The First Discovery
In 1906, the German psychiatrist Dr. Alois Alzheimer described the case of Auguste D., a woman of fifty-one who had been admitted to the hospital five years before her death with a series of symptoms that included problems with memory and comprehension, an inability to speak, disorientation and hallucinations, and behavioral issues. After she died, Dr. Alzheimer performed an autopsy. Examining her brain tissue under a microscope, he found two unusual pathologies. One of these was a massive amount of sticky, insoluble proteins lodged in the spaces between nerve cells. Today these are called beta-amyloid plaques. The other was tangled bundles of protein threads within the neurons themselves, now called neurofibrillary tangles. Plaques and tangles are now considered the hallmarks of AD.
When Dr. Alzheimer made his seminal discovery, few took notice. At that time, the most common cause of dementia was syphilis. In his day, he was much better known for his studies of this type of dementia than for the relatively infrequent Alzheimer's disease. Also, Alzheimer's disease was not as common then, because few people lived to seventy-five, the average age of onset. People only lived to forty-seven or forty-eight in 1900. (The top ten killers were infectious disease like pneumonia, small pox, influenza, and venereal diseases.)
In 1910, the condition characterized by plaques, tangles, and accompanying symptoms was first called "Alzheimer's disease" by Dr. Alzheimer's supervisor at the Royal Psychiatric Clinic in Germany. However, for fifty years following Dr. Alzheimer's discoveries, knowledge about the disease grew slowly. Continuing improvements in scientific instruments and methods allowed scientists to conduct more sophisticated studies of the biological structure of plaques and tangles. They began to recognize that the "Alzheimer's disease" defined as plaques and tangles occurring in the brains of relatively young adults were, in fact, the same structures they saw at autopsy in the brains of older people who had "senile dementia," the result of what was then called "hardening of the arteries."
The common assumption was that forgetfulness was a normal part of old age. Most people thought, "Uncle Fred is going through his second childhood," or "Grandma just can't remember where she puts things, but it's no big deal." During the 1960s, though, there was growing recognition that dementia was not, in fact, a normal part of aging but was often caused by a disease of the brain, Alzheimer's disease.
Since then, discoveries in Alzheimer's disease have come increasingly rapidly. We know now that, in most cases, symptoms of the disease emerge after age sixty-five; this is called late-onset AD. In a small number of cases, people develop the disease in their thirties, forties or fifties; this is called early-onset AD. Breakthroughs in the field of genetics have shown that early-onset cases run in families and are the result of particular genetic mutations. Late-onset AD probably results from a combination of genetic, environmental, and lifestyle factors. In both forms, the disease has the same pathology—the accumulation of beta-amyloid in plaques and neurofibrillary tangles that disrupt communication among neurons, ultimately leading to cell death.
Excerpted from THE ALZHEIMER'S PROJECT: MOMENTUM IN SCIENCE, published by Public Affairs, www.publicaffairsbooks.com.
In This Section
Momentum in Science: The Supplementary Series
- Understanding and Attacking Alzheimer's 12 min
- How Far We Have Come in Alzheimer's Research 15 min
- Identifying Mild Cognitive Impairment 20 min
- The Role of Genetics in Alzheimer's 12 min
- Advances in Brain Imaging 11 min
- Looking Into the Future of Alzheimer's 6 min
- The Connection Between Insulin and Alzheimer's 21 min
- Inflammation, the Immune System, and Alzheimer's 29 min
- The Benefit of Diet and Exercise in Alzheimer's 16 min
- Cognitive Reserve: What the Religious Orders Study is Revealing about Alzheimer's 20 min
- Searching for an Alzheimer's Cure: The Story of Flurizan 30 min
- The Pulse of Drug Development 15 min
- The DeMoe Family: Early-Onset Alzheimer's Genetics 25 min
- The Nanney/Felts Family: Late-Onset Alzheimer's Genetics 20 min
- The Quest for Biomarkers 17 min
Video: Inside the Brain: Unraveling the Mystery of Alzheimer's Disease
This 4-minute captioned video shows the progression of Alzheimer's disease in the brain.
Inside the Brain: An Interactive Tour
The Brain Tour explains how the brain works and how Alzheimer's affects it.
Alzheimer's Disease: Unraveling the Mystery
This book explains what AD is, describes the main areas in which researchers are working, and highlights new approaches for helping families and friends care for people with AD.
- About The Scientists
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- Rapid advances in our knowledge about AD have led to the development of promising new drugs and treatment strategies. However, before these new strategies can be used in clinical practice, they must be shown to work in people. Advances in prevention and treatment are only possible thanks to volunteers who participate in clinical trials.
- Among those touched by Alzheimer's (excluding self), nearly one-third provide support as a friend or relative, another 3% provide support as a healthcare professional, and the remaining two-thirds provide no support to the person suffering from Alzheimer's. When support is provided, it most often entails emotional support, followed by care-giving support. While small in comparison, more than one person in ten is providing financial support. Read more.