Intraindividual Reaction Time Variability Research Articles

From attentional fluctuations to intentional fluctuations? Monitoring behavior and intraindividual variability in time-based prospective memory.

In sharp contrast to event-based prospective memory (PM), dynamics of (re)allocation of attention between the ongoing and PM tasks have been much less investigated in time-based PM tasks. We propose an in-depth examination of attention allocation in a time-based PM task by jointly analyzing multiple indicators of time-monitoring behavior, net and time-structured intraindividual variability (IIV) in ongoing-task reaction times (OT RTs), and task performance. Results from dynamic structural equation modeling in a lifespan sample of 198 adults (19-86 years) revealed that larger fluctuations in OT RTs (net IIV) predicted poorer OT performance, but fostered a more efficient pattern of time-monitoring behavior (i.e., checking a clock more frequently and strategically, and slowing OT RTs during the PM response window) that, in turn, enhanced PM. Conversely, greater inertia in OT RTs (time-structured IIV) led to fewer clock-checks and poorer PM performance. Focusing attention on time monitoring to enhance PM performance did not detrimentally affect OT accuracy. Instead, participants showed a speed-accuracy tradeoff to optimize both OT and PM accuracies by slowing their OT RTs during the PM response window. This study therefore shows that two concomitant aspects of IIV (net and time-structured IIV) not only predicted time-monitoring behavior, but also OT and PM accuracies differentially, hence advocating for the necessity to consider both aspects of IIV and time monitoring together to better understand attention allocation policies in time-based PM tasks. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Quadratic associations between cardiovascular stress reactivity and development of cool and hot executive functions in adolescents.

Stress affects executive functions and exploring the association between stress-induced physiological reactivity and executive functions could highlight the potential mechanism of the stress-cognitive function link. Our study examined the linear and nonlinear associations between cardiovascular stress reactivity and cool and hot executive functions among adolescents. In November 2021 (T1), 273 Chinese adolescents between 11 and 14 (Mage = 12.93, SDage = 0.79) underwent a speech task during which their cardiovascular data were recorded, and they completed a Flanker task and an Emotional Stroop task. In May 2023 (T2), 253 adolescents again completed the Flanker and Emotional Stroop tasks. Cool and hot executive functions were assessed using the intra-individual reaction time variability of the Flanker task and Emotional Stroop task, respectively. Results showed that cardiovascular stress reactivity was positively linearly associated with cool executive functions at T1 and quadratically (inverted U-shaped) associated with cool executive functions at T1 and hot executive functions at T1 and T2. These findings suggest that compared to very high and very low cardiovascular reactivity, moderate to high cardiovascular reactivity to a structured social challenge is associated with better cool and hot executive functions.

Increased intraindividual variability in reaction time performance is associated with emerging cognitive decline in cognitively unimpaired adults.

To investigate whether intraindividual variability (IIV) in reaction time (RT) over monthly administered cognitive tasks is increased in cognitively unimpaired older adults who are at risk for cognitive decline, and whether this is independent of mean RT performance. N = 109 cognitively unimpaired individuals (age 77.4 ± 5.0, 61.5% female, Mini-Mental State Examination 29.1 ± 1.3) from the Harvard Aging Brain Study completed the self-administered Computerized Cognitive Composite (C3) monthly at home for up to 1 year (12.7 ± 3.2 C3 assessments). Baseline C3 assessment coincided with routine in-clinic visits, including amyloid and tau positron emission tomography imaging and standardized cognitive testing, with cognitive testing repeated annually (1.6 ± 1.2 years follow-up). The C3 includes two simple RT tasks and two complex RT tasks. IIV estimates were derived by computing intraindividual standard deviations on residual RT scores after regressing out age and session order effects. Cross-sectional associations of IIV with cognition (global cognition, memory, executive functions [EF], processing speed) and amyloid and tau burden were examined using linear regression analyses correcting for demographics and mean RT. The association between IIV and cognitive decline was assessed using linear mixed models correcting for demographic factors, mean RT, and amyloid burden. After adjusting for mean RT, increased IIV on complex RT tasks was independently associated with worse EF performance (β = -0.10, 95% CI [-.16, -0.03], p = .004), greater inferior-temporal tau deposition (β = 0.18, 95% CI [0.02, 0.34], p = .024), and faster cognitive decline in those with elevated amyloid (β = -0.62, 95% CI [-1.18, -0.06], p = .033). Increased variability in monthly RT may reflect subtle EF deficits and provide unique information about short-term cognitive decline in preclinical Alzheimer's disease. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Modulatory effects of transcutaneous auricular vagus nerve stimulation (taVNS) on attentional processes

BackgroundThe modulatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) on attention has varied in previous studies. This inconsistency might be attributed to the combined influence of the modulation effect...

