AUTHOR=Yamada Yuji , Narita Zui , Inagawa Takuma , Yokoi Yuma , Hirabayashi Naotsugu , Shirama Aya , Sueyoshi Kazuki , Sumiyoshi Tomiki 

TITLE=Electrode montage for transcranial direct current stimulation governs its effect on symptoms and functionality in schizophrenia

JOURNAL=Frontiers in Psychiatry

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2023.1243859

DOI=10.3389/fpsyt.2023.1243859

ISSN=1664-0640

ABSTRACT=<sec id="sec1"><title>Backgrounds</title><p>Patients with schizophrenia suffer from cognitive impairment that worsens real-world functional outcomes. We previously reported that multi-session transcranial direct current stimulation (tDCS) delivered to the left dorsolateral prefrontal cortex (DLPFC) improved daily living skills, while stimulation on the left superior temporal sulcus (STS) enhanced performance on a test of social cognition in these patients. To examine the region-dependent influence of tDCS on daily-living skills, neurocognition, and psychotic symptoms, this study compared effects of anodal stimulation targeting either of these two brain areas in patients with schizophrenia.</p></sec><sec id="sec2"><title>Methods</title><p>Data were collected from open-label, single-arm trials with anodal electrodes placed over the left DLPFC (N = 28) or STS (N = 15). Daily-living skills, neurocognition, and psychotic symptoms were measured with the UCSD performance-based skills assessment-brief (UPSA-B), Brief Assessment of Cognition in Schizophrenia (BACS), and Positive and Negative Syndrome Scale (PANSS), respectively. After baseline evaluation, tDCS (2 mA × 20 min) were delivered two times per day for 5 consecutive days. One month after the final stimulation, clinical assessments were repeated.</p></sec><sec id="sec3"><title>Results</title><p>Performance on the UPSA-B was significantly improved in patients who received anodal tDCS at the left DLPFC (<italic>d</italic> = 0.70, <italic>p</italic> &lt; 0.001), while this effect was absent in patients with anodal electrodes placed on the left STS (<italic>d</italic> = 0.02, <italic>p</italic> = 0.939). Significant improvement was also observed for scores on the BACS with anodal tDCS delivered to the DLPFC (<italic>d</italic> = 0.49, <italic>p</italic> &lt; 0.001); however, such neurocognitive enhancement was absent when the STS was stimulated (<italic>d</italic> = 0.05, <italic>p</italic> = 0.646). Both methods of anodal stimulation showed a significant improvement of General Psychopathology scores on the PANSS (DLPFC, <italic>d</italic> = 0.50, <italic>p</italic> = 0.027; STS, <italic>d</italic> = 0.44, <italic>p</italic> = 0.001).</p></sec><sec id="sec4"><title>Conclusion</title><p>These results indicate the importance of selecting brain regions as a target for tDCS according to clinical features of individual patients. Anodal stimulation of the left DLPFC may be advantageous in improving higher level functional outcomes in patients with schizophrenia.</p></sec><sec id="sec5"><title>Trial registration</title><p>These studies were registered within the University hospital Medical Information Network Clinical Trials Registry [(<xref ref-type="bibr" rid="ref24">24</xref>), UMIN000015953], and the Japan Registry of Clinical Trials [(<xref ref-type="bibr" rid="ref28">28</xref>), jRCTs032180026].</p></sec>