Time estimation and performance on reproduction tasks in subtypes of children with attention deficit hyperactivity disorder

Time-Perception Deficits in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis

The present meta-analysis quantified the deficit in time perception in Attention-Deficit/Hyperactivity Disorder (ADHD) throughout the lifespan and examined potential moderators of this deficit. Our sample of 824 effect sizes showed a mean g of 0.688 that was moderated by the age of the sample and working memory. Separate moderator analyses for samples below or above the age of 18 showed that the link with working memory only applied to the samples below the age of 18, whereas an effect of ADHD subtype only applied to samples 18 and above. The discussion highlights the implications for remediation and avenues for future research.

Attention-Deficit/Hyperactivity Disorder (ADHD) and Time Perception in Adults: Do Adults with Different ADHD Symptomatology Severity Perceive Time Differently? Findings from the National Czech Study

BACKGROUND Studies show neurological differences between patients with attention-deficit/hyperactivity disorder (ADHD) and healthy controls. Furthermore, it is possible that poor timing is linked with impairments in neural circuitry. This study aimed to test the hypothesis that there is a difference in time perception between adults with severe ADHD symptomatology and adults with no ADHD symptomatology. MATERIAL AND METHODS Previously, we collected data from a more extensive set of participants (n=1518) concerning the prevalence of ADHD in adulthood. We recruited participants from 3 groups defined by increasing ADHD severity out of this participant pool. Each participant was presented with 2 experimental tasks (in counterbalanced order): duration estimation and duration discrimination. RESULTS In general, we did not find any specific differences in time perception related to the severity of ADHD. Regarding duration estimation, we found that the difference between the actual and estimated durations increased with the actual duration (F(1, 7028.00)=2685.38, P<0.001). Although the differences between groups were not significant, the group×duration interaction was (F[1, 7028.00]=10.86, P<0.001), with a very small effect size (ηp²<0.001, 95% CI [0.00, 0.01]). CONCLUSIONS The results suggest that although individuals may demonstrate increased ADHD symptomatology, they may not have objectively more significant difficulties in time perception tasks than their counterparts with mild symptomatology. Nonetheless, time perception should be further studied because, as qualitative research suggests, participants with more severe ADHD symptomatology subjectively perceive more significant differences in time management in real life.

Meta-analysis: Altered Perceptual Timing Abilities in Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

We meta-analyzed studies comparing perceptual timing abilities in the range of milliseconds to several seconds in persons with attention-deficit/hyperactivity disorder (ADHD) and neurotypical participants, using the well-established time discrimination, time estimation, time production, and time reproduction paradigms.

METHOD

We searched PubMed, OVID databases, and Web of Knowledge through September 17, 2020. From 2,266 records, 55 studies were retained and meta-analyzed with random effects models. We conducted meta-regression analyses to explore moderating effects of task parameters and neuropsychological measures of working memory, attention, and inhibition on timing performance.

RESULTS

Compared with persons without ADHD, those with ADHD had significantly more severe difficulties in discriminating stimuli of very brief durations, especially in the sub-second range. They also had more variability in estimating the duration of stimuli lasting several seconds. Moreover, they showed deficits in time estimation and time production accuracy, indicative of an accelerated internal clock. Additional deficits in persons with ADHD were also found in the time reproduction paradigm, involving attentional (slower counting at short time intervals due to distraction) and motivational (faster counting at long time intervals due to increased delay aversion) functions.

CONCLUSION

There is meta-analytic evidence of a broad range of timing deficits in persons with ADHD. Results have implications for advancing our knowledge in the field (eg, for refinement of recent timing models in ADHD) and clinical practice (eg, testing timing functions to characterize the clinical phenotype of the patient and implementation of interventions to improve timing abilities).

An evaluation of the effect of methylphenidate on working memory, time perception, and choice impulsivity in children with ADHD

Individuals with Attention-Deficit Hyperactivity Disorder (ADHD) consistently exhibit a stronger preference for immediate rewards than for larger rewards available following a delay on tasks measuring choice impulsivity (CI). Despite this, however, there remains a dearth of studies examining the impact of stimulant treatment on CI as well as associated higher order (e.g., working memory [WM]) and perceptual (e.g., time perception) cognitive processes. The present study examines the effect of osmotic release oral system methylphenidate (OROS-MPH) on CI, WM and time perception processes as well as the relation among these processes before and after taking a regimen of OROS-MPH. Thirty-five children (aged 7-12 years) with a diagnosis of ADHD participating in a concurrent stimulant medication study were recruited to complete computerized assessments of CI, WM, and time perception. Children completed the assessments after administration of a placebo as well as their lowest effective dose of OROS-MPH following a 2-week titration period. The results from one-sample t-tests indicated that OROS-MPH improves both CI and WM in youth with ADHD but does not impact time perception. Further, results revealed no significant association among the various indices of cognitive performance while taking placebo or OROS-MPH. Overall, the findings suggest that while OROS-MPH improves both CI and WM in youth with ADHD, improvements in CI as a result of OROS-MPH are unlikely to be associated with the improvements in WM given the lack of association among the two. Future studies should consider alternate cognitive, emotional, and motivational mechanisms that may account for the impact of OROS-MPH on CI. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Auditory time thresholds in the range of milliseconds but not seconds are impaired in ADHD

The literature on time perception in individuals with ADHD is extensive but inconsistent, probably reflecting the use of different tasks and performances indexes. A sample of 40 children/adolescents (20 with ADHD, 20 neurotypical) was engaged in two identical psychophysical tasks measuring auditory time thresholds in the milliseconds (0.25–1 s) and seconds (0.75–3 s) ranges. Results showed a severe impairment in ADHD for milliseconds thresholds (Log10BF = 1.9). The deficit remained strong even when non-verbal IQ was regressed out and correlation with age suggests a developmental delay. In the seconds range, thresholds were indistinguishable between the two groups (Log10BF = − 0.5) and not correlated with milliseconds thresholds. Our results largely confirm previous evidence suggesting partially separate mechanisms for time perception in the ranges of milliseconds and seconds. Moreover, since the evidence suggests that time perception of milliseconds stimuli might load relatively less on cognitive control and working memory, compared to longer durations, the current results are consistent with a pure timing deficit in individuals with ADHD.

