Pathogenic Potential of Eomesodermin-Expressing T-Helper Cells in Neurodegenerative Diseases.

Eomesodermin-expressing (Eomes+) T-helper (Th) cells show cytotoxic characteristics in secondary progressive multiple sclerosis. We found that Eomes+ Th cell frequency was increased in the peripheral blood of amyotrophic lateral sclerosis and Alzheimer's disease patients. Furthermore, granzyme B production by Th cells from such patients was high compared with controls. A high frequency of Eomes+ Th cells was observed in the initial (acutely progressive) stage of amyotrophic lateral sclerosis, and a positive correlation between Eomes+ Th cell frequency and cognitive decline was observed in Alzheimer's disease patients. Therefore, Eomes+ Th cells may be involved in the pathology of amyotrophic lateral sclerosis and Alzheimer's disease. ANN NEUROL 2024;95:1093-1098.

Effect of 5-HT1A Receptor Partial Agonists of the Azapirone Class as an Add-On Therapy on Psychopathology and Cognition in Schizophrenia: A Systematic Review and Meta-Analysis.

BACKGROUND: There are ongoing efforts to examine the effect of 5-HT1A receptor partial agonists as an add-on therapy for several symptoms of schizophrenia. By conducting a systematic review and meta-analysis, we evaluated whether augmentation with 5-hydroxtrypatamine (5-HT)1A partial agonists of the azapirone class improves psychotic symptoms and attention/processing speed, a key domain of cognition, in patients with schizophrenia. METHODS: A literature search was performed from 1987 to February 25, 2022, to identify randomized controlled trials. The standardized mean difference (SMD) with 95% confidence intervals (CI) was calculated when there were 2 or more studies. Seven studies, involving 435 patients, met the inclusion criteria. RESULTS: Random-effects model meta-analyses revealed that add-on therapy with buspirone or tandospirone had a significant beneficial effect on overall psychotic symptoms (SMD = -1.13, 95% CI = -1.98 to -0.27) and positive symptoms (SMD = -0.72, 95% CI =-1.31 to -0.12), while the effect on negative symptoms did not reach statistical significance (SMD = -0.93, 95% CI = -1.90 to 0.04). A significant positive effect was also observed on attention/processing speed (SMD = 0.37, 95% CI = 0.12 to 0.61). CONCLUSIONS: These findings support the idea that some compounds that stimulate 5-HT1A receptors provide an effective pharmacologic enhancer in the treatment of schizophrenia. Further clinical trials are warranted to determine the benefits of the adjunctive use of 5-HT1A partial agonists in ameliorating symptoms and improving functional outcomes in patients with schizophrenia or other psychiatric disorders.

Soluble APP-α and APP-ß in cerebrospinal fluid as potential biomarkers for differential diagnosis of mild cognitive impairment.

OBJECTIVES: Concentrations of soluble amyloid precursor proteins-α (sAPPα) and -ß (sAPPß) in cerebrospinal fluid (CSF) may reflect the neuropathology of Alzheimer's disease (AD). We previously reported that the concentrations of both sAPPα and sAPPß were significantly higher in patients with mild cognitive impairment (MCI) due to AD (MCI-AD) than in control subjects without cognitive impairment. The present study analyzed whether these sAPPs are useful in the differential diagnosis of MCI. METHODS: A modified and sensitive method was used to analyze concentrations of sAPPα and sAPPß in CSF of patients with MCI-AD (n = 30) and MCI due to other causes (MCI-others) (n = 24). Phosphorylated tau (p-tau) and amyloid ß-protein 42 (Aß42) were also analyzed using standard methods. RESULTS: CSF concentrations of sAPPα and sAPPß were significantly higher in the MCI-AD than in the MCI-others group (p < 0.001). Furthermore, concentrations of both sAPPα and sAPPß were highly correlated with the concentration of p-tau, consistent with our previous report. CONCLUSIONS: Measurement of both sAPPs in CSF using sensitive methods can be helpful in the precise differential diagnosis of patients with MCI.

Factors associated with the use and longer duration of seclusion and restraint in psychiatric inpatient settings: a retrospective chart review.

