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Cited by 233Attention Deficit Hyperactivity DisorderNeural and Behavioral Psychology StudiesDevelopmental and Educational Neuropsychology

Evidence for higher reaction time variability for children with ADHD on a range of cognitive tasks including reward and event rate manipulations.

Open access
Epstein, Jeffery N., Langberg, Joshua M., Rosen, Paul J., Graham, Amanda, Narad, Megan E., Antonini, Tanya N., Brinkman, William B., Froehlich, Tanya +2 more·2011·Neuropsychology
DOI 10.1037/a0022155PMC PMC3522094
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Abstract

OBJECTIVE: The purpose of the research study was to examine the manifestation of variability in reaction times (RT) in children with attention deficit hyperactivity disorder (ADHD) and to examine whether RT variability presented differently across a variety of neuropsychological tasks, was present across the two most common ADHD subtypes, and whether it was affected by reward and event rate (ER) manipulations. METHOD: Children with ADHD-combined type (n = 51), ADHD-predominantly inattentive type (n = 53), and 47 controls completed five neuropsychological tasks (Choice Discrimination Task, Child Attentional Network Task, Go/No-Go task, Stop Signal Task, and N-back task), each allowing trial-by-trial assessment of RTs. Multiple indicators of RT variability including RT standard deviation, coefficient of variation and ex-Gaussian tau were used. RESULTS: Children with ADHD demonstrated greater RT variability than controls across all five tasks as measured by the ex-Gaussian indicator tau. There were minimal differences in RT variability across the ADHD subtypes. Children with ADHD also had poorer task accuracy than controls across all tasks except the Choice Discrimination task. Although ER and reward manipulations did affect children's RT variability and task accuracy, these manipulations largely did not differentially affect children with ADHD compared to controls. RT variability and task accuracy were highly correlated across tasks. Removing variance attributable to RT variability from task accuracy did not appreciably affect between-groups differences in task accuracy. CONCLUSIONS: High RT variability is a ubiquitous and robust phenomenon in children with ADHD.

Integrity signals

Registry

Crossref · 10.1037/a0022155

Cites

58 of 58 references verified0 citation errors · 0 not checkable

Statistics

26 tests recomputed · 0 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

0 of 62 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    On the Go/No-Go task, both the ADHD-Combined and ADHD-Inattentive groups had slower mean reaction times than controls.

    “On this task, both the ADHD-C (p<.01) and ADHD-I (p<.05) groups had slower mean RTs than children in the control group.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
  • Findingown data

    The ADHD-Combined group had significantly higher coefficient of variation than controls.

    “Post-hoc tests revealed significantly higher variation in the ADHD-C group than the control group (all ps<.05).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
  • Findingown data

    Both group by event rate interactions on reaction time standard deviation resulted from the ADHD-Combined group showing a greater incremental increase between the 3.5-second and 5.5-second event rates than the ADHD-Inattentive group.

    “Both interactions were a result of children with ADHD-C demonstrating a greater incremental increase in RT SD between the 3.5-sec and 5.5-sec ER conditions as compared to children with ADHD-I.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The event rate manipulation, varying inter-stimulus intervals, effectively alters arousal or state regulation.
  • Findingown data

    For the ex-Gaussian indicator sigma, the only significant effect was a main effect of event rate on all tasks except the Choice task, where it was marginal.

    “The only significant effect for the ex-Gaussian indicator sigma was for the main effect of ER on all tasks (all ps < .05) except for the Choice task (p=.09).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The event rate manipulation, varying inter-stimulus intervals, effectively alters arousal or state regulation.
  • Findingown data

    There were no group differences in mean reaction time on the other four tasks.

    “There were no group differences in RT on the other four tasks.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
  • Classified as probably not a substantial claim. 25
  • May combine two claims. 41

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    No other main or interaction effects were significant for mu.

    “No other main or interaction effects were significant.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

  • May combine two claims.

    Findingown data

    No other main effects of reward or two-way interactions on coefficient of variation were significant across tasks.

    “No other main effects of reward or two-way interactions were significant across tasks.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The reward condition, in which children earned points exchangeable for prizes, effectively manipulates reward motivation in children.

  • May combine two claims.

