Blind Woman Who Can 'See' Motion Holds Promise for Researchers
A 48-year-old Scottish woman is helping researchers around the world better understand how the brain responds to blindness and motion, thanks to her unique sense of 'sight.'
Milena Canning lost her vision nearly two decades ago after a respiratory infection and a sudden series of strokes. She remained in a coma for over 8 weeks, and Canning's doctors told her she wouldn't see again.
However, a few months after coming out of her coma, Canning could see a few things. She saw a flash of green from a shiny gift bag. She saw her daughter's ponytail moving whenever they walked, but she still couldn't see her face.
Canning consulted with doctors who then suggested she travel to the Brain and Mind Institute in London, Canada. There, Canning met with neurophysicist Jody Culham who was fascinated by Canning's abilities. Culham conducted a functional Magnetic Resonance Imaging (fMRI) exam in order to see the real-time makeup of Canning's brain and how it operated.
Culham and the rest of the neurologists discovered Canning had a rare case of Riddoch syndrome. Riddoch syndrome refers to any blind person who can consciously see an object in motion. However, those blind patients cannot see objects at rest.
"She is missing a piece of brain tissue about the size of an apple at the back of her brain -- almost her entire occipital lobes, which process vision," said Culham, a professor in the Department of Psychology and Graduate Program in Neuroscience.
"In Milena's case, we think the 'super-highway' for the visual system reached a dead end. But rather than shutting down her whole visual system, she developed some 'back roads' that could bypass the superhighway to bring some vision -- especially motion -- to other parts of the brain."
Culham said the syndrome seemed to exist despite the extensive brain damage, and thus it provided considerable new information to the researchers.
"This work may be the richest characterization ever conducted of a single patient's visual system," said Culham. "She has shown this very profound recovery of vision, based on her perception of motion."
Culham put Canning into a study where she was tested in her ability to see motion, direction, size, and speed of different balls rolling at her. Canning could get her hand open to grab the balls at precisely the right time.
While the motion test was promising, Canning struggled in correctly identifying color, the study noted. She was also 50/50 on figuring out if someone in front of her had a thumbs-up position or a thumbs-down position with their hands.
However, Culham said the results are extremely promising and could redefine conventional definitions of seeing and blindness.
"Patients like Milena give us a sense of what is possible and, even more importantly, they give us a sense of what visual and cognitive functions go together," Culham said.
Canning said her visit with the institute and Culham's office helped clarify more about how her brain functions. Canning can also get around chairs, notice brighter colors, and even see steam rising from a hot cup of coffee.
"I can't see like normal people see or like I used to see. The things I'm seeing are really strange. There is something happening and my brain is trying to rewire itself or trying different pathways," Canning said.