Objectives: To examine factors that may affect the use and duration of seclusion and restraint (SR) in psychiatric inpatient settings. Methods: First, multivariable logistic regression analysis was used to examine factors associated with the use of SR in an unmatched case-control study, comparing SR cases and controls. Second, for patients that underwent SR, multivariable linear regression analysis was used to determine factors contributing to the duration of SR. Results: Out of 213 patients, 58 underwent SR. An F00 diagnosis, a history of epilepsy, antipsychotics usage and antidepressants usage were significantly associated with the use of SR (odds ratio = 7.98; 95% CI = 1.11-57.50, odds ratio = 4.89; 95% CI = 1.12-21.36, odds ratio = 4.59; 95% CI = 1.54-13.68 and odds ratio = 0.29; 95% CI = 0.10-0.86, respectively). An F00 and F32 diagnosis significantly extended the duration of SR (coefficient = 13.10; 95% CI = 2.11-24.11 and coefficient = 20.52; 95% CI = 9.68-31.37, respectively). Conclusions: A variety of factors are associated with the use and longer duration of SR. Given the potentially harmful effects of these practices, further studies with larger samples and a wider range of quantitative outcome measures are warranted. Key points An F00 diagnosis, a history of epilepsy and antipsychotics usage may increase the use of SR. Antidepressants may decrease the use of SR. An F00 and F32 diagnosis may extend the duration of SR.

Discrete effect of each mild behavioural impairment category on dementia conversion or cognitive decline in patients with mild cognitive impairment.

BACKGROUND: Neuropsychiatric symptoms (NPS) have been recognized as risk factors for conversion to dementia in patients with mild cognitive impairment (MCI). Early detection of NPS may allow for possible interventions in such patients. The present study used mild behavioural impairment to explore the role of NPS in a wide range of patients, from those who are cognitively intact to those with dementia. METHODS: A total of 234 patients with mild cognitive impairment were followed up for up to 3 years in a Japanese cohort study. Longitudinal data from patients who developed dementia during the study and those who did not were statistically analyzed. RESULTS: Cox regression analysis revealed that only abnormal perception and thought was significant in terms of dementia conversion. Moreover, mixed-effects models indicated that baseline mild behavioural impairment symptoms did not affect cognitive trajectories such as changes in Mini-Mental State Examination or Alzheimer's Disease Assessment Scale-cognitive subscale scores. CONCLUSION: We conclude that only abnormal perception and thought content were risk factors for dementia and that NPS may not lead to deterioration of cognitive function in patients with mild cognitive impairment.

A new device-aided cognitive function test, User eXperience-Trail Making Test (UX-TMT), sensitively detects neuropsychological performance in patients with dementia and Parkinson's disease.

BACKGROUND: A newer generation neuropsychological tests can take advantage of touch screen and mobile technology. We have developed a new Android application termed "User eXperience-Trail Making Test (UX-TMT)" for neurocognitive assessment and training. This study investigated the utility, including the reliability and the validity, of the UX-TMT as a screening test for cognitive decline in adults. METHODS: A total of 84 individuals aged 27-86 years were divided into three groups; healthy controls ([HC] n = 29), people with Parkinson's disease (PD; n = 28), and people with mild cognitive impairment (MCI) and dementia (MCI&D; n = 27). We examined the distributions of the scores and the time required, and the effects of age and group on these distributions. We analyzed internal consistency and convergent validity in all samples and applied receiver operator characteristic (ROC) analysis to determine a cutoff score that could differentiate the MCI & D group from the HC group. RESULTS: 97.6% of the participants completed all of the tasks, and the average total test time required for UX-TMT was 428.8 (± 109.1) s in the HC, 542.0 (± 168.7) s in the PD, and 777.5 (± 256.1) s in the MCI&D groups, respectively. The MCI&D group showed significantly lower UX-TMT scores and longer total time in completing the task than the HC group. In an ROC analysis, a score of 21 showed high sensitivity (.83) and specificity (.92), and the UX-TMT score plus age improved sensitivity to .96. Additionally, the UX-TMT scores showed significant correlation with the Mini-Mental State Examination (Japanese version) scores (r = .77, p = .001), and Cronbach's alpha (.71-.83) indicated acceptable internal consistency. CONCLUSION: The UX-TMT demonstrated high reliability and validity to detect cognitive decline in Japanese adults, highlighting its utility as a screening tool for epidemiological and clinical research.

