Effect of low-frequency rTMS on electromagnetic tomography (LORETA) and regional brain metabolism (PET) in schizophrenia patients with auditory hallucinations.
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.
Horacek
Jiri
J
Prague Psychiatric Center, Prague, Czech Republic. horacek@pcp.lf3.cuni.cz
Brunovsky
Martin
M
Novak
Tomas
T
Skrdlantova
Lucie
L
Klirova
Monika
M
Bubenikova-Valesova
Vera
V
Krajca
Vladimir
V
Tislerova
Barbora
B
Kopecek
Milan
M
Spaniel
Filip
F
Mohr
Pavel
P
Höschl
Cyril
C
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
D019788:Fluorodeoxyglucose F18