Is Monitor Placement Putting Us At Risk?
The Age
Monday May 16, 1994
New evidence emerging in the United States suggests that an entire generation of computer users could be at risk of suffering carpal tunnel syndrome due to the way they look down at monitors.
THE IMPROPER placement of computer monitors causes the debilitating hand-and-arm injury that affects thousands of computer workers each year, commonly diagnosed as carpal tunnel syndrome (CTS), according to some experts who specialise in computer-workstation ergonomics.
One author has gone as far as to say constant strain on the neck from viewing improperly placed monitors 40 hours a week would cause CTS even if the computer user never typed a single word.
CTS is a category of repetitive strain injury (RSI) that is defined as a crushing or pinching of the median nerve that passes through the wrist-located bone and ligament tube, called the carpal tunnel.
Classic CTS symptoms are pain, numbness, and tingling in the hand. The April 1991, University of California, `Berkeley Wellness Letter' said the tingling and numbness can progress to a weakened grip and severe pain in the forearm or shoulder. `Occupational Hazards' said in the April, 1989 issue that CTS can worsen to the point where the nerves die. If this happens, the person's dysfunction of the hand or hands is irreversible, even with surgery.
In the past, computer workplace arm, wrist, and hand injuries have been blamed mostly on improper placement of the hands. The most- accepted theory is hands were never designed to lie flat in front of a computer user with fingers pounding out the same small motions over and over. Turning the hands down to lie flat twists the carpal tunnel, and the situation is aggravated by the finger movement which is said to thicken the tendons, pressing the nerve up against the bone.
The answer traditionally has been wearing wrist bandages or supports and, more and more often, surgery is used to open up the space around the median nerve. About 100,000 workers complained of CTS in 1992 and that number doubled in 1993.
But CTS is not limited to computer workstation users. It has been reported by piano and violin players, hair dressers, knitters, sewers, telephone operators, cigar rollers, and grocery store clerks.
Besides use of their hands in repetitive motions, these workers all have in common the fact that they are looking down which, according to Julia Lacy, is the true cause of the problem.
Lacy is author of a self-published book in its second printing, `How to Survive Your Computer Workstation' (CRT Services, 1990). She says her conclusions come from surveys of several thousand full-time computer users over a four-year period.
Her theory is that looking down pitches the head forward, placing strain on the neck muscles, which in turn causes spasm. These spasms aggravate the nerve that emanates from beneath the seventh vertebra of the cervical spin from the C7/C8 nerve root area, which is connected to the median nerve. This eventually causes the symptoms associated with CTS.
``The head," says Lacy, ``weighs as much as a bowling ball. Imagine the extra work neck muscles must do when the head moves off its natural pivot atop the shoulders.
``When monitors are set too low, neck muscles must hold up a very heavy head, clamping down with a vice-like grip on the C5-TI area, home of nerves found along the arm.
``Eventually these exceedingly tense nerves spasm, shooting pain down the arm and into the wrist and hand, where ultimately their branches terminate."
The C5 to TI area is seven bones, known as cervical vertebrae, that make up the cervical portion of the spine. The nerve roots that branch out from those bones are also designated by the names of the vertebrae.
Michael Gauf, managing editor of CTD News, a newsletter focused on cumulative disorders in the work place, told Newsbytes there is both medical and anecdotal evidence that a combination of repetitive motion and the improper monitor placement can cause CTS. Termed ``double crush syndrome", compression of the nerves theoretically occurs in both the cervical spine area and the wrist, causing pain and debilitation. Gauf said a number of factors could cause the cervical spine problem, including improper monitor placement, poor posture, or a bad-seating arrangement.
But Dr David Glick, an independent researcher for Neural Function Analysis, in Virginia, said his company started doing research to prove the double crush theory and ended up agreeing with Lacy's theory on CTS.
Dr Glick, who had never heard of Julia Lacy, said his survey of 496 people with CTS symptoms revealed only seven had damage in the wrist area. The overwhelming majority, 442, had neck injury in the C8 through T1 cervical area, 28 had neck and wrist injuries, 14 had shoulder injuries, and five had miscellaneous problems.
The seven who had CTS had also had corrective surgery to relieve the symptoms, which Dr Glick said permanently clouds the issue as to whether or not they ever originally needed surgery at all.
Several common sense observations make it clear that the widely accepted theory that computer keyboards cause CTS just could not be true, Dr Glick said.
One of the most-commonly reported symptoms of CTS is the loss of grip strength. A simple test shows the muscles that control grip strength are in the forearm. If a person raises an arm in front of him or her, grasps the arm just above the elbow with the other hand, then makes and releases a fist, he or she can feel the forearm muscles at work.
It is quite clear that the muscles that control the hand strength are in the forearm, not in the wrist, Dr Glick said.
Comparing nerves to water hoses in the way they transmit, Dr Glick described the flow of nerve impulses as always down, not up. For example, if a person suffers a spinal injury, they could be paralyzed from the point where the injury occurred, downward. The paralysis never occurs upstream of a nerve injury.
With these points in mind - ie that the muscles that provide the grip strength of the hand are in the forearm and that nerve damage always manifests itself below the damaged point - it is simply not possible that damage to the median nerve in the wrist could cause a lack of grip strength, Dr Glick asserts - it has to be damage above the forearm. Damage to the median nerve would affect the muscle movement needed to bring the thumb and forefinger together, like making the OK sign, and the muscles needed to produce the Spock from Star Trek ``live long and prosper" hand movement.
In addition, saying that the low or no-force repetitive motion of typing damages the nerves and muscle flies in the face of known medical facts concerning muscle, according to Dr Glick. Those interested in developing their bodies use low or no-force repetitive motion to build and tone muscles. Our bodies are made to move, Dr Glick said. Movement strengthens muscles and nerve tissue, and low force repetitive motion is not going to cause damage.
Additional support for his theory is found in motor-vehicle accident victims with cervical spine injuries, who display many of the same symptoms as do reported CTS victims, Dr Glick asserts.
Yet Lacy, Dr Glick, and others like them are flying in the face of the accepted causes of CTS symptoms. Compaq, IBM, and Apple Computer are all defendants in lawsuits filed by computer users who claim the companies' keyboards are responsible for their CTS symptoms. The 4 May issue of the `Wall Street Journal' carried this headline, ``Keyboard Users Say Makers Knew of Problems".
In addition, an entirely new generation of keyboards are being developed to tackle the CTS problem. There are keyboards split down the middle, some that raise up on the sides so hands work at a ``more natural angle", and others shaped like mounds that hands rest over that require users to learn ``chords" in order to type.
If these voices claiming the neck is the critical area are right, the new generation of laptop, palmtop, and hand-held computer users face serious problems ahead. Nearly all the lightweight, portable computers on the market now, and those proposed, require users to look down to see the monitor.
As for corrective measures, Dr Glick says the issue is not a one-size- fits-all answer, but once the cause of the ``nerve insult" in the neck is found, the symptoms disappear practically overnight. These changes include changing seating, moving the monitor, or even correcting sleeping positions. Lacy said most computer workstation users can protect themselves from CTS by making sure they do not have to bend their head, even slightly, to view the monitor.
But not every user can simply move their monitor up to eye level and correct the problem. Dr Glick said moving the monitor down may be the best way for those who have lost the normal cervical curve of the spine, and sitting upright could cause those users problems.
Dr Glick and Lacy told Newsbytes they are swimming upstream, fighting a flood of accepted CTS opinion. With the rising acceptance of computers into everyday life, there are fears an entire generation could suffer pain and physical damage. ``It's imperative this news gets out," Lacy told Newsbytes.
Newsbytes
© 1994 The Age