Evidence for a pure time perception deficit in children with ADHD

Neurodiversity and cognitive load in online learning: A focus group study

It is widely accepted that cognitive load plays a crucial role in online learning. However, despite neurodevelopmental conditions being the largest category of qualifying disabilities in education, and the rise of online learning, there is little understanding of the factors impacting cognitive load in online learning for neurodivergent students and how these factors differ from those affecting neurotypical students. This study used qualitative comparison groups with neurotypical and neurodivergent students to examine their experiences of cognitive load in online learning. A sample of 26 university students (14 neurotypical and 12 neurodivergent) participated in focus group discussions. While neurodivergent students reported many similar experiences of cognitive load in online learning compared to their neurotypical peers-such as confusion in navigating the content and technical issues-some difficulties were more present for neurodivergent students-such as transcripts including mistakes and inaccessible content presentation-creating additional barriers in effectively engaging with the educational content. The results suggest that neurotypical and neurodivergent students experience similar challenges, albeit to differing degrees of intensity, and that more research is needed to explore the relationship between neurodiversity and cognitive load in online learning.

Measuring the perception and metacognition of time

The ability of humans to identify and reproduce short time intervals (in the region of a second) may be affected by many factors ranging from the gender and personality of the individual observer, through the attentional state, to the precise spatiotemporal structure of the stimulus. The relative roles of these very different factors are a challenge to describe and define; several methodological approaches have been used to achieve this to varying degrees of success. Here we describe and model the results of a paradigm affording not only a first-order measurement of the perceived duration of an interval but also a second-order metacognitive judgement of perceived time. This approach, we argue, expands the form of the data generally collected in duration-judgements and allows more detailed comparison of psychophysical behavior to the underlying theory. We also describe a hierarchical Bayesian measurement model that performs a quantitative analysis of the trial-by-trial data calculating the variability of the temporal estimates and the metacognitive judgments allowing direct comparison between an actual and an ideal observer. We fit the model to data collected for judgements of 750 ms (bisecting 1500 ms) and 1500 ms (bisecting 3000 ms) intervals across three stimulus modalities (visual, audio, and audiovisual). This enhanced form of data on a given interval judgement and the ability to track its progression on a trial-by-trial basis offers a way of looking at the different roles that subject-based, task-based and stimulus-based factors have on the perception of time.

Memory deficits and hippocampal cytokine expression in a rat model of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a complex behavioral disorder characterized by hyperactivity, impulsivity, inattention, and deficits in working memory and time perception. While animal models have advanced our neurobiological understanding of this condition, there are limited and inconsistent data on working and elapsed time memory function. Inflammatory signaling has been identified as a key factor in memory and cognitive impairments, but its role in ADHD remains unclear. Additionally, the disproportionate investigation of male subjects in ADHD research has contributed to a poor understanding of the disorder in females. This study sought to investigate the potential connections between memory, neuroimmunology, and ADHD in both male and female animals. Specifically, we utilized the spontaneously hypertensive rat (SHR), one of the most extensively studied animal models of ADHD. Compared to their control, the Wistar-Kyoto (WKY) rat, male SHR are reported to exhibit several behavioral phenotypes associated with ADHD, including hyperactivity, impulsivity, and poor sustained attention, along with impairments in learning and memory. As the hippocampus is a key brain region for learning and memory, we examined the behavior of male and female SHR and WKY rats in two hippocampal-dependent memory tasks. Our findings revealed that SHR have delay-dependent working memory deficits that were similar to, albeit less severe than, those seen in hippocampal-lesioned rats. We also observed impairments in elapsed time processing in female SHR, particularly in the discrimination of longer time durations. To investigate the impact of inflammatory signaling on memory in these rats, we analyzed the levels of several cytokines in the dorsal and ventral hippocampus of SHR and WKY. Although we found some sex and genotype differences, concentrations were generally similar between groups. Taken together, our results indicate that SHR exhibit deficits in spatial working memory and memory for elapsed time, as well as some differences in hippocampal cytokine concentrations. These findings contribute to a better understanding of the neurobiological basis of ADHD in both sexes and may inform future research aimed at developing effective treatments for the disorder. Nonetheless, the potential mediating role of neuroinflammation in the memory symptomatology of SHR requires further investigation.

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.

Differences between subclinical attention-deficit/hyperactivity and autistic traits in default mode, salience, and frontoparietal network connectivities in young adult Japanese

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are associated with attentional impairments, with both commonalities and differences in the nature of their attention deficits. This study aimed to investigate the neural correlates of ADHD and ASD traits in healthy individuals, focusing on the functional connectivity (FC) of attention-related large-scale brain networks (LSBNs). The participants were 61 healthy individuals (30 men; age, 21.9 ± 1.9 years). The Adult ADHD Self-Report Scale (ASRS) and Autism Spectrum Quotient (AQ) were administered as indicators of ADHD and ASD traits, respectively. Performance in the continuous performance test (CPT) was used as a behavioural measure of sustained attentional function. Functional magnetic resonance imaging scans were performed during the resting state (Rest) and auditory oddball task (Odd). Considering the critical role in attention processing, we focused our analyses on the default mode (DMN), frontoparietal (FPN), and salience (SN) networks. Region of interest (ROI)-to-ROI analyses (false discovery rate < 0.05) were performed to determine relationships between psychological measures with within-network FC (DMN, FPN, and SN) as well as with between-network FC (DMN-FPN, DMN-SN, and FPN-SN). ASRS scores, but not AQ scores, were correlated with less frequent commission errors and shorter reaction times in the CPT. During Odd, significant positive correlations with ASRS were demonstrated in multiple FCs within DMN, while significant positive correlations with AQ were demonstrated in multiple FCs within FPN. AQs were negatively correlated with FPN-SN FCs. During Rest, AQs were negatively and positively correlated with one FC within the SN and multiple FCs between the DMN and SN, respectively. These findings of the ROI-to-ROI analysis were only partially replicated in a split-half replication analysis, a replication analysis with open-access data sets, and a replication analysis with a structure-based atlas. The better CPT performance by individuals with subclinical ADHD traits suggests positive effects of these traits on sustained attention. Differential associations between LSBN FCs and ASD/ADHD traits corroborate the notion of differences in sustained and selective attention between clinical ADHD and ASD.

