Greater Reaction Time Variability Research Articles

Cognitive and perceptual load have opposing effects on brain network efficiency and behavioral variability in ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder associated with suboptimal outcomes throughout the life-span. Extant work suggests that ADHD-related deficits in task performance may be magnified under high cognitive load and minimized under high perceptual load, but these effects have yet to be systematically examined, and the neural mechanisms that undergird these effects are as yet unknown. Herein, we report results from three experiments investigating how performance in ADHD is modulated by cognitive load and perceptual load during a naturalistic task. Results indicate that cognitive load and perceptual load influence task performance, reaction time variability (RTV), and brain network topology in an ADHD-specific fashion. Increasing cognitive load resulted in reduced performance, greater RTV, and reduced brain network efficiency in individuals with ADHD relative to those without. In contrast, increased perceptual load led to relatively greater performance, reduced RTV, and greater brain network efficiency in ADHD. These results provide converging evidence that brain network efficiency and intraindividual variability in ADHD are modulated by both cognitive and perceptual load during naturalistic task performance.

Resting-state EEG dynamics help explain differences in response control in ADHD: Insight into electrophysiological mechanisms and sex differences.

Reductions in response control (greater reaction time variability and commission error rate) are consistently observed in those diagnosed with attention-deficit/hyperactivity disorder (ADHD). Previous research suggests these reductions arise from a dysregulation of large-scale cortical networks. Here, we extended our understanding of this cortical-network/response-control pathway important to the neurobiology of ADHD. First, we assessed how dynamic changes in three resting-state EEG network properties thought to be relevant to ADHD (phase-synchronization, modularity, oscillatory power) related with response control during a simple perceptual decision-making task in 112 children/adolescents (aged 8-16) with and without ADHD. Second, we tested whether these associations differed in males and females who were matched in age, ADHD-status and ADHD- subtype. We found that changes in oscillatory power (as opposed to phase-synchrony and modularity) are most related with response control, and that this relationship is stronger in ADHD compared to controls. Specifically, a tendency to dwell in an electrophysiological state characterized by high alpha/beta power (8-12/13-30Hz) and low delta/theta power (1-3/4-7Hz) supported response control, particularly in those with ADHD. Time in this state might reflect an increased initiation of alpha-suppression mechanisms, recruited by those with ADHD to suppress processing unfavourable to response control. We also found marginally significant evidence that this relationship is stronger in males compared to females, suggesting a distinct etiology for response control in the female presentation of ADHD.

Cued motor processing in autism and typical development: A high-density electrical mapping study of response-locked neural activity in children and adolescents.

Motor atypicalities are common in autism spectrum disorder (ASD) and are often evident prior to classical ASD symptoms. Despite evidence of differences in neural processing during imitation in autistic individuals, research on the integrity and spatiotemporal dynamics of basic motor processing is surprisingly sparse. To address this need, we analysed electroencephalography (EEG) data recorded from a large sample of autistic (n = 84) and neurotypical (n = 84) children and adolescents while they performed an audiovisual speeded reaction time (RT) task. Analyses focused on RTs and response-locked motor-related electrical brain responses over frontoparietal scalp regions: the late Bereitschaftspotential, the motor potential and the reafferent potential. Evaluation of behavioural task performance indicated greater RT variability and lower hit rates in autistic participants compared to typically developing age-matched neurotypical participants. Overall, the data revealed clear motor-related neural responses in ASD, but with subtle differences relative to typically developing participants evident over fronto-central and bilateral parietal scalp sites prior to response onset. Group differences were further parsed as a function of age (6-9, 9-12 and 12-15 years), sensory cue preceding the response (auditory, visual and bi-sensory audiovisual) and RT quartile. Group differences in motor-related processing were most prominent in the youngest group of children (age 6-9), with attenuated cortical responses observed for young autistic participants. Future investigations assessing the integrity of such motor processes in younger children, where larger differences may be present, are warranted.

A virtual reality program to assess cognitive function in multiple sclerosis: A pilot study.

Introduction: Cognitive impairment is a debilitating symptom in people with multiple sclerosis (MS). Most of the neuropsychological tasks have little resemblance to everyday life. There is a need for ecologically valid tools for assessing cognition in real-life functional contexts in MS. One potential solution would involve the use of virtual reality (VR) to exert finer control over the task presentation environment; however, VR studies in the MS population are scarce. Objectives: To explore the utility and feasibility of a VR program for cognitive assessment in MS. Methods: A VR classroom embedded with a continuous performance task (CPT) was assessed in 10 non-MS adults and 10 people with MS with low cognitive functioning. Participants performed the CPT with distractors (i.e., WD) and without distractors (i.e., ND). The Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II), and a feedback survey on the VR program was administered. Results: People with MS exhibited greater reaction time variability (RTV) compared to non-MS participants, and greater RTV in both WD and ND conditions was associated with lower SDMT. Conclusions: VR tools warrant further research to determine their value as an ecologically valid platform for assessing cognition and everyday functioning in people with MS.