Cognitive and Exercise Training Improves Intraindividual Variability in Cognitive Performance in Older Adults: Secondary Findings of A Randomized Controlled Trial

AbstractBackgroundIncreased intraindividual variability of cognitive performance is a marker of cognitive decline. Whether computerized cognitive training (CCT) and aerobic exercise counteracts cognitive decline by reducing intraindividual variability is unknown. We investigated the effects of CCT with or without aerobic exercise on reaction time intraindividual variability in older adults.MethodThis was a secondary analysis of an 8‐week randomized controlled trial. Older adults (aged 65‐85 years) were randomized to CCT alone (n = 41), CCT with aerobic exercise (n = 41), or an active control group (n = 42). The CCT group trained using the Fit Brains® platform 3×/week for 1 hour (plus 3×/week of home‐based training). The CCT with aerobic exercise group received 15 min of walking plus 45 min of Fit Brains® 3×/week (plus 3×/week of home‐based training). The control group received sham exercise and cognitive training (3×/week for 1 hour). We extracted reaction times from the Dimensional Change Card Sort Test, Flanker Inhibitory Control and Attention Test (Flanker), and Pattern Comparison Processing Speed Test (PACPS). Intraindividual variability was measured as residual intraindividual standard deviation (residual ISD) of raw reaction time latencies. Residual ISD is an unbiased measure of variability that accounts for within and between participant source of variation that could influence reaction time latencies. We also calculated reaction time intraindividual SD (raw‐score ISD) and intraindividual coefficient of variation (ICV).ResultCompared with the control group, residual ISD improved in a processing speed task (PACPS) following CCT alone (mean difference [95% confidence interval]: ‐0.147 [‐0.230 to ‐0.065], p<0.001) and CCT with aerobic exercise (‐0.111 [‐0.195 to ‐0.027], p<0.01). Also, for processing speed, both CCT (‐0.173 [‐0.261 to ‐0.084], p<0.001) and CCT with aerobic exercise (‐0.122 [‐0.213 to ‐0.032], p<0.01) showed greater reduction in raw‐score ISD compared with controls, while only CCT reduced ICV for this task (‐0.108 [‐0.176 to ‐0.040], p<0.001). Inhibitory attention (Flanker) improved only after CCT with aerobic exercise (congruent = ‐0.128 [‐0.250 to ‐0.006], incongruent = ‐0.121 [‐0.237 to ‐0.005], both p<0.05).ConclusionA CCT program promoted cognitive health via reductions in intraindividual variability of cognitive performance and combining it with aerobic exercise resulted in broader benefits.

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders

ABSTRACTBackground: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (β = –0.208, t = –2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

24 Mindfulness-based cognitive therapy enhances executive control in recurrent depression in a randomized wait-list controlled trial