The experiences and the meaning of using MyTime in the preschool context from the perspective of children in need of special support, 5-6 years of age

BACKGROUND

Children in need of special support often display delays in time processing ability, affecting everyday functioning. MyTime is an intervention programme for systematic training of time processing ability. To support preschool children's development of time processing ability and everyday functioning, it is necessary to include their perspectives of the MyTime intervention programme. A previous study shows that MyTime is feasible with children in the preschool setting and shows positive effects on time processing ability for older children in special schools. Yet, there is a lack of knowledge regarding how preschool children experience the intervention programme and how they understand its meaning. The aim of this study was to explore the experiences and the meaning of using MyTime from the perspective of children with informal needs of special support (INS) 5-6 years of age in the preschool context.

METHODS

To explore the children's perspectives, video-recorded interviews with 21 children were analysed hermeneutically. To facilitate the interview situation with the children in need of special support, the Talking Mats© was used. Both body and spoken languages were analysed.

RESULTS

The results reveal children as active participants, willing to share their experiences of using the MyTime intervention in the preschool context. The conceptualization of the children's experiences and expressions uncovers their meaning of using the MyTime intervention as to know and to understand time by doing.

CONCLUSIONS

When children are given the opportunity to use concrete tools to understand and measure time, they experience themselves as active participants involved and engaged in the intervention. They reveal meaningful experiences to be able to manage time that facilitate their everyday functioning and participation in the preschool context.

Time processing in neurological and psychiatric conditions

A central question in understanding cognition and pathology-related cognitive changes is how we process time. However, time processing difficulties across several neurological and psychiatric conditions remain seldom investigated. The aim of this review is to develop a unifying taxonomy of time processing, and a neuropsychological perspective on temporal difficulties. Four main temporal judgments are discussed: duration processing, simultaneity and synchrony, passage of time, and mental time travel. We present an integrated theoretical framework of timing difficulties across psychiatric and neurological conditions based on selected patient populations. This framework provides new mechanistic insights on both (a) the processes involved in each temporal judgement, and (b) temporal difficulties across pathologies. By identifying underlying transdiagnostic time-processing mechanisms, this framework opens fruitful avenues for future research.

The effect of methylphenidate on pain perception thresholds in children with attention deficit hyperactivity disorder

BACKGROUND

Pain perception is important in children with attention deficit hyperactivity disorder (ADHD) since they are more likely to experience painful events due to increased accident rates. The aim of this study is to contribute to the literature concerning the relationship between ADHD diagnosis, methylphenidate (MPH) therapy, and pain thresholds, since findings regarding the change in pain perception in children with ADHD are scarce and inconsistent.

METHODS

Children aged 8-13 years constituted both the ADHD group (n = 82) and the healthy controls (n = 41). The ADHD group was divided into two subgroups, ADHD without MPH (not treated pharmacologically) and ADHD with MPH (treated pharmacologically for at least three-months). The Conners' Parent Rating Scale-Revised: Short Form was employed to assess ADHD, a visual analog scale was applied to evaluate chronic pain severity, and a manual pressure algometer was used to assess pain thresholds.

RESULT

Children with ADHD had lower pain thresholds than the healthy controls (P < 0.05). However, lower regional pain thresholds were observed in the ADHD group without MPH compared to both the healthy control and ADHD with MPH groups. Although pain thresholds in the ADHD with MPH group were regionally lower than in the healthy controls, low pain thresholds were found in fewer regions compared to the ADHD without MPH group.

CONCLUSIONS

Children with ADHD are more sensitive to pain sensation, and MPH may help normalize these individuals' pain experiences by raising pain thresholds. Families and clinicians must be aware of situations that may cause pain in children with ADHD. In addition, these children's low threshold for pain may lead them to experience it more intensely.

Misjudgement of One's Own Performance? Exploring Attention Deficit (Hyperactivity) Disorder (ADHD) and Individual Difference in Complex Music and Foreign Language Perception

In previous research, we detected that children and adolescents who were diagnosed with ADHD showed deficits in both complex auditory processing of musical stimuli and in musical performance when compared to controls. In this study, we were interested in whether we could detect similar or distinct findings when we use foreign speech perception tasks. Therefore, we recruited musically naïve participants (n = 25), music-educated participants (n = 25) and participants diagnosed with ADHD (n = 25) who were assessed for their short-term memory (STM) capacity and the ability to discriminate music and speech stimuli and we collected self-ratings of the participants' music and language performances. As expected, we found that young adults with ADHD show deficits in the perception of complex music and difficult speech perception stimuli. We also found that STM capacity was not impaired in young adults with ADHD and may not persist into young adulthood. In addition, subjective self-estimation about the participants' language and music performances revealed that the ADHD group overestimated their performance competence relatively compared to both control groups. As a result, the findings of our study suggest that individuals diagnosed with ADHD require a special training program that not only focuses on improving performance in perceptual skills of music and language but also requires metacognitive training to develop realistic self-assessment skills.

Rhythm-based assessment and training for children with attention deficit hyperactivity disorder (ADHD): a feasibility study protocol

Background

The timing-related deficits in individuals with attention deficit hyperactivity disorder (ADHD) contribute to the symptom-related difficulties and cognitive impairments. Current assessment and training measurement only target specific aspects of the timing ability, highlighting the need for more advanced tools to address timing deficits in ADHD. The aim of this study is to develop and validate a rhythm-based assessment and training (RAT) program, which intends to provide a comprehensive understanding of and enhancement to the time-related abilities of children with ADHD, thereby demonstrating its clinical efficacy.

Methods

We will use randomized crossover trials in this study, with participants being randomly assigned to either start with the RAT and then proceed to cognitive training or start with cognitive training and then proceed to the RAT. Both groups will undergo pre- and post- evaluations. The evaluation will be administered immediately before and after the 4-week training period using diagnostic questionnaires, cognitive evaluation tools, and resting electroencephalography (EEG) measurements. Notably, EEG measurements will be conducted concurrently with the RAT evaluations.

