Journalist Jay Ingram speaks with CBC Radio's Bob McDonald on Quirks & Quarks about the history of Alzheimer's disease and why a cure is still so elusive.

The End of Memory: A History of Alzheimer's and Aging is Jay Ingram's latest book. (Jay Ingram)

On his new book, The End of Memory: A Natural History of Aging and Alzheimer's, the former CBC Radio host explains that although he had a personal connection with the disease, as it afflicted his mother, "that's not why I wrote [the book]."

"I wrote it because as the disease gets more and more in our faces, I think it's important for people to just understand a little bit more of the science behind it," he said.

Ingram traces German neuropathologist Dr. Aloysius Alzheimer's early efforts in the late 1800s and early 1900s to understand "the Index Case" of the disease, a woman who came to see him when she was 51 years old.

The patient appeared to have early-onset Alzheimer's, Ingram said, and the Bavarian-born scientist spent years interviewing her and taking copious notes to establish the degree of her dementia.

"When she died, he had her brain sent to Munich and he was a fantastic microscopist," Ingram said.

'Plaques' and amyloid beta

Upon examining slides of her brain, Ingram said that Alzheimer noted "her brain was shrunken, and then he was able to identify two feature sin her brain — two unusual deposits."

Alzheimer described those deposits as "plaques" and "tangles."

Those plaques, Ingram explained, are clusters of potentially millions of molecules known as amyloid beta. Massed together, the molecules become "dark blobs sitting outside brain cells."

Even more than a century later, Ingram said, "it's that combo of recorded dementia association with these brain abnormalities that become the constellation of things that typify Alzheimer's disease."

Plaques and tangles remain the main diagnostic features of the disease, though Ingram said it's still unclear exactly how plaques cause neurons to die.

To hear more from Jay Ingram's conversation with Bob McDonald, tune in to Quirks & Quarks on Feb. 28 at noon on CBC Radio One.