[Mood disorders: When should we use repetitive transcranial magnetic stimulation?] / Troubles de l'humeur : quand recourir à la stimulation magnétique transcrânienne ?

Repeated transcranial magnetic stimulation (rTMS) is still a recent treatment in psychiatry. This article aims at updating the clinicians'knowledge about rTMS in the treatment of mood disorders (uni and bipolar depressive disorders, manic/mixed states, suicidal risk, catatonia). It is intended for clinicians who are required to indicate and/or use rTMS in their current practice. rTMShas the highest level of evidence for the treatment of unipolar depression, provided that effective parameters are used, that is to say, for classical high frequency protocols: 20 to 30 sessions, 1000 pulses/session, 5 to 20Hz, and 110 % of the motor threshold. Low frequency protocol are also efficient and well tolerated. The duration of the efficacy varies with relapses rates around 50 % at one year. Pharmacological treatment generally remains associated. With regard to manic states, and mixed states the results are preliminary and limited to a possible reduction in symptoms. In the suicidal risk associated with mood disorders, the interest of rTMS is still to demonstrate, as well as in catatonia. The current place of the rTMS is no longer disputed in the curative treatment of major depressive disorder, preferentially used after one or two lines of antidepressants upstream. Further studies are needed to confirm preliminary positive findings in other aspects of mood disorders.

High-Frequency Neuronavigated rTMS in Auditory Verbal Hallucinations: A Pilot Double-Blind Controlled Study in Patients With Schizophrenia.

INTRODUCTION: Despite extensive testing, the efficacy of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) of temporo-parietal targets for the treatment of auditory verbal hallucinations (AVH) in patients with schizophrenia is still controversial, but promising results have been reported with both high-frequency and neuronavigated rTMS. Here, we report a double-blind sham-controlled study to assess the efficacy of high-frequency (20 Hz) rTMS applied over a precise anatomical site in the left temporal region using neuronavigation. METHODS: Fifty-nine of 74 randomized patients with schizophrenia or schizoaffective disorders (DSM-IV R) were treated with rTMS or sham treatment and fully evaluated over 4 weeks. The rTMS target was determined by morphological MRI at the crossing between the projection of the ascending branch of the left lateral sulcus and the superior temporal sulcus (STS). RESULTS: The primary outcome was response to treatment, defined as a 30% decrease of the Auditory Hallucinations Rating Scale (AHRS) frequency item, observed at 2 successive evaluations. While there was no difference in primary outcome between the treatment groups, the percentages of patients showing a decrease of more than 30% of AHRS score (secondary outcome) did differ between the active (34.6%) and sham groups (9.1%) (P = .016) at day 14. DISCUSSION: This controlled study reports negative results on the primary outcome but demonstrates a transient effect of 20 Hz rTMS guided by neuronavigation and targeted on an accurate anatomical site for the treatment of AVHs in schizophrenia patients.

The nucleus accumbens: a target for deep brain stimulation in resistant major depressive disorder.

OBJECTIVE: This review aimed to investigate the therapeutic potential of Deep Brain Stimulation (DBS) for treating resistant Major Depressive Disorder (MDD). We explored the role of Nucleus accumbens (Nac) as a target for treatment. METHOD: We made a systematic review of all studies examining the mechanisms of action of high frequency brain stimulation and the pathophysiology of MDD. We also reported all the studies exploring the therapeutic potential of DBS in MDD. RESULTS: As a central relay-structure, the Nac seems to play a central role in MDD symptomatology. We investigated its role as a primary target for DBS in depressed patients. Anatomically the Nac is at the centre of the interactions between dopaminergic, serotoninergic and glutamatergic systems. Functionally, the Nac is involved in both normal and abnormal reward processes and in anhedonia and loss of motivation. Due to its central location between the emotional system, the cognitive system and motor control system, the Nac seems to have a central role in mood and feeling regulation. CONCLUSION: According to encouraging recent studies, DBS seems to be a promising technique in resistant MDD treatment.

Assessment of standard coil positioning in transcranial magnetic stimulation in depression.

Transcranial magnetic stimulation (TMS) is a non-invasive technique used in the treatment of major depression. Meta-analyses have shown that it is more efficient than a placebo and that its efficacy is enhanced by the optimum tuning of stimulation parameters. However, the stimulation target, the dorsolateral prefrontal cortex (DLPFC), is still located using an inaccurate method. In this study, a neuronavigation system was used to perform a comprehensive quantification of target localization errors. We identified and quantified 3 sources of error in the standard method: cap repositioning, interexpert variability in coil positioning and distance between the stimulated point and the expected target. For cap repositioning, the standard deviation was lower than 5mm in the 3 axes. For interexpert variability in coil positioning, the spatial dispersion of the points was higher than 10mm in 2 of the 3 axes. For interindividual anatomical variability, the distance between the actual "reference" DLPFC and its standard determination was greater than 20mm for 54% of the subjects, while one subject out of eleven was correctly targeted which means 10mm or less from the reference. Results showed that interindividual anatomical variability and interexpert variability were the two main sources of error using the standard method. Results demonstrate that a neuronavigation system is mandatory to conduct reproducible and reliable studies.