So that’s what we’re going to do in the book. We’re going to see what we know about the underlying events of Alzheimer’s disease as it relates to brain cells. What causes these brain cells to lose their ability to function properly? What causes them to die? How can we slow this sequence of events? And, ultimately, how can we determine how the disease starts? Before we get out our microscopes and our biochemical tools to understand these changes, let’s look at a short history of Alzheimer’s disease to understand how this disease was first identified and how that discovery set the stage for how things sit today.
A Very Short History of Alzheimer’s Disease
Unofficially, Alzheimer’s disease has been around as long as human beings have existed as thinking entities. It didn’t become an official disease until it was properly diagnosed by Alois Alzheimer. Dr. Alzheimer described the behavioral characteristics of Alzheimer’s disease over 100 years ago, which in itself was a major medical advancement. His work, however, went much further. He also delved into the underlying changes in the brain that were associated with the disease. To this day, his prescience defined the three primary neurological attributes of Alzheimer’s disease: the appearance of senile plaque and tangles coupled with the death of brain cells (Figure 1.2). These are still the primary criteria that are used today for defining the disease. As such, while plaques and tangles are introduced later in this chapter and will be covered throughout this volume, they are presented in much greater detail in Chapters 6 and 7.
Figure 1.2. Alois Alzheimer discovered the primary hallmarks of Alzheimer’s disease: plaques and tangles.
The Personal Side of Alzheimer’s Disease
What is Alzheimer’s disease? This might sound like a simple question to answer but it is not. This is because this disease is different things to different people. To a clinician or biomedical researcher, it is the buildup of bad stuff in the brain, the loss of specific nerve cells or changes in cognitive behavior. To a doctor, it’s the emotional challenge of having to diagnose a person with the disease and telling them they can no longer do the things they want to do. To a caregiver, it’s a 24-hour-a-day challenge without a positive outcome. To a family member, it’s the loss of the person they knew and loved. To the Alzheimer’s sufferer, it begins with the loss of their memory and dignity and ends with the loss of their whole world. To anyone who has seen the face of Alzheimer’s, all of these points of view are important because they all play a part in helping us understand this devastating disease. So let’s start with the currently held view of how the disease starts and progresses. Then, as we work our way through this book, we will develop this knowledge into the full picture of Alzheimer’s disease as it is understood today.
Figure 1.3. The basic stages in the progression of Alzheimer’s disease.
Alzheimer’s disease involves a progressive loss of mental ability that begins with mild cognitive impairment (i.e., decreased ability to think, reason, remember), or MCI, that can progress, in the worst case, to true dementia (Figure 1.3). One of the problems in research has been that different biomedical researchers and clinicians have formulated a diversity of stages and sub-stages for the disease. While these are well intentioned and of value for the researcher, they make it more difficult to discuss the disease in lay terms. So in this book, except when absolutely needed, the disease will be discussed in terms of mild cognitive impairment occurring as a prelude to dementia.
As we age our ability to remember things declines gradually. In Alzheimer’s disease, this decline is often more rapid and more devastating. Rather than symptoms like forgetting a name or the inability to immediately remember it, the disease is reflected in more severe memory impairment. Initially the memory loss is mild but worse than a normal individual of the same age and health. As it progresses, the person who is afflicted may not even realize where they are, even when in their own home or neighborhood. They may not recognize family members and friends. By the time the disease has affected a person’s ability to function socially or to continue in their job, they are in the clinical stage of dementia.
Alzheimer’s disease is a cruel affliction that progressively robs a person’s sense of self and awareness. Following a pathway to cognitive oblivion, it turns loved ones and friends into strangers and, at its worst, enemies. The very world in which the Alzheimer’s sufferer lives becomes foreign if not frightening, as altered brain cells slowly erase that person’s past and their grip on reality. Then those brain cells die, signaling the final stages of this horrific disease.
The problem with Alzheimer’s disease is that it is not like typical medical disorders like heart disease, diabetes or even cancer. Those diseases have specific symptoms that, for the most part, are clearly definable. In most cases, medical intervention and well-defined approaches for a cure are available. The course of these diseases is also fairly predictable. This is not the case with Alzheimer’s. There are multiple pathologies associated with the disease. The disease is person specific and doesn’t follow a predictable pathway. There are no available cures and even attempts to slow the disease are not well developed.
The Reality of Alzheimer’s Disease
No matter how you slice it, Alzheimer’s is a devastating disease that wreaks havoc on the lives of individuals and their families. We notice that, as we age, it can be difficult to remember a work or a name. As a senior, I was shocked when I was playing Mario Kart on my Nintendo with my grandson. I thought I was doing quite well motoring along, dropping a few banana peels and turtle shells to slow his progress. But I was 100% focused on controlling my car. The game was all I could concentrate on. Meanwhile, my grandson was not only doing everything I was doing, he was giving me hints on things I could do as well as carrying on a conversation with three other people in the room. If that didn’t demonstrate to me the loss of cognitive ability I was suffering, nothing could.
But Alzheimer’s disease presents itself as more than a short-term loss of memory or forgetfulness, it begins with a major loss in one’s ability to recall and reason. More importantly, it can progress to the state were the sufferer is often confused about where they are or what they are doing. It can cause them to forget who their loved ones are. Having said this, the disease is not something that is a natural extension of growing old. Also, the progression from loss of memory to full-fledged dementia is not a given. Understanding exactly what separates simple loss of memory from aging versus true Alzheimer’s disease is important and will become much clearer as the reader progresses through this volume.
You, Your Family and Alzheimer’s Disease
It’s tough to worry about the world around you and what the future will bring when you or someone close to you has developed Alzheimer’s disease. While the implications of losing one’s touch