    Findingown data

    On the Stop Signal Task, there was a group by reward interaction: ADHD-Combined and ADHD-Inattentive groups showed more variability in the no-reward condition than in the reward condition, while controls showed no difference.

    “There was also a Group × Reward interaction on the SST task (F(2,138)=4.19, p=.047). Children with ADHD-C (reward: M=34.2, SE=1.7; no reward: M=38.9, SE=1.6; p=.005) and ADHD-I (reward: M=32.4, SE=1.6; no reward: M=36.7, SE=1.5; p=.005) demonstrated more variability in the no reward condition compared to the reward condition. There was no difference in performance between the reward and no reward”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The reward condition, in which children earned points exchangeable for prizes, effectively manipulates reward motivation in children.

  • May combine two claims.

    Findingown data

    No main effect of reward or group by reward interaction on mean reaction time was significant on any task.

    “No main effect of reward or group × reward interaction was significant across any of the tasks.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The reward condition, in which children earned points exchangeable for prizes, effectively manipulates reward motivation in children.

  • May combine two claims.

    Findingown data

    Significant group effects on coefficient of variation were observed on the Choice, ANT, Go/No-Go, and N-back tasks, with a subthreshold group effect on the Stop Signal Task.

    “Significant group effects on CV were observed on the Choice, ANT, Go/No-Go, and N-back (all ps < .05). There was a subthreshold group effect on the SST (p = .08).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

  • May combine two claims.

    Findingown data

    The ADHD-Inattentive group was more variable than controls on the Go/No-Go and Choice tasks.

    “The ADHD-I group was also more variable than controls on the Go/No-Go task (p<.001) and Choice task (p<.05).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

  • May combine two claims.

    Findingown data

    Across all tasks except the Stop Signal Task, there was a significant effect of event rate, with less variable reaction times on faster event rate trials.

    “Across all tasks except the SST, there was a significant effect of ER (all ps <.05) with children demonstrating less variable RTs on the faster ER trials across all tasks.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The event rate manipulation, varying inter-stimulus intervals, effectively alters arousal or state regulation.

  • May combine two claims.

    Findingown data

    Children had shorter stop signal reaction times during the reward condition and as event rate became faster.

    “There was also a main effect of reward (F(1,140)=4.30, p=.04) and ER (F(2,140)=61.56, p<.0001) due to children having shorter SSRTs during the reward condition and as ER became faster.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The only task showing a difference in tau between ADHD-Combined and ADHD-Inattentive groups was the ANT, where the ADHD-Combined group had higher estimates.

    “The only task that showed a difference between the ADHD-C and ADHD-I group was on the ANT task (p<.05) where the ADHD-C group had higher estimates than the ADHD-I group.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

  • May combine two claims.

    Findingown data

    On the ANT conflict variable, there was a main effect of group and event rate; ADHD-C had higher conflict scores than controls, and conflict scores decreased as event rate became faster.

    “Finally, for the conflict variable, there was a main effect of group (F(2, 138)=3.77, p=.03) and a main effect of ER (F(2,138)=34.42, p<.0001). The main effect of group resulted from higher conflict scores in the ADHD-C group compared to controls. The main effect of ER was significant because conflict scores decreased as ER became faster.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Event rate and reward manipulations affected children's reaction time variability and task accuracy, but these manipulations largely did not differentially affect children with ADHD compared to controls.

    “Although ER and reward manipulations did affect children’s RT variability and task accuracy, these manipulations largely did not differentially affect children with ADHD compared to controls.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.
    • Rests on an assumption: The reward condition, in which children earned points exchangeable for prizes, effectively manipulates reward motivation in children.
    • Rests on an assumption: The event rate manipulation, varying inter-stimulus intervals, effectively alters arousal or state regulation.

  • May combine two claims.

    Findingown data

    Event rate had a significant main effect on accuracy on all tasks except Go/No-Go, with more errors at faster event rates.

    “Significant main effects of ER were also observed across all of the tasks (all ps < .001) except the Go/No-Go task. Children made more errors as ER became faster.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    On the ANT orienting variable, there were no significant main or interaction effects.

    “For the orienting variable, there were no significant main or interaction effects.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Reaction time variability and task accuracy were highly correlated across tasks.

    “RT variability and task accuracy were highly correlated across tasks.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

  • May combine two claims.