Time Perception Deficits in Children and Adolescents with ADHD: A Meta-analysis

OBJECTIVE

Prior studies have reported time perception impairment in children and adolescents with ADHD but the results were inconsistent.

METHOD

The current meta-analysis reviews 27 empirical studies published in English after year 2000 that compared time perception competence among children and adolescents with and without ADHD.

RESULTS

Results from 1620 participants with ADHD and 1249 healthy controls showed significant timing deficits in ADHD. Children/adolescents with ADHD perceived time less accurately (Hedges' g > 0.40), less precisely (Hedges' g = 0.66) and had higher tendency to overestimate time than their healthy counterparts. Moderator analyses indicated that the discrepancy of time perception between groups was not affected by the type of timing tasks nor the modality of stimuli used in the tasks. Nonetheless, results were moderated by age and gender.

CONCLUSION

These findings may update current understanding of the underlying neuropsychological deficits in ADHD and provide insight for future research in clinical assessments and treatments for ADHD.

Feedback-Based Learning of Timing in Attention-Deficit/Hyperactivity Disorder and Neurofibromatosis Type 1

OBJECTIVE

Patients with Neurofibromatosis Type 1 (NF1) frequently display symptoms resembling those of Attention Deficit/Hyperactivity Disorder (ADHD). Importantly, these disorders are characterised by distinct changes in the dopaminergic system, which plays an important role in timing performance and feedback-based adjustments in timing performance. In a transdiagnostic approach, we examine how far NF1 and ADHD show distinct or comparable profiles of timing performance and feedback-based adjustments in timing.

METHOD

We examined time estimation and learning processes in healthy control children (HC), children with ADHD with predominantly inattentive symptoms and those with NF1 using a feedback-based time estimation paradigm.

RESULTS

Healthy controls consistently responded closer to the correct time window than both patient groups, were less variable in their reaction times and displayed intact learning-based adjustments across time. The patient groups did not differ from each other regarding the number of in-time responses. In ADHD patients, the performance was rather unstable across time. No performance changes could be observed in patients with NF1 across the entire task.

CONCLUSIONS

Children with ADHD and NF1 differ in feedback learning-based adjustments of time estimation processes. ADHD is characterised by behavioural fluctuations during the learning process. These are likely to be associated with inefficiencies in the dopaminergic system. NF1 is characterised by impairments of feedback learning which could be due to various neurotransmitter alterations occurring in addition to deficits in dopamine synthesis. Results show that despite the strong overlap in clinical phenotype and neuropsychological deficits between NF1 and ADHD, the underlying cognitive mechanisms are different.

Time-to-Collision Estimations in Young Drivers with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder

Individuals with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) may exhibit driving difficulties due to cognitive impairments such as time perception difficulties, a construct related to the perception of time-to-collision (TTC). This study examined the timing abilities of drivers with ASD and ADHD. Sixty participants (n_ADHD = 20, n_ASD = 20, n_TD = 20) completed a time reproduction task and a TTC estimation task in a driving simulator. Results indicated drivers with ASD were less precise in time reproduction across all time intervals and over-reproduced time at shorter intervals. Drivers with ASD produced larger TTC estimates when driving at a faster speed compared to typically developing drivers. Drivers with ASD, but not ADHD, appear to present difficulties in time estimation abilities.

Increased vulnerability to impulsive behavior after streptococcal antigen exposure and antibiotic treatment in rats

RATIONALE

The inflammation induced by Group A Streptococcus (GAS) infection has been viewed as a vulnerability factor in mental disorders characterized by inhibitory control deficits, such as attention-deficit/hyperactivity disorder or obsessive-compulsive disorder. Antibiotic treatment reduces GAS symptoms; however, its effects on impulsivity have not been fully assessed.

OBJECTIVES

We investigated whether GAS exposure during early adolescence might be a vulnerability factor for adult impulsivity, if antibiotic treatment acts as a protective factor, and whether these differences are accompanied by changes in the inflammatory cytokine frontostriatal regions.

METHODS

Male Wistar rats were exposed to the GAS antigen or to vehicle plus adjuvants at postnatal day (PND) 35 (with two boosts), and they received either ampicillin (supplemented in the drinking water) or water alone from PND35 to PND70. Adult impulsivity was assessed using two different models, the 5-choice serial reaction time task (5-CSRT task) and the delay discounting task (DDT). The levels of interleukin-6 (IL-6) and IL-17 were measured in the prefrontal cortex (PFc), and the tumor necrosis factor α levels (TNFα) were measured in the PFc and nucleus accumbens (NAcc).

RESULTS

GAS exposure and ampicillin treatment increased the waiting impulsivity by a higher number of premature responses when the animals were challenged by a long intertrial interval during the 5-CSRT task. The GAS exposure revealed higher impulsive choices at the highest delay (40 s) when tested by DDT, while coadministration with ampicillin prevented the impulsive choice. GAS exposure and ampicillin reduced the IL-6 and IL-17 levels in the PFc, and ampicillin treatment increased the TNFα levels in the NAcc. A regression analysis revealed a significant contribution of GAS exposure and TNFα levels to the observed effects.

CONCLUSIONS

GAS exposure and ampicillin treatment induced an inhibitory control deficit in a different manner depending on the form of impulsivity measured here, with inflammatory long-term changes in the PFc and NAcc that might increase the vulnerability to impulsivity-related neuropsychiatric disorders.

How Is Temporal Processing Affected in Children with Attention-deficit/hyperactivity Disorder?

We compared the performance of children with ADHD and typically developing children on two temporal tasks, a bisection task and a reproduction task, in auditory and visual modalities. Children with ADHD presented a larger variability when performing auditory and visual temporal tasks. Moreover, they overestimated the durations in bisection tasks and underproduced duration intervals in the visual reproduction task. In the context of the pacemaker-accumulator model, these results suggest that temporal deficits might result from a dysfunction in the switch and/or memory impairment.

