"Brain stethoscope" and MEG helmet help doctors read patients' minds
The brain can be a tricky organ to monitor, but two new studies have demonstrated novel ways to peer inside. Stanford scientists have created what they call a "brain stethoscope" that translates brain waves into sound, allowing medical professionals to listen out for seizures that aren't accompanied by convulsions. And over at the University of Nottingham, another team has developed a wearable magnetoencephalography (MEG) helmet that means patients no longer need to lie down perfectly still inside a huge machine.
The brain stethoscope was born to help solve a problem in treating epileptic seizures. Most of us might assume that seizures are fairly easy to spot, due to the physical convulsions that they set off, but that's just one symptom of a wider problem. Seizures are essentially erratic brain wave activity, and they're not always accompanied by convulsions. These so-called "silent seizures" are far more difficult to diagnose, and if left unchecked can damage the brain.
"You might think that all seizures must cause some sort of convulsions, namely a patient who's having a seizure must fall down and shake on the ground," says Josef Parvisi, an author of the study. "But that's actually not the case, especially in critically ill patients in the intensive care units. Close to 90 percent of those patients will have silent seizures."
But seizures can't hide from electroencephalography (EEG) scans, no matter how silent. Parvisi realized these readouts were a little like sheet music – the nuances are only clear to a trained eye. So he consulted with music professor Chris Chafe to find a way to convert the signals to sounds that would clearly alert anyone to a problem.
Chafe designed an algorithm that used EEG data to modulate a synthesized voice. During normal brain activity it produces a steady hum, but when a seizure strikes it takes on a haunting sound almost like screaming, which is clearly identifiable (if a little unnerving).
To test the system, the researchers ran 84 EEG scans through the algorithm, 32 of which had seizures or similar problems hidden in them. They then played these pieces of "music" to 34 medical students and 30 nurses to determine how well they could pick up when normal brain activity transitioned into seizures.
Even without training in diagnosing epilepsy, the participants were much more likely to identify seizures represented through sound. Their accuracy shot up from 50 percent – basically guessing – when reading an EEG, to over 95 percent when listening to the stethoscope.
While the study shows that the concept is solid, the researchers are now working on how this could be implemented as tools for physicians.
Wearable MEG machine
In a separate study, a team from the University of Nottingham has developed another new tool to make it easier to peer inside the brains of patients. Normally, MEG scans require patients to lie down in huge machines and stay very still, but as any parent will tell you, that's not always an option for young kids.
The researchers developed a wearable alternative, in the form of a 3D-printed helmet packed with "quantum" sensors that act like a scaled-down version of those in a regular MEG machine. These read the tiny magnetic fields created by brain waves, and can still do so while patients are moving their heads, allowing brain waves to be monitored during a wider range of actions than can be done inside the big tube of an MEG machine.
The helmet isn't completely free-moving though. The system requires large electromagnetic coils be placed on either side of the patient to cancel out interference by the Earth's magnetic field. In trials, the MEG helmet was able to read patient's brain waves while they nodded, stretched, drank tea and even played ping pong.
"This has the potential to revolutionize the brain imaging field, and transform the scientific and clinical questions that can be addressed with human brain imaging," says Gareth Barnes, lead researcher on the project. "Our scanner can be worn on the head like a helmet, meaning people can undertake tasks whilst moving freely. Importantly, we will now be able to study brain function in many people who, up until now, have been extremely difficult to scan – including young children and patients with movement disorders. This will help us better understand healthy brain development in children, as well as the management of neurological and mental health disorders."