Objective:Adults with recurrent depression have been shown to have cognitive deficits also while in remission. Thus, it has been suggested that with a chronic course of depression, poorer executive control can be a vulnerability factor for depressive relapse. This has led to research on how cognitive remediation training can protect against recurrent depressive episodes. Findings indicate that such training has short term effects on cognitive functioning, and small effect on depression symptoms. Less focus has been on how “standard” psychotherapy can have positive effects on executive and attentional control. Mindfulness-based cognitive therapy (MBCT) has been shown to be as effective as antidepressant medication in preventing relapses of depressive episodes. Mindfulness training in healthy samples seems to improve executive and attentional control. However, the few studies of MBCT in recurrent depression show mixed effects on executive and attentional control. As far as we know, no prior study has investigated the effect of MBCT in recurrent depression with the revised version of the attention network test (ANT-R). In a randomized controlled trial, we expected that the MBCT group would show enhanced executive control and lower levels of attentional fluctuations than the wait-list controls (WLC) from pre (T0) to post (T1) treatment. We further investigated if positive effects of MBCT on executive and attentional control were associated with reduction in depression symptoms.Participants and Methods:Adults with recurrent depression in partial or full remission (N = 64) were randomized to MBCT or WLC. In the MBCT and WLC groups, 25 and 29, respectively, performed the ANT-R at T0 and T1. The attention network reaction time scores of executive control, alerting, and orienting were calculated in addition to attention fluctuations scores of intra-individual reaction time variability (IIVRT) and exgaussian-mean of longer reaction times (TAU). Self-reported depression symptoms were measured with BDI-II. The two groups were compared at baseline on full-scale IQ (WASI), executive control (D-KEFS Stroop), and processing speed (D-KEFS TMT).Results:The MBCT and WCL groups did not differ significantly in age or gender distribution, education, full-scale IQ or in baseline executive and attentional control as measured with the ANT-R, Stroop and TMT. The MBCT group showed a higher efficiency in conflict detection as measured with the executive control score from T0 to T1 compared to the WLC. This positive effect of MBCT on executive control was independent from the greater reductions in depression symptoms in the MBCT group compared to in the WLCs. However, reduction in depression symptoms at T1 was associated with enhanced efficiency in responding to alerting cues in conflict detection. No effects of MBCT compared to WLC were found at T1 on the attention fluctuation measures (IIVRT and TAU).Conclusions:The findings from the current study indicates that MBCT enhances executive control in adults with recurrent depression. As such, MBCT may target an important cognitive vulnerability factor in the chronic course of recurrent depression that may contribute to its efficacy in preventing depressive relapses. It was also observed that reductions in depression symptoms led to higher alertness in conflict detection.

Relationship between reaction time variability on go/no go tasks and neuropsychological functioning in younger and older adults

ABSTRACT Introduction Early detection of cognitive impairment in older adults is important for the prevention of dementia. Intra-individual variability in reaction time (IIV-RT) during go/no-go tasks can be used for the early detection of cognitive impairment in older adults living in the community. This study aimed to determine the relationship between IIV-RT and cognitive function during go/no-go tasks and the cutoff values for determining the risk of cognitive impairment in community-dwelling older adults. Methods This study included 31 older adults without cognitive impairment, 15 community-dwelling older adults with cognitive impairment, and 34 healthy young adults. All participants performed a go/no-go task to assess the IIV-RT. Additionally, older adults underwent neuropsychological testing. Based on the results of the Japanese version of the Montreal Test of Cognitive Abilities (MoCA-J), older adults were divided into those with normal cognition and those with cognitive impairment. Results There were significant differences in the IIV-RT among groups, including a higher IIV in the cognitively impaired group than in young adults and cognitively normal older adults. Moreover, the IIV-RT was correlated with the MoCA-J (r = −0.531, p < 0.001), Trail Making Test Part A (r = 0.571, p < 0.001), and Verbal Fluency Test scores (r = −0.442, p = 0.002). Receiver operating curve analysis showed that the area under the curve for IIV-RT was 0.935, and the cutoff value at which the IIV-RT identified cognitive impairment was 25.37%. Conclusions These findings indicate that the IIV-RT during go/no-go tasks is a useful early indicator of cognitive impairment in community-dwelling older adults.

Depression, anxiety and problematic smartphone use: the moderating roles of inhibitory control and trial-to-trial intraindividual reaction time variability

Depression, anxiety and problematic smartphone use: the moderating roles of inhibitory control and trial-to-trial intraindividual reaction time variability

Associations between intraindividual reaction time variability and prospective memory performance in patients with schizophrenia and healthy controls

ABSTRACT Introduction: Patients with schizophrenia exhibit prospective memory (PM) impairment. Intraindividual reaction time variability (IIRTV) is an index of attentional control that is required for PM. This study examined the differences in IIRTV between patients with schizophrenia and healthy controls and the relationship between IIRTV and PM performance. Method: Thirty-nine patients with schizophrenia and forty-two healthy controls were recruited to complete a PM task and the Sustained Attention to Response Task. IIRTV was calculated as the coefficient of variation (mean/SD) of reaction time over correctly responded trials in these tasks. Results: Patients with schizophrenia showed lower PM accuracy and increased IIRTV, while the associations between PM accuracy and IIRTV were significant in healthy controls but not in patients with schizophrenia. Conclusion: These findings suggest impaired PM and relationship between PM and attentional control in patients with schizophrenia.

