As we age, our senses become less acute through changes in the organs themselves, as well as changes in the brain. An ageing brain becomes less able to perceive sensations, process information, create and store memories, and learn as some neurones die through normal ageing or through disease or injury.
But maintaining a healthy brain through mental and physical exercise, as well as medical treatment, can actually improve life in our late years. Education, sensory challenges, cognitive puzzles, and exercises to improve blood flow, balance, and muscle mass all support the most important organ in the body.
Here’s how our senses change as we age.
Vision and hearing
Eyes and ears suffer the most dramatic tests of time. Nearly everyone over 55 needs corrective lenses at least part of the time. Some studies have found that impaired vision in the elderly is linked to mental decline. The reason why isn’t clear, but logic suggests the deterioration of eyesight for reading and hand-eye coordination would limit the ability to do brain-strengthening exercises.
Hearing also declines, with the ability to hear high-pitched sounds the first function to disappear. Once considered a disease of old age, younger patients are experiencing hearing loss in the high registers, thanks to our noisy world.
Ageing weakens memory. Normal degradation of memories occurs both for events of the recent past and those long ago. The elderly also lose a degree of working memory, the “mental desktop” that allows them to hold and manipulate information for a few seconds.
An elderly brain may attempt to force the recall of uncertain information by calling on the frontal lobes to assist in memory, but PET scans reveal that it has more trouble activating these lobes. However, there are practical ways to combat memory loss. Among them is simple exercise. Studies have found that exercise improved the memories of elderly women with mild cognitive impairment.
Interestingly, aerobic exercise seemed slightly better for verbal memory, and weight training slightly better for associative memory—the ability to remember things in context. One factor may be the protein cathepsin B, released by muscles during exercise. In mice, at least, that protein builds cells in the hippocampus, a brain region essential to memory.
Dementia and strokes
Neither dementia nor strokes are normal parts of the ageing process. Dementia, from the Latin for “away” and “mind,” describes a variety of symptoms that stem from as many as 50 brain disorders; all involve neurone destruction. Physicians diagnose dementia if two or more brain functions, typically including memory and language skills, are significantly impaired.
Alzheimer’s disease is the most common form of dementia, targeting the portions of the brain that are crucial to remembering, thinking, and reasoning. It is marked by an accumulation of plaques and tangles in the brain.
A stroke occurs in an instant, when a blood clot or broken artery cuts off the flow of blood to the brain. Without oxygen-rich blood, brain cells die, taking with them the cognitive and motor functions they make possible.
A disease-free brain and, at top, a brain battered by Alzheimer’s disease.
Despite the gradual decline of our senses as we age, except for a decrease in processing speed, healthy mature brains perform about as well as youthful ones in any task requiring planning, analysis, and organisation of information.
And some areas of mental ability actually increase with age. For instance, in the absence of disease, an elderly brain enjoys a larger vocabulary and sharpened language skills.
The owner of these family photos has dementia, a disease that degrades memory.
The owner of these family photos has dementia, a disease that degrades memory.
A disease-free brain and, at top, a brain battered by Alzheimer’s disease.
A disease-free brain and, at top, a brain battered by Alzheimer’s disease.