Clinical Implications of the Perception of Time in Attention Deficit Hyperactivity Disorder (ADHD): A Review

Attention deficit hyperactivity disorder (ADHD) is a lifelong neurodevelopmental disorder that can affect many areas of the daily life of individuals and is associated with poor health outcomes and with debilitating deficits in executive function. Recently, increasing numbers of research studies have begun to investigate the associations between neural and behavioral manifestations of ADHD. This review summarizes recent research on the perception of time in ADHD and proposes that this symptom is a possible diagnostic characteristic. Controlled studies on time perception have compared individuals with ADHD with typically developing controls (TDCs) and have used methods that include the Zimbardo Time Perspective Inventory (ZTPI). Practical approaches to time perception and its evaluation have shown that individuals with ADHD have difficulties in time estimation and discrimination activities as well as having the feeling that time is passing by without them being able to complete tasks accurately and well. Although ADHD has been associated with neurologic abnormalities in the mesolimbic and dopaminergic systems, recent studies have found that when individuals with ADHD are treated medically, their perception of time tends to normalize. The relationship between ADHD and the perception of time requires greater attention. Further studies on time perception in ADHD with other abnormalities, including executive function, might be approaches that refine the classification and diagnosis of ADHD and should include studies on its varied presentation in different age groups.

Comparisons between sluggish cognitive tempo and ADHD-restrictive inattentive presentation phenotypes in a clinical ADHD sample

There is a debate how different ADHD cases with a comorbid sluggish cognitive tempo (SCT) phenotype are from subjects with a pure inattentive ADHD presentation (ADHD-restrictive inattentive presentation). In this study, 214 patients aged 8-15 years from an ADHD outpatient clinic were assessed, and 100 typically developing controls (TD) were recruited as comparisons. No psychiatric comorbidities except for oppositional defiant disorder were allowed. We compared 29 cases with ADHD + SCT with 34 ADHD-RI cases and 92 TD subjects on sociodemographic profiles, CBCL subscales scores and neurocognitive findings. Regarding sociodemographic profiles (age, gender and parental education) and CBCL subscales, ADHD + SCT and ADHD-RI cases did not differ in any score (all p > 0.05). Comparing with SCT cases, ADHD-RI cases presented slower psychomotor speed and worse neurocognitive index (p < 0.001). We found that only SCT was independently associated with a lower performance in total memory score. ADHD-RI was independently associated with longer reaction time. Our findings suggest that although SCT might be expected to present longer reaction time, we found that slower psychomotor speed and longer reaction time scores were related to inattention. Overall, SCT and ADHD-RI groups were distinguished by differential associations with measures of memory and reaction time.

Effect of combined neurofeedback and game-based cognitive training on the treatment of ADHD: A randomized controlled study

Neurofeedback (NF) is referred to as a "possibly efficacious" treatment in the current evidence-based reviews; therefore, more research is needed to determine its effects especially in combination with other treatments. The present study examines the effect of NF and game-based cognitive training on children with attention deficit hyperactivity disorder (ADHD). Thirty-two male students with ADHD were assigned to NF (N = 16; M_age=10.20; SD = 1.03) and waiting list control (N = 16; M_age = 10.05; SD = 0.83) in a randomized double-blind trial. The children in the NF group based on quantitative electroencephalography (QEEG) attended 30 three times-weekly sessions. The children were examined in pretest and post-test with EEG, Integrated Visual and Auditory Continuous Performance (IVA), and Conners Parent, and Teacher Rating Scales-Revised. The treatment was found significant all the symptom variables except for attention deficit (AD) and auditory response control (ARC). Normalization of the atypical EEG features with reduced [Formula: see text] wave and increased sensory motor (SMR) activity in central zero (Cz) was recorded in the NF condition participants. However, except for SMR activity there were no significant changes in the waves of frontocentral zero (FCz). It is concluded that technology developments provide an interesting vehicle for interposing interventions and that combined NF and game-based cognitive training can produce positive therapeutic effects on brainwaves and ADHD symptomatology.

Neural Correlates of Duration Discrimination in Young Adults with Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder and Their Comorbid Presentation

Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) often co-occur and share neurocognitive deficits. One such shared impairment is in duration discrimination. However, no studies using functional magnetic resonance imaging (fMRI) have investigated whether these duration discrimination deficits are underpinned by the same or different underlying neurofunctional processes. In this study, we used fMRI to compare the neurofunctional correlates of duration discrimination between young adult males with ASD (n = 23), ADHD (n = 25), the comorbid condition of ASD+ADHD (n = 24), and typical development (TD, n = 26) using both region of interest (ROI) and whole brain analyses. Both the ROI and the whole-brain analyses showed that the comorbid ASD+ADHD group compared to controls, and for the ROI analysis relative to the other patient groups, had significant under-activation in right inferior frontal cortex (IFG) a key region for duration discrimination that is typically under-activated in boys with ADHD. The findings show that in young adult males with pure ASD, pure ADHD and comorbid ASD+ADHD with no intellectual disability, only the comorbid group demonstrates neurofunctional deficits in a typical duration discrimination region.

Is there a generalized timing impairment in Autism Spectrum Disorders across time scales and paradigms?

Individuals with ASD have abnormal motor and perceptual functions that do not currently form diagnostic criteria of ASD, but nevertheless may affect everyday behaviour. Temporal processing seems to be one of such non-diagnostic yet impaired domains, although the lack of systematic studies testing different aspects of timing in the same sample of participants prevents a conclusive assessment of whether there is a generalized temporal deficit in ASD associated with diagnostic symptoms. 17 children diagnosed with ASD and 18 typically developing age- and IQ-matched controls carried out a set of motor and perceptual timing tasks: free tapping, simultaneity judgment, auditory duration discrimination, and verbal duration estimation. Parents of participants filled in a questionnaire assessing the sense and management of time. Children with ASD showed faster and more variable free tapping than controls. Auditory duration discrimination thresholds were higher in the ASD group than controls in a sub-second version of the task, while there were no group differences in a supra-second discrimination of intervals. Children with ASD showed more variable thresholds of simultaneity judgment, and they received lower parental scores for their sense and management of time. No group differences were observed in the verbal duration estimation task in the minute-range. Different timing functions were correlated in the ASD group but not among controls, whilst several timing measures correlated with ASD symptoms. We conclude that children with ASD show a broad range of abnormalities in temporal processing tasks including motor timing, perceptual timing, and temporal perspective.

