From  the  book The Brain's Way of Healing

SPECIAL  DEVICE  continued

But Cheryl's story did not end there. She was so moved by her recovery that she decided to go back to school to become a rehabilitation professional. She did her internship at the Bachy-Rita lab. Her job was to train people to use the device that had helped her. She never dreamed who her first patient would be. Shortly after Cheryl was cured, I received an awful e-mail from Paul. He had received devastating personal news. He had been coughing, and, though he had never smoked, he was diagnosed with lung cancer that had metastasized to his brain. He underwent chemotherapy, with cisplatin, the cancer retreated, and he was able to go back to work. But just as an antibiotic had destroyed Cheryl's balance, Paul's chemotherapy destroyed his. It fell on Cheryl to train Paul to use the device he had helped invent. His balance problem was cured, and he returned to work. But in December 2005 he wrote to me that "the cancer returned ... I have even less energy!" He was able to work until shortly before he died in November 2006—about a year before neuroplasticity finally achieved wide recognition.

Dead Tissue, Noisy Tissue, and New Thoughts About the Device

One of Paul's last published works was a paper called "Is It Possible to Restore Function with Two-Percent Surviving Neural Tissue?" Here he reviewed his own work, as well as literature on humans and animals, and found an interesting coincidence. His father, Pedro, had lost 97 percent of the nerves that ran from his cerebral cortex through the brain stem to the spine. Doctors had shown that 97.5 percent of Cheryl's vestibular apparatus had been damaged. Evidence from other sources also indicated that it was possible to restore lost functions with only 2 percent of surviving neural tissue. Paul's theory was that in his father's case the rehabilitation had "apparently unmasked previously existing pathways that, prior to injury, had not had the same relationship to the recovered functions." Unmasking accounted for the neuroplastic rewiring.

But Paul, Yuri, and the team thought Cheryl's difficulties with balance had stemmed not only from loss of functioning tissue but also from the fact that her vestibular system had become very noisy: its damaged neurons were giving off disorganized, random signals that blocked detection of any useful signals from any remaining bits of healthy tissue. The balance device, which gave Cheryl more accurate information on where she was in space, reinforced the signals from the healthy neurons. Over time the brain neuroplastically reinforced these circuits, leading to her residual effect.

As I discussed in Chapter 3, the "noisy" brain, with a poor signal-to-noise ratio, applies to many forms of brain damage because surviving but damaged neurons don't necessarily "fall silent," but may still fire electrical spikes, just at different rates and rhythms than normal. In the brain, these aberrant signals can "mess up" the functioning of the healthy neurons they are connected to, and which are receiving chaotic input—unless the brain can shut down the damaged neurons. In engineering terms, Cheryl had a poor signal-to-noise ratio, meaning that not enough strong clear signals in her networks could be detected against the backdrop of other signals in the brain—the noise. A noisy brain can't perform its normal functions and soon stops doing so. Then learned nonuse sets in.

When asked to describe what it felt like to experience her brain before and after putting the device on, she said, "I always had this constant noise in my head, and not a noise I could hear, but this feeling of noise. If you could hear confusion, that is what it would sound like. And my brain was really, really confused because it didn't know what to do. I was so consumed with trying to stand up, and stay straight, and get from point A to point B. It is like you are in a room with a bazillion people talking all at once. That was what it felt like in my head. When I put that device in, it was just like, aaah, I had stepped out of that room, and I'm standing on the side of the ocean, and oh my gosh, it's quiet. It's still. But it feels so good. It's like I came back."

Meanwhile Yuri, the group's surviving neuroscientist, was struck by a number of things. When Cheryl was wearing the device, she appeared to enter a deep meditative state (the kind of relaxed state that I argue follows neuromodulation and is so helpful for neuroplastic healing). This was a surprise. Also, she and others who came to the lab for balance problems began to notice multiple unexpected yet welcome responses to the device. Though balance was the target, they saw improvements in sleep, multitasking, concentration, focus, movement, and mood. The treatment was showing benefits for patients who had different problems, such as stroke and traumatic brain injury. A few with Parkinson's, who had come for balance problems, found that their Parkinson's movement problems seemed to diminish.

The team's initial working hypothesis was that the device Cheryl used (which came to be called the Brain Port) provided accurate information to her brain about where she was in space, transmitted by the moving "champagne bubble" stimulation, and that it was this information that quieted her noisy brain, by overriding the inaccurate signals given off by her damaged tissue. The accurate information sent input to the 2.5 percent of her existing healthy tissue, exercised it, helped it build up stronger connections, and possibly recruited other brain areas to take over balance processing as well. The electrical stimulation was a medium for delivering that valuable information.

Yuri had a heretical thought. Maybe the electrical stimulation was providing a significant part of the cure. If it was only the information about where she was in space that was curative, he wondered, then why didn't Cheryl's problem get better when she looked at a wall with straight lines, or when her shoulders were touched with a finger whenever she leaned to the side? And why was the device helping so many other brain problems?

Yuri began to suspect that the energy stimulation itself was helping— as it did in the Russian sleep machines, when they cured insomnia.

"Yuri," says Mitch, "became cheerleader for the idea that it was the electrical stimulation on the tongue that was inducing the changes." 

At about that time, another group at another lab designed a study of the device, comparing users of the original device with a control group that got a version of the device that fired random electrical signals rather than information about where the subject was in space, on the assumption that random stimulation wouldn't provide useful information. "No!" Yuri protested, "that wont be a good control... the electrical stimulation alone will help." And it did.

What this suggested to Yuri was that the electrical stimulation, which started on the tongues sensory receptors and sent "spikes" to balance neurons in the brain stem, didn't stop there. The neurons in the brain stem's balance system were obviously sending spikes throughout much of the rest of the brain stem and other parts of the brain, activating them all, including areas that regulated sleep, mood, movement, and sensation. This hypothesis was confirmed when a subject used the device while his entire brain was scanned. Most of the brain lit up.

This result helped explain how the device was helping other disabilities or brain problems, especially when Yuri paired its use, and the information on balance that it provided, with appropriate mental and physical stimulation and exercises. Perhaps the device would alleviate other kinds of brain damage and, who knows, even assist ordinary learning? Paul's proteges, so eager to continue his work, suddenly suspected that they had in their hands an insight and a discovery that might allow them to make an all-purpose brain stimulator. So they made a new device, the PoNS, that, instead of providing information on where the user was in space, just provided ongoing stimulation.

Yuri knew of three other kinds of stimulators that worked like the PoNS, targeting the brain with very low stimulation. In vagus nerve stimulation (VNS), an electrode is coiled around the left vagus nerve (a cranial nerve near the carotid artery in the neck), which sends stimulation to the brain stem's nucleus tractus solitarius, one of the areas targeted by the device. At times VNS works for depression, but it requires surgery to implant a pacemaker into the chest to fire electrical stimulation. Another kind, deep brain stimulation (DBS), has been used on patients with Parkinson's disease or depression, to target the circuits in-volved  directly, with some success. But with DBSM a surgeon must implant electrodes deep in the brain. The PoNS is matter-of-factly held in the mouth as a child might hold a lollipop.

It was time to start gathering patients with different conditions and see whether this new device would help them.