    Findingown data

    As event rate slowed, children in the ADHD groups demonstrated slower reaction times and more reaction time variability on the respective tasks.

    “But as ER slowed, children in the ADHD groups demonstrated slower RTs and more RT variability on the respective tasks.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Increasing task difficulty by speeding event rate had a detrimental effect on error rates across all tasks, but only on the N-back task did event rate interact with group status.

    “Increasing task difficulty by speeding ER had a detrimental effect on error rates across all tasks but only on the N-back task did ER interact with group status.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    On the SST, the two ADHD groups demonstrated a greater benefit of reward than controls, and their reaction time variability as indicated by CV became comparable to the control group when reward was introduced.

    “On this task, the two ADHD groups demonstrated a greater benefit of reward than the controls. In fact, when reward was introduced, their RT variability as indicated by CV was comparable to the control group.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    On the N-back task, all groups had similar accuracy in the fast event rate condition; when event rate slowed, control accuracy improved whereas ADHD groups did not benefit.

    “On the N-back task, children in all groups demonstrated similar accuracy rates in the fast ER condition. However, when ER slowed, the control group’s accuracy improved whereas the children in the ADHD groups did not benefit from the slower ERs.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Task accuracy and reaction time variability were highly correlated, but task accuracy seemed to account for mostly unique between-group variance.

    “Finally, consistent with Klein et al. (2006), we found that task accuracy and RT variability were highly correlated but that task accuracy seemed to account for mostly unique between-group variance.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Klein et al. (2006)

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  • May combine two claims.

    Findingreasoning

    The Choice Discrimination task and the SST both involve forced choice discrimination, yet children with ADHD only showed a deficit in task accuracy on the SST.

    “The Choice Discrimination task and the SST both involve a forced choice discrimination yet children with ADHD only showed a deficit in task accuracy on the SST.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Reward improved accuracy across groups on the ANT, Go/No-Go, and SST tasks but did not differentially affect the ADHD and control groups.

    “Finally, the presence of reward, which improved accuracy across groups across some of the tasks (i.e., ANT, Go/No-Go, and SST) did not differentially affect the ADHD and control groups.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The control group had IQs that were above normal (mean IQ = 116) and higher than children in the ADHD groups.

    “Ultimately, the control group had IQs that were both above normal (mean IQ = 116) and higher than children in the ADHD groups.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In general, the effects were task-independent and not moderated by any task factor or moderating variable including ADHD subtype.

    “In general, these effects were task-independent and not moderated by any task factor or moderating variable including ADHD subtype.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The literature on reward effects on reaction time variability is small and inconsistent, with some studies showing improvement and others showing no effect.

    “there has been a small and inconsistent literature examining the effects of reward on RT variability with some studies showing that reward improves RT variability (Andreou, et al., 2007; Kuntsi, et al., 2009; Slusarek, Velling, Bunk, & Eggers, 2001; Uebel, et al., 2010) and others suggesting no effect of reward on RT variability (Luman, Ooserlaan, & Sergeant, 2008; Shanahan, et al., 2008).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Andreou, et al., 2007

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    • cites Kuntsi, et al., 2009

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    • cites Luman, Ooserlaan, & Sergeant, 2008

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    Study design and conductnone given

    Tasks were administered in a counterbalanced fashion.

    “Tasks were administered in a counterbalanced fashion.”
    Quote in the paperNot a substantial claim

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    Study design and conductcitation

    The study used a false discovery rate correction to control for multiple testing in the primary analyses.

    “In order to control for multiple testing (i.e., multiple outcomes for each task) in our primary analyses, a false discovery rate correction (FDR) was used (Benjamini & Hochberg 1995).”
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    • cites Benjamini & Hochberg 1995

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    Premisecitation

    The VARS has demonstrated excellent reliability and substantial validity in previous studies.

    “The VARS has demonstrated excellent reliability and substantial validity in previous studies (Wolraich, et al., 1998).”
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    • cites Wolraich, et al., 1998

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    Premisecitation

    The WASI provides a reliable estimate of expanded intellectual performance.

    “Studies have indicated that the WASI provides a reliable estimate of expanded intellectual performance.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Linear mixed models account for the expected correlation among data points collected from the same individual.