Living in the Fast Lane: Evidence for a Global Perceptual Timing Deficit in Childhood ADHD Caused by Distinct but Partially Overlapping Task-Dependent Cognitive Mechanisms

Dysfunctions in perceptual timing have been reported in children with ADHD, but so far only from studies that have not used the whole set of timing paradigms available from the literature, with the diversity of findings complicating the development of a unified model of timing dysfunctions and its determinants in ADHD. Therefore, we employed a comprehensive set of paradigms (time discrimination, time estimation, time production, and time reproduction) in order to explore the perceptual timing deficit profile in our ADHD sample. Moreover, we aimed to detect predictors responsible for timing task performance deficits in children with ADHD and how the timing deficits might be positively affected by methylphenidate. Male children with ADHD and healthy control children, all aged between 8 and 13 years, participated in this longitudinal study with three experimental sessions, where children with ADHD were medicated with methylphenidate at the second session but discontinued their medication at the remaining sessions. The results of our study reveal that children with ADHD were impaired in all timing tasks, arguing for a general perceptual timing deficit in ADHD. In doing so, our predictor analyses support the notion that distinct but partially overlapping cognitive mechanisms might exist for discriminating, estimating/producing, and reproducing time intervals. In this sense, working memory deficits in terms of an abnormally fast internal counting process might be common to dysfunctions in the time estimation/time production tasks and in the time reproduction task, with attention deficits (e.g., in terms of disruptions of the counting process) additionally contributing to time estimation/time production deficits and motivational alterations additionally contributing to time reproduction deficits. Methylphenidate did not significantly alter performance of the ADHD sample, presumably due to limited statistical power of our study. The findings of our study demonstrate a pivotal role of disturbed working memory processes in perceptual timing task performance in childhood ADHD, at the same time broadening the view for additional attentional and motivational determinants of impaired task performance.

The faster internal clock in ADHD is related to lower processing speed: WISC-IV profile analyses and time estimation tasks facilitate the distinction between real ADHD and pseudo-ADHD

Alterations in temporal processing may represent a primary cause of key symptoms in ADHD. This study is aimed at investigating the nature of time-processing alterations in ADHD and assessing the possible utility of testing time estimation for clinical diagnostics. Retrospective verbal time estimation in the range of several minutes was examined in 50 boys with ADHD and 53 boys with other mental disorders. All participants (age 7-16) attended an outpatient clinic for ADHD diagnostics. The diagnostic assessment included the WISC-IV. Subjects with ADHD made longer and less accurate duration estimates than the clinical control group. The ADHD group showed a specific WISC-IV profile with processing speed deficits. In the ADHD group there was a correlation between processing speed and quality of time estimation that was not observed in the comparison group: higher processing speed indices were related to more accurate duration estimates. The findings provide support for the presence of a faster internal clock in subjects with ADHD and lend further support to the existence of a specific WISC-IV profile in subjects with ADHD. The results show that analyzing WISC-IV profiles and time estimation tasks are useful differential diagnosis tools, particularly when it comes to distinguishing between "real ADHD" and pseudo-ADHD.

Why are they late? Timing abilities and executive control among students with learning disabilities

While a deficient ability to perform daily tasks on time has been reported among students with learning disabilities (LD), the underlying mechanism behind their 'being late' is still unclear. This study aimed to evaluate the organization in time, time estimation abilities, actual performance time pertaining to specific daily activities, as well as the executive functions of students with LD in comparison to those of controls, and to assess the relationships between these domains among each group. The participants were 27 students with LD, aged 20-30, and 32 gender and age-matched controls who completed the Time Organization and Participation Scale (TOPS) and the Behavioral Rating Inventory of Executive Function-Adult version (BRIEF-A). In addition, their ability to estimate the time needed to complete the task of preparing a cup of coffee as well as their actual performance time were evaluated. The results indicated that in comparison to controls, students with LD showed significantly inferior organization in time (TOPS) and executive function abilities (BRIEF-A). Furthermore, their time estimation abilities were significantly inferior and they required significantly more time to prepare a cup of coffee. Regression analysis identified the variables that predicted organization in time and task performance time among each group. The significance of the results for both theoretical and clinical implications are discussed. What this paper adds? This study examines the underlying mechanism of the phenomena of being late among students with LD. Following a recent call for using ecologically valid assessments, the functional daily ability of students with LD to prepare a cup of coffee and to organize time were investigated. Furthermore, their time estimation and executive control abilities were examined as a possible underlying mechanism for their lateness. Although previous studies have indicated executive control deficits among students with LD, to our knowledge, this is the first analysis of the relationships between their executive control and time estimation deficits and their influence upon their daily function and organization in time abilities. Our findings demonstrate that students with LD need more time in order to execute simple daily activities, such as preparing a cup of coffee. Deficient working memory, retrospective time estimation ability and inhibition predicted their performance time and organization in time abilities. Therefore, this paper sheds light on the mechanism behind daily performance in time among students with LD and emphasizes the need for future development of focused intervention programs to meet their unique needs.

A Study on the Validity of a Computer-Based Game to Assess Cognitive Processes, Reward Mechanisms, and Time Perception in Children Aged 4-8 Years

Background

A computer-based game, named Timo’s Adventure, was developed to assess specific cognitive functions (eg, attention, planning, and working memory), time perception, and reward mechanisms in young school-aged children. The game consists of 6 mini-games embedded in a story line and includes fantasy elements to enhance motivation.

Objective

The aim of this study was to investigate the validity of Timo’s Adventure in normally developing children and in children with attention-deficit/hyperactivity disorder (ADHD).

Methods

A total of 96 normally developing children aged 4-8 years and 40 children with ADHD were assessed using the game. Clinical validity was investigated by examining the effects of age on performances within the normally developing children, as well as performance differences between the healthy controls and the ADHD group.

