The digital avatar is essentially a mathematical model running on a computer, says Giulio Ruffini, coordinator of the Neurotwin project and chief science officer and cofounder of Neuroelectrics, a Spanish health tech startup that is developing noninvasive therapies for neurological disorders like epilepsy. To make a digital double for a patient with epilepsy, the Neurotwin team takes about half an hour’s worth of MRI data and about 10 minutes of EEG (electroencephalography) readings and uses these to create a computer model that captures the electrical activity of the brain, as well as to realistically simulate the brain’s main tissues, including the scalp, skull, cerebrospinal fluid, and gray and white matter.
The twin will include a network of embedded “neural mass models,” says Ruffini. These, he says, are basically computational models of the average behavior of many neurons connected to each other using the patient’s “connectome”—a map of the neural connections in the brain. In the case of epilepsy, some areas of the connectome could become overexcited; in the case of, say, stroke, the connectome might be altered. Once the twin has been created, the team can use it to optimize stimulation of the real patient’s brain “because we can run endless simulations on the computer until we find what we need,” Ruffini says. “It is, in this sense, like a weather forecasting computational model.”
For example, to improve treatment for an epilepsy patient, the person would wear a headcap every day for 20 minutes as it delivers transcranial electrical stimulations to their brain. Using the digital twin, Ruffini and his team could optimize the position of stimulating electrodes, as well as the level of current being applied.
Digital twinning any organ opens up a whole host of ethical questions. For example, would a patient have the right to know—or to refrain from knowing—if, say, their twin predicts that they’ll have a heart attack in two weeks? What happens to the twin after the patient dies? Will it have its own legal or ethical rights?
On the one hand, virtual body doubles provide us with exciting, revolutionary pathways to develop new treatments, says Matthias Braun, an ethicist at the University of Erlangen-Nürnberg, Germany, who has written about the ethics involved in the use of digital twins in health care. “But, on the other hand, it provides us with challenges,” he continues. For one thing, who should own a digital twin? The company building it? “Or do you have a right to say, well, I refuse the use of specific information or specific predictions with regard to my health insurance or with regard to the use in other contexts? In order to not be an infringement on autonomy or privacy, it is important that this specific person has control of the use [of their digital twin],” he says. Losing that control would result in what Braun dubs “digital slavery.”