Aggressive behaviors predict greater intraindividual reaction time variability in children: Evidence from cross-lagged panel models.

Deficits in attentional control or inhibitory control are distinct features of childhood aggressive behaviors. Lower attentional control or inhibitory control is considered to predict more aggressive behaviors, while few studies have documented the possible predictive effects of aggressive behaviors on attentional control or inhibitory control. The present study examined the bidirectional relations between aggressive behaviors and both inhibitory control and attentional control in 169 Chinese primary school children (75 girls, Mage = 7.15, SDage = 0.33), annually for 3years starting at age 7. The No-go accuracy on a Go/No-go task was used as the index of inhibitory control, and the intraindividual reaction time variability (IIRTV) of correct Go trials indicated attentional control. The aggressive behaviors subscale of the child behavior checklist-Chinese versionwas used to assess the children's aggressive behaviors. The results demonstrated a significant and stable predictive effect of previous aggressive behaviors on subsequent attentional control, with more aggressive behaviors predicting greater IIRTV at both the between-child and within-child levels. No significant effects of inhibitory control or attentional control on aggressive behaviors or sex-specific patterns were found. The findings suggest the negative impact of childhood aggressive behaviors on attentional control and underscore the importance of early prevention and intervention for childhood aggressive behaviors.

APPLICATION OF MACHINE LEARNING TECHNIQUES FOR DISTINGUISHING SCHIZOPHRENIA PATIENTS FROM HEALTHY SUBJECTS USING FRONTAL LOBE FUNCTIONS ASSESSMENTS

Machine learning (ML) represents a set of artificial in­telligence techniques that can assist in recognition of schizophrenia by classifying a person as belonging to either clinical or healthy subjects group. In the current study, we employed cognitive assessments of frontal lobe functions (the deficit of which is one of the prominent features of schizophrenia) for the training of ML models. Dataset for this research was engaged from our previous studies of two frontal lobe functions (response prepara­tion and inhibition of imitation) in case of schizophrenia. According to our knowledge, all previous cognitive ML schizophrenia studies used only the data from standard neuropsychological test batteries. Nevertheless, we em­ployed the cognitive data assessed with special experi­mental techniques that allowed us to engage Intra-indi­vidual reaction time variability (IIV) together with the classical reaction time (RT) assessment. It is important to emphasize that IIV is a cognitive measurement parameter that received vast attention of neuroscientists during the two last two decades and showed higher results in distin­guishing of schizophrenia patients from healthy subjects than standard RT in the number of studies. The result revealed statistically significant accuracy for all ML models in current study. Moreover, ML classifier with the highest accuracy outperformed the accuracy of a number of best models previously trained with standard neuropsychological test batteries datasets. Thus, cogni­tive experimental assessments of frontal lobe functions (response preparation and inhibition of imitation) can be effectively employed in developing of ML classifiers for distinguishing schizophrenia patients from healthy subjects.

A detailed examination of pitch discrimination deficits associated with auditory verbal hallucinations in schizophrenia.

Individuals with schizophrenia spectrum disorders (SSD) and a history of experiencing auditory verbal hallucinations (AVH) exhibit poor pitch discrimination relative to those with an SSD but no AVH history. The present study extended this research, asking if a lifetime history, and the current presence, of AVH exacerbated the pitch discrimination challenges that are seen in SSD. Participants completed a pitch discrimination task, where the tones presented differed in pitch by either 2%, 5%, 10%, 25% or 50%. Pitch discrimination accuracy, sensitivity, reaction time (RT) and intra-individual RT variability (IIV) were examined in individuals with SSD and AVHs (AVH+; n=46), or without AVHs (AVH-; n=31), and healthy controls (HC; n=131). Secondary analyses split the AVH+ group into state (i.e., actively experiencing AVH; n=32) and trait hallucinators (i.e., a history of, but not actively experiencing, AVH; n=16). Relative to HC, significantly poorer accuracy and sensitivity was detected in individuals with SSD at 2% and 5% pitch deviants, and in hallucinators at 10%; however, no significant differences in accuracy, sensitivity, RT nor IIV were found between AVH+ and AVH- groups. No differences between state and trait hallucinators were observed. A general SSD deficit drove the current findings. The findings may inform future research into the auditory processing capabilities of AVH+ individuals.

