Maybe you know her too. As a teenager she was an all-star for her high school soccer team and graduated from the top of her class. University was her chance to prove her passions and become a lawyer. She practiced for decades, mentored her peers but to her family she was always present as a dedicated wife and mother of three. With her lifelong learning, how is it that at 66 Suzie finds herself struggling for words, fumbling the smartphone to answer a call and searching for the oatmeal in her kitchen cabinet that she has kept in the same spot for over 40 years?

There is a backstory of course. Because when Suzie and her family got the diagnosis of Alzheimer's and saw the atrophy spots in her brain MRI this year, they knew it didn’t start yesterday.

We all have a backstory, we often have major stories in the forefront as well – and if you don’t read the signs early enough it will be extremely difficult to move sufficient lanes and make it to the exit ramp.

Note to reader — Suzie is a fictional character whose story illustrates the experiences and challenges of many individuals and families we work with who are navigating cognitive decline and dementia.

The Road Signs Are Not Clearly Marked, but the Landscape Is

Common notions of age-related changes are assumed, normalized, accepted, and more often than not surrendered to.

While biological and cognitive changes are a fact of life, the landscape of healthy aging expresses a gradual change compared to the pronounced deterioration often associated with growing older. Healthy aging looks very different from unhealthy aging. Healthy aging also does not imply a life free of accidents, illness or health complications—rather it is a process that can be attended to, nurtured and supported throughout life.

The confluence of accepting unhealthy lifestyles and disease processes as normal features of aging, together with limited self-awareness (both individually and societally) forms a dangerous slippery slope. It creates a susceptibility to not paying attention to changes in the terrain along the highway toward dementia; and secondly, not knowing which signs to look for until opportunities for meaningful intervention have narrowed.

Normal age-related biological changes include features such as slower metabolism and digestion, gradual reductions in bone density and muscle mass, and some decline in kidney function. In contrast, conditions such as Type 2 diabetes, cardiovascular disease, and osteoporosis, although increasingly common with advancing age, are not. What becomes common with age should not automatically be accepted as normal aging.

In that same regard, there are normal age-related changes in brain structure and cognitive processes that are distinct from the non-normal changes associated with cognitive impairment and neurodegenerative disease. Let us first discuss that to develop an informed understanding of how the cognitive landscape changes throughout the aging process.

What Normally Changes in Cognitive Aging—and What Doesn't?

The first step in distinguishing normal brain aging from pathological change is understanding that not all cognitive abilities age in the same way. Cognition can be broadly divided into two forms. Crystallized cognition represents the knowledge, skills, vocabulary and experience accumulated throughout life. Fluid cognition involves the ability to process new information, reason through unfamiliar situations and solve problems in real time. Crystallized abilities generally remain stable and may even improve well into later life. Fluid abilities, particularly processing speed and reaction time, tend to decline gradually with age.

Therefore, age-related cognitive change extends far beyond what we remember and what we forget. It’s a question of processing efficiency and resilience across a wide array of functions. This distinction is important because a slower cognitive response does not necessarily indicate a loss of knowledge, understanding or intellectual capacity. Furthermore, deterioration is not a uniform process.

The chart below illustrates cognitive functions normally retained versus those that decline with age. 

On a timeline that does not necessarily parallel cognitive changes, the brain undergoes gradual structural changes with age, including reductions in volume, changes in gray and white matter, and alterations in neural connectivity. Yet the relationship between brain structure and cognitive function is not straightforward. The brain retains a remarkable capacity to adapt and compensate, allowing many cognitive abilities to remain intact despite these changes. An accelerated decline in fluid cognitive abilities or a loss of previously retained crystallized abilities may indicate non-normal cognitive aging and warrants investigation as early as possible.

For a more detailed discussion of normal versus non-normal cognitive changes, including the underlying structural and functional changes in the aging brain, read our article Normal vs Non-Normal Brain Aging.

Do You Know the Road Signs? 

The signs along our highway towards dementia are not always obvious, nor are they limited to memory loss. Unfortunately, most of our patients arrive at our program once memory loss becomes prominent, by which time other signs may have been present for some time.

Some road signs warn us about the conditions ahead; others tell us that the landscape has already begun to change.

These risk factors drive a convergence of physiological changes that progressively compromise neurological function and may accelerate neurodegeneration. Depending on the nature, extent and progression of these changes, cognitive impairment may eventually emerge, presenting clinically as Mild Cognitive Impairment (MCI) or dementia. The two, however, remain clinically distinct.

Importantly, MCI is not necessarily a one-way road toward dementia. It represents a heterogeneous clinical state with considerable variability, in both its underlying causes and trajectory. Some individuals living with MCI remain stable for years, others return to normal cognitive performance, while others progress toward dementia. Understanding what is driving the impairment, and whether cognitive performance is stabilizing or deteriorating over time, is critical for optimal management and rehabilitation.

