Adam Lepak looked over at his mother and said, "You're fake."
It was a Tuesday in July, late, and Cindy Lepak could see that her 19-year-old son was exhausted. Long days like this one, with hours of physical therapy and memory drills — I had a motorcycle accident, I hit my head and have trouble remembering new things, I had a motorcycle accident — often left him making these accusations.
"What do you mean 'fake,' Adam?" she said.
He hung his head. "You're not my real mom," he said. His voice changed. "I feel sorry for you, Cindy Lepak. You live in this world. You don't live in the real world."
Doctors have known for nearly 100 years that a small number of psychiatric patients become profoundly suspicious of their closest relationships, often cutting themselves off from those who love them and care for them. They may insist that their spouse is an impostor; that their grown children are body doubles; that a caregiver, a close friend, even their entire family is fake, a duplicate version.
Such delusions are often symptoms of schizophrenia. But in the last decade or so, researchers have documented similar delusions in hundreds of people who are not schizophrenic but have neurological problems including dementia, brain surgery and traumatic blows to the head.
A small group of brain scientists is now investigating misidentification syndromes, as the delusions are called, for clues to one of the most confounding problems in brain science: identity. How and where does the brain maintain the "self"?
What researchers are finding is that there is no single "identity spot" in the brain. Instead, the brain uses several different neural regions, working closely together, to sustain and update the identities of self and others. Learning what makes identity, researchers say, will help doctors understand how some people preserve their identities in the face of creeping dementia, and how others, battling injuries like Adam's, are sometimes able to reconstitute one.
"When I wrote up my first case like this back in 1987, no one was much interested; it was a curiosity," said Dr. Todd E. Feinberg, a neurologist and psychiatrist at the Albert Einstein College of Medicine and Beth Israel Medical Center, who just published a book on the topic, "From Axons to Identity." (Axons are nerve fibers.)
"Now there's an explosion of interest in these cases," Dr. Feinberg said, "because of their relation to the self, to the neurobiology of identity — to what it means to be human."
Who Is That?
"Who is that, Adam?" a physical therapist named Mike said on a recent morning, supporting the young man's lean frame in front of a full-length mirror; a nurse supported him from the other side. "Who do you see there?"
"Mike."
"That's right," said Pat Taisey, the nurse, who spends most days with him at home when the Lepaks are at work. "But who else do you see in the mirror, Adam?"
"You. Pat."
"Yes, but who else?" she said.
An uncertain smile creased Adam's face.
Two years ago, it was not a hard question to answer. He was a first-year college student with a girlfriend, a tight group of buddies. A vegetarian; a fitness nut; a master of sarcasm, of the lunatic prank. He was the drummer for Sacred Pledge, a "straight edge" band (no drugs, no alcohol, no promiscuous sex) in the Syracuse area.
After his senior year of high school in Weedsport, he climbed into a van and drove with the band across the country, playing clubs and parties, sleeping on people's floors, Dumpster diving for food, sleeping on the beach in California.
"I was so happy we let him go," Ms. Lepak said. "He decided that that life wasn't for him." He enrolled at Cayuga Community College in nearby Auburn, N.Y.
He was running late to class in October 2007, flying over a slight rise on Weedsport Sennett Road on a Honda Interceptor motorcycle, when he saw — too late — a car in his lane, stopped to make a turn. He dodged the car; he was wearing a helmet, but he lost the bike and tumbled hard over the asphalt. He spent most of the next six months in a near-vegetative state, mute and virtually immobile.
The diagnosis was diffuse axonal injury. "The textbook definition is essentially a blow that shuts down the bundle of wires responsible for keeping us conscious," said Dr. Jonathan Fellus, a neurologist at Kessler Institute for Rehabilitation in West Orange, N.J., who has overseen Adam's gradual recovery. "It's as if the major highways have taken a hit, and now the brain has to use back roads to function. But every brain responds differently. I have given up making predictions."
Researchers who have taken images of the brain as it processes information related to personal identity have noticed that several areas are particularly active. Called cortical midline structures, they run like an apple core from the frontal lobes near the forehead through the center of the brain.
These frontal and midline areas communicate with regions of the brain that process memory and emotion, in the medial temporal lobe, buried deep beneath each ear. And studies strongly suggest that in delusions of identity, these emotion centers are either not well connected to frontal midline areas or not providing good information. Mom looks and sounds exactly like Mom, but the sensation of her presence is lost. She seems somehow unreal.
