Four hearing-aid RCDs were chosen for the second study and operated in four different positions: directly over the pacemaker site, over the site but about 18 inches away, one inch away from the atrial lead wire and one inch from the ventricular lead wire. The authors noted that no published studies or research existed at the time of the article on whether pacemaker/hearing aid proximity might create electronic interference that could adversely affect the pacemaker. The second was an exploration of the effects of several types of RCDs on several varieties of pacemaker, done within an artificial chest cavity. The first was a study on a single patient at a pacemaker center, with his physician present. Reiter and Jorge Camunas on "Hearing Aid Remote Control Devices and the Pacemaker Patient." In the article, the authors described two studies they had done on hearing aid devices and pacemakers. The April 2001 edition of the Hearing Journal carried an article by Levi A. A good example of where not to carry your RCD, according to the literature, would be a breast pocket in a shirt or a suit. Some product literature for hearing aid RCDs carry warnings that say if you have a pacemaker, you should not keep the remote control for your hearing aid near where your pacemaker was surgically installed.