Discussion

This study develops and evaluates the feasibility and effectiveness of a RAT while using EEG measurements to elucidate the underlying therapeutic mechanism of auditory rhythm at varying levels of complexity. The study will investigate the potential of RAT as a supplementary or alternative approach for managing ADHD. The multifaceted data collected will yield valuable insights to customize training agendas based on individual developmental stages and prognoses.

Can disorders of subjective time inform the differential diagnosis of psychiatric disorders? A transdiagnostic taxonomy of time

AIM

Time is a core aspect of psychopathology with potential for clinical use and early intervention. Temporal experience, perception, judgement and processing are distorted in various psychiatric disorders such as mood (depression and mania), anxiety, autistic, impulse-control, dissociative and attention-deficit/hyperactivity disorders. Can these disorders of time be used as early diagnostic or predictive markers? To answer this question, we develop a Transdiagnostic Taxonomy of (disordered) Time (TTT) that maps on to the symptomatological, phenomenal, perceptual and functional descriptions of each underlying disorder in a 2 × 2 × 2 state space. Temporal distortions may precede functional decline, and so assist efforts at early detection and intervention in at-risk groups.

METHOD

Firstly, this article integrates a psychological model of how time is processed with a subjective or phenomenological model of how time is experienced or perceived. Secondly, the integrated combined model of time is then used to heuristically map major psychiatric disorders on to the basic elements of temporal flow and integration.

RESULTS

The TTT systematically describes the basic temporal nature of eight diagnostic categories of psychiatric illness. It differentiates between diagnoses primarily associated with distorted "macro-level" phenomenal temporal experiences (i.e. anxiety, dissociation/PTSD, depression, and mania) from those primarily related to distorted 'micro-level' temporal processing (i.e. psychotic, impulse-control, autistic and attention-deficit/hyperactivity disorders).

CONCLUSIONS

The TTT allows differential diagnostic classification of various psychiatric disorders in terms of a possible underlying time disorder, making it useful for future diagnostic and predictive purposes using novel techniques of temporal processing, time perception, passage of time, and time perspective.

Late prenatal immune activation in mice induces transgenerational effects via the maternal and paternal lineages

Prenatal exposure to infectious or noninfectious immune activation is an environmental risk factor for neurodevelopmental disorders and mental illnesses. Recent research using animal models suggests that maternal immune activation (MIA) during early to middle stages of pregnancy can induce transgenerational effects on brain and behavior, likely via inducing stable epigenetic modifications across generations. Using a mouse model of viral-like MIA, which is based on gestational treatment with poly(I:C), the present study explored whether transgenerational effects can also emerge when MIA occurs in late pregnancy. Our findings demonstrate that the direct descendants born to poly(I:C)-treated mothers display deficits in temporal order memory, which are similarly present in second- and third-generation offspring. These transgenerational effects were mediated via both the maternal and paternal lineages and were accompanied by transient changes in maternal care. In addition to the cognitive effects, late prenatal immune activation induced generation-spanning effects on the prefrontal expression of gamma-aminobutyric acid (GABA)ergic genes, including parvalbumin and distinct alpha-subunits of the GABAA receptor. Together, our results suggest that MIA in late pregnancy has the potential to affect cognitive functions and prefrontal gene expression patterns in multiple generations, highlighting its role in shaping disease risk across generations.

Global-Local Processing in ADHD Is Not Limited to the Visuospatial Domain: Novel Evidence From the Auditory Domain

OBJECTIVE

Global-local visuospatial processing has been widely investigated in both healthy and clinical populations. Recent studies indicated that individuals with ADHD lack a global processing bias. However, the extant literature regarding global-local processing style focuses solely on the visual modality.

METHODS

ADHD (N = 21) and typically developed (TD) controls (N = 24) underwent an auditory global-local task, in which they had to decide whether the melody is ascending or descending in global or local conditions.

RESULTS

TD controls exhibited a classic global processing bias in the auditory task. The ADHD group exhibited no global processing bias, indicating similar processing for global and local dimensions, implying that individuals with ADHD are distracted by incongruent information in global and local conditions similarly, in both visual and auditory tasks.

CONCLUSION

A lack of global processing bias in ADHD is not limited to the visuospatial modality and likely reflects a broader and more general processing style.

Time Perception in Adult ADHD: Findings from a Decade-A Review

Time perception is impaired in adult ADHD. Since the term time perception subsumes different constructs, including time estimation, time reproduction, time production, and duration discrimination, it remains open whether certain domains are more affected than other domains in adult ADHD. The aim of this explorative review is to present the current state of research on time perception in adult ADHD by analysing studies from the past 10 years. A review of the literature addressing adult ADHD time perception, time estimation, and time reproduction was performed. The search strategy was conducted by using the databases "PubMed", "Medline", and "PSYNDEX". The results of the present review indicate that the number of studies on time perception in adult ADHD is very scarce. Moreover, the main investigated domains of time perception in the past decade were time estimation, time reproduction and time management. Whereas some of the found studies were able to demonstrate a distinct deficit in time estimation, time reproduction and time management other studies were unable to demonstrate a clear association between ADHD and time estimation and time reproduction deficits. However, the diagnostic protocols, study design, and methodology varied between studies. Further studies on time estimation and time reproduction need to be carried out.

Weak impacts of neuropsychological measures on symptoms of attention deficit hyperactivity disorder in university students

OBJECTIVE

Attention deficit hyperactivity disorder (ADHD) is involved in broad neuropsychological domains, including response inhibition, timing, delay aversion, sustained attention, and working memory. This study aimed to examine the relationship between ADHD symptoms and neuropsychological measures in university students.

METHODS

A total of 167 graduate and undergraduate students participated in the study. Neuropsychological characteristics were comprehensively assessed using stop signal, delay discounting, time discrimination, sensorimotor synchronization, continuous performance, and digit span tasks. ADHD symptoms were assessed using the Japanese version of Conners' ADHD Rating Scale.

RESULTS

ADHD symptoms were significantly correlated with some neuropsychological measures, such as the false alarm rate in the continuous performance task; however, these correlations were not strong. In the multiple regression analyses, models including neuropsychological measures were significantly associated with ADHD symptoms, but the coefficients of determination ranged from 0.06 to 0.08. Thus, most of the variance in ADHD symptoms was not explained by neuropsychological measures.

