Intra-individual Variability In Response Time Research Articles

The interplay of dopaminergic genotype and parent-child relationship in relation to intra-individual response time variability in preschoolers: A replication study.

Intra-individual response time variability (IIRTV) during cognitive performance is increasingly recognized as an important indicator of attentional control (AC) and related brain region function. However, what determinants contribute to preschoolers' IIRTV received little attention. The present study explored the interaction of dopaminergic polygenic composite score (DPCS) and the parent-child relationship in relation to preschoolers' IIRTV. In the initial sample, 452 preschoolers (M age=5.17, SD=0.92) participated in the study. The modified Flanker task was used to evaluate children's IIRTV and their parents were requested to complete the Parent-Child Relationship Scale to assess the parent-child relationship (closeness/conflict). DNA data were extracted from children's saliva samples, and a DPCS was created by the number of COMT, DAT1, and DRD2 alleles associated with lower dopamine levels. Results showed that DPCS significantly interacted with the parent-child closeness to impact preschoolers' IIRTV. Specifically, preschoolers with higher DPCS exhibited lower IIRTV under higher levels of the parent-child closeness, and greater IIRTV under lower levels of the parent-child closeness compared to those with lower DPCS, which supported the differential susceptibility theory (DST). A direct replication attempt with 280 preschoolers (M age=4.80, SD=0.86) was conducted to investigate whether the results were in accordance with our exploratory outcomes. The interactive effect of DPCS and the parent-child closeness on IIRTV was confirmed. Additionally, the significant interactive effect of DPCS and the parent-child conflict on IIRTV was found in the replication study. The findings indicate that preschoolers' IIRTV, as an indicator of AC and related brain region function, is influenced by the interactions of dopaminergic genotypes and the parent-child relationship. RESEARCH HIGHLIGHTS: We investigated the Gene × Environment mechanism to underline the intra-individual response time variability as an indicator of attentional control (AC) in Chinese preschoolers. Dopaminergic polygenic composite score (COMT, DAT1, and DRD2) interacted with the parent-child relationship to predict preschoolers' intra-individual reaction time variability. A direct replication attempt has been conducted, and the results were in accordance with our exploratory outcomes, which increased the credibility of the present findings. The findings highlight the importance of considering precursors, including polygenic and environmental factors, which contribute to the development of early cognitive performance such as AC.

Assessment and Training of Perceptual-Motor Function: Performance of College Wrestlers Associated with History of Concussion.

Concussion may affect sport performance capabilities related to the visual perception of environmental events, rapid decision-making, and the generation of effective movement responses. Immersive virtual reality (VR) offers a means to quantify, and potentially enhance, the speed, accuracy, and consistency of responses generated by integrated neural processes. A cohort of 24 NCAA Division I male wrestlers completed VR assessments before and after a 3-week VR training program designed to improve their perceptual-motor performance. Prior to training, the intra-individual variability (IIV) among 40 successive task trials for perceptual latency (i.e., time elapsed between visual stimulus presentation and the initiation of movement response) demonstrated strong discrimination between 10 wrestlers who self-reported a history of concussion from 14 wrestlers who denied ever having sustained a concussion (Area Under Curve ≥ 0.750 for neck, arm, and step movements). Natural log transformation improved the distribution normality of the IIV values for both perceptual latency and response time (i.e., time elapsed between visual stimulus presentation and the completion of movement response). The repeated measures ANOVA results demonstrated statistically significant (p < 0.05) pre- and post-training differences between groups for the IIV in perceptual latency and the IIV in response time for neck, arm, and step movements. Five of the six IIV metrics demonstrated a statistically significant magnitude of change for both groups, with large effect sizes. We conclude that a VR assessment can detect impairments in perceptual-motor performance among college wrestlers with a history of concussion. Although significant post-training group differences were evident, VR training can yield significant performance improvements in both groups.

The Longitudinal Relationships between Family Functioning and Children’s Conduct Problems: The Moderating Role of Attentional Control Indexed by Intraindividual Response Time Variability

The Longitudinal Relationships between Family Functioning and Children’s Conduct Problems: The Moderating Role of Attentional Control Indexed by Intraindividual Response Time Variability

Reward-Seeking Deficits in Major Depression: Unpacking Appetitive Task Performance with Ex-Gaussian Response Time Variability Analysis.

