A very high-pitched tone produced by video display terminals could be raising anxiety levels among some office workers, two researchers at the University of Evansville in Indiana report.

A small device in the bowels of the computer tube vibrates 16,000 times per second, producing a non-stop monotone squeal at the upper limits of human hearing.Studies of the tone in the mid-1980s dismissed it as unimportant for a simple reason: Most adults have lost so much high-frequency hearing that the high-pitched tone is inaudible. Out of earshot, out of mind.

But communications professors Caroline Dow and Douglas Covert disputed those assessments. They found many in a group of college-age women they tested could hear the tone.

Anxiety and irritation was higher in those who could hear the tone. The researchers suggested the added stress could reduce their decision-making prowess on a job.

One way to eliminate that stress, the researchers offered, might be to block out the tone with ear plugs. How employers might feel about computer users wearing ear plugs was not evaluated.