Alzheimer’s Disease and the Growing Dementia Epidemic

Most of us know someone—relative, friend, or colleague—suffering from dementia, a medical term that describes symptoms of impaired cognition (memory and thinking), behavior, social abilities, and daily functioning. Dementia isn’t a specific disease and can range in severity from mild to severe. It has many different non-reversible and reversible causes.

Alzheimer’s, a progressive degenerative brain disease, is the most common cause of dementia. In early stage Alzheimer’s, memory impairment is mild, and changes in personality and intellect are subtle. As the disease progresses, impairment becomes moderate, then severe. Death often occurs seven to 10 years after diagnosis. Alzheimer’s is principally a disease of the elderly. More than 95 percent of Americans with Alzheimer’s are 65 years old or older.

Why do we hear so much more about Alzheimer’s now compared to 25 years ago? Is Alzheimer’s a new disease?

No, Alois Alzheimer first described Alzheimer’s 100 years ago as a dementia associated with characteristic plaque and tangle lesions in the brain. The number of Americans with Alzheimer’s increased markedly in recent decades because our population is aging, and this trend will continue. An estimated 5.2 million Americans have Alzheimer’s in 2013. According to projections, 11 to 16 million Americans will have Alzheimer’s in 2050. The current and projected financial burdens are staggering.

What is the difference between the normal memory loss from aging and Alzheimer’s?

Our brains change somewhat during normal aging. As a result, many elderly people experience a normal, mild decline in memory. Although the first sign of any memory loss may raise concern about Alzheimer’s, a large majority of the elderly (ages 65 to 85) doesn’t have Alzheimer’s or any other type of progressive dementia.

They may experience a slow, mild decline in memory, but not the rapidly progressive and devastating cognitive decline, change in personality, behavioral difficulties, and other symptoms of Alzheimer’s. Although dementia increases significantly in people who are older than 85, most elderly people don’t experience dementia.

Can Alzheimer’s be accurately diagnosed?

Yes, but not in the earliest stages. Unfortunately, there are no medical tests for specifically diagnosing Alzheimer’s. The diagnosis is 100 percent accurate only at autopsy through a brain examination. Specialized memory clinics diagnose Alzheimer’s with 80-95 percent accuracy.

Clinical assessment begins with mental status and physical examination, and cognitive testing to ascertain the presence of a memory disorder. If warranted, further assessment follows with blood, imaging, and other diagnostic tests with the goal of ruling out treatable causes of dementia.

Alzheimer’s remains a diagnosis of exclusion of all other possible causes of dementia. Many other disorders can resemble early or moderate stage Alzheimer’s, including memory impairment caused by reversible conditions like depression or vitamin deficiency, other non-reversible, progressive dementias, or other causes.

Earliest stage diagnosis—even before any symptoms occur—is currently a hot research area. It’s thought that the best chance of developing effective treatments for Alzheimer’s is to intervene in the earliest stages before irreversible pathological processes occur.

Can current treatments prevent, reverse, or slow the neurodegeneration of Alzheimer’s?

No treatment has been proven to affect the underlying progressive pathological process of Alzheimer’s.

Are the approved treatments for the cognitive symptoms of Alzheimer’s effective?

FDA-approved treatments for the cognitive symptoms of Alzheimer’s include two classes of compounds involved in brain neurotransmission (messaging) related to memory and other cognitive functions:

  • Acetylcholinesterase inhibitors (AChEI)
    • Donepezil (Aricept)
    • Rivastigmine (Exelon)
    • Galantamine (Razadyne)
  • Glutamate modulator
    • Memantine (Namenda)

These drugs are very effective at increasing cognitive function for months to a few years in some patients but are aren’t effective in others.

A trial of one or more of these drugs as single agents or in combination is generally warranted in Alzheimer’s patients. AChEIs and Memantine haven’t been proven to slow the underlying progression of Alzheimer’s, but some researchers believe they might slow clinical decline. Other drugs are available for behavioral and other symptoms of Alzheimer’s.

Why does diagnosis matter when no known treatment can halt or slow Alzheimer’s?

Precise diagnosis of significant cognitive decline or dementia is essential for ruling out treatable causes of reversible dementia. It also has some implications for current treatment of irreversible dementia (e.g., drugs used to treat cognitive and behavioral symptoms of Alzheimer’s may be detrimental in patients with other types of dementia). Furthermore, patients and their families need to know the cause in order to understand and plan for life with dementia.

How does Alzheimer’s cause death?

Infections including pneumonia, bedsores, and bladder cause death in patients with late stage severe Alzheimer’s. These patients have lost motor coordination, are incapacitated, lack understanding of their disease and motivation, making them unable to comply with treatment.

What are the risk factors and how can I reduce my chances of getting Alzheimer’s?

A combination of factors, including risk genes (nature), and traits, behaviors, and environmental factors (nurture factors, some of which are preventable) are seen to be the cause of Alzheimer’s, like many neurodegenerative and some cardiovascular diseases affecting mostly the elderly.

Age is the greatest risk factor for developing Alzheimer’s. Our understanding of the disease’s genetic mechanisms is incomplete. True familial Alzheimer’s, where dominant genes of parents cause the disease in their children, accounts for less than five percent of cases.

Heredity appears to play a larger role through risk genes, which increase the probability of developing Alzheimer’s. We cannot modify our age or genes. Preventable/reversible factors include physical inactivity, high cholesterol (especially in midlife), diabetes, smoking, and obesity.

Unfortunately, no known compound, prescription, or over-the-counter, natural or synthetic, has been proven to halt, slow, or reverse Alzheimer’s.

Interestingly, exercise training has been shown to increase the size of the hippocampus and improve memory, but its role in preventing Alzheimer’s isn’t clear.

What’s going on in the R&D of effective treatments for Alzheimer’s?

Despite recent clinical drug trials for Alzheimer’s treatment failing, there is cause for optimism. Three large clinical trials are taking place in 2013 aimed at prevention of this devastating disease.

An intervention that would delay both disease onset and progression by one year would result in approximately 9.2 million fewer Alzheimer’s cases, worldwide, in 2050, nearly all among those needing a high level of expensive care.

ABOUT THE AUTHOR
Dr. Tim Tankosic, a FOCUS Senior Advisor, has over 25 years of experience as a consultant, advisor, and director/manager for pharmaceutical, biotechnology, diagnostics, and device industries. He has broad experience in major therapeutic areas and technologies and particular expertise in neuroscience and oncology. Dr. Tankosic has published extensively about health care technologies, products, and markets. He can be reached at ttankosic@aquapartners.net.