While it has been clear since ancient times that some people lose their intellectual abilities (cognitive function) as they age, Alzheimer’s disease was not identified until 1906. That year, a German neurologist, Alois Alzheimer (1864-1915) carried out an autopsy on Auguste D., a 56-year-old Frankfurt woman who had died after 5 years of progressive mental deterioration. Her condition had been marked by irrational jealousy, increasing confusion, loss of memory and ultimately the ability to take care of herself. Using new staining methods, Alzheimer noticed a bizarre disorganization of the nerve cells in her cerebral cortex (the part of the brain responsible for memory and reasoning). The cells were bunched up like a rope tied in knots. He called these knots neurofibrillary tangles. He further noticed unexpected accumulations of cellular debris around the knotted nerves, which he called senile plaques. In an article published in 1907, Alzheimer speculated that these nerve tangles and plaques might have been responsible for Auguste D.’s dementia.

As the years passed more autopsies of severely demented individuals revealed the same cerebral abnormalities. A prominent German psychiatrist, Emil Kraepelin (1856-1926), proposed naming the new disease after his countryman, Alzheimer.

Fifty years after Alzheimer’s discovery, physicians continued to believe that the disease named after him was very rare, but by the 1960’s researchers demonstrated that it was the leading cause of age-related dementia. As recently as the 1980’s, physicians viewed Alzheimer’s disease as a psychiatric disorder due to its impact on memory, reasoning, and behaviour. Today, however, experts insist that Alzheimer’s is a medical illness because it results from physical changes in the brain.