neural communication
  2. Vascular dementia
    Caused by damage to blood vessels due to a lack of blood supply, oxygen, or nutrients to the brain
  3. Frontal-temporal dementia
    Caused by death of nerve cells in the frontal and temporal lobes that cause the lobes to shrink (about 60% of cases are between 45 and 60 years of age)
  4. Lewy body dementia
    Caused by Lewy bodies, a buildup of clumps of the protein alpha-synuclein in the cortex

If you are uncertain about the symptoms observed, complete this helpful worksheet from the Alzheimer’s Association that teases apart 10 early signs of dementia from normal cognitive aging.

12 Risk Factors of Cognitive Decline

Cognitive decline risk factorsIdentification of risk factors has significant implications for treating existing cognitive decline and also for postponing, reducing, and preventing cognitive decline and dementia.

Risk factors do not cause cognitive decline and dementia but are associated with increases in the incidence, onset, or odds of developing the disease.

A meta-analysis and systematic review by the Lancet Commission (Livingston et al., 2020) identified 12 modifiable risk factors for dementia likely to have the greatest impact on dementia prevention:

  1. Less education
  2. High blood pressure
  3. Hearing impairment
  4. Smoking
  5. Obesity
  6. Depression
  7. Physical inactivity
  8. Diabetes
  9. Low social contact
  10. Excessive alcohol consumption
  11. Traumatic brain injury
  12. Air pollution

Managing risk factors of dementia is a lifelong process that begins in childhood. For example, higher childhood education and lifelong education reduces risk (Livingston et al., 2020). Hypertension, diabetes, high cholesterol, and high body mass index in midlife are related to increased risk of dementia later in life (Hugo & Ganguli, 2018).

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Cognitive Decline With Age: 5 Examples

Performance in attention, memory, executive function, language, and visuospatial skills declines with age as part of the normal aging process (Murman, 2015). This process is known as cognitive aging or age-related cognitive decline.

Contrary to what you may think, there is little evidence that normal cognitive aging has consequences for one’s overall level of functioning. Disturbances in day-to-day functioning are not typically found until the level of cognitive decline reaches a pathological stage (Salthouse, 2012).

The typical profile of normal cognitive aging is an increase in crystallized abilities until about 60 years of age and a simultaneous decrease in fluid abilities beginning in early adulthood and continuing throughout the lifespan (Salthouse, 2019).

Crystallized abilities reflect accumulated knowledge that increases in size and complexity across our lifespan. The facts you know about cooking, your knowledge of honeybees, and your own personal life experiences are examples of crystalized ability (Salthouse, 2012).

Fluid abilities reflect novel problem-solving. They rely on our capacity to quickly process new information and problem-solve in real time using reason and logic. Examples can be something as simple as remembering your neighbor’s name at the grocery to learning how to tango.

Decreases in processing speed and sensory perception are also evident in normal cognitive aging.

It is helpful to keep this profile in mind as we tease apart the signs and symptoms of normal versus pathological cognitive decline.

Examples of normal age-related cognitive decline can include:

  1. Spontaneous memory retrieval
    Changes in the retrieval of information from memory without a visual cue; for example, difficulty recalling what to buy at the grocery store without a list (Harada et al., 2013)
  2. Source memory
    Changes in remembering where you learned something; for example, difficulty remembering if you heard about an upcoming concert from a friend, social media, or the local paper (Harada et al., 2013)
  3. Prospective memory performance
    Changes in remembering to perform future activities; for example, difficulty remembering to take fish oil tablets with each meal (Harada et al., 2013)
  4. Visual processing speed
    Changes in ability to process visual information quickly; for example, taking longer to find the aspirin in your medicine cabinet and reading road signs while driving (Owsley, 2011)
  5. Working memory
    Difficulty in tasks that require manipulation, reorganization, or integration of the contents of working memory; for example, planning and cooking a meal to be served at a specific time (Glisky, 2007)

These changes do not occur in a silo. They interact with one another to affect day-to-day functioning differently as we age and may involve the same underlying cognitive processes.

For example, slower processing speed makes it more difficult to keep in mind the steps of a recipe (working memory), particularly when attention is divided (talking to partner), which may delay the goal of getting dinner on the table at 6 p.m. (executive function).

It is important to keep in mind that not all individuals will experience these changes in their lifetime. There is a great deal of individual variability in the onset and severity of symptoms, as well as implications of specific changes on everyday functioning (Glisky, 2007).

