Читать книгу The Alzheimer's Epidemic - Danton O'Day - Страница 27

As we age, significant changes in personality can be a signal that something is amiss with our brains. Or as a doctor might say, “Significant behavioral changes might be indicative of an underlying neurological disorder”. Thus, changes in how a person interacts with others or behaves in the presence of others might indicate neurological changes linked to mild cognitive impairment. Similarly, when an individual starts to act differently in normal surroundings or shows deficiencies in how they deal with the activities of normal daily living, then negative neurological changes might be occurring. It is important to determine that these kinds of changes aren’t due to non-neurological stresses such as family strife, breakups, financial difficulties or the multitude of daily stressors we all face in life and which affect how we behave. Having used the term “mild cognitive impairment” several times already, let’s take a look at what this means because it is a key early stage in the progression of Alzheimer’s disease.

As we will unravel in this volume, true Alzheimer’s disease is a continuum of events rather than a stepwise process. However, we need to break it up into definable steps for simplicity and to allow us to comprehend the progress of the disease. Figure 3.4 summarizes this continuum which will be explained here, with details of each topic forthcoming throughout this book. Essentially this figure includes information that has been covered up to this point and is simply presented in a different way to show the interrelationship between the topics we’ve been covering and to set the stage for some future topics.

Figure 3.4. The continuum of events in Alzheimer’s disease.

As mentioned above, the preclinical stage of Alzheimer’s disease is when the disease is set in motion but undetectable with today’s knowledge and technologies. The accumulation of amyloid beta and its coagulation or precipitation as amyloid plaques signals the early changes that are occurring in the Alzheimer’s brain. These lead to miscommunication between the neurons which is manifest as the loss of memory and other attributes that define “Mild Cognitive Impairment” or MCI. As the amyloid plaques continue to accumulate, a second culprit comes into play—tangles of fine filaments in brain cells called “neurofibrillary tangles”. As this is occurring, the signs and symptoms of Alzheimer’s are continuing to progress, along with major changes in brain structure. These include more serious and extensive miscommunication between neurons as well as the atrophy of the brain. These changes ultimately lead to dementia. So let’s begin our understanding of these events by covering mild cognitive impairment. In later chapters we’ll get into the nitty-gritty of amyloid plaques (Chapter 6) and neurofibrillary tangles (Chapter 7).