Siamese Twins – A Modern-day Case
Krista Hogan and Tatiana Hogan were born on October 25, 2006. The Siamese twin girls are joined at the head, a condition called craniopagus conjoined twins. The girls are unusual in that they also share a connection between their brains. They were born in Vancouver, British Columbia and live with their mother and three other siblings in a small apartment next to their grandmother in nearby Vernon, British Columbia. The girls are the only unseparated craniopagus twins currently living in Canada.
The interconnected nervous systems of these girls makes them unique, even among craniopagus twins. Their brains are connected through a neural bridge between their thalami. The thalamus is the sensory processing hub of the brain. This interconnection allows each girl to see out of any of their four collective eyes. It also allows one twin to feel it when the other twin is tickled. It is also believed that they can share thoughts, although this has not been objectively verified.
When one twin uses the eyes of the other to see there is an internal shift that takes place suggesting that a decision has to be made to use this ability. Even more interesting is that the twins have different tastes in food. Tatiana hates ketchup, while Krista loves it. Krista dislikes the breading on her chicken McNuggets and scrapes it off. Tatiana, on the other hand likes the breading on her chicken McNuggets. It is believed that somehow the twins can selectively block out certain shared sensory input. What this may mean to our understanding of the ability of the brain to change and adapt is still not know, but it promises to be very revealing. By studying these two little girls, as they develop, we should gain a greater understanding of the development of personality, empathy and consciousness.
Historically, conjoined twins elicit public fascination for their physical difference and rarity. They were often depicted as nonhuman, examples of freaks and nature gone horribly wrong, destined only for lives in circus sideshows. As the public’s attitude toward handicapped people changed and as medical techniques improved during the 20th century, separation of conjoined twins became a realistic solution for many.
Doug Cochrane, a neurosurgeon at B.C. Children’s Hospital and a member of the medical team at the twin’s birth recalls, “At the time the immediate reaction to conjoined twins was, ‘gee whiz’ you’ve got to get them separated. You’ve got to make them normal. They’ve got to fit our social context of what normality is.” However, “It’s not my role to create injury for the sake of social conformity.” Added Dr. Cochrane. He determined that it was not possible to separate the twins without creating neurological injury that would be more devastating than their existing disability. Dr. Cochrane concluded “They give us the opportunity to appreciate the differences and similarities we all share; we are all human, they are very much human. The fact that they are different just makes them something to be cherished, and not something that goes into the circus.”