CHANGES IN PERFORMANCE
Nevertheless, some decline in brain function is inevitable as we age. The first system to show its age is memory. Brains begin requiring more time to learn and store information in late middle age.
At the same time, the prefrontal cortex experiences a drop in its ability to hold information in so called working memory. Dr. Restak likens working memory to the desktop of a computer. It’s where information is kept ready at hand for immediate use, such as when each new sentence you read in a romance novel builds on what you’ve read immediately before. Or, it’s what you use when you enter a grocery store and check off items from your mental list of things to buy.
As both long term and working memory decline, the brain takes longer to file information for later use, longer to retrieve it when it’s needed, and longer to make decisions. People in their late 60s or older typically find it harder to filter out the “noise” of distractions and concentrate on tasks at hand. An overabundance of information, all too common in a heavily wired world of instant communication, may overload the elderly person’s mental desktop in ways that a younger mind could more easily handle.
Deterioration of the frontal lobes’ ability to maintain sufficient working memory explains why elderly drivers often struggle with traffic that they easily negotiated in their youth. As you drive, your prefrontal cortex constantly manipulates information arriving through the peripheral nervous system. Speed, direction, information on road side signs, weather conditions, and constant feedback on the position of vehicles and pedestrians must get processed simultaneously as you change lanes, keep an eye on the cars around you, and search for your exit. A young adult’s brain handles such variables with little difficulty. An older driver’s brain, however, may get overwhelmed. As a result, grandpa may prefer to drive the old highway rather than the eight-lane interstate.