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Abstract Background Transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (DLPFC) is a promising technique for enhancing working memory (WM) performance in healthy and psychiatric populations. However, limited information is available about the effectiveness of transcranial random noise stimulation (tRNS) applied to the left DLPFC on WM. This study investigated the effectiveness of tRNS on WM compared with that of tDCS, which has established functional evidence. Methods This randomized, double-blind, sham-controlled trial enrolled 120 healthy right-handed adults who were randomly allocated to four stimulation groups: tRNS + direct current (DC) offset, tRNS, tDCS, or sham. Each stimulus was placed over the left DLPFC and had a current intensity of 2 mA applied for 20 min during the dual n-back task. The dual n-back task was repeated thrice: pre-stimulation, during stimulation, and post-stimulation. The d-prime scores, and response times were calculated as the main outcome measures. A linear mixed model was created to identify the main effects and interactions between the groups and times, with the group and time as fixed effects, and baseline performance and the subject as a covariate and random effect, respectively. The relationships between the benefit of each stimulus and baseline WM performance were also examined. Results For the d-prime score during stimulation, the tRNS group significantly performed better than the sham group at online assessment (β = 0.310, p = 0.001). In the relationships between the benefit of each stimulus and baseline WM performance, the tRNS group had significantly larger negative line slopes than the sham group for the d-prime score (β = −0.233, p = 0.038). Conclusions tRNS applied to the left DLPFC significantly improved WM performance and generated greater benefits for healthy individuals with lower WM performance. These findings highlight the potential utility of tRNS for enhancing WM performance in individuals with lower WM performance and contribute evidence for clinical application to patients with cognitive decline. Trial Registration This study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000047365) on April 1, 2022; https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000054021 .

Background and Aims: The clinical characteristics and risk factors involved in the development of liver fibrosis in the subtypes of steatotic liver disease (SLD) remain unknown. We examined the clinical characteristics of SLD subtypes using a large Japanese cohort. Methods: We performed a cross-sectional analysis (total n = 108,446). In this cohort, SLD was diagnosed by ultrasonography. Individuals with none of the cardiometabolic risk factors were excluded. Results: According to their nonalcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated steatotic liver disease (MASLD) status based on the database, participants with cardiometabolic criteria were allocated to the MASLD, MASLD with increased alcohol intake (MetALD), and alcohol-associated liver disease (ALD) with metabolic dysfunction groups. Of 30,857 subjects with SLD, 21,488 (69.6%) had NAFLD, and 20,922 (67.8%) had MASLD. There were few differences in the clinical characteristics between NAFLD and MASLD. After adjustment for clinical variables, we found that male patients with MetALD [odds ratio (OR) 2.26; 95% confidence interval (CI) 1.87–2.84] and ALD with metabolic dysfunction (OR 3.92; 95% CI 2.85–5.39) had a significantly higher risk for advanced liver fibrosis (diagnosed by Fibrosis-4 (FIB-4) index >2.67) compared to those with MASLD. In female patients with ALD, metabolic dysfunction (OR 5.80; 95% CI 2.51–13.4) and systemic blood pressure of ≥130 mmHg were significant risk factors for high FIB-4 (males: OR 3.38, 95% CI 2.51–4.55; females: OR 4.34, 95% CI 2.66–7.07, P < .001). Conclusion: Alcohol intake and systolic blood pressure are independent contributors to liver fibrosis progression assessed by FIB-4 in SLD.

Abstract Background The left dorsolateral prefrontal cortex (DLPFC) is involved in early-phase manual dexterity skill acquisition when cognitive control processes, such as integration and complexity demands, are required. However, the effectiveness of left DLPFC transcranial direct current stimulation (tDCS) on early-phase motor learning and whether its effectiveness depends on the cognitive demand of the target task are unclear. This study aimed to investigate whether tDCS over the left DLPFC improves non-dominant hand dexterity performance and determine if its efficacy depends on the cognitive demand of the target task. Methods In this randomized, double-blind, sham-controlled trial, 70 healthy, right-handed, young adult participants were recruited. They were randomly allocated to the active tDCS (2 mA for 20 min) or sham groups and repeatedly performed the Purdue Pegboard Test (PPT) left-handed peg task and left-handed assembly task three times: pre-tDCS, during tDCS, and post tDCS. Results The final sample comprised 66 healthy young adults (mean age, 22.73 ± 1.57 years). There were significant interactions between group and time in both PPT tasks, indicating significantly higher performance of those in the active tDCS group than those in the sham group post tDCS (p

Abstract Background Risk ratio is a popular effect measure in epidemiological research. Although previous research has suggested that logistic regression may provide biased odds ratio estimates when the number of events is small and there are multiple confounders, the performance of risk ratio estimation has yet to be examined in the presence of multiple confounders. Methods We conducted a simulation study to evaluate the statistical performance of three regression approaches for estimating risk ratios: (1) risk ratio interpretation of logistic regression coefficients, (2) modified Poisson regression, and (3) regression standardization using logistic regression. We simulated 270 scenarios with systematically varied sample size, the number of binary confounders, exposure proportion, risk ratio, and outcome proportion. Performance evaluation was based on convergence proportion, bias, standard error estimation, and confidence interval coverage. Results With a sample size of 2500 and an outcome proportion of 1%, both logistic regression and modified Poisson regression at times failed to converge, and the three approaches were comparably biased. As the outcome proportion or sample size increased, modified Poisson regression and regression standardization yielded unbiased risk ratio estimates with appropriate confidence intervals irrespective of the number of confounders. The risk ratio interpretation of logistic regression coefficients, by contrast, became substantially biased as the outcome proportion increased. Conclusions Regression approaches for estimating risk ratios should be cautiously used when the number of events is small. With an adequate number of events, risk ratios are validly estimated by modified Poisson regression and regression standardization, irrespective of the number of confounders.