Emmanuel Poulet

Slow transcranial magnetic stimulation can rapidly reduce resistant auditory hallucinations in schizophrenia

BACKGROUND Almost a quarter of patients with schizophrenia present with resistant auditory verbal hallucinations (AVH), a phenomenon that may relate to activation of brain areas underlying speech perception. Repetitive transcranial magnetic stimulation (rTMS) at 1 Hz reduces cortical activation, and recent results have shown that 1-Hz left temporoparietal rTMS may reduce AVH. The aim of this study was to replicate recent data and investigate whether low-frequency rTMS with a high total stimulation number delivered in a shorter 5-day block produces similar benefit. METHODS Ten right-handed schizophrenia patients with resistant AVH received 5 days of active rTMS and 5 days of sham rTMS (2,000 stimulations per day at 90% of motor threshold) over the left temporoparietal cortex in a double-blind crossover design. The two weeks of stimulation were separated by a 1-week washout period. RESULTS AVH were robustly improved (56%) by 5 days active rTMS, whereas no variation was observed after sham. Seven patients were responders to active treatment, five of whom maintained improvement for at least 2 months. CONCLUSIONS These data confirm the efficiency of low-frequency rTMS applied to the left temporoparietal cortex, compared with sham stimulation, in reducing resistant AVH. This improvement can be obtained in only 5 days without serious initial adverse events.

Efficacité de la stimulation magnétique transcrânienne (rTMS) dans le traitement de la dépression : revue de la littérature

Resume Depuis 10 ans, l’evaluation de l’interet therapeutique de la stimulation magnetique transcrânienne repetee (rTMS) fait l’objet d’un interet croissant. Basee sur le principe d’induction decouvert par Michael Faraday en 1831, la rTMS pourrait constituer une methode therapeutique antidepressive et, peut-etre, une alternative a l’electroconvulsivotherapie (ECT). Afin de faire le point des connaissances dans ce domaine, nous avons analyse les principaux travaux realisesa ce jour au travers de leur diversite methodologique par l’intermediaire d’une consultation de la banque de donnees informatisee Medline et d’une base de donnees disponible en ligne (ISTS), completee d’une recherche manuelle ; nous avons retenu 66 etudes qui font l’objet de cette revue. Malgre l’heterogeneite de ces publications en termes de methodologie et de parametres de traitements, les proprietes antidepressives de la rTMS semblent se dessiner (37 % de sujets repondeurs vs 20 % dans les groupes controles sur 30 etudes analysables) et ceci ouvre des perspectives interessantes, dans le traitement des depressions resistantes et peut-etre en tant que potentialisateur des antidepresseurs dans les autres formes de depression. Cependant, un grand nombre d’inconnues subsistent (methodologie du traitement et indications privilegiees), ce qui justifie le developpement de travaux d’evaluation structures sur de grands echantillons.

Can transcranial direct current stimulation (tDCS) alleviate symptoms and improve cognition in psychiatric disorders

Abstract Objectives. Since the discovery of psychopharmacological treatments in the early 1950s, followed by the development of second-generation antidepressants and antipsychotics, biological psychiatry has not achieved much progress. Recent technological advances in the field of non-invasive brain stimulation open new perspectives in the treatment of psychiatric disorders. Amongst them, transcranial direct current stimulation (tDCS) modulates cortical excitability and induces long-lasting effects. Here, we aimed at evaluating whether tDCS has potential to be developed as an innovative treatment in psychiatry. Methods. We conducted a systematic review of the current state of development and application of tDCS in psychiatric disorders, exploring clinical and cognitive effects, especially in major depressive disorder (MDD), schizophrenia and substance use disorder. Results. Systematic literature search yielded 40 publications: 22 in MDD, nine in schizophrenia, seven in substance use disorder, one in obsessive–compulsive disorder and one in mania. Our findings indicated beneficial clinical effects of tDCS for MDD and a promising literature in schizophrenia and substance use disorder. Conclusions. Despite methodological differences, the data published to date are promising and supports the use of tDCS as a treatment for psychiatric disorders. However, its place regarding other treatments still has to be determined before becoming a routine clinical treatment.