Shared genetic etiology between ADHD, task-related behavioral measures and brain activation during response inhibition in a youth ADHD case–control study

Impaired response inhibition is commonly present in individuals with attention-deficit/hyperactivity disorder (ADHD) and their unaffected relatives, suggesting impaired response inhibition as a candidate endophenotype in ADHD. Therefore, we explored whether behavioral and neural correlates of response inhibition are related to polygenic risk scores for ADHD (PRS-ADHD). We obtained functional magnetic resonance imaging of neural activity and behavioral measures during a stop-signal task in the NeuroIMAGE cohort, where inattention and hyperactivity-impulsivity symptoms were assessed with the Conners Parent Rating Scales. Our sample consisted of 178 ADHD cases, 103 unaffected siblings, and 173 controls (total N = 454; 8–29 years), for whom genome-wide genotyping was available. PRS-ADHD was constructed using the PRSice-2 software. We found PRS-ADHD to be associated with ADHD symptom severity, a slower and more variable response to Go-stimuli, and altered brain activation during response inhibition in several regions of the bilateral fronto-striatal network. Mean reaction time and intra-individual reaction time variability mediated the association of PRS-ADHD with ADHD symptoms (total, inattention, hyperactivity-impulsivity), and activity in the left temporal pole and anterior parahippocampal gyrus during failed inhibition mediated the relationship of PRS-ADHD with hyperactivity-impulsivity. Our findings indicate that PRS-ADHD are related to ADHD severity on a spectrum of clinical, sub-threshold, and normal levels; more importantly, we show a shared genetic etiology of ADHD and behavioral and neural correlates of response inhibition. Given the modest sample size of our study, future studies with higher power are warranted to explore mediation effects, suggesting that genetic liability to ADHD may adversely affect attention regulation on the behavioral level and point to a possible response inhibition-related mechanistic pathway from PRS-ADHD to hyperactivity-impulsivity.

Family Functioning and Intraindividual Reaction Time Variability Interactively Predict Children's Externalizing Problems.

Family functioning including family adaptability and family cohesion, and intraindividual reaction time variability (IIV) which serves as an index of attentional control has been found to relate to children's externalizing problems. However, it remains unknown whether family functioning interacts with children's IIV to predict their externalizing problems based on the diathesis-stress model. The present study examined this concern. Participants included 168 (Mage = 7.35 years, SD = 0.48; 48% boys) and 155 (Mage = 8.32 years, SD = 0.45; 49% boys) children at the first (T1) and second (after one year, T2) measurements, respectively. At T1, a flanker task was used to assess children's IIV. Mothers reported family functioning using the Chinese version of the Family Adaptability and Cohesion Scales, and children's externalizing problems using the Chinese version of the Child Behavior Checklist. At T2, mothers reported children's externalizing problems again. Results indicated that family functioning negatively and IIV positively correlated with children's externalizing problems. Furthermore, family functioning interacted with children's IIV to predict their externalizing problems concurrently and longitudinally. Specifically, low family functioning combined with greater IIV predicted prospective externalizing problems. Findings suggested that better attentional control (indexed by lower IIV) may buffer the negative effect of poor family functioning.

Reaction Time Variability in Children Is Specifically Associated With Attention Problems and Regional White Matter Microstructure

BackgroundIncreased intraindividual variability (IIV) in reaction times (RTs) has been suggested as a key cognitive and behavioral marker of attention problems, but findings for other dimensions of psychopathology are less consistent. Moreover, while studies have linked IIV to brain white matter microstructure, large studies testing the robustness of these associations are needed. MethodsWe used data from the Adolescent Brain Cognitive Development (ABCD) Study baseline assessment to test the associations between IIV and psychopathology (n = 8622, age = 8.9–11.1 years) and IIV and white matter microstructure (n = 7958, age = 8.9–11.1 years). IIV was investigated using an ex-Gaussian distribution analysis of RTs in correct response go trials in the stop signal task. Psychopathology was measured by the Child Behavior Checklist and a bifactor structural equation model was performed to extract a general p factor and specific factors reflecting internalizing, externalizing, and attention problems. To investigate white matter microstructure, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were examined in 23 atlas-based tracts. ResultsIncreased IIV in both short and long RTs was positively associated with the specific attention problems factor (Cohen’s d = 0.13 and d = 0.15, respectively). Increased IIV in long RTs was also positively associated with radial diffusivity in the left and right corticospinal tract (both tracts, d = 0.12). ConclusionsUsing a large sample and a data-driven dimensional approach to psychopathology, the results provide novel evidence for a small but specific association between IIV and attention problems in children and support previous findings on the relevance of white matter microstructure for IIV.

