Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
What does it mean to be older? For many of us, part of the description of the stereotypical elderly person would be memory problems and perhaps an inability to think clearly. In fact, associating old age with cognitive decline is so prevalent that many people believe dementia is an inevitable part of aging. It’s not.
So, is forgetting things normal? Absolutely. People of all ages forget things, of course, and while you may experience more forgetfulness as an older adult, it generally should not set off alarm bells. To understand why, it’s helpful to explore the relationship between aging, normal cognitive changes, mild cognitive impairment, dementia, and Alzheimer’s. The brain changes that most people undergo as they get older can be thought of as a continuum, with dementia (including Alzheimer’s) at the far end of it.
Our brain, just like our joints, skin, and every other part of our anatomy, will undergo changes as we get older. Obviously, those changes don’t occur at the same rate in everyone. You’ve probably known someone well into their 80s or 90s whose mind, as the saying goes, was still “sharp as a tack” (just as you may encounter older people with flawless skin). Unfortunately, for every such “cognitive super ager,” there’s a person who began complaining about memory and thinking problems several decades earlier. In either case, if you live long enough, eventually your brain, like the rest of your body, will change.
As we age, blood flow to our brains begins to decrease. The brain itself, or parts of it, begin to shrink. Inflammation increases. And the connections between brain cells become less fluid. When you put these things together, you end up with a brain that is noticeably less capable of some—though certainly not all— aspects of cognition.
Once you reach middle age, and especially in your senior years, you can expect to begin to see some mild evidence of the changes mentioned above. For example, most people find it harder to multitask than they did when they were younger, and they may find that words and names come with greater difficulty. Many also find it harder to stay focused on cognitive tasks.
While those things are certainly frustrating and sometimes embarrassing, they are all within the realm of normal age-related changes to cognition. Many people panic when they first recognize a pattern of such changes, fearing that they are in the early stages of Alzheimer’s disease. For the vast majority of people, however, this is not the case. After all, there’s a big difference between not being able to think of the word “provisional” during a work presentation and not remembering that you just asked your spouse what time it was 30 seconds ago.
It may feel like the normal cognitive changes that come with aging are debilitating, but they aren’t, and that’s what sets them apart from more serious conditions. Most people can go on learning new things and performing difficult cognitive tasks well into their senior years, though they may need to adjust their thinking strategies and find ways around their new challenges.
Mild cognitive impairment (MCI) is a category that describes someone experiencing cognitive problems that go beyond normal age-related changes but don’t meet the definition of dementia. This population breaks down into thirds: one third of them will get better, one third of them will neither improve nor worsen, and one third of them will go on to develop some form of dementia. Because of this, it’s important not to conflate MCI with “early Alzheimer’s,” since MCI is not necessarily a precursor to that more serious disease.
MCI is marked by lapses in decision-making, language, and spatial awareness, but these deficiencies are not significant enough to disrupt everyday functioning, and most people with this condition can continue to live independently.
Dementia is an umbrella term for several conditions that entail progressive cognitive deterioration. Most forms of dementia are irreversible and will worsen until people are unable to take care of their own daily needs such as housework, cooking, driving, tracking appointments. prescriptions, and personal hygiene.
The dementia umbrella includes Alzheimer’s disease, frontotemporal dementia, Lewy Body dementia, and vascular dementia. Dementia also can be caused by conditions including Parkinson’s disease, Huntington’s disease, and Creutzfeldt-Jakob disease. Dementia is not always disease-related, however. It can be caused by temporary conditions such as drug interactions, sleep irregularities, or leaking cerebrospinal fluid. In such cases, correcting the underlying problem may make the dementia go away. But for Alzheimer’s, vascular dementia, Lewy body dementia, and frontotemporal dementia, there is no cure.
Alzheimer’s disease is the most prevalent form of dementia. It’s currently the sixth leading cause of death in the United States. About 11% of people over age 65 have the disease, as do nearly a third of those over 85. Only 5% of people with Alzheimer’s are diagnosed before age 65.
A tiny fraction—only 1%—of Alzheimer’s cases are purely genetic, caused by a mutation that, for an unlucky few, makes Alzheimer’s a virtual certainty at a young age. The other 99% of cases are considered “sporadic,” meaning that they have no single cause but rather are driven by a bewildering multitude of potential factors including genetics but also diet, exercise, education level, race, and gender.
In Alzheimer’s, the brain undergoes changes far beyond those associated with normal aging. The brains of people with Alzheimer’s become damaged by high levels of plaques formed from a protein called amyloid, and by tangles of another protein called tau. Both the nerve cells (neurons) and the connections between neurons (synapses) are corrupted. If you were to examine the brain of someone with Alzheimer’s disease and compare it to that of a person with normal age-related cognitive changes, there would be no mistaking them.
Alzheimer’s disease typically first manifests in the hippocampus, a part of the brain that serves as a sorting-room for new information coming in. When you take in a piece of information, the hippocampus appears to choose whether to retain it as a short-term memory or file it away to be recalled as long-term. When the hippocampus begins to malfunction, the person starts to experience lapses in short-term memory. As the disease progresses, it begins to affect other parts of the brain, including those associated with sensory processing, language, and decision-making.
Because Alzheimer’s typically first manifests as short-term memory problems, it’s easy to wonder if an episode of forgetfulness is a harbinger of the disease. It’s most likely not. But if you begin to experience serious lapses that truly are alarming, talk to your doctor.
