Transcranial direct current stimulation in schizophrenia

Regulatory Considerations for the Clinical and Research Use of Transcranial Direct Current Stimulation (tDCS): review and recommendations from an expert panel

The field of transcranial electrical stimulation (tES) has experienced significant growth in the past 15 years. One of the tES techniques leading this increased interest is transcranial direct current stimulation (tDCS). Significant research efforts have been devoted to determining the clinical potential of tDCS in humans. Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity on international regulatory pathways. We therefore convened a group of research and clinician experts on tDCS to review the research and clinical use of tDCS. In this report, we review the regulatory status of tDCS, and we summarize the results according to research, off-label and compassionate use of tDCS in the following countries: Australia, Brazil, France, Germany, India, Iran, Italy, Portugal, South Korea, Taiwan and United States. Research use, off label treatment and compassionate use of tDCS are employed in most of the countries reviewed in this study. It is critical that a global or local effort is organized to pursue definite evidence to either approve and regulate or restrict the use of tDCS in clinical practice on the basis of adequate randomized controlled treatment trials.

Removal of Transcranial a.c. Current Stimulation artifact from simultaneous EEG recordings by superposition of moving averages

Transcranial Current Stimulation (tCS) is a recent development for non-invasive brain stimulation. At present tCS introduces large artifacts into simultaneous EEG (electroencephalogram) recordings, which must be removed to enable brain changes from during the stimulation to be monitored. This paper presents a new approach for removing artifacts of transcranial Alternating Current Stimulation (tACS) from simultaneous EEG. Termed the Superposition of Moving Averages (SMA) our approach is independent of the number of EEG channels used and has a low computational complexity for use in real-time online artifact removal and data responsive stimulation. Compared to a Principal Component Analysis (PCA) approach our results show that SMA achieves superior artifact removal performance, especially with regards to the use of low channel count EEG devices.

AZURPSY – Schizophrénie et symptômes négatifs : de la physiopathologie aux innovations thérapeutiques

L’association « AZUR Psy » regroupe des psychiatres investis dans la recherche et l’innovation en psychiatrie qui mènent des travaux en collaboration entre les hôpitaux de l’inter-région Sud. La schizophrénie est une des thématiques privilégiée de cette association, les symptômes négatifs et les troubles cognitifs étant des facteurs pronostics majeurs du fonctionnement quotidien des patients. Ces symptômes restent encore aujourd’hui peu accessibles aux stratégies thérapeutiques pharmacologiques. L’objet de cette session « Forum des associations » est de présenter des travaux récents et en cours qui s’attachent à mieux comprendre les symptômes négatifs et améliorer la prise en charge des patients par des innovations thérapeutiques. Le professeur Eric Fakra présentera une revue de la littérature sur la physiopathologie des symptômes négatifs et des dysrégulations émotionnelles chez les patients schizophrènes [1]. Les travaux récents des membres de l’association utilisant une approche intégrant la biologie moléculaire et l’imagerie fonctionnelle seront également exposés. Le docteur Bruno Giordana présentera une revue de la littérature sur les méthodes de remédiation cognitive actuellement disponibles [2]. Il présentera l’intérêt de développer un nouveau programme intégratif s’adressant à des patients déficitaires et hospitalisés au long cours. Le docteur Jérôme Attal présentera les techniques de neurostimulation (stimulation magnétique transcrânienne répétée (rTMS), stimulation transcrânienne par courant continu (tDCS), stimulation cérébrale profonde) qui font actuellement l’objet de plusieurs protocoles de recherche dans le champ des symptômes négatifs [3]. Ces techniques pourraient devenir de nouvelles stratégies thérapeutiques pour les patients. Il exposera ainsi un projet de recherche en cours sur l’efficacité de la tDCS sur les symptômes négatifs dans la schizophrénie impliquant plusieurs membres de notre association. Enfin, cette session souhaite être l’occasion de présenter et de partager ce modèle de partenariat inter-régional original dans le champ de la recherche en psychiatrie et d’ouvrir notre association à de futures collaborations.

Negative symptoms of schizophrenia: clinical characteristics, pathophysiological substrates, experimental models and prospects for improved treatment

Schizophrenia is a complex and multifactorial disorder generally diagnosed in young adults at the time of the first psychotic episode of delusions and hallucinations. These positive symptoms can be controlled in most patients by currently-available antipsychotics. Conversely, they are poorly effective against concomitant neurocognitive dysfunction, deficits in social cognition and negative symptoms (NS), which strongly contribute to poor functional outcome. The precise notion of NS has evolved over the past century, with recent studies - underpinned by novel rating methods - suggesting two major sub-domains: "decreased emotional expression", incorporating blunted affect and poverty of speech, and "avolition", which embraces amotivation, asociality and "anhedonia" (inability to anticipate pleasure). Recent studies implicate a dysfunction of frontocortico-temporal networks in the aetiology of NS, together with a disruption of cortico-striatal circuits, though other structures are also involved, like the insular and parietal cortices, amygdala and thalamus. At the cellular level, a disruption of GABAergic-glutamatergic balance, dopaminergic signalling and, possibly, oxytocinergic and cannibinoidergic transmission may be involved. Several agents are currently under clinical investigation for the potentially improved control of NS, including oxytocin itself, N-Methyl-d-Aspartate receptor modulators and minocycline. Further, magnetic-electrical "stimulation" strategies to recruit cortical circuits and "cognitive-behavioural-psychosocial" therapies likewise hold promise. To acquire novel insights into the causes and treatment of NS, experimental study is crucial, and opportunities are emerging for improved genetic, pharmacological and developmental modelling, together with more refined readouts related to deficits in reward, sociality and "expression". The present article comprises an integrative overview of the above issues as a platform for this Special Issue of European Neuropsychopharmacology in which five clinical and five preclinical articles treat individual themes in greater detail. This Volume provides, then, a framework for progress in the understanding - and ultimately control - of the debilitating NS of schizophrenia.