Synergistic effects of high early-life stress exposure and HIV infection on reaction time variability.

Addressing comorbidities contributing to cognitive impairment in people living with HIV (PLWH) remains imperative. Prior studies utilizing reaction time intra-individual variability (RT-IIV), a robust behavioral marker of cognitive dysfunction, demonstrate increased cognitive impairment in adults living with HIV who have high early life stress (ELS) exposure relative to those with low-ELS exposure. Yet, it is unknown whether RT-IIV elevations are due to high-ELS alone or both HIV-status and high-ELS. In the current study, we explore the potential additive effects of HIV and high-ELS exposure on RT-IIV to better characterize the independent and combined effects of these factors on RT-IIV among PLWH. We assessed 59 PLWH and 69 HIV-negative healthy control (HC) participants with either low or high ELS on RT-IIV during a working memory task (1-back). We observed a significant interaction between HIV status and ELS exposure on RT-IIV, PLWH who had experienced high ELS demonstrating RT-IIV elevations relative to all other groups. In addition, RT-IIV was significantly associated with ELS exposure in PLWH, but not in the HC group. We also observed associations between RT-IIV and measures of HIV-disease severity (plasma HIV viral load, nadir CD4) among PLWH. Taken as a whole, these findings provide novel evidence of the combined effects of HIV and high-ELS exposure on RT-IIV, and thus suggest HIV-related and ELS-related neural abnormalities may act in an additive or synergistic manner to affect cognition. Such data warrant further investigation into the neurobiological mechanisms associated with HIV and high-ELS exposure that contribute to increased neurocognitive dysfunction among PLWH.

Fluctuations in reaction time performance as a marker of incipient amyloid‐related cognitive decline in clinically unimpaired older adults.

AbstractBackgroundAccumulating evidence suggests that fluctuations in reaction time (RT) performance across assessments, usually defined by intraindividual variability in RT (IIV‐RT), are associated with cognitive impairment and decreased neurobiological integrity. Computerized cognitive testing facilitates the study of IIV‐RT, allowing for precise and frequent RT measurements in remote settings. We investigated whether quantifying IIV‐RT over months on various remotely administered computerized RT tasks could aid in the detection of emerging cognitively decline in initially clinically unimpaired (CU) older adults with elevated Alzheimer’s disease (AD) biomarkers.MethodN = 114 CU individuals (age 77.6±5.1, 61% female, MMSE 29±1.2, n = 33 amyloid‐positive as measured using PiB‐PET imaging) from the Harvard Aging Brain Study (HABS) completed the self‐administered Computerized Cognitive Composite (C3) monthly at‐home on an iPad for up to one year (11.7±3.2 C3 assessments). Baseline C3 assessment coincided with participants’ HABS in‐clinic visit including Preclinical Alzheimer’s Cognitive Composite (PACC) testing, and participants had 1.8±1.2 subsequent years follow‐up PACC testing available. The C3 includes two basic RT tasks (Detection [DET]; Identification [IDN]), and two complex RT tasks (One Card Learning [OCL]; One Back [ONB]) that also require working memory skills. IIV‐RT measures were derived for each task by computing the intraindividual standard deviation between mean RTs across all monthly visits for each participant. Subsequently, IDN and DET IIV‐RT were combined into a basic IIV‐RT composite, and OCL and ONB IIV‐RT into a complex IIV‐RT composite. Linear mixed models were used to investigate the association between both IIV‐RT composites and PACC decline adjusting for covariates (age, sex, education, amyloid status (+/‐)) and their interaction with time.ResultGreater IIV‐RT on complex RT tasks was associated with steeper decline on the PACC (Time*IIV‐RT ß = ‐1.3, 95%CI[‐2.57 – ‐0.03],p = .04) (Figure 1), which was driven by amyloid‐positive individuals (Time*Amyloid[+]*IIV‐RT ß = ‐3.52, 95%CI[‐6.43 – ‐0.61],p = .02) (Figure 2). In contrast, greater IIV‐RT on basic RT tasks was only associated with baseline PACC performance (IIV‐RT ß = ‐4.29, 95%CI[‐7.32 – ‐1.26],p = .007) but not with PACC change over time.ConclusionOur findings suggest that fluctuations in RT performance over monthly‐repeated complex RT tasks may reflect evidence of early amyloid‐related neurodegeneration and provide a marker of incipient cognitive decline in preclinical AD.

