Brain Stride has been created to help you track your brain health using data-driven and research validated tools. We follow the latest research on possible disease interventions and measurement strategies in order to develop brain health tracking tools for the general population. One such approach is to use cognitive tests that not only measure decline in cognition, but age-related improvements as well. Keep reading to learn more.
Overview
Brain performance relies heavily on the stages of memory and cognitive learning we experience throughout our lifetime. The factors that influence our brain’s state and performance change because of aging processes. A brain state—such as sleeping, meditating, or intently focusing—can be thought of as a unique way of functioning. Factors that determine your day-to-day brain state include neurochemistry, genetics, nutrition, microbiology, and hormones. As people age, their brainwave patterns change slightly. For example, the proportion of time our brain spends emitting theta waves tends to decrease after childhood. It is thought that these changes in brain state and oscillatory activity result from structural changes in the brain, such as increased myelination in the frontal lobe. In this article, we’ll explore the stages of memory and cognitive learning from middle to late life. In the past, scientists believed that the brain was relatively static after puberty but, more recent discoveries have shown that our brains actually change during late adulthood, and that these changes offer benefits as well as drawbacks. By understanding normal brain changes and their effect on cognitive learning, you can identify the differences between normal aging and cognitive impairment. It’s difficult to determine subjectively whether you’re at risk for dementia and memory loss. For example, you might wonder whether losing your keys is a sign of declining cognitive ability [1]. Or, you might struggle to think of a word while talking to someone. It turns out that losing your keys and searching for words are actually a normal part of cognition after 50. Keep reading for a detailed explanation of how your cognition and learning change throughout later memory stages.
Stages of Memory and Cognitive Learning
Our first concrete memory abilities emerge around 3 years of age. Declarative memory manifests as storage of facts and events. Declarative memory also includes the lexicon, semantics, and number theory. Shortly after declarative memory capacities emerge in young children, their capacity for working memory becomes evident as well. Working memory differs from declarative memory in that it has more than one state. Dr. Alan Baddeley developed a framework to describe how these states are integrated together. The first module of this framework is the central executive system. It acts as an administrator by determining which pieces of information are priorities and which are not. The central executive system manages working memory by directing our attention to the features or ideas deemed most relevant. A second module is known as the phonological loop. Appearing around age 7, the phonological loop is a mechanism for repeating words mentally. You may be familiar with this type of memory after rehearsing a phone number in your head several times [2,3]. The visuospatial sketchpad is a module used to visualize an image or a map. Information held in this system is represented with images or specific visual features. Interestingly, the visuospatial sketchpad tool is available to children younger than 7, suggesting that the phonological loop is related to reading ability. Most research supports the idea that our memory capacities reach their maximum in the teens and early 20’s. According to this article from Harvard Health Publishing, the idea that mental capacities plateau and remain constant until middle age is somewhat of a myth.
Cognition and Memory after 50
The stages of memory and cognitive learning are more complex and nuanced than originally thought. In fact, some aspects of cognition improve with age instead of declining [4]. To start, we’ll focus on the good news. As you age, the neurons in your brain grow new connections and the strength of connections already in place improves. Because of this, older brains are better at recruiting several areas in the cortex to complete a particular task. Younger brains, in contrast, tend to use one or two cortical regions to process a task. Since current connections strengthen and new ones develop in aging brains, you may find yourself getting better at identifying relationships between many different sources of information. Being able to identify relationships among sources makes inductive reasoning easier over time, since you can more easily identify the specific effects of global changes. Your ability to hold thoughtful discussions increases with age — though your processing speed for speech may be slower. Cognitive tasks requiring little effort or those done automatically are well-preserved in older people [5].
Skills that decline with age
But what about the cognitive learning skills that decline with age? Here are the changes you should expect. First, it might take longer than usual for you to finish tasks at work, and you might find yourself driving more slowly. This is a result of changes in executive function, a cognitive domain used for planning and following directions. On average, people between 50 and 100 have trouble remembering names or what they had for dinner last night [4]. The specific cause of slower verbal processing time is linked to our ability to recognize new information. In order to form new connections in the brain to support the learning of new concepts, we first have to understand that the concept being presented is novel. With age, decreased connectivity in the hippocampus [6].
What causes declines in memory stages and cognitive learning?
Aside from changes in the hippocampus, declines in cognitive learning across memory stages are strongly linked with cardiovascular health. As the blood flow to the brain decreases slightly over time, the organ’s function changes to accommodate the decrease. Lower blood supply doesn’t equate to poor cognition – instead, the brain’s adaptation to lower blood volume may be indicative of it’s lowered energy consumption. Since multiple anatomical structures in the brain are activated simultaneously, it’s difficult to say for sure whether a deficit in one area leads to any specific outcome. There are several domains of cognition that researchers focus on to track changes in thinking, and executive function is the domain in which attention resides. Declines in attentional ability have far reaching consequences because it is involved in every task (besides habitual and automatic ones). Selective attention is the ability to attend to stimuli while ignoring others. Depending on the similarity of target stimuli to each other and distractors, as well as the total number of distractors, it may be easier or more difficult to selectively attend to the targets. Some types of information can interfere with our ability to attend to the right characteristic, such as similar colors, sizes, or movements. Researchers are still working to understand why some older people perform poorly on cognitive tests, yet other people do as well or better than younger counterparts.
One major influence on cardiovascular health is your body composition profile. In the past, dietitians and trainers focused on weight loss but not on the specific component being reduced, which resulted in many people being “skinny-fat” – a state where they lost muscle while maintaining or even increasing their fat content. Thankfully, there are body composition analyzers that can be used in combination with cognitive testing to track exactly how your brain performance changes relative to your physical health.
Key take-aways
Your brain function and states will change throughout the aging process. We now know that some types of cognition actually improve over time, instead of declining overall as was previously thought. Declarative memory abilities decrease over time, but the ability to synthesize multiple sources of information increases. Inductive reasoning ability increases as well. The changes in cognition could be caused by decreased blood flow to the brain or cardiovascular problems, such as high blood pressure (hypertension). To track your own changes in cognition over time, use cognitive tests and have your biomarkers measured. Getting a body composition scan provides further insight into the relationship between the health of your brain and the rest of your body.
References
[1] Harvard Health Publishing. (n.d.). Looking for an earlier sign of Alzheimer’s disease.
[2] Introduction of the phonological loop. (n.d.).
[3] Moore, T. (n.d.). Rehearsal.
[4] Harvard Health Publishing. (n.d.). How memory and thinking ability change with age.
[5] Murman, D. (2015). The Impact of Age on Cognition. Seminars in Hearing, 36(03), 111–121. doi: 10.1055/s-0035-1555115
[6] Yassa. (2011, June 1).