    “Linear mixed models account for the expected correlation among data points collected from the same individual.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Children with ADHD show neuropsychological deficits across a wide range of cognitive skills including response inhibition, working memory, delay aversion, and attention.

    “children with Attention Deficit Hyperactivity Disorder (ADHD) demonstrate neuropsychological deficits across a wide range of cognitive skills including response inhibition, working memory, delay aversion, and attention (Nigg, 2005; Solanto, et al., 2001; Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nigg, 2005

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    • cites Solanto, et al., 2001

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    • cites Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005

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    Study design and conductnone given

    Controls were matched to the ADHD sample on age, gender, and ethnicity.

    “Controls were matched to the ADHD sample according to age, gender and ethnicity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    High reaction time variability is a ubiquitous and robust phenomenon in children with ADHD.

    “High RT variability is a ubiquitous and robust phenomenon in children with ADHD.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The sample of children with ADHD is representative of children with ADHD generally, so findings generalize to that wider population.

  • May combine two claims.

    Premisecitation

    The DISC-P has demonstrated substantial reliability and validity across many studies and was used as the primary diagnostic instrument.

    “The DISC-P has demonstrated substantial reliability and validity across a multitude of studies (Shaffer, et al., 2000) and was used as the primary diagnostic instrument of ADHD in the present study.”
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    • cites Shaffer, et al., 2000

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    Study design and conductown data

    Children with omitted data did not differ from children whose data were used on age, sex, race, IQ, comorbid disorders, or ADHD symptom scores.

    “Children with omitted data did not differ from those whose data was used in the analyses (all ps>.05).”
    Quote in the paperSubstantial claim

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    Study design and conductcitation

    Diagnostic status was determined using methodology similar to the MTA study, requiring parent and teacher symptom reports.

    “Diagnostic status was determined using methodology similar to that employed by the Multimodal Treatment Study of ADHD (MTA Cooperative Group, 1999).”
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    • cites MTA Cooperative Group, 1999

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    Study design and conductnone given

    Children were medication naïve and remained so during all sessions.

    “Children were all medication naïve and remained so during all three sessions.”
    Quote in the paperSubstantial claim

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    Premisecitation

    Existing research on the relationship between ADHD subtype and reaction time variability is mixed: some studies find no differences, some find ADHD-Combined higher, and some find ADHD-Inattentive higher.

    “Some studies have found no differences between the ADHD-Predominantly Inattentive Type (ADHD-I) and ADHD-Combined (ADHD-C) subtypes (Nigg, Blaskey, Huang-Pollock, & Rappley, 2002; Shanahan, et al., 2008; Simmonds, et al., 2007; Vaurio, et al., 2009) while others have found that patients with ADHD-C display increased RT variability compared to patients with ADHD-I (de Zeeuw, et al., 2008; Mullins,”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nigg, Blaskey, Huang-Pollock, & Rappley, 2002

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    • cites de Zeeuw, et al., 2008

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    • cites Desman, et al., 2008

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    Interpretationcitation

    The lack of differences between ADHD-C and ADHD-I on reaction time speed, reaction time variability, and accuracy was predicted and is consistent with many previous studies.

    “The lack of differences between the ADHD-C and ADHD-I groups on RT speed, RT variability, and accuracy was predicted and is consistent with many previous studies examining these differences (Nigg, et al., 2002; Shanahan, et al., 2008; Simmonds, et al., 2007; Vaurio, et al., 2009).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nigg, et al., 2002

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    • cites Shanahan, et al., 2008

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    • cites Simmonds, et al., 2007

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    Premisecitation

    Research has shown that varying event rate frequently within task (jittering) improves reaction time variability across all children and differentially improves reaction time variability in children with ADHD compared to controls.

    “Research has shown that varying ER frequently within task (i.e., jittering) both improves RT variability across all children (Wodka, Simmonds, Mahone, & Mostofsky, 2009) and differentially improves RT variability in children with ADHD compared to controls (Ryan, Martin, Denckla, Mostofsky, & Mahone, 2010).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Wodka, Simmonds, Mahone, & Mostofsky, 2009

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    • cites Ryan, Martin, Denckla, Mostofsky, & Mahone, 2010

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  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    Differences in study methods may account for differences in results across studies.