Attention deficits in Brazilian health care workers with chronic pain.

The impact of COVID-19 on chronic pain (CP) in non-infected vulnerable South American subjects is unknown. Healthcare workers (HCWs) are at increased risk for CP. During the pandemic, many HCWs with CP kept working. Knowing how cognition is affected by CP in these subjects is an important subject for work safety. The attention domain has a pivotal role in cognition. Previously, the Continuous Visual Attention Test (CVAT) was applied to detect specific attention deficits in fibromyalgia patients. The present investigation described CP prevalence in non-infected Brazilian HCWs during the pandemic and assessed HCWs' attentional performance with the aid of the CVAT. This study was carried out at a reference University Hospital in Rio de Janeiro, Brazil. HCWs of both sexes, aged 20 or older, were interviewed from August to December 2020. A 90-second version of the CVAT was performed. The average reaction time to correct responses and the respective intraindividual reaction time variability for correct responses to target (VRT) was determined. Omission and commission errors were also calculated. Then, for each participant we calculated the Z-scores of the CVAT variables based on the distribution of CVAT performance of 211 healthy subjects (reference-comparison group). HCWs with Z-scores > 1.64 were classified as significantly impaired. From the 154 selected HCWs, 72 reported CP during the pandemic (prevalence = 47%). Post hoc ANCOVAs showed that the average correct VRT was significantly higher in the CP group than in the non-CP group (F = 4.99, df = 1/150, p = 0.027, η2 = 0.032). The percentage of participants with impaired VRT performance was 30% (n = 21) in the CP group and 16% (n = 13) in the non-CP group. The difference between these two propositions reached significance (χ2 = 3.96, df = 1, p = 0.047). As VRT is associated with the sustained-attention subdomain, our data suggest that this subdomain is disrupted in the CP group.

Cumulative life course adversity, mental health, and cognition in the UK biobank

The association between adversity and cognition varies according to the specific adversity, when the adversity was experienced, and the cognitive domains investigated. Disentangling the effect of adversity and the underlying mechanistic pathway is therefore difficult. The association between adversity (i.e., maltreatment) accumulated over the life course and cognitive flexibility, as well as two potential mediators (i.e., intra-individual variability in reaction time and depression) of this association, were investigated. Data stem from the baseline population of the UK Biobank study (N = 73,489, Mdnage = 56, SDage = 7.628, 55.740% of women). Cumulative life course adversity (specifically maltreatment) was measured with items based on the Childhood Trauma Questionnaire (CTS-5) and items adapted from the British Crime Survey. Depression was assessed with the Patient Health Questionnaire-9 (PHQ-9). Intra-individual variability in reaction time was measured with a reaction time test “snap game” and the Trail Making Test A and B were used as a measure of cognitive flexibility. A path analysis was performed on these data. Higher cumulative adverse experiences were associated with lower performance in cognitive flexibility (β = .016, p < .001, 95% CI [0.009, 0.024]), and this effect was partly mediated by the level of depression (22.727% of the total effect of cumulative life course adversity on cognitive flexibility was mediated by depression (β = .005, p < .001, 95% CI [0.004, 0.007])). No association between cumulative life course adverse experiences and intra-individual variability in reaction time was found, nor was any indirect association between cumulative life course adversity and performance in cognitive flexibility via intra-individual variability in reaction time. The association between cumulative life course adversity, depression, and performance in cognitive flexibility has been highlighted. In contrast, no indirect effect between cumulative life course adversity and performance in cognitive flexibility via intra-individual variability in reaction time was found, suggesting that it is not a potential mechanism underlying the association between cumulative life course adversity and executive function.