What started with four patients with a puzzling form of amnesia turned into 14, and doctors are searching for others.
Dr. Jed Barash, a neurologist in the Boston area, noticed a pattern between 2012 and 2015. Four patients, mysteriously stricken with a sudden amnesia, had the same rare finding on MRI: A pair of tiny structures deep in their brains, called the hippocampus, was completely knocked out on both sides.
The hippocampus is a seahorse-shaped structure that plays a role in memory and emotion. The patients could remember earlier things, but they couldn’t make new memories, a phenomenon called anterograde amnesia.
Also peculiar, three of the four patients tested positive for opioids. The fourth, who was not tested, was known to have a history of opioid abuse. The patients, ages 22 to 52, came to the hospital between October 2012 and November 2015.