Auditory hallucinations are characteristic symptoms of schizophrenia with high clinical importance. It was repeatedly reported that low frequency (≤1Hz) repetitive transcranial magnetic stimulation (rTMS) diminishes auditory hallucinations. A neuroimaging study elucidating the effect of rTMS in auditory hallucinations has not yet been published.

To evaluate the changes of brain metabolism after low-frequency rTMS in patients with auditory hallucinations.

Low-frequency rTMS (0.9Hz, 100% of motor threshold, 20 min.) applied to the left temporo-parietal cortex was used for ten days in the treatment of medication-resistant auditory hallucinations in schizophrenia (N=12). The effect of rTMS on the brain metabolism (18FDG PET) was measured before and after the treatment.

We found a significant improvement in the total and positive symptoms, and on the hallucination scales (HCS, AHRS). The rTMS decreased the brain metabolism in the left superior temporal gyrus and in interconnected regions and effected increases in the contralateral cortex and in the frontal lobes (SPM).

The findings implicate that the effect is connected with decreased metabolism in the cortex underlying the rTMS site while facilitation of metabolism is propagated by transcallosal and intrahemispheric connections. Stereotactic neuronavigation of rTMS (SN rTMS) is a unique technology to target the rTMS coil with a high degree of anatomic accuracy based on the evaluation of the neuroimaging. Our finding enable the use of stereotactic neuronavigation of rTMS in auditory hallucination and pilot data are presented.

This research was supported by the projects 1M0517 MSMT CR and NR8792 of IGA MZ CR.