In June 2012, the case of HK Derryberry was reported, a blind 20-year-old man who could clearly recall every day of his life since the age of about 11. Derryberry had been born at 27 weeks, weighing just over and was in neonatal intensive care for 96 days. A severe brain hemorrhage was the likely cause of cerebral palsy, and his prematurity resulted in congenital blindness. He told researchers that his memories are rich in sensory and emotional details, regardless of whether they are from years ago or yesterday. About 90% of his memories are in the first person, compared with an average of 66% in the general population. Brandon Ally and his team, at Vanderbilt University, Nashville, Tennessee, conducted a series of tests with the subject, including a brain scan that was compared with 30 age-matched controls. His brain was smaller than average (probably a result of his premature birth at 27 weeks). His right amygdala, however, was 20% larger, with enhanced functional connectivity between the right amygdala and hippocampus and in other regions. In 2016, HK's remarkable life story was published by HarperCollins Christian Publishing in a book entitled "The Awakening of HK Derryberry: My Unlikely Friendship with the Boy Who Remembers Everything". It was written by his mentor Jim Bradford with the help of Andy Hardin.