title: Effect of low-frequency rTMS on electromagnetic tomography (LORETA) and regional brain metabolism (PET) in schizophrenia patients with auditory hallucinations.
abstract: BACKGROUND
  Auditory hallucinations are characteristic symptoms of schizophrenia with high clinical importance. It was repeatedly reported that low frequency (<or=1 Hz) repetitive transcranial magnetic stimulation (rTMS) diminishes treatment-resistant auditory hallucinations. A neuroimaging study elucidating the effect of rTMS in auditory hallucinations has yet to be published.
  
  
  OBJECTIVE
  To evaluate the distribution of neuronal electrical activity and the brain metabolism changes after low-frequency rTMS in patients with auditory hallucinations.
  
  
  METHODS
  Low-frequency rTMS (0.9 Hz, 100% of motor threshold, 20 min) applied to the left temporoparietal cortex was used for 10 days in the treatment of medication-resistant auditory hallucinations in schizophrenia (n = 12). The effect of rTMS on the low-resolution brain electromagnetic tomography (LORETA) and brain metabolism ((18)FDG PET) was measured before and after 2 weeks of treatment.
  
  
  RESULTS
  We found a significant improvement in the total and positive symptoms (PANSS), 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. We detected a decrease in current densities (LORETA) for the beta-1 and beta-3 bands in the left temporal lobe whereas an increase was found for beta-2 band contralaterally.
  
  
  CONCLUSIONS
  Our 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. The LORETA indicates that the neuroplastic changes affect the functional laterality and provide the substrate for a metabolic effect.
authors.affiliation: Prague Psychiatric Center, Prague, Czech Republic. horacek@pcp.lf3.cuni.cz
authors.forename: Jiri
authors.initials: J
authors.lastname: Horacek
authors.forename: Martin
authors.initials: M
authors.lastname: Brunovsky
authors.forename: Tomas
authors.initials: T
authors.lastname: Novak
authors.forename: Lucie
authors.initials: L
authors.lastname: Skrdlantova
authors.forename: Monika
authors.initials: M
authors.lastname: Klirova
authors.forename: Vera
authors.initials: V
authors.lastname: Bubenikova-Valesova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Krajca
authors.forename: Barbora
authors.initials: B
authors.lastname: Tislerova
authors.forename: Milan
authors.initials: M
authors.lastname: Kopecek
authors.forename: Filip
authors.initials: F
authors.lastname: Spaniel
authors.forename: Pavel
authors.initials: P
authors.lastname: Mohr
authors.forename: Cyril
authors.initials: C
authors.lastname: Höschl
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D055590:Electromagnetic Phenomena / Q000379:methods; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006212:Hallucinations / Q000209:etiology / Q000473:pathology*; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000150:complications; D012720:Severity of Illness Index; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000379:methods; D050781:Transcranial Magnetic Stimulation
chemical_list: D019788:Fluorodeoxyglucose F18