This article explores the normal symptoms associated with cognitive aging, and symptoms that are more severe and could be indicative of Alzheimer’s disease or other forms of dementia.
In the recently released movie, Mr. Holmes, actor Ian McKellen portrays the aging detective’s fight to conceal signs of cognitive decline. McKellen masterfully portrays Holmes’ struggles to recall details of his final and most disturbing case. At some moments the great deducer’s memory is as sharp as ever, but at other times his recall is patchy or even deceiving. Behavioral cues such as writing an important name on his cuff, herbal remedies such as Royal Jelly and Prickly Ash, and even drugs are of limited value.
We in the audience cannot help but feel the anguish Holmes experiences as he recognizes that his memory is failing. We hope, as he seems to hope, that his lapses are momentary and not predictive of future decline. Holmes, like so many older adults with cognitive decline, appears intent on protecting his independence and hiding his growing difficulty, even from the very caring physician who clearly is not deceived.
The Aging Brain: Normal Symptoms to Expect
Many of Holmes’ symptoms are familiar to older adults, though symptoms of normal cognitive aging are less intrusive and frequent. Brain processing speed peaks as early as age 30 and then declines gradually with age. Slowed processing speed may be an important contributor to many other aspects of cognitive aging. The “tip of the tongue” inability to recall a somewhat familiar name begins as early as our 30s. As we age, it takes more effort to “multitask” by dividing attention between two or more areas of concern. It is not unusual or necessarily pathological as we grow older to misplace an object of minor significance. Forgetting the reason for walking to another room, a failure of prospective memory, can also become more common with increasing age. Certain types of problem solving behavior grouped together as examples of “executive function” often become less fluid and automatic in later years.
Cognitive aging reflects brain aging, although there is not a simple relationship between these two. Beginning after age 20, the brain’s gray matter begins to lose volume. This is especially notable in the prefrontal cortex, an area important for reasoning and abstraction. Decreased metabolic activity in the dorsomedial prefrontal cortex, for example, may help explain older adults’ lesser ability to “mentalize,” or figure out others’ mental states. The hippocampi, important in new learning and memory, also lose volume. Shrinkage of brain regions that connect the hippocampi to other brain areas, may contribute to normal age-related memory difficulties.
The aging of our brains is a highly individualized process and does not depend only on the number of years one has lived. Genetic predisposition, medical health, diet, alcohol use, smoking, and physical activity are some of the factors that affect how our brains age.
It’s Not all Bad News
It is important to remember that certain cognitive faculties are resistant to the effects of aging. Vocabulary, for example, often continues to improve with age. Object recognition and the ability to locate objects in relationship to each other do not decline with age until very late in life. Crystallized intelligence, which is the ability to solve a current problem by applying lessons learned from similar past situations, is sustained until late in life.
Among older adults who cross the line between “normal cognitive aging” and pathological cognitive decline, the most common diagnosis is Alzheimer’s disease. Alzheimer’s disease, unlike typical cognitive aging, reflects a severe destruction of brain cells in very specific brain areas and results in symptoms that are more severe and more frequent:
- Are you experiencing memory loss, for example forgetting that significant things have happened and not just temporarily forgetting a name?
- Are you taking longer to accomplish normal daily tasks?
- Do you lose track of where you are?
- Are you having trouble handling money and paying bills?
- Have you made decisions that were misguided, such as falling victim to scams directed at older people?
- Have those close to you expressed concern about changes in your personality, such as loss of initiative and spontaneity, or increased anxiety or irritability?
At a later stage of difficulty, attention span becomes shorter. A person may develop inappropriate anger outbursts. Recognition of friends and even family members can be impaired. Language understanding and expression and organizing thoughts become more difficult. An affected person may be unable to carry out activities that involve multiple sequenced steps, such as following a recipe. It becomes more difficult to learn new things or to cope with new or unexpected situations. Restlessness is common, and impulses may be under less voluntary control. In more advanced stages, reality testing may be affected.
It does not take a master detective to recognize signs of cognitive difficulty, but determining their significance can require considerable expertise. It is important to pay serious attention to signs of possible cognitive decline and to seek evaluation when they are present. A thorough assessment is likely to include the taking of a detailed medical history, a physical examination, blood and possibly cerebrospinal fluid testing, and neuroimaging.
Some 9 percent of apparent dementias represent reversible disorders and the right treatments can diminish the harm associated with many other dementias. Even among dementias that are not yet considered reversible, an accurate diagnosis can guide the way to a best choice for reducing cognitive and behavioral symptoms.
Healthy Brain Aging
For those of us eager to reduce the toll that age takes on brain health and function, remember that healthy physical activity, adequate sleep, good nutrition, avoidance of smoking, moderation in alcohol use, stress reduction, and social engagement will help pave the way to healthier brain aging.
Extra Reading: If you are interested in a lengthier discussion of these issues, you may enjoy reading the following article:
- Harada CN, Natelson Love MC, Triebel K. Normal Cognitive Aging. Clin Geratr Med 23013;29(4):737-752.
- Alzheimer’s Disease Toolkit (Helpful Information to Understand and Manage Alzheimer's Disease)
This content was last updated on: November 14, 2016
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