CONCLUSION

These findings suggest that the impact of each neuropsychological measure on ADHD symptoms was weak in university students, and ADHD symptoms cannot be explained by neuropsychological characteristics, which are currently considered core characteristics of ADHD. In addition, ADHD symptoms assessed by self-rating questionnaire in the non-clinical sample might not reflect the degree of real ADHD severity.

Open assessment of the therapeutic and rate-dependent effects of brain balance center® and interactive metronome® exercises on children with attention deficit hyperactivity disorder

The aim of this open study was to delineate domains of benefit and effect size measures to design an appropriately powered randomized control trial to assess the efficacy of Brain Balance^@ exercises and Interactive Metronome^@ training (BB/IM) on ADHD symptoms in children. Participants underwent an extensive 15-week, 5 time per week, at-home training program. Results were assessed in 16 youths with ADHD (14M/2F, 10.8±1.7 years) who completed the program and compared to 8 typically developing controls (4M/F4, 11.0±1.8 years). BB/IM was associated with a significant reduction of 8.3 and 8.2 points on the Conner's Parent Rating Scale - Revised and the ADHD Rating Scale - IV. BB/IM was not associated with improvement on the Quotient ADHD System but with rate-dependent effects on hyperactivity and attention that were similar to previously reported effects of low dose methylphenidate. Both therapeutic and rate-dependent effects were observed on the Tower of London. The study provides information that could be used to design a randomized control trial, which is required for proof of efficacy. A key limitation is that 59% of the 39 enrolled participants with ADHD dropped out of the study and a new study should include multiple ratings during the course of treatment.

Contraction bias in temporal estimation

When asked to compare the perceptual features of two serially presented objects, participants are often biased to over- or under-estimate the difference in magnitude between the stimuli. Overestimation occurs consistently when a) the two stimuli are relatively small in magnitude and the first stimulus is larger in magnitude than the second; or b) the two stimuli are relatively large in magnitude and the first stimulus is smaller in magnitude than the second; underestimation consistently occurs in the complementary cases. This systematic perceptual bias, known as the contraction bias, was demonstrated for a multitude of perceptual features and in various modalities. Here, we tested whether estimation of time-duration is affected by the contraction bias. In each trial of three experiments (n = 20 each), participants compared the duration of two visually presented stimuli. Findings revealed over- and under-estimation effects as predicted by the contraction bias. Here, we discuss this asymmetry and describe how these findings can be explained via a Bayesian inference framework.

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).

Training the brain to time: the effect of neurofeedback of SMR-Beta1 rhythm on time perception in healthy adults

The timing ability plays an important role in everyday activities and is influenced by several factors such as the attention and arousal levels of the individuals. The effects of these factors on time perception have been interpreted through psychological models of time, including Attentional Gate Model (AGM). On the other hand, research has indicated that neurofeedback (NFB) training improves attention and increases arousal levels in the clinical and healthy population. Regarding the link between attentional processing and arousal levels and NFB and their relation to time perception, this study is a pilot demonstration of the influence of SMR-Beta1 (12-18 Hz) NFB training on time production and reproduction performance in healthy adults. To this end, 12 (9 female and 3 males; M = 26.3, SD = 3.8) and 12 participants (7 female and 5 males; M = 26.9, SD = 3.1) were randomly assigned into the experimental (with SMR-Beta1 NFB) and control groups (without any NFB training), respectively. The experimental group underwent intensive 10 sessions (3 days a week) of the 12-18 Hz up-training. Time production and reproduction performance were assessed pre and post NFB training for all participants. Three-way mixed ANOVA was carried out on T-corrected scores of reproduction and production tasks. Correlation analysis was also performed between SMR-Beta1 and time perception. While NFB training significantly influenced time production (P < 0.01), no such effect was observed for the time reproduction task. The results of the study are finally discussed within the frameworks of AGM, dual-process and cognitive aspects of time perception. Overall, our results contribute to disentangling the underlying mechanisms of temporal performance in healthy individuals.

Neuromorphological and Neurofunctional Correlates of ADHD and ADD in the Auditory Cortex of Adults

Attention deficit (hyperactivity) disorder (AD(H)D) is one of the most common neurodevelopmental disorders in children with up to 60% probability of prevailing into adulthood. AD(H)D has far-fetching negative impacts on various areas of life. Until today, no observer-independent diagnostic biomarker is available for AD(H)D, however recent research found evidence that AD(H)D is reflected in auditory dysfunctions. Furthermore, the official diagnostic classification systems, being mainly the ICD-10 in Europe and the DSM-5 in the United States, are not entirely consistent. The neuro-auditory profiles of 82 adults (27 ADHD, 30 ADD, 25 controls) were measured via structural magnetic resonance imaging (MRI) and magnetoencephalography (MEG) to determine gray matter volumes and activity of auditory subareas [Heschl’s gyrus (HG) and planum temporale (PT)]. All three groups (ADHD, ADD, and controls) revealed distinct neuro-auditory profiles. In the left hemisphere, both ADHD and ADD showed reduced gray matter volumes of the left HG, resulting in diminished left HG/PT ratios. In the right hemisphere, subjects with ADHD were characterized by lower right HG/PT ratios and ADD by a similar right HG/PT ratio compared to controls. Controls and ADD had well-balanced hemispheric response patterns, ADHD a left-right asynchrony. With this study, we present the structural and functional differences in the auditory cortex of adult patients with AD(H)D.

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.