Major depressive disorder (MDD) has extensive ties to motivation, including impaired response time (RT) performance. Average RT, however, conflates response speed and variability, so RT differences can be complex. Because recent studies have shown inconsistent effects of MDD on RT variability, the present research sought to unpack RT performance with several key improvements: (1) a sample of adults (n = 78; 18 MDD, 60 Control) free of antidepressant medication; (2) an unambiguously appetitive task with appealing incentives at stake; and (3) ex-Gaussian RT modeling, which can unconfound speed and variability by estimating parameters for the mean (Mu) and standard deviation (Sigma) of the normal component and the mean of the exponential component (Tau). The groups had comparable Mu and Sigma parameters, but the MDD group had a significantly larger Tau, reflecting greater intraindividual RT variability. The findings suggest that MDD's effect on average RT can stem from greater intraindividual variability, not from overall slowness. Possible mechanisms, such as impaired executive processes in MDD and difficulties maintaining stable mental representations of incentives, are considered.

Dynamic Attention Regulation for Prospective Goals in Schizophrenia

Whether patients with schizophrenia are impaired in flexibly regulating attention in accordance with fluctuations in cognitive demand to achieve optimal task performance remains unclear. To address this issue, 47 patients with schizophrenia and 47 matched control participants were recruited to complete a time-based prospective memory task. Every 2-min block before the target time was divided into four 30-s intervals, after which the time check and intraindividual response time variability (IIRTV) across these intervals were calculated. Patients with schizophrenia displayed significantly higher IIRTV across all four time intervals and checked time less frequently during the last 30-s interval relative to control subjects. Moreover, the reduced change in time-checking frequency and IIRTV between the first and the last 30-s intervals was related to poorer time-based prospective memory performance in patients with schizophrenia. Our findings provide initial evidence that an inefficient capacity to dynamically allocate attentional resources during an ongoing task hinders dual-task performance in schizophrenia.

A 4-year longitudinal neuroimaging study of cognitive control using latent growth modeling: developmental changes and brain-behavior associations

Despite theoretical models suggesting developmental changes in neural substrates of cognitive control in adolescence, empirical research has rarely examined intraindividual changes in cognitive control-related brain activation using multi-wave multivariate longitudinal data. We used longitudinal repeated measures of brain activation and behavioral performance during the multi-source interference task (MSIT) from 167 adolescents (53% male) who were assessed annually over four years from ages 13 to 17 years. We applied latent growth modeling to delineate the pattern of brain activation changes over time and to examine longitudinal associations between brain activation and behavioral performance. We identified brain regions that showed differential change patterns: (1) the fronto-parietal regions that involved bilateral insula, bilateral middle frontal gyrus, left pre-supplementary motor area, left inferior parietal lobule, and right precuneus; and (2) the rostral anterior cingulate cortex (rACC) region. Longitudinal confirmatory factor analyses of the fronto-parietal regions revealed strong measurement invariance across time implying that multivariate functional magnetic resonance imaging data during cognitive control can be measured reliably over time. Latent basis growth models indicated that fronto-parietal activation decreased over time, whereas rACC activation increased over time. In addition, behavioral performance data, age-related improvement was indicated by a decreasing trajectory of intraindividual variability in response time across four years. Testing longitudinal brain-behavior associations using multivariate growth models revealed that better behavioral cognitive control was associated with lower fronto-parietal activation, but the change in behavioral performance was not related to the change in brain activation. The current findings suggest that reduced effects of cognitive interference indicated by fronto-parietal recruitment may be a marker of a maturing brain that underlies better cognitive control performance during adolescence.

Default mode network connections supporting intra-individual variability in typically developing primary school children: An EEG study.

Objective: Intraindividual variability in response time (RT) provides information about attention abilities beyond accuracy and mean RT. It could be an endophenotype for a wide range of clinical disorders and a general marker of neurological health or maladaptation. The default mode network (DMN) and the central executive and the salience networks (CEN + SN) support response stability in adults. The aim of this study was to explore the associations of resting-state connectivity of the DMN and the CEN + SN with lapses of attention in typically developing primary schoolchildren. Method: RT variability was measured by RT standard deviation in the self-paced Stroop-like Animal Size Test in 137 children aged 6-11 years. Electrophysiological signatures of the DMN and the CEN + SN were obtained using a seed-based oscillatory power envelope correlation in conjunction with beamformer spatial filtering. Results: Statistical nonparametric mapping showed that RT variability was positively associated with connectivity between the DMN and the posterior insula and the right temporal cortex (PFWE-corr < .006), suggesting that a greater focus of self-reflective internal attention may be associated with obstructed transition to an active processing mode. RT variability was negatively associated with connectivity between the DMN and the anterior cingulate and the anterior insula (PFWE-corr = .001) overlapping with the SN, which handles top-down cognitive regulation. These associations were specifically found for the anterior DMN seed in the medial prefrontal cortex, which is involved in emotion and motivational circuits. Conclusions: Default network connectivity supporting RT variability may be involved in the development of internalizing and externalizing problems in childhood. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Genome-wide association study reveals novel genetic locus associated with intra-individual variability in response time