Results

Our analyses in the normally developing children showed developmental effects; that is, older children made fewer inhibition mistakes (r=−.33, P=.001), had faster (and therefore better) reaction times (r=−.49, P<.001), and were able to produce time intervals more accurately than younger children (ρ=.35, P<.001). Discriminant analysis showed that Timo’s Adventure was accurate in most classifications whether a child belonged to the ADHD group or the normally developing group: 78% (76/97) of the children were correctly classified as having ADHD or as being in the normally developing group. The classification results showed that 72% (41/57) children in the control group were correctly classified, and 88% (35/40) of the children in the ADHD group were correctly classified as having ADHD. Sensitivity (0.89) and specificity (0.69) of Timo’s Adventure were satisfying.

Conclusions

Computer-based games seem to be a valid tool to assess specific strengths and weaknesses in young children with ADHD.

Temporal reproduction and its neuroanatomical correlates in adults with attention deficit hyperactivity disorder and their unaffected first-degree relatives

BACKGROUND

Little is known about time perception, its putative role as cognitive endophenotype, and its neuroanatomical underpinnings in adults with attention deficit hyperactivity disorder (ADHD).

METHOD

Twenty adults with ADHD, 20 unaffected first-degree relatives and 20 typically developing controls matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional grey-matter volumes. Temporal processing was investigated as a putative cognitive endophenotype using a temporal reproduction paradigm. General linear modelling was employed to examine the relationship between temporal reproduction performances and grey-matter volumes.

RESULTS

ADHD participants were impaired in temporal reproduction and unaffected first-degree relatives performed in between their ADHD probands and typically developing controls. Increased grey-matter volume in the cerebellum was associated with poorer temporal reproduction performance.

CONCLUSIONS

Adults with ADHD are impaired in time reproduction. Performances of the unaffected first-degree relatives are in between ADHD relatives and controls, suggesting that time reproduction might be a cognitive endophenotype for adult ADHD. The cerebellum is involved in time reproduction and might play a role in driving time performances.

Systematic Underreproduction of Time Is Independent of Judgment Certainty

We recently proposed that systematic underreproduction of time is caused by a general judgment bias towards earlier responses, instead of reflecting a genuine misperception of temporal intervals. Here we tested whether this bias can be explained by the uncertainty associated with temporal judgments. We applied transcranial magnetic stimulation (TMS) to inhibit neuronal processes in the right posterior parietal cortex (PPC) and tested its effects on time discrimination and reproduction tasks. The results show increased certainty for discriminative time judgments after PPC inhibition. They suggest that the right PPC plays an inhibitory role for time perception, possibly by mediating the multisensory integration between temporal stimuli and other quantities. Importantly, this increased judgment certainty had no influence on the degree of temporal underreproduction. We conclude that the systematic underreproduction of time is not caused by uncertainty for temporal judgments.

Music and Sound in Time Processing of Children with ADHD

ADHD involves cognitive and behavioral aspects with impairments in many environments of children and their families' lives. Music, with its playful, spontaneous, affective, motivational, temporal, and rhythmic dimensions can be of great help for studying the aspects of time processing in ADHD. In this article, we studied time processing with simple sounds and music in children with ADHD with the hypothesis that children with ADHD have a different performance when compared with children with normal development in tasks of time estimation and production. The main objective was to develop sound and musical tasks to evaluate and correlate the performance of children with ADHD, with and without methylphenidate, compared to a control group with typical development. The study involved 36 participants of age 6-14 years, recruited at NANI-UNIFESP/SP, subdivided into three groups with 12 children in each. Data was collected through a musical keyboard using Logic Audio Software 9.0 on the computer that recorded the participant's performance in the tasks. Tasks were divided into sections: spontaneous time production, time estimation with simple sounds, and time estimation with music.

RESULTS

(1) performance of ADHD groups in temporal estimation of simple sounds in short time intervals (30 ms) were statistically lower than that of control group (p < 0.05); (2) in the task comparing musical excerpts of the same duration (7 s), ADHD groups considered the tracks longer when the musical notes had longer durations, while in the control group, the duration was related to the density of musical notes in the track. The positive average performance observed in the three groups in most tasks perhaps indicates the possibility that music can, in some way, positively modulate the symptoms of inattention in ADHD.

Adjustment of Time Perception in the Range of Seconds and Milliseconds: The Nature of Time-Processing Alterations in Children With ADHD

OBJECTIVE

The nature of time-processing alterations in ADHD was assessed by means of duration judgments and temporal set-shifting tasks lasting several seconds and milliseconds.

METHOD

After training with visual sample stimuli for long and short durations, 31 children with ADHD and 29 controls estimated the durations of test stimuli. During testing, the temporal context was systematically varied by shifting the duration of stimulus sets to longer or shorter intervals.

RESULTS

Children with ADHD generally overestimated the durations of stimuli on the seconds scale. Their assessment of stimuli on the milliseconds scale can be characterized as less-efficient adaptations to new temporal sets alongside otherwise normal discrimination performance.

CONCLUSION

Findings support a pure time perception alteration in ADHD. In addition, results provide first evidence that difficulties in mental set-shifting, which have been reported for other tasks, extend to temporal processing in children with ADHD.

Interval timing deficits assessed by time reproduction dual tasks as cognitive endophenotypes for attention-deficit/hyperactivity disorder

The literature has suggested timing processing as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD); however, whether the subjective internal clock speed presented by verbal estimation and limited attention capacity presented by time reproduction could be endophenotypes for ADHD is still unknown. We assessed 223 youths with DSM-IV ADHD (age range: 10-17 years), 105 unaffected siblings, and 84 typically developing (TD) youths using psychiatric interviews, intelligence tests, verbal estimation and time reproduction tasks (single task and simple and difficult dual tasks) at 5-second, 12-second, and 17-second intervals. We found that youths with ADHD tended to overestimate time in verbal estimation more than their unaffected siblings and TD youths, implying that fast subjective internal clock speed might be a characteristic of ADHD, rather than an endophenotype for ADHD. Youths with ADHD and their unaffected siblings were less precise in time reproduction dual tasks than TD youths. The magnitude of estimated errors in time reproduction was greater in youths with ADHD and their unaffected siblings than in TD youths, with an increased time interval at the 17-second interval and with increased task demands on both simple and difficult dual tasks versus the single task. Increased impaired time reproduction in dual tasks with increased intervals and task demands were shown in youths with ADHD and their unaffected siblings, suggesting that time reproduction deficits explained by limited attention capacity might be a useful endophenotype of ADHD.