Young and restless, old and focused: Age-differences in mind-wandering frequency and phenomenology.

The consistently observed age-accompanied diminution in mind-wandering stands seemingly opposed to accounts that present mind-wandering as a failure of executive control. This study examined the impact of aging on the frequency and phenomenology of mind-wandering and investigated distinct variables mediating age-related differences in unintentional and intentional mind-wandering. Thirty-four younger and 34 healthy older adults completed a neuropsychological test battery and contrast change detection task embedded with experience sampling probes asking participants to discriminate the nature of their thoughts. Results revealed age-related decreases in unintentional and intentional mind-wandering, but equivalent task accuracy. Parallel mediations demonstrated that older adults reduced their unintentional mind-wandering through having less anxiety and greater task engagement than younger adults. Despite the evidence of age-related decline on cognitive function tests, neither executive function nor task demand variables further contributed to the model. Our results adjudicate between competing theories, highlighting the roles of affective and motivational factors in unintentional mind-wandering. Intentional mind-wandering showed no significant associations with the neuropsychological measures; however, intentional mind-wandering was associated with more false alarms, which was mediated by greater reaction time variability (RTV). In the context of the exploitation/exploration framework, we suggest that younger adults were more inclined to intentionally mind-wander, indexed by increased RTV, while preserving comparable performance accuracy to older adults. Conversely, older adults exploited greater task focus, marked by reduced RTV, with less bias toward, or resources for, exploration of the mind-wandering space. Therefore, dispositional and strategic factors should be considered in future investigations of mind-wandering across the lifespan. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Neurocognitive markers of late‐onset ADHD: a 6‐year longitudinal study

There is an increased interest in 'late-onset' attention-deficit/hyperactivity disorder (ADHD), referring to the onset of clinically significant ADHD symptoms after the age of 12years. This study aimed to examine whether unaffected siblings with late-onset ADHD could be differentiated from stable unaffected siblings by their neurocognitive functioning in childhood. We report findings from a 6-year prospective, longitudinal study of the Dutch part of the International Multicenter ADHD Genetics (IMAGE) study, including individuals with childhood-onset (persistent) ADHD (n=193), their siblings with late-onset ADHD (n=34), their stable unaffected siblings (n=111) and healthy controls (n=186). At study entry (mean age: 11.3) and follow-up (mean age: 17.01), participants were assessed for ADHD by structured psychiatric interviews and multi-informant questionnaires. Several neurocognitive functions were assessed at baseline and after 6years, including time reproduction, timing variability (reaction time variability and time production variability), reaction time speed, motor control and working memory; intelligence was taken as a measure of overall neurocognitive functioning. Siblings with late-onset ADHD were similar to individuals with childhood-onset ADHD in showing longer reaction times and/or higher error rates on all neurocognitive measures at baseline and follow-up, when compared to healthy controls. They differed from stable unaffected siblings (who were similar to healthy controls) by greater reaction time variability and timing production variability at baseline. No significant group by time interaction was found for any of the tasks. For unaffected siblings of individuals with ADHD, reaction time variability and timing production variability may serve as neurocognitive marker for late-onset ADHD.

The Impact of Sleep Deprivation on Continuous Performance Task Among Young Men With ADHD

Objective: To identify the impact of sleep deprivation on functioning of young adults with or without ADHD on a continuous performance attention task. Method: Thirty-four men (M age = 25.38) with (n = 16) or without (n = 18) ADHD completed a continuous performance task before and after 25 hr of sustained wakefulness in a controlled environment. Results: In both groups, sleep deprivation caused a decline in performance on all variables: omission errors, commission errors, reaction time, and reaction time variability. In addition, the ADHD group made more omission and commission errors, and had greater reaction time variability. Conclusion: Sleep deprivation has a detrimental effect on attention functioning among young adults. In addition, although young adults with ADHD generally perform worse on continuous performance tasks than young adults without ADHD, the groups are similarly affected by sleep deprivation.

EEG-ERP dynamics in a visual Continuous Performance Test

Brain dynamics research has highlighted the contributions of the ongoing EEG to ERP and behavioural responses. This study examined the effects of state-related EEG changes, from rest to the task and within the task, on stimulus-response efforts in a visual Continuous Performance Test (CPT). EEG was recorded from fifty-six adults at rest with eyes-closed (EC) then eyes-open (EO), and during the CPT. Principal Components Analyses decomposed the EEG obtained from EC, EO and the task-based periods immediately pre-cue (PC) and pre-imperative (PI), and the ERPs to the cued Go/NoGo imperatives. EC amplitudes were correlated with Go/NoGo ERP amplitudes and behavioural outcomes. EEG amplitude changes from EO to PC, and from PC to PI, were assessed as predictors of these response measures. Longer mean reaction time (RT) was associated with greater RT variability (RTV) and reduced Go P2. The two EC alpha components correlated positively with RTV, and NoGo P1 and P2 positivity. Delta/theta amplitude reductions from PC to PI predicted Go N1-1 and NoGo N2b enhancements. Alpha-1 decreases from PC to PI predicted larger P2 and poorer NoGo accuracy rates, while alpha-3 decrements positively predicted NoGo P1. These findings highlight the ongoing alpha arousal effects on stimulus-response efforts, and the low frequency shifts in the cue to imperative interval associated with stimulus anticipation and response preparation. These relationships offer novel insights into the effects of pretask EEG activity, and within-task EEG changes, on attention and cognitive control processes.