Intra-individual response time variability (IIRTV) is proposed as a viable endophenotype for many psychiatric disorders, particularly attention-deficit hyperactivity disorder (ADHD). Here we assessed whether IIRTV was associated with common DNA variation genome-wide and whether IIRTV mediated the relationship between any associated loci and self-reported ADHD symptoms. A final data set from 857 Australian young adults (489 females and 368 males; Mage = 22.14 years, SDage = 4.82 years) who completed five response time tasks and self-reported symptoms of ADHD using the Conners’ Adult ADHD Rating Scale was used. Principal components analysis (PCA) on these response time measures (standard deviation of reaction times and the intra-individual coefficient of variation) produced two variability factors (labelled response selection and selective attention). To understand the genetic drivers of IIRTV we performed a genome-wide association analysis (GWAS) on these PCA-derived indices of IIRTV. For the selective attention variability factor, we identified one single-nucleotide polymorphism (SNP) attaining genome-wide significance; rs62182100 in the HDAC4 gene located on chromosome 2q37. A bootstrapping mediation analysis demonstrated that the selective attention variability factor mediated the relationship between rs62182100 and self-reported ADHD symptoms. Our findings provide the first evidence of a genome-wide significant SNP association with IIRTV and support the potential utility of IIRTV as a valid endophenotype for ADHD symptoms. However, limitations of this study suggest that these observations should be interpreted with caution until replication samples become available.

Working Memory and Intraindividual Variability in Response Time Mediate Fluid Intelligence Deficits Associated With ADHD Symptomology

Objective: To determine if decreased fluid intelligence was associated with ADHD, and was mediated by deficits in working memory and intraindividual variability in motor responding. Method: The present study tested 142 young adults from the general population on a range of working memory, response time, and fluid intelligence tasks, and an ADHD self-report symptoms questionnaire. Results: Total and hyperactive ADHD symptoms correlated significantly and negatively with fluid intelligence, but this association was fully mediated by both working memory and intraindividual variability in response time. However, inattentive symptoms were not associated with fluid intelligence. Conclusion: These results have important implications for clinicians using speeded psychometric tests as part of their assessment battery, working memory interventions for ADHD patients that focus on performance improvement without controlling for response consistency, and also demonstrate potential differences in the neuropsychological profiles of ADHD subtypes.

Attentional fluctuations in preschoolers: Direct and indirect relations with task accuracy, academic readiness, and school performance

Attentional control fluctuates in the presence of internal and external distractors, wandering on and off a given task. The current study investigated individual differences in attentional fluctuations in 250 preschoolers. Attentional fluctuations were assessed via intra-individual variability in response time in a Go/No-Go task. Greater fluctuations in attentional control were linked to lower task accuracy. In addition, greater attentional fluctuations predicted lower performance in a task of cognitive flexibility, the Dimensional Change Card Sort task. Attentional fluctuations were also associated with laboratory measures of academic readiness in preschool, as assessed by the Applied Problems and Letter–Word Identification subscales of the Woodcock–Johnson III Tests of Achievement, which in turn predicted teacher reports of academic performance in first grade. Attentional fluctuations also had indirect associations with emergent math skills in preschool, via cognitive flexibility, as well as indirect associations with first-grade teacher reports of academic performance, via the relations between cognitive flexibility and emergent math skills in preschool. These results suggest that consistency is an important aspect of attentional control during early childhood.

Individual variability in attention and language performance in aphasia: a study using Conner’s Continuous Performance Test

