Cognitive Science

Normal Aging vs Cognitive Decline


As we get older, our bodies and minds change. Although physical changes like age spots or stiff joints are most noticeable, changes in thinking or cognition occur gradually, too. And when we start to notice them it can be seriously disconcerting.

While we can't see it happening, the brain also undergoes physical changes as we age. This includes:

  • loss of volume in the areas responsible for memory and planning
  • reduced connectivity between brain cells
  • decreased blood flow in the brain
  • increase in inflammation

These changes can cause a slight decrease in certain areas of cognition.

What is considered normal forgetfulness and what is not? Though it can be difficult to discern between memory lapses that typically occur with aging and lapses that signal cognitive decline, there are some key differences.

Normal aging brings subtle changes in your ability to think and remember. Most older adults will notice these symptoms from time to time:

  • a slower pace of thinking
  • some difficulty paying attention
  • some difficulty holding information in the mind while multitasking
  • some difficulty finding words and remembering names

Our cognitive abilities tend to peak around age 30 and decline slowly after that. (On a brighter note, not all of the cognitive changes associated with aging are negative. Some things tend to improve as you get older, including vocabulary, reading ability, and verbal memory.)

When changes go beyond what is expected for your age, the cognitive decline may be diagnosed, based on severity, as mild cognitive impairment (MCI) or dementia.

With MCI, the decline in thinking and memory is more severe than what would be expected for someone’s age but it does not interfere with their ability to do everyday activities. People with MCI are at higher risk for developing dementia than people without it, but not everyone with MCI progresses to dementia. Someone with MCI may forget important events like appointments or start to feel overwhelmed by making decisions.

Dementia is a broad term used to describe a decline in thinking and memory that is more severe than would be expected for someone’s age and is serious enough to interfere with their ability to do everyday activities. Alzheimer’s disease (AD) is the most common cause of dementia, representing 60-80% of cases, but other causes include vascular dementia and Parkinson’s disease. Dementia often affects memory first, but can also impact language, reasoning, and social behavior. Someone with dementia may struggle handling money or navigating around familiar places, and may repeat themselves frequently.

So some cognitive changes are expected with normal aging, while more severe impairments could be signs of cognitive decline. But it's not always clear where issues like forgetting names and losing your train of thought fall on this spectrum. That's where cognitive testing can help. If you're concerned, you can monitor thinking and memory through regular assessments or talk to your doctor about a professional evaluation.

References:

  • Healthy Aging. UCSF Weill Institute for Neurosciences Memory and Aging Center. Accessed August 19, 2020. https://memory.ucsf.edu/sympto... the Aging Brain Affects Thinking. National Institute on Aging. Accessed August 19, 2020. https://www.nia.nih.gov/health... Cognitive Impairment Symptoms and Causes. (2018, August 23). Mayo Clinic. Accessed August 19, 2020. https://www.mayoclinic.org/dis... Happens to the Brain in Alzheimer’s Disease? National Institute on Aging. Accessed August 19, 2020. https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease

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