Fifteen young subjects with normal hearing participated in this study, which was designed to test the outer hair cell function. Distortion product otoacoustic emissions (DPOAE) were assessed immediately before and immediately after a 10-minute exposure to EMF from a GSM cell phone. Half of the participants used a 900 MHz and half an 1800 MHz phone. The SARs were 0.41 and 0.19 W/kg respectively. The exposure was double-blind, and a sham exposure was also tested in a counterbalanced order. A controlled sound exposure, in the form of running speech at a typical conversational level was also used.

There was no evidence that the EMF exposure induced any changes in the two forms of DPOAE generation (the place-fixed and time-domain windowing mechanisms).