In Israel’s Loewenstein Rehabilitation Hospital, the patient known as LI1 is a prisoner of her own body. She is a 51-year-old woman who was paralysed by a stroke several months ago. Suffering from “locked-in syndrome”, she is completely aware but unable to move or speak. She cannot even control the blinks of her eyes. And yet LI1 has recently been able answer questions from her doctors and communicate with her family through written messages. All she has to do is sniff.
LI1 uses a ‘sniff controller’, an incredible new technology that allows paralysed patients to control machines with their noses. It’s the brainchild of Anton Plotkin and Lee Sela at the Weizmann Institute of Science. Whenever a patient sniffs, the device measures the change in pressure inside their noses. It converts these into electrical signals that are passed to a computer via a simple USB connection. With just a sniff, people can move a cursor on a screen, allowing locked-in patients to write messages. Quadriplegics can even use the device to surf the web, or drive a wheelchair.
This technology was developed almost by accident in the lab of Noam Sobel, who studies the way of brains process our sense of smell. The group use a device called an olfactometer, which produces waves of smell to see how sensitive a person’s senses are. For one of their experiments, the team rigged the olfactometer so that volunteers triggered the odour pulse themselves when they sniffed. “We noticed that sniffs are a very good and fast trigger,” says Sobel. “It then simply dawned on us that instead of triggering odor, we could trigger anything: letters in a text writer or turns of a wheelchair. The rest just flowed (or rather, rushed) from there.” It’s a fantastic example of the useful and unpredictable roads that basic scientific research can lead to.