Musical Performance in Adolescents with ADHD, ADD and Dyslexia—Behavioral and Neurophysiological Aspects

Research has shown that dyslexia and attention deficit (hyperactivity) disorder (AD(H)D) are characterized by specific neuroanatomical and neurofunctional differences in the auditory cortex. These neurofunctional characteristics in children with ADHD, ADD and dyslexia are linked to distinct differences in music perception. Group-specific differences in the musical performance of patients with ADHD, ADD and dyslexia have not been investigated in detail so far. We investigated the musical performance and neurophysiological correlates of 21 adolescents with dyslexia, 19 with ADHD, 28 with ADD and 28 age-matched, unaffected controls using a music performance assessment scale and magnetoencephalography (MEG). Musical experts independently assessed pitch and rhythmic accuracy, intonation, improvisation skills and musical expression. Compared to dyslexic adolescents, controls as well as adolescents with ADHD and ADD performed better in rhythmic reproduction, rhythmic improvisation and musical expression. Controls were significantly better in rhythmic reproduction than adolescents with ADD and scored higher in rhythmic and pitch improvisation than adolescents with ADHD. Adolescents with ADD and controls scored better in pitch reproduction than dyslexic adolescents. In pitch improvisation, the ADD group performed better than the ADHD group, and controls scored better than dyslexic adolescents. Discriminant analysis revealed that rhythmic improvisation and musical expression discriminate the dyslexic group from controls and adolescents with ADHD and ADD. A second discriminant analysis based on MEG variables showed that absolute P1 latency asynchrony |R-L| distinguishes the control group from the disorder groups best, while P1 and N1 latencies averaged across hemispheres separate the control, ADD and ADHD groups from the dyslexic group. Furthermore, rhythmic improvisation was negatively correlated with auditory-evoked P1 and N1 latencies, pointing in the following direction: the earlier the P1 and N1 latencies (mean), the better the rhythmic improvisation. These findings provide novel insight into the differences between music processing and performance in adolescents with and without neurodevelopmental disorders. A better understanding of these differences may help to develop tailored preventions or therapeutic interventions.

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.

Feasibility of an intervention to facilitate time and everyday functioning in preschoolers

BACKGROUND

Children in need of special support (INS) often display delays in time-processing ability (TPA) affecting everyday functioning. Typically developing (TD) children are not yet mature to use the information of a clock.

AIM

To investigate the feasibility of an intervention program, MyTime, to facilitate TPA and everyday functioning in pre-school children, including the subjective experiences of pre-school staff and the children.

MATERIALS AND METHODS

The intervention sample consisted of 20 children: 4 INS and 16 TD. Intervention was given daily in 8 weeks with MyTime in the pre-school environment. Data collection procedures were evaluated and children were assessed for TPA pre- and post intervention. Everyday functioning were assessed by teachers, parents and children. Experiences of the intervention were assessed by a group interview with teachers and a Talking Mats© evaluation with children.

RESULTS

MyTime worked well in pre-school and indicated an increase in the children's TPA and everyday functioning. The program was perceived simple to use by teachers and children highlighted the importance to understand the duration of time.

CONCLUSION

The program MyTime was found to be feasible in the pre-school environment. Significance: The assessment and program design can be used to investigate intervention effectiveness in a randomised study.

Do Inattention/Hyperactivity and Motor Timing Predict Children's Virtual Road-Crossing Performance?

OBJECTIVE

The goal of this investigation was to examine how individual variation in inattention and hyperactivity is related to motor timing difficulties and whether children's performance on simple laboratory timing tasks is related to their performance on a virtual road-crossing task using a head-mounted virtual reality display system.

METHODS

Participants were a community sample of 92 9- to 11-year-old children. Parents completed questionnaires assessing their child's inattention and hyperactivity. Children completed two simple motor timing tasks (duration discrimination and synchronization-continuation) and crossed roads with continuous traffic in a head-mounted VR system.

RESULTS

Higher parent-reported inattention and hyperactivity predicted poorer performance in the duration discrimination and synchronization-continuation tasks, but not the virtual pedestrian road-crossing task. Children with higher tap onset asynchrony in the synchronization-continuation task had poorer timing of entry into the gap in the virtual pedestrian road-crossing task.

CONCLUSIONS

The findings provide further evidence that timing deficits are associated with individual differences in inattention and hyperactivity and that timing difficulties may be a risk factor for functional difficulties in everyday life.

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.

Time Perception is a Focal Symptom of Attention-Deficit/Hyperactivity Disorder in Adults

Attention-Deficit/Hyperactivity Disorder (ADHD) is classically associated with symptoms that include inattentiveness, hyperactivity, and impulsivity together with a variety of other observable externalized symptoms. ADHD has also been associated with specific internalized cognitive symptoms, including restlessness and emotional impulsivity. This disorder has been recognized as a lifelong condition and can be recognized by a variety of unique cognitive phenomena. In addition to the frequently ignored affective symptoms exhibited by individuals diagnosed with ADHD, problems with time perception have been noted, although these are considered to be secondary issues. Temporal shifts in cognitive processing, however, may be at the very root of ADHD-related symptoms, given the importance of coordinated signal translation in the construction of behavior. In this review, we consider the evidence that suggests that differences in time perception are a central symptom in adults with ADHD. Some of these differences include the feeling of time moving faster, which causes difficulties in prospective time tasks and inaccuracies in time estimation tasks. We analyze the literature from both neurological and psychological perspectives and include an assessment of tools that can be administered via computer to measure time perception. We also suggest several computer-based methods that might be used to address problems with time perception in both children and adults. We strongly recommend the inclusion of ADHD symptoms associated with time perception in the next revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM) published by the American Psychiatric Association.

Movement-Related Potentials Associated with Motor Timing Errors as Determined by Internally Cued Movement Onset

OBJECTIVE

Accurate motor timing is critical for efficient motor control of behaviors; however, the effect of motor timing abilities on movement-related neural activities has rarely been investigated. The current study aimed to examine the electrophysiological correlates of motor timing errors.

METHODS

Twenty-two healthy volunteers performed motor timing tasks while their electroencephalographic and electromyographic (EMG) activities were simultaneously recorded. The average of intervals between consecutive EMG onsets was calculated separately for each subject. Motor timing error was calculated as an absolute discrepancy value between the subjects' produced and given time interval. A movement-related potential (MRP) analysis was conducted using readings from Cz electrode.

RESULTS

Motor timing errors and MRPs were significantly correlated. Our principal finding was that only Bereitschaftpotential (BP) and motor potential (MP), not movement monitoring potential, were significantly attenuated in individuals with motor timing errors. Motor timing error had a significant effect on the amplitude of the late BP and MP.

CONCLUSION

The findings provide electrophysiological evidence that motor timing errors correlate with the neural processes involved in the generation of self-initiated voluntary movement. Alterations in MRPs reflect central motor control processes and may be indicative of motor timing deficits.

