Tatiana and Krista go to school

This story originally ran in the fall of 2011, when Tatiana and Krista Hogan started kindergarten

Not many kids get to delay the start of kindergarten by a few days so they can fly to Manhattan for a network television appearance, but then few children are as unique as Tatiana and Krista Hogan. Last Wednesday, the twins from Vernon, B.C., who are conjoined at the head, and their parents, Felicia Simms and Brendan Hogan, were the star attractions on Anderson Cooper’s new syndicated daytime talk show. One month from their fifth birthdays, they’re back with their kindergarten classmates at Okanagan Landing Elementary, enjoying every minute of it.

“They love school,” says grandmother Louise McKay. The staff at the school have gone out of their way to make the girls comfortable, including setting aside a quiet room if they need a break and retrofitting a special toilet, she says. “They have a really nice team behind them, they’re helping us out trying to figure out ways of accommodating Tati and Krista so they’re comfortable at school.”

The girls have certainly caused a stir. One girl, especially, followed them around the first few hours, clearly curious. They quickly formed a friendship. “Every morning she waits for Tati and Krista to get there, and takes them over to play finger puppets,” says McKay. “They’re laughing and giggling.”

The path to kindergarten has been a remarkable achievement—a team effort that includes the extended family of 12 others that share two floors of a rented Vernon home, the school district, and the medical staff at B.C. Children’s Hospital in Vancouver.

Earlier this summer, Maclean’s accompanied the girls as they underwent a battery of neurological tests at the hospital. The results, released to the family in September, confirm some of what makes the girls unique: they can see through each other’s eyes, as their parents have long suspected.

At the hospital on that sunny June day, the girls were treated like old friends as staff in the diagnostic neurophysiology department gently attached a tangle of electrodes to their heads and bodies to measure their brains’ electrical response to a series of visual, sound and touch stimuli. For some of the tests the girls were given a mild sedative, which zoned out Tatiana, the smaller of the two, and had the opposite effect on Krista. “Wake up sleepyhead,” Krista chirped. “Sissy,” mumbled Tatiana, “I’m really tired.”

The family recently returned to Vancouver to meet with Dr. Juliette Hukin, a pediatric neurologist, to review the results. “She was just blown away,” says Simms of the doctor’s response. The tests showed the girls have slightly different visual perspectives. “Tatiana can see through both of Krista’s eyes,” says Simms. “Krista can see only through one of Tatiana’s eyes.” Since the girls look in different directions because of the way their skulls are fused, it means they have a huge degree of peripheral vision, and they deal with what must be an astonishing amount of visual information, somewhat akin to watching two television programs at once. “They must be able to shut it off,” says their grandfather, Doug McKay, “because otherwise it would be so confusing.”

Hukin, in an interview with Maclean’s, said the question of how the girls deal with sensory overload is one of many still to be answered. “On one hand, it’s a gift to be able to see more than other people, but on the other hand, it may be distracting,” she said. “I worry about their visual processing in the future, but maybe they’ll be able to figure it out. The young brain is very adaptable, and they’ve done remarkably well so far in working through the challenges of being conjoined.”

Future tests may eventually try to confirm the anecdotal evidence that the twins can taste what the other is eating. (Tatiana, for instance, openly rebels when Krista puts ketchup on her food, her parents report.) Then there’s the million-dollar question: can the girls actually read each other’s thoughts, as the family believes? “It’s really fascinating, isn’t it?” Hukin says with a laugh. “I don’t think we’re going to know the answer to that for a while.” It may have to wait until the girls can better verbalize such complex concepts. “It’s been almost five years since they were born,” Hukin said, “but it’s still very early in their development so it will certainly become more interesting over time.”

While the girls share a bridge between the thalamus, essentially the brain’s sensory relay station, nothing precludes them from forging strong, separate identities, as they obviously have, the neurologist said. “Most of their brain is separate—I would expect they will continue to develop their own personalities.”

Certainly, the girls seemed to charm Cooper, who is better known for reporting from war zones and disasters and is also the prime-time anchor on CNN. Before the pre-taped segment started, Cooper was on his belly, chatting with the girls and eating grapes. “It was really awesome to see someone that famous down on the floor, playing with little girls,” says Simms.

Cooper invited on the show his network colleague, Dr. Sanjay Gupta, CNN’s chief medical correspondent and a practising neurosurgeon. Gupta used a scan of the twins’ “zippered” brains to show what Canadian doctors had long since concluded: that it would be impossible to separate the girls. He outlined the brain tissue linking each girl’s thalamus, “the switch centre of the brain, where everything we do, we see, we touch comes through this area.” That shared connection, he said, “is something that’s never been seen before. It’s that what potentially makes them able to share all sorts of things: thoughts, visions, hearing, taste. This is what’s amazing to me as a neurosurgeon, I’m just completely blown away by this.”

Cooper was more curious about how the girls cope with day-to-day life, and the public’s response to them. Simms said most children have little problem accepting the twins, but a few parents have been so uncomfortable they’ve pulled their children away from playing with the girls. “Do you realize what you’re teaching your kid?” Simms recalls thinking. “You’re teaching that child that it’s not right to be different.”

How the girls cope with their physical difference and their profound bond as they mature is a mystery yet to unfold. The priority for doctors at Vancouver’s children’s hospital, said Hukin, is not satisfying medical curiosity but seeking ways to help the girls adjust to school, to keep them healthy and to help them realize their potential.

“They’re just truly remarkable girls, and so is their family, actually,” she said. “I just hope for the future they will continue to get good support so that they are able to be, well, kids, I guess.”