Assessment Tools: 5 Tests, Questionnaires & Scales

Cognitive decline assessmeA diagnosis of MCI requires more than a subjective report of cognitive changes.

A thorough medical history, input from family members, a physical examination, evaluation of mood, cognitive testing, and blood and imaging tests may all be used to get a clear clinical picture of symptoms and differentiate symptoms from normal cognitive decline or dementia (Alzheimer’s Association, 2022).

Common tests of cognition, informant report, and daily functioning include:

  1. Mini-Mental State Examination (MMSE)
    The MMSE is a widely used clinical test to diagnose MCI that measures five areas of cognition: orientation, registration, attention and calculation, word recall, and language. It shows low validity and diagnostic accuracy in less-educated populations (Custodio et al., 2017).
  2. Memory Alteration Test
    This short cognitive screening tool is designed to discriminate between healthy older adults, people with MCI, and those with Alzheimer’s using five domains of memory: temporal orientation, short-term memory, semantic memory, free recall, and facilitated recall (Rami et al., 2010). This test is highly sensitive in diagnosing MCI in diverse populations (Breton et al., 2018). Access a preview of the study here.
  3. Clock Drawing Test
    The Clock Drawing Test is a nonverbal screening tool for dementia. Patients draw a clock and are asked to draw the hands at “10 minutes past 11 o’clock”. The test measures planning, abstract thinking, visual-spatial skills, short-term memory, understanding verbal instructions, and more. It is highly accurate in discriminating normal cognition from early cognitive decline (Aprahamian et al., 2009).
  4. Bristol Activities of Daily Living Scale
    The Bristol Activities of Daily Living Scale is a commonly used caregiver-report scale of functioning across 20 daily living activities (Bucks et al., 1996).
  5. Cornell Scale for Depression in Dementia
    The Cornell Scale is used to quantify depressive symptoms reported by patient and/or caregiver (Alexopoulos et. al., 1988). It is the gold standard in patients with dementia.

Recommended reading: Mental Status Exams: 10 Best Templates, Questions & Examples.

How to Prevent Cognitive Decline: 10 Tips

“It is never too early or never too late in the life course for dementia prevention.”

Livingston et al., 2020, p. 413

The benefit of increasing awareness of the risks of cognitive decline and dementia is the impact we can make on prevention. The Lancet Commission (Livingston et al., 2020) reports that the 12 risk factors they identified can account for 40% of dementia cases worldwide.

Theoretically, because these risk factors are potentially modifiable, 40% of cases could be prevented or delayed.

The following tips are based on the findings of a wide-range of high-quality studies reported by the Lancet Commission (Livingston et al., 2020) and are proposed to make the greatest impact on prevention of cognitive decline and dementia.

  1. Social contact
    More frequent social contact in our 50s is related to better cognitive functioning later in life. Social contact in our 60s lowers the risk of dementia later in life.
  2. Use hearing aids
    Check hearing regularly. When hearing loss worsens and is unaided, the risk of dementia increases.
  3. Protect your head
    Traumatic brain injury is associated with an increased risk of dementia and Alzheimer’s disease. Risk increases with the number of injuries.
  4. Control blood pressure
    Check blood pressure regularly and treat high blood pressure. Aim for a systolic blood pressure of less than 120 mm Hg.
  5. Remain physically active
    Weekly exercise (breaking a sweat) in midlife decreases the risk of dementia. Aim for 150 minutes of moderate to vigorous aerobic activity per week.
  6. Keep body mass index less than 30
    Weight loss in midlife is associated with improvement in attention and memory.
  7. Improve cardiovascular health
    Consider cardiovascular health as a cluster of factors in midlife that taken together can protect against dementia. Maintain healthy glucose levels, cholesterol levels, blood pressure, and body mass index. Eat a healthy diet and exercise regularly.
  8. Control alcohol use
    Keep alcohol use to less than 21 units per week. Units of alcohol in common drinks can be found here along with the formula for calculating units.
  9. Don’t smoke
    Stopping smoking, even at an older age, can reduce the risk of dementia.
  10. Protect sleep
    Track the quality and quantity of sleep and treat sleep disorders such as obstructive sleep apnea. Find useful advice in our Sleep Hygiene Tips article.

The proposed mechanisms behind these protective factors are reduced neuropathological damage across time and increased and maintained cognitive reserve (Livingston et al., 2020).

Think of cognitive reserve as an extra layer of protection against cognitive decline due to good physical health, higher education, or a complex occupation, even in the face of symptoms.