    “Differences in study methods may account for differences in results across studies.”
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    Interpretationreasoning

    It is possible that the focus and/or saliency of the reward condition attenuated the ability to detect effects of reward and interaction with group.

    “However, it is possible that in our study the focus and/or saliency of the reward condition attenuated our ability to detect effects of reward and interaction with group.”
    Quote in the paperNot a substantial claim

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    Interpretationreasoning

    The 1.5-second lower end of the event rate manipulation is likely as fast as can be tolerated, but the upper bound of 5.5 seconds may not have fully tested upper bound effects of slow event rate on performance.

    “Although the 1.5 sec lower end of the ER manipulation is likely as fast an ER as can be tolerated, the upper bound ER used in this study was 5.5 sec. This “slow” ER may not have fully tested the upper bound effects of slow ER on performance.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    This type of reward benefit was predicted and has been previously reported.

    “This is the type of benefit that was predicted and has been previously reported (Andreou, et al., 2007; Kuntsi, et al., 2009; Slusarek, et al., 2001; Uebel, et al., 2010).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Andreou, et al., 2007

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    • cites Kuntsi, et al., 2009

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    • cites Slusarek, et al., 2001

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  • May combine two claims.

    Interpretationreasoning

    The present study may have inadvertently produced a jittering effect and attenuated any detrimental effect of long event rates on reaction time variability outcomes.

    “Hence, the present study may have inadvertently produced a “jittering effect” and attenuated any detrimental effect of long ERs on our RT variability outcomes.”
    Quote in the paperSubstantial claim

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    Interpretationnone given

    Ceiling effects on the tau variable on the Choice and ANT tasks may have prevented detection of reward effects.

    “Alternatively, ceiling effects on the tau variable on the Choice and ANT tasks may have prevented detection of reward effects.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The reward condition may have lacked saliency for participants with ADHD.

    “Our reward condition may also have lacked saliency for the participants with ADHD.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Several prevailing ADHD theoretical models emphasize the need for immediate versus delayed rewards for children with ADHD.

    “Certainly, several prevailing ADHD theoretical models emphasize the need for immediate versus delayed rewards for children with ADHD (Barkley, 1997; Sagvolden, et al., 2005).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Barkley, 1997

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    • cites Sagvolden, et al., 2005

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    Interpretationreasoning

    The prevalent pattern across the two studies suggests that reaction time variability and task accuracy both uniquely account for between-group differences.

    “Overall, the prevalent pattern of findings across the two studies suggests that RT variability and task accuracy both uniquely account for between-group differences.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Premisecitation

    ADHD-related deficits are likely multi-dimensional and there are likely multiple pathways to ADHD manifestation.

    “Indeed, ADHD-related deficits are likely multi-dimensional (Nigg, 2005; Willcutt, et al., 2005) and there are likely multiple pathways to ADHD manifestation (Nigg, Willcutt, Doyle, & Sonuga-Barke, 2005; Solanto, et al., 2001; Sonuga-Barke, 2003).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nigg, 2005

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    • cites Willcutt, et al., 2005

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    • cites Nigg, Willcutt, Doyle, & Sonuga-Barke, 2005

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Changing the focus of rewards to reaction time speed or reaction time variability may have altered the outcome variable where reward effects were observed.

    “Changing the focus of the rewards to RT speed or RT variability may have altered the outcome variable where reward effects were observed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The schedule of delayed rewards may have attenuated the effects of reward for children with ADHD and may explain the absence of significant group by reward interaction effects.

    “It is possible that the schedule of delayed rewards may have attenuated the effects of reward for children with ADHD and may explain why we found no significant group × reward interaction effects.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Other disorders comorbid with ADHD, such as ODD/CD, could not be tested and may have contributed to the observed between-group differences.

    “It is also possible that other disorders comorbid with ADHD, such as ODD/CD which could not be tested in our analyses, may have contributed to the observed between-group differences.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The study did not measure autism spectrum disorders and thus cannot replicate Geurts et al.'s finding.

    “In this study, we did not measure ASD and thus cannot replicate this finding in our analyses.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Geurts et al. (2008) showed that children with ADHD and comorbid autism spectrum disorders had elevated reaction time variability.