Reducing the TUTs that hurt: the impact of a brief mindfulness induction on emotionally valenced mind wandering

ABSTRACTNegative mood has been linked to poorer sustained attention and increased mind wandering. Mindfulness training appears to reduce negative mood and mind wandering. The current study examined whether a mindfulness induction moderated the impact of a negative mood manipulation on sustained attention task performance and emotionally valenced mind wandering. One hundred and two participants underwent a mindfulness induction, relaxation induction, or were assigned to a wait-list control condition. Participants subsequently completed a negative mood manipulation and sustained attention task. Rates of negatively valenced mind wandering were lower in mindfulness induction participants relative to the control condition participants. Negatively valenced mind wandering was associated with poorer SART performance and greater reaction time variability following the thought probe in the control and relaxation conditions, but not the mindfulness condition. We suggest that brief mindfulness inductions may reduce the deleterious influence of negative mind wandering on sustained attention task performance.

Increased Intra-Subject Variability of Reaction Times and Single-Trial Event-Related Potential Components in Children With Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is an increasingly common neurodevelopmental disorder that affects 1 in 59 children. The cognitive profiles of individuals with ASD are varied, and the neurophysiological underpinnings of these developmental difficulties are unclear. While many studies have focused on overall group differences in the amplitude or latency of event related potential (ERP) responses, recent research suggests that increased intra-subject neural variability may also be a reliable indicator of atypical brain function in ASD. This study aimed to identify behavioral and neural variability responses during an emotional inhibitory control task in children with ASD compared to typically developing (TD) children. Children with ASD showed increased variability in response to both inhibitory and emotional stimuli, evidenced by greater reaction time variability and single-trial ERP variability of N200 and N170 amplitudes and/or latencies compared to TD children. These results suggest that the physiological basis of ASD may be more accurately explained by increased intra-subject variability, in addition to characteristic increases or decreases in the amplitude or latency of neural responses. Autism Res 2020, 13:221-229. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The cognitive functions including memory, attention, executive functions, and perception, of individuals with ASD are varied, and the physiological underpinnings of these profiles are unclear. In this study, children with ASD showed increased intra-subject neural and behavioral variability in response to an emotional inhibitory control task compared to typically developing children. These results suggest that the physiological basis of ASD may also be explained by increased behavioral and neural variability in people with ASD, rather than simply characteristic increases or decreases in averaged brain responses.

The pattern of attentional deficits in Parkinson's disease

BackgroundCognitive impairment without dementia is frequent in Parkinson's disease. It often presents as a dysexecutive syndrome with deficient attentional resource allocation. The nature of attention deficits in Parkinson's disease has rarely been investigated with robust, theory-based tasks. The main objective of the present study was to investigate attention disorders in Parkinson's disease patients by applying a paradigm based on a model of attention. We also sought to identify the main demographic and clinical characteristics associated with attention deficits in Parkinson's disease. MethodsEighty non-demented Parkinson's disease patients and 60 healthy controls participated in the study. Attention was assessed in a computer-controlled reaction time paradigm. The test session comprised a simple reaction time task and four choice reaction time tasks: a go/no-go task, a one-dimension, focused-attention task, a two-dimension, divided-attention task and an alternating task. Performance was assessed by composite measures: (i) cognitive reaction time, corresponding to the difference between the simple reaction time and the choice reaction time in the given condition, and (ii) reaction time variability, corresponding to the sum of the coefficients of variance of the reaction times. Accuracy was also considered. ResultsApart from an overall slowing and greater reaction time variability, Parkinson's disease patients were only significantly impaired in the alternating condition. This set-shifting impairment was associated with their performance in the go/no-go and divided-attention conditions. ConclusionOur systematic assessment of the different attentional subcomponents revealed that mental flexibility is particularly impaired in non-demented Parkinson's disease patients.

Attention-Deficit/Hyperactivity Disorder and Behavioral Inhibition: A Meta-Analytic Review of the Stop-signal Paradigm

Deficient behavioral inhibition (BI) processes are considered a core feature of attention deficit/hyperactivity disorder (ADHD). This meta-analytic review is the first to examine the potential influence of a wide range of subject and task variable moderator effects on BI processes--assessed by the stop-signal paradigm--in children with ADHD relative to typically developing children. Results revealed significantly slower mean reaction time (MRT), greater reaction time variability (SDRT), and slower stop-signal reaction time (SSRT) in children with ADHD relative to controls. The non-significant between-group stop-signal delay (SSD) metric, however, suggests that stop-signal reaction time differences reflect a more generalized deficit in attention/cognitive processing rather than behavioral inhibition. Several subject and task variables served as significant moderators for children's mean reaction time.