 Left: 10Hz, 100 RMT, 30 Trains, 5 second duration, 25 second inter-train interval Right: as above, BUT, applied with a Medtronic sham coil Sham: the following applied with a sham coil Left: 10Hz, 100 RMT, 30 Trains, 5 second duration, 25 second inter-train interval Right: 1 Hz, 100 RMT, 1 Train of 600 pulses Missed sessions will be made up by an extension of the treatment duration but only one missed session will be allowed weekly and only one missed session in a row. 