    “In a recent study, Geurts et al. (2008) showed that children with ADHD and comorbid autism spectrum disorders had elevated RT variability.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Geurts et al. (2008)

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    Premisecitation

    Whether to control for IQ differences is controversial since poor performance on IQ tests is likely affected by ADHD-related cognitive deficits such as inattention while performing IQ tests.

    “Whether to control for IQ differences is controversial since poor performance on IQ tests is likely affected by ADHD-related cognitive deficits (e.g., inattention) while performing IQ tests (Willcutt, et al., 2005).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Willcutt, et al., 2005

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    The discrepancy in IQ scores across groups may have exacerbated between-group differences.

    “This discrepancy in IQ scores across groups may have exacerbated between-group differences.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The study used only typically-developing children and did not include a group with psychopathology, so it cannot conclude whether the between-group differences are unique to the ADHD condition.

    “Another limitation of our control group is that we used only typically-developing children and did not include a group with psychopathology. As a result, we are not able to conclude whether the between-group differences are unique to the ADHD condition.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Many neuropsychological studies comparing children with ADHD to controls find IQ discrepancies.

    “Many neuropsychological studies comparing children with ADHD to controls find IQ discrepancies (see Barkley, 2006 for review).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Barkley, 2006

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The pattern of results was demonstrated in a medication-naïve sample of children with ADHD, suggesting that higher reaction time variability is likely attributable to the ADHD condition as opposed to any possible effects of medication history on brain function.

    “This pattern of results was demonstrated in a medication-naïve sample of children with ADHD suggesting that higher RT variability is likely attributable to the ADHD condition as opposed to any possible effects of medication history on brain function (Andersen, 2005).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Andersen, 2005

      Not checked in the free run.

59 of 59

  • The paper relies on this without support.

    The five computer-based tasks validly assess the distinct neuropsychological constructs they are intended to measure.

    “Participants completed five computer-based neuropsychological tasks (Choice Discrimination Task, Child Attentional Network Task, Go/No-Go task, Stop Signal Task, and N-back task) that assessed a range of neuropsychological domains (e.g., response inhibition, working memory, and attention).”

  • The paper relies on this without support.

    The reward condition, in which children earned points exchangeable for prizes, effectively manipulates reward motivation in children.

    “Incentive was manipulated within tasks for all participants, such that participants were able to earn points for performance on half of the trials of each task.”

  • The paper relies on this without support.

    The event rate manipulation, varying inter-stimulus intervals, effectively alters arousal or state regulation.

    “Three different ERs were used within each task. Stimulus presentation was held constant at 500 msec for each task.”

  • The paper relies on this without support.

    The sample of children with ADHD is representative of children with ADHD generally, so findings generalize to that wider population.

    “One hundred and fifty-one children aged 7–11 participated in the present study. The study included 104 children who met diagnostic criteria for ADHD (53 ADHD-I; 51 ADHD-C) and 47 controls.”

  • The paper relies on this without support.

    The five cognitive tasks used in the study measure the intended cognitive constructs of working memory, response inhibition, and attention.

    “Increased variability among children with ADHD was evident across a range of cognitive tasks assessing a variety of cognitive skills (i.e., working memory, response inhibition, and attention).”

  • The paper relies on this without support.

    The event rate and reward manipulations were capable of enhancing subject arousal as intended.

    “Children with ADHD demonstrated increased RT variability across a variety of ER and reward conditions designed to enhance subject arousal.”
6 of 6

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • ADHD between-group differences in reaction time variability tend to be larger than most other neuropsychological indicators.

    “These ADHD between-group differences on RTV tend to be larger in magnitude than most other neuropsychological indicators [15].”

    From Reaction Time Variability in ADHD: A Review (2012) · cites this paper as [15]

  • WISC-IV Coding and Symbol Search have strong psychometrics: internal consistency .85 and .79, and test-retest .84 and .80.

    “The two subtests have strong psychometric properties [28] with internal consistency values of .85 for Coding and .79 for Symbol Search, and test-retest correlations of .84 for Coding and .80 for Symbol Search [29].”