Losing track of time through delayed body representations

The ability to keep track of time is perceived as crucial in most human societies. However, to lose track of time may also serve an important social role, associated with recreational purpose. To this end a number of social technologies are employed, some of which may relate to a manipulation of time perception through a modulation of body representation. Here, we investigated an influence of real-time or delayed videos of own-body representations on time perception in an experimental setup with virtual mirrors. Seventy participants were asked to either stay in the installation until they thought that a defined time (90 s) had passed, or they were encouraged to stay in the installation as long as they wanted and after exiting were asked to estimate the duration of their stay. Results show that a modulation of body representation by time-delayed representations of the mirror-video displays influenced time perception. Furthermore, these time-delayed conditions were associated with a greater sense of arousal and intoxication. We suggest that feeding in references to the immediate past into working memory could be the underlying mental mechanism mediating the observed modulation of time perception. We argue that such an influence on time perception would probably not only be achieved visually, but might also work with acoustic references to the immediate past (e.g., with music).

Time estimation deficits in childhood mathematics difficulties

Time perception has not been comprehensively examined in mathematics difficulties (MD). Therefore, verbal time estimation, production, and reproduction were tested in 13 individuals with MD and 16 healthy controls, matched for age, sex, and intellectual skills. Individuals with MD performed comparably to controls in time reproduction, but showed a tendency to be less accurate on tasks of verbal time estimation and time production. More specifically, these individuals overestimated the duration of a time interval in the verbal time estimation task and showed underproduction when required to produce a time sample. All previous significant comparisons remained significant after controlling for the effects of interval duration, working memory, attention allocation, and quantity estimation. These findings lead us to suggest that time estimation, and more specifically the "internal clock," is abnormally fast in individuals with MD. Results are discussed in terms of Meck and Church's model of temporal processing and Dehaene's triple code model for number processing.

Time reproduction performance is associated with age and working memory in high-functioning youth with autism spectrum disorder

Impaired temporal processing has historically been viewed as a hallmark feature of attention deficit hyperactivity disorder. Recent evidence suggests temporal processing deficits may also be characteristic of autism spectrum disorder (ASD). However, little is known about the factors that impact temporal processing in children with ASD. The purpose of this study was to assess the effects of co-morbid attention problems, working memory (WM), age, and their interactions, on time reproduction in youth with and without ASD. Twenty-seven high-functioning individuals with ASD and 25 demographically comparable typically developing individuals (ages 9-17; 85% male) were assessed on measures of time reproduction, auditory WM, and inattention/hyperactivity. The time reproduction task required depression of a computer key to mimic interval durations of 4, 8, 12, 16, or 20 sec. Mixed effects regression analyses were used to model accuracy and variability of time reproduction as functions of diagnostic group, interval duration, age, WM, and inattention/hyperactivity. A significant group by age interaction was detected for accuracy, with the deficit in the ASD group being greater in younger children. There was a significant group by WM interaction for consistency, with the effects of poor WM on performance consistency being more pronounced in youth with ASD. All participants tended to underestimate longer interval durations and to be less consistent for shorter interval durations; these effects appeared more pronounced in those who were younger or who had poorer WM performance. Inattention/hyperactivity symptoms in the ASD group were not related to either accuracy or consistency. This study highlights the potential value of temporal processing as an intermediate trait of relevance to multiple neurodevelopmental disorders.

The internal and external validity of sluggish cognitive tempo and its relation with DSM-IV ADHD

Studies of subtypes of DSM-IV attention-deficit/hyperactivity disorder (ADHD) have provided inconsistent support for the discriminant validity of the combined type (ADHD-C) and predominantly inattentive type (ADHD-I). A large sample of children and adolescents with ADHD (N = 410) and a comparison group without ADHD (N = 311) were used to test the internal and external validity of sluggish cognitive tempo (SCT), a dimension characterized by low energy and sleepy and sluggish behavior. SCT scores were then incorporated in analyses of ADHD subtypes to test whether the discriminant validity of ADHD-C and ADHD-I could be improved by including SCT symptoms as part of the criteria for ADHD-I. Factor analyses of parent and teacher ratings indicated that six SCT items loaded on a factor separate from symptoms of ADHD and other psychopathology, providing important support for the internal validity of SCT. The external validity of SCT was supported by significant associations between SCT and measures of functional impairment and neuropsychological functioning when symptoms of ADHD and other psychopathology were controlled. However, contrary to initial predictions, high levels of SCT did not identify a subgroup of ADHD-I that was clearly distinct from ADHD-C. Instead, the current results suggest that DSM-IV inattention and SCT are separate but correlated symptom dimensions that are each independently associated with important aspects of functional impairment and neuropsychological functioning.

The impact of financial reward contingencies on cognitive function profiles in adult ADHD

Objectives

Although it is well established that cognitive performance in children with attention-deficit/hyperactivity disorder (ADHD) is affected by reward and that key deficits associated with the disorder may thereby be attenuated or even compensated, this phenomenon in adults with ADHD has thus far not been addressed. Therefore, the aim of the present study was to examine the motivating effect of financial reward on task performance in adults with ADHD by focusing on the domains of executive functioning, attention, time perception, and delay aversion.

Methods

We examined male and female adults aged 18–40 years with ADHD (n = 38) along with a matched control group (n = 40) using six well-established experimental paradigms.

Results

Impaired performance in the ADHD group was observed for stop-signal omission errors, n-back accuracy, reaction time variability in the continuous performance task, and time reproduction accuracy, and reward normalized time reproduction accuracy. Furthermore, when rewarded, subjects with ADHD exhibited longer reaction times and fewer false positives in the continuous performance task, which suggests the use of strategies to prevent impulsivity errors.

