The tolerability of rTMS treatment in schizophrenia with respect to cognitive function.

INTRODUCTION

The purpose of this study was to assess tolerability and safety of high-frequency rTMS with regard to cognitive performance when conducted as "add-on" treatment in chronic schizophrenia in-patients (n=32).

METHODS

Patients, who were on stable antipsychotic treatment, were randomly assigned to verum or sham condition (double-blind). In the verum group, ten sessions of 10 Hz rTMS with a total of 10 000 stimuli were applied over the left dorsolateral prefrontal cortex (PFC) at 110% of motor threshold over a period of two weeks. The sham group received corresponding sham stimulation. RTMS effects on cognitive performance were assessed with a neuropsychological test battery consisting of the following tests: trail making test A and B (TMT), Wisconsin card sorting test (WCST), D2 attention task and the "short test of general intelligence" (KAI).

RESULTS

No statistically significant deterioration of cognitive performance was observed as a result of rTMS treatment. Moreover it was shown that in the verum group patients with a less favourable performance on the WCST at baseline tend to improve after rTMS treatment with regard to psychopathology as opposed to patients in the control group.

DISCUSSION

The stability of cognitive function suggests good tolerability of rTMS treatment in schizophrenia. The absence of evidence for cognitive deterioration could be due to low and short stimulation parameters.