A randomized sham-controlled trial of transcranial and intranasal photobiomodulation in Japanese patients with mild cognitive impairment and mild dementia due to Alzheimer's disease: a protocol.

Introduction: Photobiomodulation (PBM) is a novel strategy for cognitive enhancement by improving brain metabolism and blood flow. It is potentially beneficial for patients with Alzheimer's disease (AD). We present a study protocol for a randomised controlled trial designed to evaluate the efficacy and safety of PBM. Method and analysis: This is a single-centre, parallel-group, randomised, sham-controlled study. We enroll patients with mild cognitive impairment or dementia due to AD and assigned them to receive either active or sham stimulation at home for 12 weeks, with three sessions per week (20 min each). The stimulation involves invisible near-infrared light delivered by five applicators (one in a nostril, one on the frontal scalp, and three on the occipital scalp). The primary outcome will be the mean change in the Alzheimer Disease Assessment Scale-cognition from baseline to Week 12. We will also measure cognitive function, activity of daily living, behavioral and psychological symptoms, and caregiver burden. We will collect data at clinics at baseline and Week 12 and remotely at home. We estimate a sample size of 30 (20 active and 10 sham) based on an expected mean difference of -6.9 and an SD of 4.8. We use linear models for the statistical analysis. Ethics and dissemination: The National Center of Neurology and Psychiatry Clinical Research Review Board (CRB3200004) approved this study. The results of this study will be published in a scientific peer-reviewed journal. Trial registration details Japan Registry of Clinical Trials jRCTs032230339.

Assessment of Gray Matter Microstructural Alterations in Alzheimer's Disease by Free Water Imaging.

Background: Cortical neurodegenerative processes may precede the emergence of disease symptoms in patients with Alzheimer's disease (AD) by many years. No study has evaluated the free water of patients with AD using gray matter-based spatial statistics. Objective: The aim of this study was to explore cortical microstructural changes within the gray matter in AD by using free water imaging with gray matter-based spatial statistics. Methods: Seventy-one participants underwent multi-shell diffusion magnetic resonance imaging, 11C-Pittsburgh compound B positron emission tomography, and neuropsychological evaluations. The patients were divided into two groups: healthy controls (n = 40) and the AD spectrum group (n = 31). Differences between the groups were analyzed using voxel-based morphometry, diffusion tensor imaging, and free water imaging with gray matter-based spatial statistics. Results: Voxel-based morphometry analysis revealed gray matter volume loss in the hippocampus of patients with AD spectrum compared to that in controls. Furthermore, patients with AD spectrum exhibited significantly greater free water, mean diffusivity, and radial diffusivity in the limbic areas, precuneus, frontal lobe, temporal lobe, right putamen, and cerebellum than did the healthy controls. Overall, the effect sizes of free water were greater than those of mean diffusivity and radial diffusivity, and the larger effect sizes of free water were thought to be strongly correlated with AD pathology. Conclusions: This study demonstrates the utility of applying voxel-based morphometry, gray matter-based spatial statistics, free water imaging and diffusion tensor imaging to assess AD pathology and detect changes in gray matter.

Augmentation therapy with serotonin1A receptor partial agonists on neurocognitive function in schizophrenia: A systematic review and meta-analysis.