Conclusions

Taken together, our results support the existence of both cognitive and motivational mechanisms for the disorder, which is in line with current models of ADHD. Furthermore, our data suggest cognitive strategies of “stopping and thinking” as a possible underlying mechanism for task improvement that seems to be mediated by reward, which highlights the importance of the interaction between motivation and cognition in adult ADHD.

Temporal processing impairment in children with attention-deficit-hyperactivity disorder

The current study aimed to investigate temporal processing in Chinese children with Attention-Deficit-Hyperactivity Disorder(ADHD) using time production, time reproduction paradigm and duration discrimination tasks. A battery of tests specifically designed to measure temporal processing was administered to 94 children with ADHD and 100 demographically matched healthy children. A multivariate analysis of variance (MANOVA) and a repeated measure MANOVA indicated that children with ADHD were impaired in time processing functions. The results of pairwise comparisons showed that the probands with a family history of ADHD performed significantly worse than those without family history in the time production tasks and the time reproduction task. Logistic regression analysis showed duration discrimination had a significant role in predicting whether the children were suffering from ADHD or not, while temporal processing had a significant role in predicting whether the ADHD children had a family history or not. This study provides further support for the existence of a generic temporal processing impairment in ADHD children and suggests that abnormalities in time processing and ADHD share some common genetic factors.

Time estimation abilities of college students with ADHD

OBJECTIVE

To evaluate the time estimation abilities of college students with ADHD on a novel, complex task that approximated academically oriented activities.

METHOD

Totally 20 college students with ADHD were compared to a sample of 20 non-ADHD students. Both groups completed a task, and scores were obtained for time to complete the task, errors made, prospective time estimate, confidence in estimate, and retrospective time estimate. In addition, scores were calculated for the difference between prospective estimate and actual time as well as the difference between retrospective estimate and actual time.

RESULTS

Controlling for cognitive ability, the ADHD participants were significantly different from the non-ADHD participants on all dependent measures except confidence and errors.

CONCLUSION

College students with ADHD showed retrospective time estimation difficulties that may be related to academic functioning in the college setting.

Temporal processing in schizophrenia: effects of task-difficulty on behavioral discrimination and neuronal responses

Deficits in temporal judgment in schizophrenia have been observed in behavioral and electrophysiological studies for years. The functional neuroanatomy of temporal judgment in schizophrenia is, however, poorly understood. Recent neurophysiological research suggests that timing deficits in this population may not be widespread across all timing tasks, but specifically associated with high levels of difficulty. We evaluated differences between individuals with schizophrenia (N=16) and healthy subjects (N=18) during a temporal discrimination task at two levels of difficulty. Subjects were studied with functional magnetic resonance imaging (fMRI) at 3T while discriminating tone durations. Behaviorally, the schizophrenia group performed worse than the control group at both levels of difficulty. Similarly, group differences in patterns of brain activation were observed across both difficulty conditions. In the easy condition, individuals with schizophrenia showed less activation in the supplementary motor area and insula/opercula, regions known to be involved in temporal processing. These group differences increased in the difficult condition. In addition, the striatum was less active in individuals with schizophrenia in the difficult condition. Comparing the difficult to easy conditions revealed robust differences in the bilateral striatum and the insula/opercula, suggesting that the striatum plays a key role in temporal processing deficits in schizophrenia, especially under difficult conditions. These observations suggest that temporal judgment deficits reflect widespread neuroanatomical network involvement in schizophrenia, some of which are not directly related to task difficulty. These findings shed light on disparate findings in the timing literature regarding the role of task difficulty in temporal judgment deficits in schizophrenia.

Deficits in interval timing measured by the dual-task paradigm among children and adolescents with attention-deficit/hyperactivity disorder

BACKGROUND

The underlying mechanism of time perception deficit in long time intervals in attention-deficit/hyperactivity disorder (ADHD) is still unclear. This study used the time reproduction dual task to explore the role of the attentional resource in time perception deficits among children and adolescents with ADHD.

METHODS

Participants included 168 children and adolescents with DSM-IV ADHD and 90 control children and adolescents without ADHD, aged 10 to 17 years, in Taipei. The DSM-IV diagnoses of ADHD and other psychiatric comorbid conditions were made by clinical assessments and confirmed by the psychiatric interviews of both parents and participants using the Chinese Kiddie Epidemiologic version of the Schedule for Affective Disorders and Schizophrenia. The participants were also assessed by using the Wechsler Intelligence Scale for Children-3(rd) edition (WISC-III), and time reproduction tasks (the single task and the simple and difficult versions of the dual tasks) at 5-second, 12-second, and 17-second intervals. The linear mixed model was used for data analysis.

RESULTS

Children and adolescents with ADHD had less precise time reproduction than the controls in all three tasks except the 5-second interval of the single task. There were significant interactions between group and interval (12-second vs. 5-second, p = .030; 17-second vs. 5-second, p < .001), and between group and task (simple dual task vs. single task, p = .016; difficult dual task vs. single task, p < .001) after controlling for FSIQ, comorbidity, sex, age, use of methylphenidate, and the performance of the non-temporal tasks in dual tasks, if relevant.

CONCLUSIONS

Significantly increased estimation errors in ADHD with increased task difficulties suggest that impaired timing processing in children and adolescents with ADHD during long time intervals may be accounted for by the limited attentional capacity rather than a primary problem in timing per se. This finding does not apply to rapid time intervals, in which cerebellar circuitry is important.

Sense of Time in Children with Attention-Deficit/Hyperactivity Disorder (ADHD)

Parents of children with attention-deficit/hyperactivity disorder (ADHD) frequently report that their children have a poor sense of time. Several studies looking at the perception of time mentioned a form of temporal myopia. The present study investigates the sense of time in children with ADHD. Twenty-two French-speaking Swiss children with ADHD and 22 controls between the ages of 6 and 13 years were tested using a conventional time knowledge questionnaire and two Piagetian time conservation tasks. Parents were asked to complete the “It’s about time” questionnaire. Better performance was observed in matched control group children than in children with ADHD on a conventional time knowledge questionnaire. For children under 10 years of age, the two Piagetian time conservation tasks were able to differentiate children with and without ADHD. Parents of ADHD children reported more frequently that their children had time-related difficulties in daily activities. This study suggests that children with ADHD take longer to develop several time-related abilities.