Development of Young Children's Time Perception: Effect of Age and Emotional Localization

Time perception is a fundamental aspect of young children’s daily lives and is affected by a number of factors. The present study aimed to investigate the precise developmental course of young children’s time perception from 3 to 5 years old and the effects of emotion localization on their time perception ability. A total of 120 children were tested using an adapted time perception task with black squares (Experiment 1) and emotional facial expressions (Experiment 2). Results suggested that children’s time perception was influenced by stimulus duration and improved gradually with increasing age. Both accuracy and reaction time were affected by the presentation sequence of emotional faces, indicating an effect of emotion localization. To summarize, young children’s time perception showed effects of age, stimulus duration, and emotion localization.

Impaired auditory and visual time reproduction in adult patients with attention deficit-hyperactivity disorder

Objective: Although impaired time perception is associated with significant disturbance in the everyday functioning of adult patients with Attention Deficit-Hyperactivity Disorder (ADHD), it is not very well studied. The present study aimed to evaluate both visual and auditory time reproduction (TR) by using eight time intervals in adult ADHD patients compared to healthy controls (HC).Method: Wechsler Adult Intelligence Scale-R (WAIS-R), Adult Attention Deficit-Hyperactivity Disorder Self-Report Scale (ASRS), Wender Utah Rating Scale (WURS), Hyperfocusing Scale (HS), Beck Depression Inventory (BDI) and a 2-back task were administered to participants. In TR tasks, participants reproduced the same duration of the auditory/visual stimulus by pressing a key and absolute discrepancy scores (ADS) were calculated. A 2 (Group) x 2 (Task Modality) x 8 (Time Interval: 500, 1000, 2000, 4000, 6000, 8000, 12000 and 16000 msec) mixed-design ANOVA was performed.Results: All clinical scores of ADHD group were higher than HC (p < .001) while WAIS-R and 2-back performances of the groups were similar. Mixed-design ANOVA yielded significant Group and Time Interval main effects as well as a Group X Time Interval effect (both p < .001). ADHD patients had larger ADS than HC and as time intervals increased, error levels increased. Errors for time intervals >8000 msec were more prominent in patients. For both TR tasks, ASRS-hyperactivity/impulsivity scores were the main predictor of ADS in the linear regression analysis, while ASRS-attention deficit and HS scores were excluded.Conclusion: Results of the present study indicate significant TR impairment in adult ADHD regardless of task modality (visual or auditory), depressive symptoms and working memory performances. Longer time intervals in TR tasks differentiated patients better and TR impairment was associated with hyperactivity/impulsivity. These findings should be replicated in larger samples and underlying neurobiological components of impaired TR need to be examined in future research.

Dopamine Precursor Depletion in Healthy Volunteers Impairs Processing of Duration but Not Temporal Order

Studies in animals and humans have implicated the neurotransmitter dopamine in duration processing. However, very few studies have examined dopamine's involvement in other forms of temporal processing such as temporal order judgments. In a randomized within-subject placebo-controlled design, we used acute phenylalanine/tyrosine depletion (APTD) to reduce availability of the dopamine precursors tyrosine and phenylalanine in healthy human volunteers. As compared to a nutritionally balanced drink, APTD significantly impaired the ability to accurately reproduce interval duration in a temporal reproduction task. In addition, and confirming previous findings, the direction of error differed as a function of individual differences in underlying dopamine function. Specifically, APTD caused participants with low baseline dopamine precursor availability to overestimate the elapse of time, whereas those with high dopamine availability underestimated time. In contrast to these effects on duration processing, there were no significant effects of APTD on the accuracy of discriminating the temporal order of visual stimuli. This pattern of results does not simply represent an effect of APTD on motor, rather than perceptual, measures of timing because APTD had no effect on participants' ability to use temporal cues to speed RT. Our results demonstrate, for the first time in healthy volunteers, a dopaminergic dissociation in judging metrical (duration) versus ordinal (temporal order) aspects of time.

Disorder-specific alterations of tactile sensitivity in neurodevelopmental disorders

Alterations of tactile processing have long been identified in autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). However, the extent to which these alterations are disorder-specific, rather than disorder-general, and how they relate to the core symptoms of each disorder, remains unclear. We measured and compared tactile detection, discrimination, and order judgment thresholds between a large sample of children with ASD, ADHD, ASD + ADHD combined and typically developing controls. The pattern of results suggested that while difficulties with tactile detection and order judgement were more common in children with ADHD, difficulties with tactile discrimination were more common in children with ASD. Interestingly, in our subsequent correlation analyses between tactile perception and disorder-specific clinical symptoms, tactile detection and order judgment correlated exclusively with the core symptoms of ADHD, while tactile discrimination correlated exclusively with the symptoms of ASD. When taken together, these results suggest that disorder-specific alterations of lower-level sensory processes exist and are specifically related to higher-level clinical symptoms of each disorder.

Timing behavior in genetic murine models of neurological and psychiatric diseases

How timing behavior is altered in different neurodevelopmental and neurodegenerative disorders is a contemporary research question. Genetic murine models (GMM) that offer high construct validity also serve as useful tools to investigate this question. But the literature on timing behavior of different GMMs largely remains to be consolidated. The current paper addresses this gap by reviewing studies that have been conducted with GMMs of neurodevelopmental (e.g. ADHD, schizophrenia, autism spectrum disorder), neurodegenerative disorders (e.g., Alzheimer's disease, Huntington's disease) as well as circadian and other mutant lines. The review focuses on those studies that specifically utilized the peak interval procedure to improve the comparability of findings both within and between different disease models. The reviewed studies revealed timing deficits that are characteristic of different disorders. Specifically, Huntington's disease models had weaker temporal control over the termination of their anticipatory responses, Alzheimer's disease models had earlier timed responses, schizophrenia models had weaker temporal control, circadian mutants had shifted timed responses consistent with shifts in the circadian periods. The differences in timing behavior were less consistent for other conditions such as attention deficit and hyperactivity disorder and mutations related to intellectual disability. We discuss the implications of these findings for the neural basis of an internal stopwatch. Finally, we make methodological recommendations for future research for improving the comparability of the timing behavior across different murine models.

