Post-error slowing reflects the joint impact of adaptive and maladaptive processes during decision making

Errors and their consequences are typically studied by investigating changes in decision speed and accuracy in trials that follow an error, commonly referred to as "post-error adjustments". Many studies have reported that subjects slow down following an error, a phenomenon called "post-error slowing" (PES). However, the functional significance of PES is still a matter of debate as it is not always adaptive. That is, it is not always associated with a gain in performance and can even occur with a decline in accuracy. Here, we hypothesized that the nature of PES is influenced by one's speed-accuracy tradeoff policy, which determines the overall level of choice accuracy in the task at hand. To test this hypothesis, we investigated post-error adjustments in subjects performing the same task while they were required to either emphasize speed (low accuracy) or cautiousness (high accuracy) in two distinct contexts (hasty and cautious contexts, respectively) experienced on separate days. Accordingly, our data indicate that post-error adjustments varied according to the context in which subjects performed the task, with PES being solely significant in the hasty context. In addition, we only observed a gain in performance after errors in a specific trial type, suggesting that post-error adjustments depend on a complex combination of processes that affect the speed of ensuing actions as well as the degree to which such PES comes with a gain in performance.

Unbiased post-error slowing in interference tasks: A confound and a simple solution

We typically slow down after committing an error, an effect termed post-error slowing (PES). Traditionally, PES has been calculated by subtracting post-correct from post-error RTs. Dutilh et al. (Journal of Mathematical Psychology, 56(3), 208-216, 2012), however, showed PES values calculated in this way are potentially biased. Therefore, they proposed to compute robust PES scores by subtracting pre-error RTs from post-error RTs. Based on data from a large-scale study using the flanker task, we show that both traditional and robust PES estimates can be biased. The source of the bias are differential imbalances in the percentage of congruent vs. incongruent post-correct, pre-error, and post-error trials. Specifically, we found that post-correct, pre-error, and post-error trials were more likely to be congruent than incongruent, with the size of the imbalance depending on the trial type as well as the length of the response-stimulus interval (RSI). In our study, for trials preceded by a 700-ms RSI, the percentages of congruent trials were 62% for post-correct trials, 66% for pre-error trials, and 56% for post-error trials. Relative to unbiased estimates, these imbalances inflated traditional PES estimates by 37% (9 ms) and robust PES estimates by 42% (16 ms) when individual-participant means were calculated. When individual-participant medians were calculated, the biases were even more pronounced (40% and 50% inflation, respectively). To obtain unbiased PES scores for interference tasks, we propose to compute unweighted individual-participant means by initially calculating mean RTs for congruent and incongruent trials separately, before averaging congruent and incongruent mean RTs to calculate means for post-correct, pre-error and post-error trials.

Effectiveness of Ginger in the Treatment of Type 2 Diabetes Mellitus: A Pilot Study of the Randomized Clinical Trial Type

Objective: To analyze the effectiveness of ginger in the reduction of the glycemic, lipid and anthropometric levels in people with Type 2 Diabetes Mellitus. Materials and method: A double-blind pilot study of the randomized clinical trial type, conducted between October 2017 and January 2018. The inclusion criteria were as follows: individuals with type 2 diabetes, aged from 18 to 80 years old, using oral antidiabetic drugs, and with glycated hemoglobin values between 7 % and 10 %. The participants were randomized and allocated in two different groups. In the experimental group, the participants used 1.2 g of ginger and, in the control group, 1.2 g of placebo. The primary outcome was the reduction in blood glucose. The reduction in the lipid and anthropometric levels was the secondary outcome. The intervention lasted four weeks. Results: A total of 21 participants were included in the study. The use of 1.2 g of ginger resulted in noticeable reductions in the anthropometric and lipid levels in 30 days of follow-up, but it did not reduce the glycemic levels. Conclusions: In this study, it was shown that ginger capsules, in doses of 1.2 g a day, can help to reduce anthropometric measures and lipid levels in the population under study; however, it had no effect on the glycemic levels.

Age-related effects on a novel dual-task Stroop paradigm

The Stroop task is a traditional measure of cognitive control processes, yet results remain mixed when it comes to assessing age-related differences perhaps in part due to strategies participants use to reduce inhibitory control demands required for success on the task. Thirty-three older adults and 34 younger adults completed a Baseline (traditional, single-task) version of Stroop, followed by two, novel dual-task Stroop variants: Color-Dual (maintain secondary count of prespecified font color regardless the lexical content) and Lexical-Dual (maintain secondary count of prespecified word regardless the font color). With regard to Baseline performance, we predicted an Age x Trial Type interaction in which older adults would be selectively impaired on Incongruent trials compared to younger adults, and this prediction was supported. When we added secondary task demands, we predicted a Trial Type x Dual-Task Type interaction in which performance in the Lexical-Dual condition would be worse than performance in the Color-Dual condition. This prediction was also supported, suggesting that having a secondary task that activated the irrelevant stream of information required more inhibitory control. Finally, we also predicted that Age would interact with Trial Type and Dual-Task Type, which was partially supported in response latencies and more definitively supported in error rates. Overall, our results indicate that Stroop performance is differentially influenced by additional dual-task demands that potentially minimize strategy usage, which has implications for both young and older adult Stroop performance.