ABSTRACTBackground: Individual variability in attention in aphasia is important because moment-to-moment fluctuations in attention could might influence language performance.Aims: Moment-to-moment variability in performance has been considered a feature of aphasia. The aim of the current work is to study the possible relationship between moment-to-moment intraindividual fluctuations in attention and their possible relationship with language disorders in people with aphasia (PWA).Methods & Procedures: 24 controls and 21 PWA matched by age and sex took part in the study. Language assessment included phonological processing (phonological discrimination, word and pseudoword repetition), lexical access (auditory lexical decision, spoken word-to-picture matching and naming), and semantic association (object–action association, semantic association, and odd-one-out). Attention assessment employed a comprehensive test of basic attention functions (Conner’s Continuous Performance Test II). We studied the association between indices of intraindividual variability in response time in Conner’s Continuous Performance Test and linguistic performance in both groups.Outcomes & Results: PWA showed increased response times and also increased intraindividual variability in response speed. Moreover, only in this group, response speed variability was significantly associated with speech discrimination and with performance in semantic association tasks. Indices of intraindividual variability predicted performance in linguistic tasks in PWA, even after accounting for language performance in related tasks.Conclusion: The current results provide additional support to evidence suggesting a relationship between attention skills and some aspects of linguistic performance in PWA, and draw attention to the putative importance of processing speed instability.

Development of salience-driven and visually-guided eye movement responses.

Development of visuospatial attention can be quantified from infancy onward using visually-guided eye movement responses. We investigated the interaction between eye movement response times and salience in target areas of visual stimuli over age in a cohort of typically developing children. A preferential looking (PL) paradigm consisting of stimuli with six different visual modalities (cartoons, contrast, form, local motion, color, global motion) was combined with the automated measurement of reflexive eye movements. Effective salience was defined as visual salience of each target area relative to its background. Three classes of PL stimuli were used: with high- (cartoon, contrast), intermediate- (local motion, form), and low-effective salience (global motion, color). Eye movement response times to the target areas of the six PL stimuli were nonverbally assessed in 220 children aged 1-12 years. The development of response times with age was influenced by effective salience: Response times to targets with high salience reached stable values earlier in development (around 4 years of age) than to targets with low salience (around 9 years of age). Intra-individual response time variability was highest for low-salient stimuli, and stabilized later (around 4 years) than for highly salient stimuli (2 years). The improvement of eye movement response times to visual modalities in PL stimuli occurred earlier in development for highly salient than for low-salient targets. The present age-dependent and salience-related results provide a quantitative and theoretical framework to assess the development of visuospatial attention, and of related visual processing capacities, in children from 1 year of age.

Alpha-2A adrenergic receptor gene variants are associated with increased intra-individual variability in response time

Intra-individual variability in response time has been proposed as an important endophenotype for attention deficit hyperactivity disorder (ADHD). Here we asked whether intra-individual variability is predicted by common variation in catecholamine genes and whether it mediates the relationship between these gene variants and self-reported ADHD symptoms. A total of 402 non-clinical Australian adults of European descent completed a battery of five cognitive tasks and the Conners' Adult ADHD Rating Scale. Exclusion criteria included the presence of major psychiatric or neurologic illnesses and substance dependency. A total of 21 subjects were excluded due to incomplete data or poor quality cognitive or genotyping data. The final sample comprised 381 subjects (201 males; mean age=21.2 years, s.d.=5.1 years). Principal components analysis on variability measures yielded two factors (response selection variability vs selective attention variability). Association of these factors with catecholamine gene variants was tested using single-step linear regressions, with multiple comparisons controlled using permutation analysis. The response selection variability factor was associated with two ADRA2A single-nucleotide polymorphisms (SNPs) (rs1800544, rs602618), p corrected=0.004, 0.012, respectively, whereas the selective attention variability factor was associated with a TH SNP (rs3842727), p corrected=0.024. A bootstrapping analysis indicated that the response selection variability factor mediated the relationship between the ADRA2A SNP rs1800544 and self-reported ADHD symptoms. Thus this study finds evidence that DNA variation in the ADRA2A gene may be causally related to ADHD-like behaviors, in part through its influence on intra-individual variability. Evidence was also found for a novel association between a TH gene variant and intra-individual variability.

A predictive coding perspective on autism spectrum disorders

A predictive coding perspective on autism spectrum disorders

Does response variability predict distractibility among adults with attention-deficit/hyperactivity disorder?

Increased intraindividual variability in response time (RTSD) has been observed reliably in attention-deficit/hyperactivity disorder (ADHD) and has often been used as a measure of inattention. RTSD is assumed to reflect attentional lapses and distractibility, though evidence for the validity of this connection is lacking. We assessed whether RTSD is an indicator of inattention by comparing RTSD on the stop-signal task (SST) with performance on the delayed oculomotor response (DOR) task, a measure of distractibility. Participants included 30 adults with ADHD and 28 controls. Participants completed the SST and the DOR task, which measured subjects' ability to maintain attention and avoid distraction by inhibiting reflexive saccades toward distractors. On the SST, the ADHD group was slower to inhibit than were controls, indicating poorer inhibitory control in ADHD. The ADHD group also displayed slower reaction times (RTs), greater RTSD, and more omission errors. On the DOR task, the ADHD group displayed more premature saccades (i.e., greater distractibility) than did controls. Greater variability in RT was associated with increased distraction on the DOR task, but only in ADHD participants. Results suggest that RTSD is linked to distractibility among adults with ADHD and support the use of RTSD as a valid measure of inattention in ADHD.