    From Neurocognition in children with cognitive disengagement syndrome: accurate but slow (2024) · cites this paper as [28]

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value: F(4,141)=3.51, p = .03

    Minor

    The paper reports p = .03 here; recomputing from the test statistic and its degrees of freedom gives p = .009. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .03 · recomputed p = .009

  • Inconsistent p-value: F(2,138)=4.19, p = .047

    Minor

    The paper reports p = .047 here; recomputing from the test statistic and its degrees of freedom gives p = .017. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .047 · recomputed p = .017

2 of 2

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upF(4, 141) = 3.51reported p = .03 · recomputed p = .009

    “F(4,141)=3.51, p = .03”

  • Doesn’t add upF(2, 138) = 4.19reported p = .047 · recomputed p = .017

    “F(2,138)=4.19, p = .047”

  • Not confirmedF(1, 138) = 6.44reported p = .04 · recomputed p = .012

    “F(1,138)=6.44, p = .04”

  • Not confirmedF(1, 116) = 6.13reported p = .04 · recomputed p = .015

    “F(1,116)=6.13, p = .04”

  • Not confirmedF(1, 141) = 6.26reported p = .09 · recomputed p = .013

    “F(1,141)=6.26, p = .09”

  • Not confirmedF(4, 135) = 3.88reported p = .02 · recomputed p = .005

    “F(4,135)=3.88, p = .02”

  • Not confirmedF(1, 139) = 7.04reported p = .03 · recomputed p = .009

    “F(1,139)=7.04, p = .03”

  • Not confirmedF(1, 141) = 20.76reported p = .0005 · recomputed p < .001

    “F(1,141)=20.76, p = .0005”

  • Not confirmedF(1, 141) = 5.04reported p = .07 · recomputed p = .026

    “F(1,141)=5.04, p = .07”

  • Not confirmedF(4, 116) = 3.28reported p = .04 · recomputed p = .014

    “F(4,116)=3.28, p = .04”

  • ConsistentF(4, 136) = 3.39reported p = .03 · recomputed p = .011

    “F(4,136)=3.39, p = .03”

    The paper states a correction for multiple tests

  • ConsistentF(4, 141) = 5reported p = .004 · recomputed p < .001

    “F(4,141)=5.00, p = .004”

    The paper states a correction for multiple tests

  • ConsistentF(1, 141) = 10.32reported p = .006 · recomputed p = .002

    “F(1,141)=10.32, p = .006”

    The paper states a correction for multiple tests

  • ConsistentF(1, 138) = 17.73reported p = .0005 · recomputed p < .001

    “F(1,138)=17.73, p = .0005”

    The paper states a correction for multiple tests

  • ConsistentF(1, 141) = 8.7reported p = .01 · recomputed p = .004

    “F(1,141)=8.70, p = .01”

    The paper prints p at a floor (such as p < .001)

  • ConsistentF(2, 140) = 3.37reported p = .04 · recomputed p = .037

    “F(2,140)=3.37, p = .04”

  • ConsistentF(1, 140) = 4.3reported p = .04 · recomputed p = .040

    “F(1,140)=4.30, p = .04”

  • ConsistentF(2, 140) = 61.56reported p < .0001 · recomputed p < .001

    “F(2,140)=61.56, p < .0001”

  • ConsistentF(2, 138) = 41.13reported p < .0001 · recomputed p < .001

    “F(2,138)=41.13, p < .0001”

  • ConsistentF(2, 138) = 3.77reported p = .03 · recomputed p = .025

    “F(2, 138)=3.77, p = .03”

  • ConsistentF(2, 138) = 34.42reported p < .0001 · recomputed p < .001

    “F(2,138)=34.42, p < .0001”

  • ConsistentF(2, 141) = 5.98reported p = .003 · recomputed p = .003

    “F(2,141)=5.98, p = .003”

  • ConsistentF(2, 138) = 5reported p = .008 · recomputed p = .008

    “F(2,138)=5.00, p = .008”

  • ConsistentF(2, 116) = 8.98reported p = .0002 · recomputed p < .001

    “F(2,116)=8.98, p = .0002”

  • ConsistentF(2, 136) = 2.17reported p = .12 · recomputed p = .118

    “F(2,136)=2.17, p = .12”

  • ConsistentF(2, 141) = 2.24reported p = .11 · recomputed p = .110

    “F(2,141)=2.24, p = .11”

26 of 26

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • A reported reward interaction is later said not to exist

    Major

    The results report a significant group-by-reward interaction for reaction-time variability on the Stop-Signal task. The discussion later says that no significant group-by-reward interactions were found.