Background: In a previous meta-analysis, the use of serotonin1A(5-HT1A) receptor partial agonists of the azapirone class as an add-on therapy was associated with beneficial effects on positive symptoms and attention/processing speed in schizophrenia patients. This meta-analysis builds on that study by examining the effects of adjunctive treatment with 5-HT1A partial agonists in improving other domains of neurocognitive function in schizophrenia patients. Methods: A literature search was performed from 1987 to May 2023 to identify randomized controlled trials. The standardized mean difference (SMD) with 95 % confidence intervals (CI) was calculated when there were two or more studies. Four studies, involving 313 patients, met the inclusion criteria and were used in the analysis. Results: 5-HT1A partial agonists (buspirone or tandospirone) did not have a significant effect on verbal learning (SMD = 0.08, 95 % CI = -0.31 to 0.47) or working memory (SMD = 0.15, 95 % CI = -0.09 to 0.39). Regarding executive functions (Wisconsin Card Sorting Test), positive but non-significant results were seen with the category number (SMD = 0.26, 95 % CI = -0.81 to 1.32), while non-significant effects were noted for percent preservation errors (SMD = -0.10, 95 % CI = -0.53 to 0.33). Conclusions: The absence of any significant benefits in the cognitive domains studied here may have been due to the variance in the concomitant medication (typical vs atypical antipsychotic drugs), the level of cognition at baseline, or other factors. Further studies with various types of 5-HT1A agonists are warranted to examine the potential cognitive efficacy of stimulating these receptors.

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

Backgrounds: 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. Methods: 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. Results: Performance on the UPSA-B was significantly improved in patients who received anodal tDCS at the left DLPFC (d = 0.70, p < 0.001), while this effect was absent in patients with anodal electrodes placed on the left STS (d = 0.02, p = 0.939). Significant improvement was also observed for scores on the BACS with anodal tDCS delivered to the DLPFC (d = 0.49, p < 0.001); however, such neurocognitive enhancement was absent when the STS was stimulated (d = 0.05, p = 0.646). Both methods of anodal stimulation showed a significant improvement of General Psychopathology scores on the PANSS (DLPFC, d = 0.50, p = 0.027; STS, d = 0.44, p = 0.001). Conclusion: 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. Trial registration: These studies were registered within the University hospital Medical Information Network Clinical Trials Registry [(24), UMIN000015953], and the Japan Registry of Clinical Trials [(28), jRCTs032180026].

Relationship between the tau protein and choroid plexus volume in Alzheimer's disease.

Tau protein accumulation in the brain is thought to be one of the causes of Alzheimer's disease (AD). Recent studies found that the choroid plexus (CP) has a role in ß-amyloid and tau protein clearance in the brain. We evaluated the relationships between CP volume and the ß-amyloid and tau protein depositions. Participants were 20 patients with AD and 35 healthy subjects who underwent MRI and PET scanning using the ß-amyloid tracer 11C-PiB and the tau/inflammatory tracer 18F-THK5351. We computed the volume of the CP and estimated the relationships between the CP volume and ß-amyloid and tau protein/inflammatory deposition by Spearman's correlation test. The CP volume was significantly positively correlated with both the standardized uptake value ratio (SUVR) of 11C-PiB and the SUVR of 18F-THK5351 in all participants. The CP volume was also significantly positively correlated with the SUVR of 18F-THK5351in patients with AD. Our data suggested that the volume of the CP was a good biomarker for the evaluation of tau deposition and neuroinflammation.

Transcranial Direct Current Stimulation on the Left Superior Temporal Sulcus Improves Social Cognition in Schizophrenia: An Open-Label Study.

Background: Patients with schizophrenia show impairments of social cognition, which cause poor real-world functional outcomes. Transcranial direct current stimulation (tDCS) delivered to frontal brain areas has been shown to partially alleviate disturbances of social cognition. In this study, we aimed to determine whether multisession tDCS targeting the superior temporal sulcus (STS), a brain region closely related to social cognition, would improve social cognitive performance in patients with schizophrenia. Methods: This was an open-label, single-arm trial to investigate the benefits and safety of multisession tDCS over the left STS. Fifteen patients received tDCS (2 mA × 20 min) two times per day for 5 consecutive days. Anodal and cathodal electrodes were placed over the left STS and right supraorbital regions, respectively. Assessments with the Social Cognition Screening Questionnaire (SCSQ), the Hinting Task (HT), the Brief Assessment of Cognition in Schizophrenia (BACS), and the Positive and Negative Syndrome Scale (PANSS) were conducted at baseline and 1 month after the final stimulation. Results: Significant improvements were found on theory of mind, as measured using the SCSQ (d = 0.53) and the HT (d = 0.49). These changes on social cognition were not correlated with those of neurocognition, as measured using the BACS or psychotic symptoms, as measured using the PANSS. There were no adverse events of serious/moderate levels attributable to tDCS. Conclusion: These results suggest that administration of multisession tDCS with anode stimulation targeting the left STS provides a novel strategy to improve functional outcomes in patients with schizophrenia. Ethics Statement: The National Center of Neurology and Psychiatry Clinical Research Review Board (CRB3180006) approved this study. Trial Registration: This study was registered within the Japan Registry of Clinical Trials (jRCTs032180026).