Neural indicators of error processing and intraindividual variability in reaction time in 7 and 9 year‐olds

Childhood is associated with improvements in task accuracy, response time, and reductions in intraindividual trial-to-trial variability in reaction times. The aims of this study were to investigate neural indicators of error monitoring to better understand the mechanisms underlying these cognitive developments in primary school aged children. Specifically, this study explored the development of error processing in 36 children aged 7 years and 41 children aged 9 years, as indexed by two electrophysiological indices of error processing, the error-related negativity (ERN) and the error positivity (Pe). Notably, the amplitude and latency of the ERN and Pe did not differ significantly between the age groups. However, intraindividual variability in response time (RT) was strongly related to ERN amplitude. These data suggest the utility of comparing neural and behavioral indicators of cognitive performance in children and uniquely highlight the importance of considering intraindividual variability in task performance in studies that explore error processing.

Negative Priming Within a Stroop Task in Children and Adolescents With Attention-Deficit Hyperactivity Disorder, Their Siblings, and Independent Controls

Objective: Negative priming (NP) is the slowed response to a stimulus that was previously ignored. Response times in NP task conditions were compared with the interference provided by congruent/incongruent stimuli in a Stroop condition in the same task in children diagnosed with attention-deficit hyperactivity disorder (ADHD), their unaffected siblings, and independent controls. Method: Speed, accuracy, and variability of responses were compared using a computerized NP Stroop test for 35 children with ADHD, 24 siblings without diagnosis, and 37 independent healthy controls aged 6 to 17 years. Results: NP was evident at test onset for congruent trials in children without a diagnosis and was reduced initially in those with ADHD occurring in the absence of a significant Stroop interference effect and independently of age or symptom severity. Incongruency masked NP effects. Cases showed more intraindividual response-time variability. Conclusions: Both NP in normal children and its reduction in ADHD cases attenuated across trials reflecting the increased facilitation from previous stimulation.

Functional brain correlates of response time variability in children

During tasks requiring response inhibition, intra-individual response time variability, a measure of motor response preparation, has been found to correlate with errors of commission, such that individuals with higher variability show increased commission errors. This study used fMRI to examine the neural correlates of response variability in 30 typically developing children, ages 8–12, using a simplified Go/No-go task with minimal cognitive demands. Lower variability was associated with Go activation in the anterior cerebellum (culmen) and with No-go activation in the rostral supplementary motor area (pre-SMA), the postcentral gyrus, the anterior cerebellum (culmen) and the inferior parietal lobule. For both Go and No-go events, higher variability was associated with activation in prefrontal cortex and the caudate. The findings have implications for neuropsychiatric disorders such as ADHD and suggest that during response inhibition, children with more consistent performance are able to rely on premotor circuits involving the pre-SMA, important for response selection; those with less consistent performance instead recruit prefrontal circuits involved in more complex aspects of behavioral control.

Semantic priming in a first and second language: evidence from reaction time variability and event-related brain potentials

We investigated individual differences in second language (L2) proficiency by looking at the efficiency or automaticity of semantic priming using behavioural and event-related brain potential (ERP) measures. In Experiment 1, 37 first language (L1) English speakers varying in second language (L2, French) proficiency made living/non-living judgments to English and French nouns in lists blocked by language. Sixty critical words were each presented twice, once primed by a semantic associate in the preceding trial (e.g. ADULT, CHILD) and once unprimed (e.g. RABBIT, CHILD). Measures of response time (RT) and intra-individual variability in response time (coefficient of variation, CV) were obtained. The CV provided an index of processing efficiency that has been related to automaticity. Participants performed faster and with lower CVs (i.e. with greater efficiency) in L1 than L2, and the more highly proficient bilinguals had lower CVs than the less proficient bilinguals. Experiment 2 replicated these results with 29 participants and provided an electrical brain activity measure of processing efficiency using the N400 ERP. The similar pattern of results obtained between the behavioural and N400 ERP CV measures supported the idea that the CV measure of electrical brain activity can provide useful information about the automaticity or efficiency of cognitive processing.