Transcranial magnetic stimulation of left temporoparietal cortex and medication-resistant auditory hallucinations

Background: Neuroimaging studies suggest that auditory hallucinations (AHs) of speech arise, at least in part, from activation of brain areas underlying speech perception. One-hertz repetitive transcranial magnetic stimulation (rTMS) produces sustained reductions in cortical activation. Recent results of 4-day administration of 1-Hz rTMS to left temporoparietal cortex were superior to those of sham stimulation in reducing AHs. We sought to determine if a more extended trial of rTMS could significantly reduce AHs that were resistant to antipsychotic medication. Methods: Twenty-four patients with schizophrenia or schizoaffective disorder and medication-resistant AHs were randomly allocated to receive rTMS or sham stimulation for 9 days at 90% of motor threshold. Patients receiving sham stimulation were subsequently offered an open-label trial of rTMS. Neuropsychological assessments were administered at baseline and during and following each arm of the trial. Results: Auditory hallucinations were robustly improved with rTMS relative to sham stimulation. Frequency and attentional salience were the 2 aspects of hallucinatory experience that showed greatest improvement. Duration of putative treatment effects ranged widely, with 52% of patients maintaining improvement for at least 15 weeks. Repetitive transcranial magnetic stimulation was well tolerated, without evidence of neuropsychological impairment. Conclusions: These data suggest that the mechanism of AHs involves activation of the left temporoparietal cortex. One-hertz rTMS deserves additional study as a possible treatment for this syndrome.