Review the World Health Organization’s recommendations for reducing the risk of cognitive decline and dementia along with the strength of the evidence to date.

Can Cognitive Decline Be Stopped or Reversed?

Preventing cognitive declineMild cognitive impairment is a stage of cognitive fluctuation between normal cognition and dementia.

Some people go on to have dementia, others maintain MCI, and some revert to normal cognition.

Two separate meta-analyses report an overall reversion rate to normal cognition after MCI diagnosis of approximately 18% to 24% of cases (Malek-Ahmadi, 2016; Canevelli et al., 2016).

A longitudinal study in Sweden followed over 1,000 individuals from diagnosis of MCI to either reversion, continued MCI, or dementia (Overton et al., 2023). At a follow-up, which averaged about seven years, reversion rates of 43% and 48%, depending on the criteria used to diagnose MCI.

Factors predicting a reversion from MCI to normal cognition include the following (Overton et al., 2023):

  • Impairment in a single domain of cognition rather than multiple domains
  • Cohabitation at the time of MCI diagnosis rather than living alone
  • Alcohol consumption rather than no alcohol use
  • Lower BMI at time of MCI diagnosis
  • Older age at MCI diagnosis

A separate study found that not having arthritis, openness to new experiences, higher complex mental activity, better smelling ability, and better visual acuity predicted greater likelihood of reversion to normal cognition from MCI (Sachdev et al., 2013).

The bestselling book by Dale Bredesen (2017) titled The End of Alzheimer’s details a program he designed to prevent and reverse cognitive decline based on his research on factors that lead to Alzheimer’s.

He recommends monitoring and assessing brain health beginning at age 45 with a cognoscopy, a bundle of cognitive tests, blood work, medical history, and imaging.

What is a cognoscopy?! - Mark Hyman, MD

Watch this video of Bredesen as he describes why we should monitor brain health and the tests that comprise a cognoscopy.

As a caveat, the efficacy of Bredesen’s program and the research he cites to support the program are reviewed in the Lancet by Joanna Hellmuth (2020). She reviews the limitations of the research and implications for the program. She concludes the evidence is not worth the claim that the program reverses or prevents cognitive decline.

Resources From PositivePsychology.com

Improving the quality of your sleep is one lifestyle intervention for protecting yourself from cognitive decline. Track your sleep with our helpful Two-Week Sleep Diary.

For an overview of the benefits of maintaining cognitive health, check out our article What Is Cognitive Health & Why Is It Crucial for Wellbeing?

In addition, for testing purposes, take a peek at 12 Most Reliable Mental Health Assessment Tools.

Increase your awareness of self-care techniques that can improve brain health with our Self-Care Checkup.

For more exercises and games to enhance cognitive health, read our article How to Improve Cognitive Function: 6 Exercises and Tests.

One of the best ways to protect cognitive health is to maintain cardiovascular health with a goal of 150 minutes per week of aerobic exercise. Our post 10 Neurological Benefits of Exercise explains how exercise affects the brain.

If you’re looking for more science-based ways to help others enhance their wellbeing, check out this signature collection of 17 validated positive psychology tools for practitioners. Use them to help others flourish and thrive.

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Expand your arsenal and impact with these 17 Positive Psychology Exercises [PDF], scientifically designed to promote human flourishing, meaning, and wellbeing.

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A Take-Home Message

We are all familiar with how to improve our cardiovascular fitness and to build muscle strength to meet physical goals we set for ourselves. Similarly, research is pointing to a recipe we can follow for great brain health at any age.

Although there is currently no cure for dementia, it can be very empowering to start monitoring and measuring metrics related to improving brain health.

Lifestyle changes including exercise, blood pressure control, quality sleep, and glucose control may slow the progression of cognitive decline and decrease the risk of dementia (Alzheimer’s Association, 2022). So much of prevention of cognitive decline and dementia is about reducing the risk we can control.

What levers can you pull to further protect your brain?

We hope you enjoyed reading this article. Don’t forget to download our three Positive Psychology Exercises for free.

Frequently Asked Questions

The first signs of cognitive decline are changes in the conscious recollection of when and where personally experienced events took place (episodic memory).

There is no cure for cognitive decline. You can protect yourself by controlling known risk factors.

Having active bowel movement (having a bowel movement within 10 minutes at least four days a week) was found to be negatively associated with mild cognitive impairment (Huang et al., 2020).

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