Figure 3.5. The general relationship between aging and the onset and progression of Alzheimer’s disease.
So the first clinical stage for the onset of Alzheimer’s is mild cognitive impairment. At this stage, close friends and family are often the first to notice changes in a person’s ability to recall things or in minor changes in their ability to reason. But not all symptoms are reflected in verbal communication. Often changes in emotional behavior occur, including anxiety, anger and irrational fears such as being abandoned by a loved one. One study revealed that 80% of people with mild cognitive impairment suffer from depression, making it the most significant behavioral change associated with this stage of Alzheimer’s disease. Changes in sleep patterns are also a common attribute. Of course, these are but a sampling of the changes that occur.
People suffering from Alzheimer’s disease express a vast array of behavioral characteristics. Thus, clinicians and researchers need to focus on a select group of these behaviors to make their assessment of the stage that person is in. Through cognitive psychological testing, the severity of the memory impairment can be assessed. With no other explanation being present for the behavioral changes, it may be concluded that mild cognitive impairment exists. While the changes of mild cognitive impairment are of concern, people suffering from it are still able to function relatively normally because their general intellectual function remains intact. Other than moments of confusion, disorientation or inability to recall, their daily activities remain relatively normal.
Various psychological tests can reveal the onset of mild cognitive impairment. It can also be assessed by measuring the levels of specific biomarkers such as amyloid beta and the protein tau, as well as changes in brain activity and function. The subject of biomarkers is detailed in Chapter 11. To repeat, the fact that a person is suffering from mild cognitive impairment doesn’t mean that the disease will progress to dementia. In fact, it may not progress at all.
Some researchers have studied the frequency of progression. As might be expected, they have found that progression is linked to age. Thus individuals over the age of 75 who had mild cognitive impairment were more than 60% likely to progress to the dementia stage. In contrast, those under 75 years of age had an over 80% chance that the disease would not progress. The severity of mild cognitive impairment was also a strong indicator of disease progression. Those who had moderate mild cognitive impairment had a 70% chance that the disease would progress compared to a chance of less than 40% for those with mild or minimal cognitive impairment. It should be noted that only a few of these studies have been done to date. Also, the number of subjects in the studies that have been carried out has been quite low. These deficiencies rule out strong statistical analyses, leaving us with only general conclusions and numbers that are less than solid. This means the numbers should not be taken strictly at face value but only used as an indicator of the general chances for disease progression from mild cognitive impairment to dementia.
Since Alzheimer’s is a progressive disease, some researchers prefer to divide mild cognitive impairment into early (EMCI) and late MCI (LMCI). Just like the term SCI (severe cognitive disorders), while it is possible to define these categories with specific diagnostic procedures, it is more useful for the researcher to make such definitions than it is for us to use them as we try to understand the essence of the disease.
Attributes of Dementia: Delusions
If Alzheimer’s disease does progress, it moves from these mild cognitive impairment stages to dementia. The progression of Alzheimer’s disease to dementia is associated with a number of emotional changes, many of which are observed with mild cognitive impairment but now are seen with greater frequency and with heightened expression. With dementia, the person will typically experience one or more of the following: anxiety, various fears (e.g., abandonment), despair, anger and depression. They may also show compulsive behaviors and tend to suffer from hypochondria.
Delusions are also a common characteristic of Alzheimer’s disease dementia. The simplest definition of delusions is that they are false beliefs, impressions or opinions. Typically the caregiver will have trouble convincing the Alzheimer’s sufferer that their delusions are unfounded. Since delusions occur in about 31% of all cases, they are of serious concern to family members and caregivers. The presence of delusions in the Alzheimer’s individual is often a sign of worsening behavior that likely will lead to early admission to a long-term care residence as well as increased caregiving. So there are many reasons to understand the signs and symptoms of delusions. This is typically done through the administration of psychological tests. These are carried out in conjunction with other questionnaires that assess behavior, quality of life as well as the ability to function in the real world. Questionnaires can also be given to reveal the burden that is put on caregivers who are responsible for looking after those suffering from delusional behaviors.
The accumulated research reveals that delusions arise due to the deterioration of the frontal lobe of the brain. Poor frontal lobe functioning is also linked to impaired activities in the Alzheimer’s individual’s daily life. CT (Computerized Tomography) scans show more lesions in frontal lobe white matter in delusional sufferers compared to normal individuals. PET (Positron Emission Tomography) studies show a reduced uptake of glucose in the frontal lobe of individuals with delusional behavior caused by Alzheimer’s disease. The sugar glucose is an energy source for cells and a reduced uptake by neurons signals their decreased energy needs. This in turn indicates that these cells are less functional than normal brain cells. As if this weren’t enough, delusional Alzheimer’s individuals also show increased levels of amyloid plaques in their frontal lobes. These and other aspects of the Alzheimer’s brain are discussed in Chapter 4 as well as elsewhere throughout the book.
With dementia, individuals progressively lose their ability to respond to the world around them. They become unable to perform the normal activities of daily life or to simply carry on a conversation. They often fail to recognize loved ones or remember who they are. This loss of cognitive awareness likely underlies many of the symptoms of the dementia stage of Alzheimer’s disease where increased levels of panic and anxiety are not uncommon. Hypochondria is common in about 30% of dementia individuals. So too are increases in obsessive behavior, paranoia and depression. One study revealed that around 40% of dementia sufferers experienced one or more of these behavioral symptoms. Around 13% of individuals ultimately become antisocial while over 20% exhibit schizoid behavior. Some can become violent. Of all of these behaviors, schizoid and paranoid tendencies increase the greatest degree in the progression from MCI to dementia. Family caregivers usually are no longer able to care for the Alzheimer’s sufferer by the dementia stage. Full-time care is required which often is only available in a long-term care home.
It is critical to reiterate that the severity of MCI is not a 100% predictor of progression to dementia. Not all MCI individuals will suffer from dementia. It has been estimated that about 15% of people with MCI progress to the dementia stage per year. In one study, 25% of the MCI group had not progressed to dementia even after 10 years. Currently, there is no way to determine which MCI individual will progress to full-fledged dementia.
Types of Dementia
What exactly is dementia? Dementia is an all-inclusive term that describes a variety of conditions and diseases that result from abnormal neuron function and/or death. Alzheimer’s is the most common form of dementia. Your doctor might use criteria provided by the Diagnostic and Statistical Manual of Mental Disorders to determine if dementia exists. These criteria include a decline in one’s memory along with one or more symptoms from a list.
This list includes:
•The