Alzheimers trial brings at-risk patients hope for the future, but new doubts in the present [Video]

Tyson Haller was in his early 50s when he learned he had a family history of one of the most feared diseases in medicine.

He and his older sister, Whitney Haller, made the discovery when they stumbled on the online obituary of their father, who left when they were children. The notice said their Dad died in 2005 at the age of 75, “from complications resulting from a long battle with Alzheimer’s.”

That line nagged at Mr. Haller as he went about his busy days, dividing his time between working in the commercial office furniture business in Toronto and raising a son he welcomed late in life.

The trim and gregarious cycling enthusiast, now 60, thought about it whenever he forgot a name he should have remembered. He wondered if he was experiencing run-of-the-mill aging or the earliest signs of an illness that could siphon away his memories, leaving him …