[accessibleimage] Fw: sensory treatment

An interesting article about sensory substitution.
enjoy ....


New York Times: November 23, 2004.
New Tools to Help Patients Reclaim Damaged Senses.
By SANDRA BLAKESLEE.
     
Cheryl Schiltz vividly recalls the morning she became a wobbler. Seven years 
ago, recovering from an infection after surgery with the aid of a common 
antibiotic, she climbed out of bed feeling pretty good. 

"Then I literally fell to the floor," she said recently. "The whole world 
started wobbling. When I turned my head, the room tilted. My vision blurred. 
Even the air felt heavy."

The antibiotic, Ms. Schiltz learned, had damaged her vestibular system, the 
part of the brain that provides visual and gravitational stability. She was 
forced to quit her job and stay home, clinging to the walls to keep from 
toppling over. 

But three years ago, Ms. Schiltz volunteered for an experimental treatment - a 
fat strip of tape, placed on her tongue, with an array of 144 microelectrodes 
about the size of a postage stamp. The strip was wired to a kind of carpenter's 
level, which was mounted on a hard hat that she placed on her head. The level 
determined her spatial coordinates and sent the information as tiny pulses to 
her tongue. 

The apparatus, called a BrainPort, worked beautifully. By "buzzing" her tongue 
once a day for 20 minutes, keeping the pulses centered, she regained normal 
vestibular function and was able to balance. 

Ms. Schiltz and other patients like her are the beneficiaries of an astonishing 
new technology that allows one set of sensory information to substitute for 
another in the brain.

Using novel electronic aids, vision can be represented on the skin, tongue or 
through the ears. If the sense of touch is gone from one part of the body, it 
can be routed to an area where touch sensations are intact. Pilots confused by 
foggy conditions, in which the horizon disappears, can right their aircraft by 
monitoring sensations on the tongue or trunk. Surgeons can feel on their 
tongues the tip of a probe inside a patient's body, enabling precise movements. 

Sensory substitution is not new. Touch substitutes for vision when people read 
Braille. By tapping a cane, a blind person perceives a step, a curb or a puddle 
of water but is not aware of any sensation in the hand; feeling is experienced 
at the tip of the cane.

But the technology for swapping sensory information is largely the effort of 
Dr. Paul Bach-y-Rita, a neuroscientist in the University of Wisconsin Medical 
School's orthopedics and rehabilitation department. More than 30 years ago, Dr. 
Bach-y-Rita developed the first sensory substitution device, routing visual 
images, via a head-mounted camera, to electrodes taped to the skin on people's 
backs. The subjects, he found, could "see" large objects and flickering candles 
with their backs. The tongue, sensitive and easy to reach, turned out to be an 
even better place to deliver substitute senses, Dr. Bach-y-Rita said. 

Until recently sensory substitution was confined to the laboratory. But 
electronic miniaturization and more powerful computer algorithms are making the 
technology less cumbersome. Next month, the first fully portable device will be 
tested in Dr. Bach-y-Rita's lab.

The BrainPort is nearing commercialization. Two years ago, the University of 
Wisconsin patented the concept and exclusively licensed it to Wicab Inc., a 
company formed by Dr. Bach-y-Rita to develop and market BrainPort devices. 
Robert Beckman, the company president, said units should be available a year 
from now.

Meanwhile, a handful of clinicians around the world who are using the BrainPort 
on an experimental basis are effusive about its promise.

"I have never seen any other device do what this one does," said Dr. F. Owen 
Black, an expert on vestibular disorders at the Legacy Clinical Research and 
Technology Center in Portland, Ore. "Our patients are begging us to continue 
using the device." 

Dr. Maurice Ptito, a neuroscientist at University of Montreal School of 
Optometry, is conducting brain imaging experiments to explore how BrainPort 
works.

Dr. Eliana Sampaio, a neuroscientist at the National Conservatory of Arts and 
Métiers in Paris, is using the BrainPort to study brain plasticity. Sensory 
substitution is based on the idea that all sensory information entering the 
brain consists of patterns carried by nerve fibers.

In vision, images of the world pass through the retina and are converted into 
impulses that travel up the optic nerve into the brain. In hearing, sounds pass 
through the ear and are converted into patterns carried by the auditory nerve 
into the brain. In touch, nerve endings on skin translate touch sensations into 
patterns carried into the brain. 

These patterns travel to special sensory regions where they are interpreted, 
with the help of memory, into seeing, hearing and touch. Patterns are also 
seamlessly combined so that one can see, hear and feel things simultaneously. 

"We see with the brain, not with the eyes," Dr. Bach-y-Rita said. "You can lose 
your retina but you do not lose the ability to see as long as your brain is 
intact." 

Most important, the brain does not seem to care if patterns come from the eye, 
ear or skin. Given the proper context, it will interpret and understand them. 
"For me, it happened automatically, within a few minutes," said Erik 
Weihenmayer, who has been blind since he was 13.