Abstract MP30: Reporting of Sex-Specific Results in Randomized Clinical Trials of Acute Stroke (2010-2020)

Introduction: When reporting primary results, it is recommended that RCTs report sex-specific outcomes. We reviewed the reporting of sex-specific outcomes in contemporary acute stroke RCTs. Methods: We searched MEDLINE for manuscripts published between 2010 and June 2020 in one of nine major clinical journals reporting the primary results of phase 2 or 3 stroke RCTs. Eligible trials tested a therapeutic intervention initiated within one month of stroke onset. Reporting of sex-specific primary results was the outcome of interest. We also investigated whether the trial formally tested for an interaction between sex and treatment and if that interaction test was statistically significant. We performed bivariate analyses using Fisher’s exact tests to identify study-level factors associated with sex-specific reporting including journal, geographic region, trial phase, sample size, stroke type, trial type (e.g. thrombolytic, EVT, secondary prevention), and industry funding. Temporal trends using two-year time periods were also explored. Results: Of the 115 studies identified, sex-specific primary outcome data were reported in 37% (n=42). Reporting varied significantly by journal, with NEJM (61%) and Lancet journals (40%) having the highest rates (p=0.03) (Table). Reporting also differed by geographic region (p=0.03), trial phase (p=0.05), and sample size (p<0.01). Reporting did not vary significantly by stroke type, trial type, or industry involvement. While not significant, there was a positive temporal trend in favor of greater reporting in later publications (p=0.09). Of the 29 trials that formally tested for an interaction between sex and treatment, only one significant interaction was found. Conclusions: Although reporting of sex-specific outcomes improved from 2010 to 2020, the prevalence of reporting in major journals is still low. Further efforts are required to ensure that journals and authors comply with reporting guidelines.

A-172 Monolingual Advantage in Visual Task-Shifting in English-Speaking Individuals When Compared to English-and-Spanish-Speaking Bilingual Individuals

Objective Researchers reported that bilinguals have an advantage in visual task-shifting (VTS) and associated this advantage with executive functions (EF). We found self-reported monolinguals were faster than bilinguals when comparing switch (SW) and no-switch (NSW) incongruent trials on VTS, and that memory and age were significant predictors, not EF. Our aim is to repeat previous analyses with a sample of individuals matched on language fluency. Method Participants were 881 adults (Age: M = 31.64 ± 8.64; Men = 517; Monolingual = 646; Bilingual = 235; Education: M = 14.92 ± 2.05) from the Consortium for Neuropsychiatric Phenomics (UL1DE019580, PL1MH083271). Participants completed VTS, Memory, and EF tasks, including English Letter Fluency and, if bilingual, Spanish. Participants were dichotomized into the monolingual group if English letter fluency was at least low average, and the bilingual group if English/Spanish letter fluencies were at least low average. Results Response times (RTs) for short and long incongruent trials were computed in two-way ANCOVAs with Group (monolingual, bilingual) as between-participant and Trial Type (SW, NSW) as within-participant factors, and Age and Education as covariates. Short trials revealed main effects of Group (p = .034), as monolinguals achieved faster RTs than bilinguals, and main effects of Trial Type (p &lt; .001), as RTs for NSW was faster than SW. Long trials were nonsignificant (p &gt; .05). Hierarchical stepwise regressions revealed EF (p = .032) and Age (p = .004) significantly predicted Primary and Residual VTS performance. Conclusions Our results are inconsistent with literature. We found English monolinguals were faster than English/Spanish bilinguals when controlled for Age and Education. Further, the neuropsychological correlates revealed Age and EF are important predictors of VTS that should be further examined.

One-Hour Oral Glucose Tolerance Tests for the Prediction and Diagnostic Surveillance of Type 1 Diabetes

Context Once islet autoantibody–positive individuals are identified, predicting which individuals are at highest risk for type 1 diabetes (T1D) is important. A metabolic risk score derived from 2-hour oral glucose tolerance test (OGTT) data, the Diabetes Prevention Trial-Type 1 risk score (DPTRS), can accurately predict T1D. However, 2-hour OGTTs are time-consuming and costly. Objective We aimed to determine whether a risk score derived from 1-hour OGTT data can predict T1D as accurately as the DPTRS. Secondarily, we evaluated whether a 1-hour glucose value can be used for diagnostic surveillance. Methods The DPTRS was modified to derive a 1-hour OGTT risk score (DPTRS60) using fasting C-peptide, 1-hour glucose and C-peptide, age, and body mass index. Areas under receiver operating curves (ROCAUCs) were used to compare prediction accuracies of DPTRS60 with DPTRS in Diabetes Prevention Trial–Type 1 (DPT-1) (n = 654) and TrialNet Pathway to Prevention (TNPTP) (n = 4610) participants. Negative predictive values (NPV) for T1D diagnosis were derived for 1-hour glucose thresholds. Results ROCAUCs for T1D prediction 5 years from baseline were similar between DPTRS60 and DPTRS (DPT-1: 0.805 and 0.794; TNPTP: 0.832 and 0.847, respectively). DPTRS60 predicted T1D significantly better than 2-hour glucose (P &lt; .001 in both cohorts). A 1-hour glucose of less than 180 mg/dL had a similar NPV, positive predictive value, and specificity for T1D development before the next 6-month visit as the standard 2-hour threshold of less than 140 mg/dL (both ≥ 98.5%). Conclusion A 1-hour OGTT can predict T1D as accurately as a 2-hour OGTT with minimal risk of missing a T1D diagnosis before the next visit.