Relationships Between the Deposition of Amyloid-ß and Tau Protein and Glymphatic System Activity in Alzheimer's Disease: Diffusion Tensor Image Study.

BACKGROUND: Amyloid-ß (Aß) and tau protein accumulation in the brain is thought to be one of the causes of Alzheimer's disease (AD). Recent study found that the glymphatic system was waste drainage system in the brain and promoting the elimination of Aß and tau protein. OBJECTIVE: We evaluated the relationships between the glymphatic system activity and the Aß and tau protein deposition. METHODS: Subjects were 21 patients with AD and 36 healthy subjects who underwent diffusion tensor imaging (DTI) scan and the positron emission tomography (PET) using with the Aß tracer: 11C-PiB and the tau/inflammatory tracer: 18F-THK5351. We computed diffusion tensor image analysis along the perivascular space (DTI-ALPS) index as the proxy of glymphatic system activity, and estimated the relationships between the DTI-ALPS index and Aß and tau protein/inflammatory deposition. RESULTS: We found significant negative correlations between DTI-ALPS index and the standard uptake value ratio (SUVR) of 11C-PiB in the bilateral temporal and left parietal cortices and left posterior cingulate gyrus in all subjects. Further, we detected significant negative correlations between DTI-ALPS index and the SUVR of 18F-THK5351 in the bilateral temporal cortices and right parietal cortex in all participants, too. CONCLUSION: Our data suggested that DTI-ALPS index was a good biomarker for the evaluation of Aß and tau deposition and neuroinflammation, and this marker might be effective to estimate the glymphatic system activity.

Free water derived by multi-shell diffusion MRI reflects tau/neuroinflammatory pathology in Alzheimer's disease.

Introduction: Free-water (FW) imaging, a new analysis method for diffusion magnetic resonance imaging (MRI), can indicate neuroinflammation and degeneration. We evaluated FW in Alzheimer's disease (AD) using tau/inflammatory and amyloid positron emission tomography (PET). Methods: Seventy-one participants underwent multi-shell diffusion MRI, 18F-THK5351 PET, 11C-Pittsburgh compound B PET, and neuropsychological assessments. They were categorized into two groups: healthy controls (HCs) (n = 40) and AD-spectrum group (AD-S) (n = 31) using the Centiloid scale with amyloid PET and cognitive function. We analyzed group comparisons in FW and PET, correlations between FW and PET, and correlation analysis with neuropsychological scores. Results: In AD-S group, there was a significant positive correlation between FW and 18F-THK5351 in the temporal lobes. In addition, there were negative correlations between FW and cognitive function in the temporal lobe and cingulate gyrus, and negative correlations between 18F-THK5351 and cognitive function in the same regions. Discussion: FW imaging could be a biomarker for tau in AD alongside clinical correlations.

Efficacy and Safety of Multi-Session Transcranial Direct Current Stimulation on Social Cognition in Schizophrenia: A Study Protocol for an Open-Label, Single-Arm Trial.

