Working on a computer terminal can be a pain in the neck, not to mention the wrist, arms and shoulders. But when you're being monitored electronically by your employer, the pain gets worse.

That's the finding of a new study that found that workers whose performance was tracked by computers suffered more job stress than those watched over by humans. The workers questioned were randomly picked from among directory assistance operators, service representatives and clerks at the seven regional telephone companies, the so-called Baby Bells, all of which use video display terminals (VDTs) to do their job. The companies declined to participate in the study, conducted by the University of Wisconsin for the Communications Workers of America (CWA).

The study showed that twice as many workers who were electronically monitored by their supervisors reported wrist pains and 20 percent more reported neck pains than those who were not electronically monitored. The study also showed greater incidents of depression, tension and extreme anxiety among electronically monitored workers, although the differences were in the 10 percent to 15 percent range.

"Electronic monitoring is seen as a major cause/promoter of psychological and physical health complaints. Monitored workers reported more boredom, high tension, extreme anxiety and depression, anger and severe fatigue than non-monitored workers," the study said.

Or, in the scientific terms of the study, "the threat of job loss is a very potent stressor."

The study comes at a time when the use of VDTs is on a dramatic rise throughout the workplace. With that rise has been an increased concern over the impact of the equipment on the health safety of the worker, in terms of both repetitive motion injuries and potential radiation hazards from the computer monitors.

For millions of American workers, the computer has become something of an electronic assembly line where employers can tell to the exact minute when, who and where a mistake was made. The computer tells all, the number of keystrokes per minute, the amount of time it takes to process every form, the length of a break. In the telecommunications industry, there's an additional stress: electronic eavesdropping to judge an individual's performance with the public.

Employees are monitored by supervisors either watching the information typed into the computer -- often the case in the telephone industry -- or simply listening in on telephone conversations with customers.

There have been major studies of repetitive motion injuries, such as carpal tunnel syndrome, an inflammation of the wrist muscles, that have resulted from constant keyboard use and the improper positioning of the equipment, but this, according to the authors, is the first major effort to add the problem of mental stress to the debate.

Michael J. Smith, principal author of the study, is chair of the industrial engineering department at the University of Wisconsin, which conducted the study, and the former chief of the stress research section of the National Institute of Occupational Safety and Health. In his report, Smith cautioned that because only slightly more than 20 percent of the 2,900 employees surveyed responded to questionnaires, further detailed studies at two additional sites would be conducted to verify the findings.

CWA President Morton Bahr said in a prepared statement that the study shows that "the VDT is not a benign machine: It is potentially very hazardous to workers' health." He said the findings of the new study "have repercussions far beyond the telecommunications industry. The VDT is the centerpiece of today's office and the office of the future." "Ten years ago, our union represented some 10,000 VDT operators in telecommunications," Bahr said. "Today, we represent more than 425,000 VDT workers. ... Resolving the problems caused by VDTs will become an ever more pressing issue, because of their increasingly adverse impact on the health of our nation's work force."

Bahr said the study should send a message to employers to "stop using secret monitoring like an electronic whip to over-supervise and infantilize adult workers."

The Conference Board, a business-oriented research organization in New York, said a recent survey of nearly 400 employers showed that approximately two-thirds of those companies thought monitoring was either ineffective or counterproductive.

But Burke Stintson, a spokesman for American Telephone & Telegraph Co., which has been in a long fight with the CWA over the electronic monitoring issue, said such monitoring is necessary, particularly to check on telephone operators to assure that customers received courteous treatment and correct information.

"I don't know of any other way except random checks on operators," he said. "I guess the bottom line is we think it {monitoring} is a basic to the industry."