One of the most irritating things about hospitals is the regulation about switching off mobile phones. I’ve often wondered whether there was any real evidence to support the injunction. Now, the New York Times reports that a study published in the latest edition of the Mayo Clinic Journal says that it was all baloney.

Another article in the same journal describes an experiment testing cellphones at the Mayo Clinic in Rochester, Minn., over a four-month period in 2006. The researchers used various phones and wireless handheld devices in 75 patient rooms and the intensive care unit, where patients were nearby or connected to a total of 192 medical machines of 23 types.

In 300 tests of ringing, making calls, talking on the phone and receiving data, there was not a single instance of interference with the medical apparatus. For many of the tests, the cellphones were working at lower received signal strengths — that is, showing fewer bars on the screen — which means they were operating at the highest power output levels. The authors conclude with a recommendation to relax existing cellphone rules.

But Mr. Shein said changing hospital cellphone regulations on the basis of these findings might be premature. “I think it’s dangerous for someone to go around doing ad hoc testing and conclude that it’s not going to be an issue for others,” he said. “There was no result, but there may have been if the circumstances had been slightly different.”

Dr. David L. Hayes, the senior author and a professor of medicine at the Mayo Clinic College of Medicine, disagreed. “Cellphone technology is the same throughout the country,” he said, “and hospital equipment is similar. I don’t think that testing in another part of the U.S. is going to have different results.

“I’m advocating based on this testing that we should change the rules,” Dr. Hayes continued, “and in fact many people ignore the rules anyway. In a way, the policy is already antiquated and violated de facto.”

During the 18 months that Sue was in an out of hospital, the injunction against mobiles proved a nightmare for me as I tried to be with her while keeping in touch with our children and those who were looking after them while I was away from home. I often had the dark suspicion that the real reason for the ban was to safeguard the business model of the firm which provided bedside fixed-line telephones at an extortionate cost.