BACKGROUNDS: Social cognition is defined as the mental operations underlying social behavior. Patients with schizophrenia elicit impairments of social cognition, which is linked to poor real-world functional outcomes. In a previous study, transcranial direct current stimulation (tDCS) improved emotional recognition, a domain of social cognition, in patients with schizophrenia. However, since social cognition was only minimally improved by tDCS when administered on frontal brain areas, investigations on the effect of tDCS on other cortical sites more directly related to social cognition are needed. Therefore, we present a study protocol to determine whether multi-session tDCS on superior temporal sulcus (STS) would improve social cognition deficits of schizophrenia. METHODS: This is an open-label, single-arm trial, whose objective is to investigate the efficacy and safety of multi-session tDCS over the left STS to improve social cognition in patients with schizophrenia. The primary outcome measure will be the Social Cognition Screening Questionnaire. Neurocognition, functional capacity, and psychotic symptoms will also be evaluated by the Brief Assessment of Cognition in Schizophrenia, UCSD Performance-Based Skills Assessment-Brief, and Positive and Negative Syndrome Scale, respectively. Data will be collected at baseline, and 4 weeks after the end of intervention. If social cognition is improved in patients with schizophrenia by tDCS based on this protocol, we may plan randomized controlled trial.

Acceptability of escitalopram versus duloxetine in outpatients with depression who did not respond to initial second-generation antidepressants: A randomized, parallel-group, non-inferiority trial.

BACKGROUNDS: Antidepressants are widely used to treat major depressive disorder. First-line treatments with antidepressants are only successful in one-third of patients; however, evidence from randomized controlled trials on second-line treatments is limited. Moreover, recently acceptability is suggested to be a good indicator of overall treatment success. METHODS: This is a multi-center two-arm, three-phased randomized controlled trial performed in Japan from December 2013 to March 2017 comparing the acceptability of escitalopram and duloxetine as a second-line drug. Patients, who failed to respond to antidepressants such as sertraline, paroxetine, fluvoxamine, milnacipran or mirtazapine for at least 3 weeks, were randomized to either escitalopram (Group A) or duloxetine (Group B) in Step 1 (8 weeks). In Step 2 (8 weeks), the drug was switched to the other if the first drug failed. The discontinuation rate at the end of Step 1 was the primary endpoint and non-inferiority of escitalopram vs duloxetine was tested. In addition, change in clinical measures from baseline were also assessed at the end of Step 1, 2 and up to 52 weeks. RESULTS: At the end of Step 1, Group A (n = 82) was significantly superior to Group B (n = 78) in discontinuation rate (4.9% to 19.2%, P = 0.007). The change in clinical indices from baseline were not different between the groups at either timepoint. LIMITATIONS: As the major reason for discontinuation in Group B was the "withdrawal of consent" the concrete reason could not be verified. CONCLUSIONS: As a second-line treatment drug, escitalopram was suggested to be non-inferior to duloxetine in acceptability. TRIAL REGISTRATION: UMINCTR(UMIN000012367), registered on December 1st, 2013 and last updated on April 4th, 2017.

High-dose antipsychotic drug use as a predictor for readmission of inpatients with borderline personality disorder: A retrospective chart review in a Japanese psychiatric hospital.

OBJECTIVE: This study aimed to determine predictors associated with readmission of inpatients with borderline personality disorder. METHODS: This observational study evaluated 83 inpatients with borderline personality disorder admitted to the National Center of Neurology and Psychiatry Hospital in Japan from January 2013 to January 2016. Data were retrospectively obtained from electronic medical records. RESULTS: There was no significant difference in the daily antipsychotic dose equivalent to chlorpromazine at admission between the readmitted and nonreadmitted groups, which indicated that there was no between-group difference in the psychiatric disease severity at admission. Multivariate logistic regression analyses revealed that the use of antipsychotics equivalent to >400 mg of chlorpromazine at discharge was associated with readmission within 1 year. CONCLUSIONS: In conclusion, high-dose antipsychotic drug use at discharge may be a risk factor for readmission. The present findings may have important clinical implications since they alert physicians to a possible predictor for readmissions of patients with borderline personality disorder.

Effect of multi-session prefrontal transcranial direct current stimulation on cognition in schizophrenia: A systematic review and meta-analysis.

