While interference is rarely clinically important, more study is needed. A study by Mayo Clinic researchers found that cellular telephones interfered with the operation of external devices that monitor the heart and lungs, however, in most instances, the interference was not sufficient to meaningfully hinder interpretation of data. The most severe interference occurred when the cellular telephone was held one to two inches from the most vulnerable area of external cardiopulmonary monitoring devices. Among the 526 tests, interference was deemed clinically important in 7.4 percent.
Researchers recommend that additional testing be conducted.
Clinically important was defined as any interference that might hinder interpretation of data or cause the equipment to malfunction. The banning of cellular telephones within hospitals has not been based on objective experimental or clinical testing, but on theoretical concerns that wireless technology could interfere with medical equipment, the study s authors said. Considerable research has been done on the potential interactions of wireless technology and implanted devices. Research on the interaction of the cellular telephone and external equipment in a hospital has been general and inconclusive. The study appears in the January issue of Mayo Clinic Proceedings.