Mr. Weihenmayer, a 35-year-old adventurer who climbed to the summit of Mount 
Everest two years ago, recently tried another version of the BrainPort, a hard 
hat carrying a small video camera. Visual information from the camera was 
translated into pulses that reached his tongue.

He found doorways, caught balls rolling toward him and with his small daughter 
played a game of rock, paper and scissors for the first time in more than 20 
years. Mr. Weihenmayer said that, with practice, the substituted sense gets 
better, "as if the brain were rewiring itself." 

Ms. Schiltz, too, whose vestibular system was damaged by gentamicin, an 
inexpensive generic antibiotic used for Gram-negative infections, said that the 
first few times she used the BrainPort she felt tiny impulses on her tongue but 
still could not maintain her balance. But one day, after a full 20-minute 
session with the BrainPort, Ms. Schiltz opened her eyes and felt that something 
was different. She tilted her head back. The room did not move. "I went running 
out the door," she recalled. "I danced in the parking lot. I was completely 
normal. For a whole hour." Then, she said, the problem returned. 

She tried more sessions. Soon her balance was restored for three hours, then 
half a day. Now working with the BrainPort team at the University of Wisconsin, 
Ms. Schiltz wears the tongue unit each morning. Her balance problems are gone 
as long as she keeps to the regimen. 

How the device produces a lasting effect is being investigated. The vestibular 
system instructs the brain about changes in head movement with respect to the 
pull of gravity. Dr. Bach-y-Rita speculated that in some patients, a tiny 
amount of vestibular tissue might survive and be reactivated by the BrainPort.

Dr. Black said he had seen the same residual effect in his own pilot study. "It 
decays in hours to days," he said, "but is very encouraging."

Blind people who have used the device do not report lasting effects. But they 
are amazed by what they can see. Mr. Weihenmayer said the device at first felt 
like candy pop rocks on his tongue. But that sensation quickly gave way to 
perceptions of size, movement and recognition. 

Mr. Weihenmayer said that on several occasions he was able to find his wife, 
who was standing still in an outdoor park, but he admitted that he also once 
confused her with a tree. Another time, he walked down a sidewalk and almost 
went off a bridge.

Nevertheless, he is enthusiastic about the future of the device. Mr. 
Weihenmayer likes to paraglide, and he sees the BrainPort as a way to deliver 
sonar information to his tongue about how far he is from the ground. 

Dr. Ptito is scanning the brains of congenitally blind people who, wearing the 
BrainPort, have learned to make out the shapes, learned from Braille, of 
capital letters like T, B or E. The first few times they wore the device, he 
said, their visual areas remained dark and inactive - not surprising since they 
had been blind since birth. But after training, he said, their visual areas 
lighted up when they used the tongue device. The study has been accepted for 
publication in the journal Brain. 

Dr. Ptito says he would like to see if he could teach his subjects how to read 
drifting letters like those in advertising displays. Not seeing motion is a big 
problem for the blind, he said.

In another approach, Dr. Peter Meijer, a Dutch scientist working independently, 
has developed a system for blind people to see with their ears. A small device 
converts signals from a video camera into sound patterns delivered by stereo 
headset to the ears. Changes in frequency connote up or down. Changes in pixel 
brightness are sensed as louder or softer sounds. 

Dr. Yuri Danilov, a neuroscientist and engineer who works with Dr. Bach-y-Rita, 
said the research team had thought of dozens of applications for the BrainPort, 
which he called a "USB port to the brain." 

In one experiment, a leprosy patient who had lost the ability to experience 
touch with his fingers was outfitted with a glove containing contact sensors. 
These were coupled to skin on his forehead. Soon he experienced the data coming 
from the glove on his forehead, as if the feelings originated in his 
fingertips. He said he cried when he could touch and feel his wife's face.

The federal government has also shown interest in sensory substitution 
technology. The Navy is exploring the use of a tongue device to help divers 
find their way in dark waters at night, said Dr. Anil Raj, director of the 
Institute for Human and Machine Cognition at the University of West Florida in 
Pensacola. 

The sensors detect water surges, informing Navy Seals if they are following the 
correct course. The Army is thinking about sending infrared signals from night 
goggles directly to the tongue, Dr. Raj said. 

In another application, student pilots have been fitted with body sensors 
attached to aircraft instruments. When the airplane starts to pitch or change 
altitude, they can feel the movements on their chests. 

Sensory substitution technology may eventually help millions of people overcome 
their sensory disabilities. But the devices may also have more frivolous uses: 
in video games, for example. 

Dr. Raj said the tongue unit had already been tried out in a game that involved 
shooting villains. "In two minutes you stop feeling the buzz on your tongue and 
get a visual representation of the bad guy," he said. "You feel like you have 
X-ray vision. Unfortunately it makes the game boring."

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