Transcranial magnetic stimulation in the treatment of schizophrenic symptoms: a double blind sham controlled study.

BACKGROUND: Schizophrenia is a disabling disease with a significant proportion of patients experiencing persistent symptoms. Repetitive transcranial magnetic stimulation (rTMS) is a promising new therapeutic tool that could benefit to schizophrenic patients. In this study we sought to assess the efficacy of active rTMS compared to sham stimulation in the treatment of patients with schizophrenia. METHOD: Eighteen schizophrenic patients according to DSM-IV criteria were randomly allocated to receive active or sham rTMS for 10 days over the left temporoparietal cortex (80% of the motor threshold, 1Hz, five trains of 1 min). Psychopathological dimensions were measured with the positive and negative syndrome scale and clinical global impression at baseline and after 10 session of rTMS. RESULTS: All patients were improved at the end of the trial but no significant group differences were found. Patients receiving sham stimulation showed the same pattern of improvement compared to active condition on all the subscales of the positive and negative syndrome scale and clinical global impression scores (p>0.05). CONCLUSION: In our study, active rTMS failed to show superiority over sham stimulation in the treatment of schizophrenic symptoms. Although previous results have shown that rTMS reduces auditory hallucination, its efficacy on other positive schizophrenic symptoms is not yet established. Nevertheless, the results of our study, even though negative, provide further insights in the pathophysiology of schizophrenia.

[Transcranial magnetic stimulation in cognition and neuropsychology]. / Stimulation magnétique transcrânienne et fonctions cognitives.

Classical neuropsychology relies on patients with irreversible brain lesions and cognitive impairments give informations about normal brain function. Transcranial Magnetic Stimulation (TMS) is a non-invasive method which involves placing an electromagnetic coil on the scalp. A pulse generates a magnetic field and this one passes, unattenuated by the skin and scalp, into the cortex inducing a current which results in neural activity. The technique shows a good temporal resolution and, moreover, because it represents an interference technique, can be said to have excellent functional resolution. For this reason, TMS appears to be a new tool for research in neuropsychology, producing transitory 'virtual lesion'effects which could help to understand how, when and where cognitive tasks are performed. The purpose of this article is to review recent research using TMS in cognition and neuropsychology, in a non exhaustive way. In safety studies, single TMS over motor cortex can produce simple movements. Several groups have applied TMS to the study of visual processing and found an impaired detection of visual stimuli. In a same way, TMS can disrupt speech when it was delivered in the language dominant hemisphere. Studies on the memory effects of TMS have been conflicting and the results seem to depend on the choice of paradigm and parameters. Other study depicted improvements in executive functioning after TMS on the left middle frontal gyrus or a diminution in reaction time during an analogic reasoning task. Moreover, some facial emotions seem to be less recognizable after TMS. Although TMS seem to be a new tool for neuro-psychological investigations in healthy subjects, few studies reported cognitive effects of rTMS treatment in psychiatry. In a therapeutic view, many of these trials have supported a significant effect of TMS, but in some studies the effect is small and short lived. Several groups have reported on the use of rTMS as a treatment in resistant major depression and the impact on cognition functioning. Most of results tend to find no adverse cognitive effects after several weeks of daily rTMS in depressed patients, compared to Electroconvulsivo-therapy (ECT). The effects of transcranial magnetic stimulation (TMS) on hallucination severity and neurocognition were studied in a recent study. A statistically significant improvement was observed on a hallucination scale and on one cognitive measure. TMS is a promising tool for cognitive neuroscience and can provide complementary information to the one obtained using neuropsychological tests, and the one obtained using functional imaging techniques, which have superior spatial but inferior temporal resolution.