Parietal double-cone coil stimulation in tinnitus

Non-pulsatile tinnitus is considered to be an auditory phantom percept. The extremely emotional context of disabling tinnitus often leads to a higher level of selective attention directed toward the tinnitus. As such, tinnitus is a continuously distracting auditory event. Auditory attention is associated with the activation of the intraparietal sulcus (IPS), and modulating the IPS with 10 Hz transcranial magnetic stimulation (TMS) creates the ability to ignore salient distractors. Thus, it can be expected that modulating the parietal area might interfere with the perception of tinnitus. The effect of TMS on tinnitus is evaluated using a double-cone coil tilted to the left parietal area in 24 individuals (study 1) and in 40 individuals with the double-cone coil symmetrically overlying both parietal areas (study 2). When transient tinnitus suppression is noted, the patient is asked to estimate the decrease in tinnitus in percentage using the numeric rating scale. The procedure is repeated with stimulations at sham, 1 and 10 Hz, each stimulation session consisting of 200 pulses for study 1 and for study 2 stimulations at sham, 1, 5, and 10 Hz, each stimulation session consisting of 200 pulses. For both studies, the order of the different stimulation frequencies was randomized over the participants. For study 1, patients report a significant transient reduction of the tinnitus percept for 10 Hz stimulation in comparison with, respectively, pre-treatment, sham, and 1 Hz stimulation, with a suppression effect of 11.36 %. No significant effect was obtained for 1 Hz stimulation with the coil tilted toward the left parietal area. For study, 2 patients revealed a significant suppression effect on 1, 5, and 10 Hz in comparison with pre-treatment. However, only stimulation at 5 and 10 Hz had a significant difference in comparison with sham with a suppression effect of, respectively, 8.78 and 9.50 %. Our data suggest that the parietal area is involved in tinnitus perception and that 10 Hz TMS using the double-cone coil overlying the parietal area can modulate tinnitus.