Cross-sectional evaluation of cognitive functioning in children, adolescents and young adults with ADHD

Attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood, albeit with changes in clinical symptoms throughout the life span. Although effect sizes of neuropsychological deficits in ADHD are well established, developmental approaches have rarely been explored and little is yet known about age-dependent changes in cognitive dysfunction from childhood to adulthood. In this cross-sectional study, 20 male children (8-12 years), 20 adolescents (13-16 years), and 20 adults (18-40 years) with ADHD and a matched control group were investigated using six experimental paradigms tapping into different domains of cognitive dysfunction. Subjects with ADHD were more delay-aversive and showed deficits in time discrimination and time reproduction, but they were not impaired in working memory, interference control or time production. Independent of age, the most robust group differences were observed with respect to delay aversion and time reproduction, pointing to persistent dysfunction in the mesolimbic reward circuitry and in the frontal-striatal-cerebellar timing system in subjects with ADHD. Across all tasks, effect sizes were lowest for adolescents with ADHD compared to age-matched controls. Developmental dissociations were found only for simple stimuli comparison, which was particularly impaired in ADHD children. Thus, in line with current multiple-pathway approaches to ADHD, our data suggest that deficits in different cognitive domains are persistent across the lifespan, albeit less pronounced in adolescents with ADHD.

Looking before you leap: a theory of motivated control of action

The acquisition of volitional control depends, in part, on developing the ability to countermand a planned action. Many tasks have been used to tap the efficiency of this process, but few studies have investigated how it may be modulated by participants’ motivation. Multiple mechanisms may be involved in the deliberate exercise of caution when incentives are provided. For example, control may involve modulation of the efficiency of the countermanding process, and/or inhibitory modulation of the impulse to go. One of the most commonly used paradigms to assess control of action is the Stop Signal Task, in which a primary Go stimulus is occasionally followed by a countermanding Stop signal, allowing a Stop Signal Reaction Time (SSRT) to be inferred as the outcome of a “horse race” between the go and countermanding processes. Here, we present a computational model in which high task motivation modulates proactive pre-stimulus inhibition of the go response. This allows responses to be calibrated so as to fall within a time-window that maximizes the probability of success, regardless of trial type, but does not decrease the observed SSRT. We report empirical support for the model from a sample of typically developing children, and discuss the broader implications for operationalizing measures of volitional control.

Inhibitory functioning across ADHD subtypes: recent findings, clinical implications, and future directions

Although growing consensus supports the role of deficient behavioral inhibition as a central feature of the combined subtype of ADHD (ADHD/C; Barkley 1997 Psychol Bull 121:65-94; Nigg 2001 Psychol Bull 127:571-598), little research has focused on how this finding generalizes to the primarily inattentive subtype (ADHD/I). This question holds particular relevance in light of recent work suggesting that ADHD/I might be better characterized as a disorder separate from ADHD/C (Diamond 2005 Dev Psychopathol 17:807-825; Milich et al. 2001 Clin Psychol Sci Pract 8:463-488). This article describes major findings in the area of inhibitory performance in ADHD and highlights recent research suggesting important areas of divergence between the subtypes. In particular, preliminary findings point to potential differences between the subtypes with respect to how children process important contextual information from the environment, such as preparatory cues that precede responses and rewarding or punishing feedback following behavior. These suggestive findings are discussed in the context of treatment implications, which could involve differential intervention approaches for each subtype targeted to the specific deficit profiles that characterize each group of children. Future research avenues aimed toward building a sound theoretical model of ADHD/I and a better understanding of its relation to ADHD/C are also presented. Specifically, investigators are encouraged to continue studying the complex interplay between inhibitory and attentional processes, as this area seems particularly promising in its ability to improve our understanding of the potentially distinct pathologies underlying the ADHD subtypes.

Time reproduction in children with ADHD and their nonaffected siblings

OBJECTIVE

Time reproduction is deficient in children with attention-deficit/hyperactivity disorder (ADHD). Whether this deficit is familial and could therefore serve as a candidate endophenotype has not been previously investigated. It is unknown whether timing deficits are also measurable in adolescent children with ADHD and nonaffected siblings.

METHOD

These issues were investigated in 226 children with ADHD, 188 nonaffected siblings, and 162 normal controls ages 5 to 19. Children participated in a visual and auditory time reproduction task. They reproduced interval lengths of 4, 8, 12, 16, and 20 seconds.

RESULTS

Children with ADHD and their nonaffected siblings were less precise than controls, particularly when task difficulty was systematically increased. Time reproduction skills were familial. Time reproduction deficits were more pronounced in younger children with ADHD than in older children. Children with ADHD could be clearly dissociated from control children until the age of 9. After this age, group differences were somewhat attenuated, but were still present. Differences between nonaffected siblings and controls were constant across the age range studied. Deficits were unaffected by modality.

CONCLUSIONS

Time reproduction may serve as a candidate endophenotype for ADHD, predominantly in younger children with (a genetic risk for) ADHD.

Effect of task difficulty on the functional anatomy of temporal processing

Temporal processing underlies many aspects of human perception, performance and cognition. The present study used fMRI to examine the functional neuroanatomy of a temporal discrimination task and to address two questions highlighted by previous studies: (1) the effect of task difficulty on neuronal activation and (2) the involvement of the dorsolateral prefrontal cortex (DLPFC) in timing. Twenty healthy subjects were scanned while either judging whether the second in a pair of tones was shorter or longer in duration than the standard tone or simply responding to the presentation of two identical tones as a control condition. Two levels of difficulty were studied. Activation during the less difficult condition was observed only in the cerebellum and superior temporal gyrus. As difficulty increased, additional activation of the supplementary motor area, insula/operculum, DLPFC, thalamus and striatum was observed. These results suggest the cerebellum plays a critical role in timing, particularly in gross temporal discrimination. These results also suggest that recruitment of frontal and striatal regions during timing tasks is load-dependent. Additionally, robust activation of the dorsolateral prefrontal cortex under conditions of minimal working memory involvement supports the specific involvement of this region in temporal processing rather than a more general involvement in working memory.