Changing lanes before the road signs 

It is crucial to recognize that declines in processing efficiency within brain regions and networks can occur before structural deterioration becomes detectable on conventional imaging. Furthermore, functional pathway disruption and structural pathology often overlap, yet neither follows an identical timetable in every individual. Both may precede noticeable changes in cognitive performance.

For a deeper understanding of the road signs of cognitive decline, MCI, and possible progression to dementia, read Mild Cognitive Impairment: The Gray Zone of Brain Aging.

The Exit Ramp Is Not at a Fixed Mile Marker 

Because cognitive decline and dementia are driven by a myriad of health and lifestyle factors, the critical questions become: To what degree do the underlying health conditions remain modifiable, and how willing is the individual to engage in meaningful lifestyle change?

In the previous section we learned about the early road signs—the 14 risk factors identified by the 2024 Lancet Commission on dementia prevention. Ultimately, the biological burden associated with these risk factors involves a convergence of inflammatory, metabolic, vascular, mitochondrial and other physiological processes. These disturbances compromise oxygen and nutrient delivery, cellular energy production, neuronal signaling, repair mechanisms and the clearance of metabolic waste. In short, they affect multiple physiological systems and neurological functions throughout the body.

Importantly, they rarely occur independently. Rather, they interact and reinforce one another, progressively compromising neurological function and contributing to structural neurodegeneration.

What is the cumulative effect?

A growing biological burden that may accelerate cognitive decline, often long before the individual becomes aware of noticeable changes in cognitive performance.

Cognitive Reserve May Make for a Smoother Ride

Cognitive Reserve, developed through a lifetime of education, learning, experience and cognitive engagement, may function as a resilience shield against the functional consequences of underlying neurological degeneration. Studies have demonstrated that greater functional adaptability and compensatory neural activity can help sustain cognitive performance despite underlying deterioration, allowing the brain to tolerate a greater pathological burden before symptoms become apparent.

The reserve is not inexhaustible, however. While greater cognitive reserve may delay the onset of noticeable symptoms, more extensive degeneration may have occurred by the time those symptoms emerge. This may help explain why some individuals with higher cognitive reserve experience a more rapid decline following a diagnosis of Alzheimer's dementia.

Most importantly, cognitive reserve is not simply a fixed resource accumulated earlier in life. Continued learning, cognitive engagement, physical activity and targeted cognitive training may help support neurological adaptability and compensatory capacity, even in later life.

The therapeutic opportunity, therefore, lies in understanding the balance between the underlying biological burden and the brain's remaining capacity to adapt and compensate. So we have to ask:

• To what degree can the physiological processes driving cognitive decline still be modified?
• What functional capacities can be preserved, strengthened or supported?
• To what extent are the individual and their family willing and able to engage in meaningful, sustained intervention?

The Window of Opportunity is therefore neither fixed nor identical for everyone. As neurological deterioration progresses, opportunities for meaningful intervention may narrow, and therapeutic goals may change. However, the presence of cognitive impairment, or even a diagnosis of dementia, does not necessarily mean that all opportunities to improve function, preserve independence or support quality of life have disappeared.

For a deeper understanding of the biological processes driving cognitive decline, the role of cognitive reserve, and how the timing of intervention may influence outcomes, read our article The Window of Opportunity in Cognitive Aging.

If You Can Read the Signs, You Can Navigate the Mountain Pass 

Within a week of the Alzheimer's diagnosis, and still processing the shock involved, Suzie and her family must have asked themselves, “What signs did we have along the way that would have made a big difference?”

Was it the anemia and postpartum depression, the insulin resistance that never fully reached a diabetic state? What about the bloating issues that resulted in her gallbladder removal, or her later struggles with menopause, HRT and then insomnia?

Individually, these health challenges may not have appeared particularly significant in relation to her cognitive health. Yet metabolic, inflammatory and other physiological disturbances can persist below the threshold of a diagnosed disease, influencing neurological health over many years.

If you can read the signs, then navigating the mountain roads later in life may give you the opportunity to enjoy the views and plan for some nice picnics instead of worrying about each next step forward. Dementia does not occur in a vacuum. It is a process that can develop over decades, but it is not an inevitable consequence of aging.

Recognizing the early signs creates opportunities to investigate, intervene, rehabilitate, compensate, support function and potentially alter aspects of that trajectory while more capacity remains.

As dementia becomes an increasingly significant health challenge across the Western world, the search for pharmaceutical treatments continues. Yet opportunities to influence our cognitive future also begin much closer to home— in the health conditions we attend to, the choices we make and the lifestyle lanes we travel throughout our lives.

Where Do You Stand on Your Cognitive Journey?

Understanding your current cognitive performance is an important first step toward recognizing changes and making informed decisions about your brain health.

Our Introductory Cognitive Health Consultation provides an opportunity to assess key cognitive functions, better understand your current cognitive profile and discuss potential opportunities for meaningful intervention.