  • The discussion extends an event-rate accuracy effect to an excluded task

    Minor

    The discussion says faster event rates increased errors across all tasks, whereas the results explicitly exclude the Go/No-Go task from the significant event-rate effects on accuracy.

  • The stated ANT duration is shorter than its trial schedule

    Minor

    The ANT has 48 trials at each of three event rates in each half of the task. Using the stated rates of 1.5, 3.5, and 5.5 seconds gives 1,008 seconds, or 16 minutes 48 seconds, before any additional cue time-not the reported 14 minutes 48 seconds.

  • Six outcomes are called five

    Minor

    The parenthetical list contains six summary measures, not five.

    Reported 5 · recomputed 6

4 of 4

Cites

Flagged first, then by citations

Research works printed but not linked: 9

  1. Barkley R ADHD and the Nature of Self-control 1997 New York Guilford Press
  2. Barkley RA Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment 2006 New York The Guilford Press
  3. Benjamini Y Hochberg Y Controlling the false discovery rate: a practical and powerful approach to multiple testing Journal of the Royal Statistical Society, Series B (Methodological) 1995 57 1 298 300
  4. Douglas V Peters K Hale G Lewis M Toward a clearer definition of the attentional deficit of hyperactive children Attention and the development of cognitive skills 1978 New York Plenum Press 173 248
  5. Lezak MD Neuropsychologial Assessment 1995 New York Oxford University Press
  6. Logan GD Dagenbach D Carr TH On the ability to inhibit thought and action: A users' guide to the stop signal paradigm Inhibitory processes in attention, memory, and language 1994 San Diego Academic Press 189 239
  7. Luce RD Response times: Their role in inferring elementary mental organization 1986 New York Oxford University Press
  8. Quay HC Sergeant LMBJ Attention deficit disorder and the behavioral inhibition system: The relevance of the neuropsychological theory of Jeffrey A Gray Attention deficit disorder: Criteria, cognition, and intervention 1988 Oxford, England Pergamon Press
  9. Rapport MD Kofler MJ Alderson RM Timko TM DuPaul GJ Variability of attention processes in ADHD: Observations from the classroom Journal of Attention Disorders 2009 12 563 573 19255371

Cited by

Sorted by citations

Authors
Epstein, J. N., Langberg, J. M., Rosen, P. J., Graham, A., Narad, M. E., Antonini, T. N., Brinkman, W. B., Froehlich, T., Simon, J. O., & Altaye, M.
Affiliations
Cincinnati Children's Hospital Medical Center (US)
ORCID
Venue
Neuropsychology
Publisher
American Psychological Association (APA)
Published
2011-07
Volume
25
Issue
4
Pages
427-441
ISSN
  • 0894-4105 (ISSN-L)
  • 1931-1559
DOI
10.1037/a0022155
PMC
PMC3522094
OpenAlex
W2017404969
Cited by
233
References
58
Citations by year
2026: 3 · 2025: 9 · 2024: 10 · 2023: 20 · 2022: 11 · 2021: 23 · 2020: 18 · 2019: 16 · 2018: 7 · 2017: 12 · 2016: 23 · 2015: 14 · 2014: 20 · 2013: 26 · 2012: 18
FWCI
14.66
Type
journal article
Language
en
Update notices
correction (2012-12-31)
Open access
Locations
  • Neuropsychology (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Institutes of Health (R01MH074770)
  • National Institute of Mental Health (K24 MH064478, K23 MH083881; K23 MH083027)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Attention Deficit Hyperactivity Disorder
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Neural and Behavioral Psychology Studies
  • Social Sciences › Psychology › Neuropsychology and Physiological Psychology › Developmental and Educational Neuropsychology
Keywords
attention deficit hyperactivity disorder, reaction time variability, children, ADHD subtypes, reward, event rate, ex-Gaussian distribution, task accuracy, attentional networks, go/no-go task, stop-signal task, n-back task, coefficient of variation
MeSH terms
Attention Deficit Disorder with Hyperactivity, Child, Choice Behavior, Cognition Disorders, Discrimination, Psychological, Female, Humans, Inhibition, Psychological, Male, Neuropsychological Tests, Psychomotor Performance, Reaction Time, Reward, Reproducibility of Results

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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