The Efficacy and Safety of Low Frequency Repetitive Transcranial Magnetic Stimulation for Treatment-resistant Depression: The Results From a Large Multicenter French RCT

CONTEXT The aim of this study was to assess whether the combination of low frequency repetitive transcranial magnetic stimulation (rTMS) and venlafaxine (150-225 mg/day) is effective and safe for treatment-resistant unipolar depression (TRD). METHOD In a multicenter (18 centers) randomized double blind controlled trial with three arms, 170 patients were allocated to receive active rTMS combined with active venlafaxine (n = 55), active rTMS combined with placebo venlafaxine (n = 60) or sham rTMS combined with active venlafaxine (n = 55). The patients received once daily sessions of active or sham 1 Hz rTMS applied over the right dorsolateral prefrontal cortex (360 pulses/day delivered at 120% of the resting motor threshold) for two to six weeks; rTMS was combined with active or sham venlafaxine (mean dose: 179.0 ± 36.6 mg/day). The primary outcome was the number of patients who achieved remission, which was defined as an HDRS17 score <8. RESULTS We reported a similar significant antidepressant effect in the 3 groups (P < 10(-6)), with a comparable delay of action and a comparable number of remitters at the endpoint (28% in the combination group, 41% in the rTMS group and 43% in the venlafaxine group; P = 0.59). CONCLUSION Low frequency rTMS appears to be as effective as venlafaxine and as effective as the combination of both treatments for TRD. Because of its short session duration (the duration of one session was 8.5 min) and its safety, slow rTMS might be a useful alternative treatment for patients with TRD.

Transcranial direct current stimulation in treatment-resistant obsessive–compulsive disorder: An open-label pilot study

BACKGROUND Obsessive-compulsive disorder (OCD) is a severe mental illness. OCD symptoms are often resistant to available treatments. Abnormalities within the orbitofronto-striato-pallido-thalamic circuitry, especially orbitofrontal cortex (OFC) hyperactivity and cerebellar hypoactivity have been observed in patients. Non-invasive brain stimulation studies have indicated that transcranial direct current stimulation (tDCS) may be a useful alternative to alleviate treatment-resistant symptoms in various neuropsychiatric conditions. METHODS In an open-label pilot study, 8 patients with treatment-resistant OCD received 10 sessions (twice a day) of 2mA tDCS applied with the cathode over the left OFC and the anode over the right cerebellum. OCD (Y-BOCS and OCD-VAS) as well as depressive (MADRS) symptoms were measured 4 times: one time before tDCS and 3 times after (immediately after, 1 and 3months after the 10th tDCS session). RESULTS We reported a significant 26.4% (±15.8) decrease of Y-BOCS score (p=0.002). The beneficial effect lasted during the 3month follow-up. No effect of tDCS was observed on depressive symptoms. At end point, 5 out of 8 patients had a decrease of ≥25%; and 3 out of 8 patients had a decrease of ≥35% in Y-BOCS score. tDCS was well tolerated. CONCLUSION tDCS with the cathode placed over the left OFC combined with the anode placed over the right cerebellum is a suitable and safe approach to decrease OCD symptoms in patients with treatment-resistant OCD. Large scale randomized controlled studies are needed to confirm this promising result.

Neural effects of mindfulness-based interventions on patients with major depressive disorder: A systematic review

HIGHLIGHTSThe prefrontal cortex, cingulate cortex, and basal ganglia are modified after MBI in depression.Attentional processes and self‐awareness are key aspects of the effects of MBI on depression.The MBI‐induced neural changes are correlated with clinical improvements. ABSTRACT Growing evidence has suggested that mindfulness‐based interventions (MBIs) could have beneficial effects on the acute phase of depression and on the prevention of depressive relapse or recurrence. Despite growing clinical interest, the effects of MBIs on brain functioning in patients with MDD remain unclear. The aim of this systematic review was to assess the changes in brain functioning associated with MBIs in patients with MDD. A systematic search was conducted, and of the 56 articles found, 8 were eligible. MBIs have modulatory effects on several brain regions implicated in the pathophysiology of MDD, such as the prefrontal cortex, the basal ganglia, the anterior and posterior cingulate cortices, and the parietal cortex. These regions have been implicated in self‐awareness, attention and emotion regulation. Some of these findings were consistent with the effects of MBIs observed in healthy subjects and patients with other psychiatric disorders, especially enhanced activity in the frontal and subcortical regions related to the improved somatosensory awareness. Further studies are needed to elucidate the mechanisms of MBIs in MDD.

Duration but not intensity influences transcranial direct current stimulation (tDCS) after-effects on cortical excitability

Recent studies have shown heterogeneous results regarding the influence of intensity and duration of motor transcranial direct current stimulation (tDCS) on cortical excitability. In this pilot crossover study including 14 healthy participants, we compared the effects of a single session of anodal-tDCS set with two commonly used durations (20 and 30minutes) and intensities (1 and 2mA) on short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Regardless of the current intensity, 20minutes of tDCS increased SICI (3ms inter-stimulus interval ISI) and decreased ICF (7ms ISI); 30minutes of tDCS did not affect cortical excitability.