Patients with schizophrenia experience cognitive deficits that play a central role in predicting functional outcomes. In this study, we sought to evaluate the effect of transcranial direct current stimulation (tDCS) on cognition using meta-analysis. A search was performed from inception to 8 January 2019, to identify randomized controlled trials assessing the ability of tDCS to ameliorate cognitive deficits in patients with schizophrenia and schizoaffective disorder. The effect size, calculated as the standardized mean difference (Hedge's g), was obtained with a random effect model. We analyzed mean effects on specific cognitive domains that were evaluated in four or more studies. Nine articles were included in the systematic review, which encompassed 270 patients: 133 in the active stimulation group and 137 in the sham stimulation group. Meta-analysis demonstrated a significant mean effect of tDCS on working memory (SMD = 0.49, 95% CI = 0.16 to 0.83), while non-significant results were produced for other domains. These findings were supported by sensitivity analyses indicating that the results would not change in a meaningful way after the exclusion of each single study, and meta-regression analyses verifying the consistent effect irrespective of any moderators. Thus, tDCS may provide a potential option to improve working memory deficits in individuals with schizophrenia. Further trials examining the cognitive benefit of tDCS with medication or other adjunctive treatments are warranted.

Effects of multisession transcranial direct current stimulation as an augmentation to cognitive tasks in patients with neurocognitive disorders in Japan: a study protocol for a randomised controlled trial.

INTRODUCTION: Transcranial direct current stimulation (tDCS) is a potentially novel strategy for cognitive enhancement in patients with disorders. We present a study protocol for a randomised controlled trial designed to evaluate the safety and efficacy of tDCS combined with cognitive tasks on cognition in such patients. METHOD AND ANALYSIS: This is a two-arm, parallel-design, randomised, sham-controlled trial, in which participants and raters will be blinded at a single centre. Stratified randomisation will be conducted, and a randomisation sequence will be generated through the Electronic Data Capture system. Patients who met the Diagnostic and Statistical Manual of Mental Disorders-5 criteria for neurocognitive disorders will be recruited and randomised to receive either active (2 mA for 20 min) or sham (stimulation ramped up and down for 1 min) stimulation in 10 sessions over five consecutive days. A direct current will be transferred by a 35 cm2 saline-soaked sponge electrode. An anode will be placed over the left dorsolateral prefrontal cortex, and a cathode will be placed over the right supraorbital cortex. Calculation tasks will be conducted in both arms as a cognitive task for 20 min during the stimulation. This task consists of basic arithmetic questions, such as single-digit addition, subtraction, multiplication and division. The primary outcome will be the mean change in the Alzheimer Disease Assessment Scale-cognition at Day 5 after baseline. Depressive symptoms, as measured by the geriatric depression scale, and quality of life, as measured by the Medical Outcomes Study 36-item Short-Form Health Survey, will also be assessed. Data will be collected at baseline, within 3 days following the final stimulation and 1 month thereafter. The estimated sample size is 46 per group based on the assumptions that an estimated mean difference is -1.61 and SD is 2.7. Mixed models for repeated measures will be used for the statistical analysis. ETHICS AND DISSEMINATION: The National Center of Neurology and the Psychiatry Clinical Research Review Board (CRB3180006) approved this study. The results of this study will be published in a scientific peer-reviewed journal. TRIAL REGISTRATION DETAILS: Japan Registry of Clinical Trials jRCTs032180016.

A Meta-Analysis of the Effect of Multisession Transcranial Direct Current Stimulation on Cognition in Dementia and Mild Cognitive Impairment.

There have been increasing efforts to investigate the effects of neuromodulation techniques, such as transcranial direct current stimulation (tDCS), on cognitive impairment in dementia and related conditions. In this systematic review and meta-analysis, we assessed the efficacy of multisession anodal tDCS compared with sham stimulation for improving global cognition and specific cognitive domains in both Alzheimer's disease and mild cognitive impairment. Eight articles meeting the criteria for inclusion in the meta-analysis were selected. Five studies used the Mini-Mental State Examination to examine mild cognitive impairment and dementia. In a fixed-effect model, there was a mean difference in the change score of -0.13 points. Three trials for dementia using the Alzheimer's Disease Assessment Scale-Cognition showed a mean difference of -0.53 points. At present, there is a lack of clear evidence concerning the efficacy of multisession anodal tDCS due to the small number of studies and different measures used. This underscores the need for further investigations using larger samples and common outcome measures.