“Dad is getting awfully forgetful - could he have Alzheimer’s?” That’s becoming a more common question. It is becoming more likely to encounter someone with Alzheimer’s dementia as the proportion of elderly in our society increases. Some forgetfulness is normal for most of us as we age but many of us carry the fear of developing Alzheimer’s or another form of dementia.
The word dementia stems from the Latin de- “apart or away” and mentis “mind.” It is characterized by a progressive decline in cognitive and behavioral function due to damage or disease in the brain beyond what is expected in normal aging. Alzheimer’s dementia or AD is the most common type of dementia.
Approximately 5.5 million people in the U.S. suffer from clinically significant AD. There are many more who have mild disease (mild cognitive impairment) and remain functional. Most cases of AD are sporadic, while about seven percent of cases are genetic in origin.
About 14 percent of individuals over age 65 and 40 percent of those over 80 have AD. It is estimated that by the year 2030 there will be 7.7 million Americans over age 65 with AD. The cost of caring for Americans with AD is over $100 billion a year and the cost of caring for the average AD sufferer comes close to $200,000 over his or her lifetime.
Alzheimer’s is a type of dementia resulting from specific anatomic changes in the brain. The two hallmark findings of brain tissue examined under the microscope are neurofibrillary tangles (NFT) and senile plaques (SP). Alois Alzheimer first described these abnormalities in 1907.
Although NFTs and SPs are found in AD, they can also be seen in other neurodegenerative diseases such as Chronic Traumatic Encephalopathy (CTE), the degenerative brain disorder found in NFL football players, and highlighted in the movie Concussion. NFTs and SPs must be found in sufficient numbers and in a specific anatomic pattern in the brain to make the diagnosis of AD.
Normally, nerve cells (neurons) are very ordered, following specific paths that allow them to communicate with other neurons. These connections allow us to think and act clearly. The appearance of normal nerve cells would be analogous to straight strands of hair. The nerve cells in AD look like badly hair and the senile plaques that form are like mixing bubble gum in the tangles. The resulting mess of nerve cells drastically reduces the ability of the cells to communicate clearly.
The diagnosis of AD is very complex and there are numerous criteria that have to be met that are too complex to detail here. Diagnosis usually requires the involvement of a team of medical experts. A doctor usually starts by doing a history and physical exam along with some basic blood work to look for other conditions that can mimic AD. These may include, among others, infections, vitamin deficiencies, depression, and thyroid disease.
The next level of testing usually involves brain-imaging tests such as CT scans or MRIs. A brain wave test or EEG may also be done, and genetic testing may be done if there is a family history of AD. Specialized neuropsychological testing may be done to identify exactly which parts of the brain are affected.
The earliest finding in AD is that of slowly progressive memory loss. Forgetfulness is what causes most people to worry they may be developing AD. Occasionally forgetting things like where you placed your keys or why you came into a room is usually not a cause for concern. It’s more worrisome when memory problems start to consistently disrupt daily functioning. There is a list of ten warning signs found on the Alzheimer’s Association website at bit.ly/3ajnKKV. This site also contains a wealth of information about the disease.
The underlying cause of AD has been very elusive. Recent research is shedding light on the biochemical pathways leading resulting in AD. This is providing scientists with targets for drug therapy to prevent the disease instead of just trying to slow the progression with currently available medications. Hopefully Alzheimer’s will be soon be a disease of the past.