Ady Barkan loved taking afternoon runs on the California coast and holding his newborn son, Carl. But one day, he noticed a troubling weakness in his hand. At first, he brushed it off as carpal tunnel syndrome, but after a week of neurological exams and two MRIs, he learned the cause of the problem: amyotrophic lateral sclerosis, better known as ALS or Lou Gehrig’s disease. At age 32, Ady was given just three to four years to live. Yet despite the...