A novel approach to intra-individual performance variability in ADHD

Patients with attention deficit/(hyperactivity) disorder (AD(H)D) show increased intra-individual variability (IIV) in behavioral performance. This likely reflects dopaminergic deficiencies. However, the precise performance profile across time and the pattern of fluctuations within it have not yet been considered, partly due to insufficient methods. Yet, such an analysis may yield important theory-based implications for clinical practice. Thus, in a case-control cross-sectional study, we introduce a new method to investigate performance fluctuations in patients with ADD (n = 76) and ADHD (n = 67) compared to healthy controls (n = 45) in a time estimation task. In addition, we also evaluate the effects of methylphenidate (MPH) treatment on this performance pattern in 29 patients with AD(H)D. Trial-by-trial differences in performance between healthy controls and patients with AD(H)D do not persist continuously over longer time periods. Periods during which no differences in performance between healthy controls and patients occur alternate with periods in which such differences are present. AD(H)D subtype and surprisingly also medication status does not affect this pattern. The presented findings likely reflect (phasic) deficiencies of the dopaminergic system in patients with AD(H)D which are not sufficiently ameliorated by first-line pharmacological treatment. The presented findings carry important clinical and scientific implications.

Time knowledge impairments in children with ADHD

BACKGROUND

A large number of studies have shown time perception impairment and reaction time (RT) variability in children with attention deficit hyperactivity disorder (ADHD), and have discussed the causes of such difficulties. However, very few studies have investigated time knowledge (i.e., the correct representation and use of time units) in children with ADHD.

METHODS

We evaluated time knowledge in 33 children with ADHD, aged 8-12 years, who had consulted a reference center for learning disabilities in Paris, matched for age and gender with 33 typically developing (TD) children. We used a simple questionnaire-based survey and neuropsychological tests for cognitive and attentional skills.

RESULTS

The acquisition of time knowledge was delayed in children with ADHD compared with TD children (P<0.01). At the end of primary school, children with ADHD obtained time knowledge scores that were close to those of TD children at the beginning of primary school. In children with ADHD, time knowledge was significantly related to the working memory index (P<0.05), but not to ADHD presentation (with or without hyperactivity).

CONCLUSION

This study shows time knowledge impairment in children with ADHD, and paves the way for new screening tests and rehabilitation focused on time knowledge and time-related skills, in order to improve patient care and autonomy.

Medial prefrontal cortex and the temporal control of action

Across species, the medial prefrontal cortex guides actions in time. This process can be studied using behavioral paradigms such as simple reaction-time and interval-timing tasks. Temporal control of action can be influenced by prefrontal neurotransmitters such as dopamine and acetylcholine and is highly relevant to human diseases such as Parkinson's disease, schizophrenia, and attention-deficit hyperactivity disorder (ADHD). We review evidence that across species, medial prefrontal lesions impair the temporal control of action. We then consider neurophysiological correlates in humans, primates, and rodents that might encode temporal processing and relate to cognitive-control mechanisms. These data have informed brain-stimulation studies in rodents and humans that can compensate for timing deficits. This line of work illuminates basic mechanisms of temporal control of action in the medial prefrontal cortex, which underlies a range of high-level cognitive processing and could contribute to new biomarkers and therapies for human brain diseases.

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.

Time contraction caused by a distractor in children and adults: The influence of inhibition capacities

The aim of this study was to examine the cognitive processes involved in time contraction caused by a non-temporal distractor during the presentation of a temporal stimulus. To this aim 95 children aged 5 to 8 years old as well as 25 adults were first trained to discriminate, on two visual temporal bisection tasks, a short standard duration (400 or 600 ms) from a long one (1500 or 2400 ms). They had then to decide whether intermediate stimulus duration was more similar to the short or to the long standard duration. Furthermore, a 40 ms distractor taking the form of a 4 cm diameter rosette, either did or did not appear during the temporal stimulus. Participants' task was to report whether they had been exposed to the short or long standard duration. Subsequently, each subject's capacities in terms of memory skills (short term and working memory), as well as attention (selective attention and inhibition), were assessed using different neuropsychological tests. The results showed a shortening effect of the perceived time from non-distractor to distractor trials, which also turned out to attenuate with the age increase. Interestingly, inhibition was found to mediate this effect while the other cognitive variables were found to be of no significance. We therefore discussed the importance of categorizing two attentional interferences: one related to attention control and the other to attentional resources.

Occupational performance goals and outcomes of time-related interventions for children with ADHD

BACKGROUND

Children with attention deficit hyperactivity disorder (ADHD) have difficulties with occupational performance, related to difficulties with time-processing ability.

AIMS

To examine the outcome of a multimodal time-related intervention designed to support children aged 9-15 years with ADHD, to achieve their occupational performance goals and improve satisfaction with occupational performance. A further aim was to compare the children's ratings of outcome with their parents' ratings and to analyse the occupational performance goals.

MATERIAL AND METHODS

A pre-post design was used. Participants were 27 children, aged 9-15 years. Children and parents rated occupational performance and satisfaction at baseline and follow-up, after 24 weeks, using the Canadian Occupational Performance Measure (COPM). The intervention consisted of time-skills training and time-assistive devices (TADs). Descriptive and non-parametric statistics were used.

RESULTS

Significant improvements were found in reported performance and satisfaction. Children's were higher than those of their parents. Most goals were about carrying out daily routines, knowing the duration of an activity and knowing what will happen in the near future.

CONCLUSION AND SIGNIFICANCE

The study contributes to knowledge about suitable interventions for children with ADHD who have time-related difficulties. Occupational therapy interventions, including TADs and time-skills training, resulted in significantly improved occupational performance.

Time perception in children with attention deficit-hyperactivity disorder (ADHD): Does task matter? A meta-analysis study

We aimed to assess the effects of the nature of the task on time perception deficit (TPD) in children with attention deficit-hyperactivity disorder (ADHD). The inconsistent results from 12 studies in children with ADHD revealed that the problem of time estimation was more obvious in prospective tasks in long-duration intervals. The modality is not a decisive factor. Only two studies reported the subtypes of ADHD that showed TPD in all subtypes. Children with ADHD have difficulties in time perception (TP). The problem is obvious in different types of modality including visual and auditory, in different types of task time estimation, time reproduction, and especially in longer duration.

