Alirio, a coffee farmer and participant in the Medelln Alzheimers drug trialsSteve Russell/Toronto Star via Getty ImagesValley of ForgettingJennie Erin Smith (Riverhead Books)After working in health journalism for over 10 years, I have covered countless drug trials some runaway successes, others out-and-out failures, and everything in between. But I am ashamed to admit that I have rarely considered how these highs and lows affect the people involved.In Valley of Forgetting: Alzheimers families and the search for a cure, journalist Jennie Erin Smith puts them in the spotlight in her story of a