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Vol. LXVII, No. 12
June 5, 2015

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Brain Stethoscope
New Device Listens to Brain, May Help Epileptic Patients

It was a harmonious pairing. A neurologist and a composer/music researcher teamed up to hear the rhythms of the brain. Their invention, currently in testing, might help diagnose seizures earlier to foster earlier intervention and prevent permanent brain damage.

It all began when Dr. Josef Parvizi, associate professor of neurology and neurological sciences at Stanford University, was enjoying a concert of cosmic sounds: the Kronos Quartet had converted radio waves from outer space into music. He wondered: can we record brain waves as music? So Parvizi contacted Dr. Chris Chafe, director of Stanford’s Center for Computer Research in Music and Acoustics (CCRMA), to find out.

Parvizi and Chafe presented their research at the NIMH Director’s Innovation Speaker Series recently. After years of collaboration, they have invented a prototype—the brain stethoscope—that sonifies brain waves. They’re testing this device on seizure patients in the hospital; there’s potential for the portable, simple-to-use gadget to help anyone detect neurological danger, even in non-medical settings such as in the car, at work or at home.

Drs. Chris Chafe (l) and Josef Parvizi of Stanford are collaborating on what amounts to a “brain stethoscope.”

Drs. Chris Chafe (l) and Josef Parvizi of Stanford are collaborating on what amounts to a “brain stethoscope.”

Photo: Ernie Branson

The brain stethoscope uses a patented algorithm that allows slow signals from the brain to be converted to sounds in real time. This process of data sonification and frequency modulation builds on the earlier research of Dr. John Chowning, a pioneer in computer music and founding director of CCRMA. Chafe’s work has effectively created the first sonified seizure.

“It’s so important to have art and artistic activity in an institution that is known to be a home for great engineers,” said Parvizi. “This interdisciplinary work we did took us outside the range of comfort of medical practice and music and created a platform for an innovative way of diagnosing brain conditions.”

Heeding the Warnings of Epilepsy

More than 2 million Americans suffer from epilepsy, a condition characterized by recurring seizures. If untreated, prolonged seizures can cause cognition problems, brain damage, even death.

Many seizures go undetected because most patients don’t exhibit behavioral signs until the seizure becomes severe, said Parvizi. In a condition known as non-convulsive status epilepticus, the brain stethoscope can be especially effective as an early diagnosis device.

In fact, many ongoing seizures even go undetected in the hospital. It can take hours for a technician to arrive, glue on electrodes and record an EEG (electroencephalogram). Then the results must be interpreted by a trained neurologist, said Parvizi. What’s more, it’s costly to have trained technicians and electrophysiologists on staff; many hospitals don’t have EEG machines.

The brain stethoscope incorporates electrode design, microelectronics and sonification bundled into a small, inexpensive device that’s attached to the head. Said Parvizi, “The brain is acting very differently [during seizure] and causes altered mental status, but you need a device where you can hear the tone” for earlier diagnosis.

Parvizi showed a video of an epileptic patient during a seizure. In the early stages, the patient was able to repeat words read to her. Without EEG, we wouldn’t know from her normal behavior that she was having a seizure. But as the seizure progressed, she stopped the task and became increasingly confused and uncommunicative. Chafe played an audio clip of the patient’s EEG during the word-repetition task.

Listening in on the Brain

In the audio clip, we hear a stable tone that soon starts to waver; the sound gets increasingly rapid and eventually becomes frantic. As the seizure migrates from one side of the brain to the other, the audio switches to a male voice, representing the other, now dominant hemisphere. “You can hear the rhythms of the seizure, also the magnitude of the signals and the loudness and modulated qualities,” said Chafe. “These are all acoustic parameters being driven by, or performed by, the seizure and it’s something we can do in real time.”

The brain stethoscope instantly recodes brain waves; it takes less than 10 seconds to determine if the patient is in seizure. Computer chips record electrical wave forms from the patient’s head and use Chafe’s algorithms to turn brain signals into sound, complete with voice pitch inflections. The process relates back to Chowning’s method of taking a stable, flat tone that increases in vibrato as it modulates.

As the seizure progresses, the tones become increasingly discordant. Parvizi said, “These are not the most pleasant sounds and we want them to stay unpleasant because we want them to signal danger to someone recording them.”

An Opus of Hope: Potential and Future Applications

The brain stethoscope acts like a cardiac stethoscope. Anyone can use it, even with no medical training. In a recent survey among untrained high school students using the device, there was a near 90 percent accuracy rate in detecting normal vs. abnormal sounds.

The average person can listen to the brain waves of a spouse or child or infant, or even one’s own brain waves, and hear when something’s starting to go awry. The device is cheap to produce and has the potential to help patients in hospitals and doctor’s offices, in homes, schools and offices, as well as in facilities in poorer countries.

“We are really looking forward to a future where this device sees the light of day and becomes available to anyone, anywhere,” said Parvizi.

There may also be additional medical applications including detecting early signs of stroke, abnormal heart rhythms, sleep patterns and psychological disorders.

Though Parvizi and Chafe come from two different disciplines, their combined expertise has created a revolutionary biofeedback tool. “This is an example of how this type of collegiality and collaboration and going outside of the box can lead to a new, innovative way of thinking,” said Parvizi. “Hopefully this will save a lot of lives in the future.”

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