Behavioral rhythm and EEG rhythm to determine timing deficits in attention deficit hyperactivity disorder symptoms

One characteristic of attention deficit hyperactivity disorder (ADHD) is a timing deficit, i.e. difficulty tapping a self-selected pace and keeping the pace. The timing disorder is reported to relate to the frontal brain area. However, optimal means for evaluating this timing deficit and the corresponding neural mechanisms that accompany ADHD symptoms have not been identified. To address the issue, we required participants to tap one key of a keyboard sequentially and to maintain arbitrary tempos of their tapping intervals. We assessed ADHD symptoms using the Adult ADHD Self-Report Scale (ASRS) and evaluated brain activity via electroencephalography (EEG). Behavioral results indicated that the high ASRS group displayed a large inter-tap-interval gap (defined as the distribution of the time difference between the current tapping interval and the last one). Moreover, EEG results indicated that the work-load related brain activity (i.e. frontal beta activity) was higher in the high ASRS group. These results suggest that our tasks and analyses are useful for the evaluation of ADHD symptoms, although it was preliminary due to the small sample size and the non-patient data.

Spontaneous and stimulus-driven rhythmic behaviors in ADHD adults and controls

Many aspects of human behavior are inherently rhythmic, requiring production of rhythmic motor actions as well as synchronizing to rhythms in the environment. It is well-established that individuals with ADHD exhibit deficits in temporal estimation and timing functions, which may impact their ability to accurately produce and interact with rhythmic stimuli. In the current study we seek to understand the specific aspects of rhythmic behavior that are implicated in ADHD. We specifically ask whether they are attributed to imprecision in the internal generation of rhythms or to reduced acuity in rhythm perception. We also test key predictions of the Preferred Period Hypothesis, which suggests that both perceptual and motor rhythmic behaviors are biased towards a specific personal 'default' tempo. To this end, we tested several aspects of rhythmic behavior and the correspondence between them, including spontaneous motor tempo (SMT), preferred auditory perceptual tempo (PPT) and synchronization-continuations tapping in a broad range of rhythms, from sub-second to supra-second intervals. Moreover, we evaluate the intra-subject consistency of rhythmic preferences, as a means for testing the reality and reliability of personal 'default-rhythms'. We used a modified operational definition for assessing SMT and PPT, instructing participants to tap or calibrate the rhythms most comfortable for them to count along with, to avoid subjective interpretations of the task. Our results shed new light on the specific aspect of rhythmic deficits implicated in ADHD adults. We find that individuals with ADHD are primarily challenged in producing and maintaining isochronous self-generated motor rhythms, during both spontaneous and memory-paced tapping. However, they nonetheless exhibit good flexibility for synchronizing to a broad range of external rhythms, suggesting that auditory-motor entrainment for simple rhythms is preserved in ADHD, and that the presence of an external pacer allows overcoming their inherent difficulty in self-generating isochronous motor rhythms. In addition, both groups showed optimal memory-paced tapping for rhythms near their 'counting-based' SMT and PPT, which were slightly faster in the ADHD group. This is in line with the predictions of the Preferred Period Hypothesis, indicating that at least for this well-defined rhythmic behavior (i.e., counting), individuals tend to prefer similar time-scales in both motor production and perceptual evaluation.

ADHD Symptoms in Adults and Time Perspectives - Findings From a Czech National Sample

Introduction

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders, affecting individuals in all stages of their lives and leading to a variety of negative quality of life outcomes. The disorder is associated with marked differences related to time perception and time perspectives, and this area of research is currently becoming more prominent and gaining ground in showing new aspects of ADHD that were considered secondary (i.e., time perception differences, affective differences). In this study, we looked at ADHD symptoms in adults, correlated lifestyles, and time perspectives as defined by the Zimbardo Time Perspective Inventory (ZTPI). The ZTPI is a useful standardized scale to measure one’s time perspective anchoring in the categories of past positive, past negative, present fatalistic, present hedonistic, and future oriented. This is the first study on adult ADHD and time perspectives conducted in the Czechia.

Methodology

A national representative sample of Czech adults aged 18–65 was recruited by the STEM/MARK Agency. The individuals were assessed for ADHD symptoms with the Adult ADHD Self-Report Scale (ASRS v.1.1). Furthermore, a demographic and lifestyle questionnaire was administered along with the ZTPI to assess time perspectives. Statistical calculations were conducted to find correlations between ADHD symptoms as assessed by the ASRS and the various categories of the ZTPI.

Results

ADHD symptoms were found to be positively correlated with the present hedonistic perspective along with the past negative perspective. Gender was a strong factor in both ADHD symptoms, with males being more likely to show symptoms and to have a present hedonistic perspective. In females, the past negative perspective was most prominent. Education and age were negatively correlated with ADHD symptomatology and the present hedonistic perspective also decreased with age unlike the past negative perspective. Other time perspectives such as future orientation was seen in individuals with lower ADHD symptoms and higher levels of educational achievement.

Conclusion

Researching ADHD symptoms and their connection to time perspectives can increase knowledge of both the disorder and how time perspectives tie into it. We wish to also raise awareness of the possible utility of the ZTPI scale when working with individuals with ADHD.

The Time Knowledge Questionnaire for children

Based on a definition of time knowledge as the correct representation and use of the various time units, a validated questionnaire, the Time Knowledge Questionnaire (TKQ) has been developed with norms for typically developing children aged 6–11 years. The TKQ is a relatively short (10–45 min) and innovative tool, comprising 25 questions broken down into 7 categories. The TKQ has good internal consistency. A total score and two summary scores are provided, assessing conventional time and estimative time respectively. A clinical application of the tool was shown to be of interest for children with disorders or disabilities.

Temporal Preparation, Impulsivity and Short-Term Memory in Depression

Patient suffering of major depressive disorder (MDD) often complain that subjective time seems to "drag" with respect to physical time. This may point toward a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. "Temporal preparation" refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect reduced inhibitory control causing oculomotor impulsivity. In contrast, the latency of visually guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased. In conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. Moreover, oculomotor impulsivity interacted with temporal preparation. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD.