In the classic science-fiction movie Forbidden Planet,
space travelers from Earth land on a distant planet, where they
encounter the remnants of a technologically advanced
civilization. Even though they are not from this distant planet,
the space travelers are able to communicate with one of the alien
computers. They do this by connecting themselves to glowing head
probes. By doing this the space traveler's thoughts and feelings
are directly conveyed to the alien computer over a neural link.
In the science-fiction movie The Matrix, the world is
run by machines that use humans as batteries so sustain
themselves. A group of humans brake the grip of the machines and
begin to wage a war on their metallic oppressors. These people
are able to fight the machines with the help of computers. Each
one of these people has a jack in the back of his or her head
that is connected to a computer. By doing this, the people are
able to turn their thoughts, such as dodging bullets and knowing
Kung-Fu, into reality.
The idea of people having their minds linked to
computers has appeared throughout works of science-fiction. The
way this idea works is very simple. A person thinks of a command
and the computer immediately responds. 'Thought recognition
would be the ultimate computer interface, the machine acting as
an extension of the human nervous system itself.'(Lusted, Hugh S.
and Knapp, R. Benjamin Controlling Computers with Neural Signals
Scientific American, October 1996) This technology would prove
very useful for people with neuromuscular handicaps. The purpose
of this paper is to show how controlling computers with neural
signals will help make life easier for people with handicaps and
how it will affect the future.
Computer technology has advanced considerably in the
last forty years. Even with all these advances, constructing a
versatile neural junction between a human brain and an electronic
one remains a formidable challenge.(Lusted, Hugh S. and Knapp, R.
Benjamin Controlling Computers with Neural Signals Scientific
American, October 1996) Attempts to tie the nervous system to
external electronic circuits are, however, well worth pursuing.
The results may provide means for effortless communication with
computers.
The closest thing to computer thought recognition right
now is voice recognition. Voice recognition software has been in
development since the 1950's. This software has been available
and affordable for the past three or four years to the general
public. The purpose of voice recognition software is to allow
the user to dictate words into a microphone that are transformed
into either text for word processing or commands for navigation,
without the use of a keyboard.(Communication Technology for
Disabled Persons. Erich E. Sutter in Handbook of Amyotrophic
Lateral Sclerosis. Edited by Richard Alan Smith. Marcel Dekker,
1992) This is helpful for physically-challenged users that are
unable to use a keyboard. It is also a timesaver for people with
poor typing skills.
Computer thought recognition is more complicated than
just linking the human brain with a computer. That statement is
a very crude way of explaining this idea. As you may already
know, the electrical nature of the human nervous system--the
basis for direct neural control of computers--has been recognized
for more than a century. In 1849, the German physiologist Emil
Heinrich Du Bois-Reymond, first reported the detection of minute
electrical discharges created by the contraction of the muscles
in his arms.(Lusted, Hugh S. and Knapp, R. Benjamin Controlling
Computers with Neural Signals Scientific American, October 1996)
He made these observations using a primitive device for measuring
voltages called a galvanometer.
Galvanometers are used with direct current are most commonly of
the D'Arsonval type. A small coil of fine wire held by two
springs is pivoted between a pole of a permanent magnate. The
current moving through the wire causes the coil to develop a
magnetic field of its own, which makes it rotate with respect to
the magnate. (Galvanometer http://www.optonline.com/comptons/
ceo/01810_A.html) Du Bois-Reymond attached the wire of this
instrument to his body using pieces of saline-soaked blotting
paper to keep electrical resistance in the connection to a
minimum. He soon realized that the skin was like a barrier to
the basic muscle signals. To get past this problem, Du
Bois-Reymond induced a blister on each one of his arms. He then
removed the skin and placed the paper electrode within the
wounds. He was then able to capture electrical signals that were
about thirty times stronger than those he could obtain with the
skin intact.
Given these early investigations a foundation was built
for a technique that serves well today to monitor muscle
contractions. Modern silver chloride electrodes and sensitive
electronic amplifiers, small muscle impulses--provide easily
those muted by passage through the skin--provide easily
registered voltages. (Lusted, Hugh S. and Knapp, R. Benjamin
Controlling Computers with Neural Signals Scientific American,
October 1996) This phenomenon was first exploited by medical
researchers during the 1970's to devise mechanized prostheses
that could operate by sensing muscle contractions. Other
scientists realized that electrical impulses from active muscle
fibers could also help people who suffered from diseases or
injuries that left them too weak to move any of their limbs. The
only thing they needed was to have electrodes placed near
unimpaired muscles. Following that strategy, even profoundly
handicapped individuals can manipulate electronic equipment with
the electrical signal from muscles (called an electromyographic
signal, ...