Implicit sequence learning in young people with Tourette syndrome with and without co-occurring attention-deficit/hyperactivity disorder

Impaired habit-learning has been proposed to underlie the tic symptoms of Tourette syndrome (TS). However, accounts differ in terms of how habit-learning is altered in TS, with some authors proposing habit formation is impaired due to a deficient ‘chunking’ mechanism, and others proposing habit-learning is overactive and tics reflect hyperlearned behaviours. Attention-deficit/hyperactivity disorder (ADHD) frequently co-occurs with TS and is known to affect cognitive function in young people with co-occurring TS and ADHD (TS + ADHD). It is unclear, however, how co-occurring ADHD symptoms affect habit-learning in TS. In this study, we investigated whether young people with TS would show deficient or hyperactive habit-learning, and assessed the effects of co-occurring ADHD symptoms on habit-learning in TS. Participants aged 9–17 years with TS (n = 18), TS + ADHD (n = 17), ADHD (n = 13), and typical development (n = 20) completed a motor sequence learning task to assess habit-learning. We used a 2 (TS-yes, TS-no) × 2 (ADHD-yes, ADHD-no) factorial analysis to test the effects of TS, ADHD, and their interaction on accuracy and reaction time indices of sequence learning. TS was associated with intact sequence learning, but a tendency for difficulty transitioning from sequenced to non-sequenced performance was suggestive of hyper-learning. ADHD was associated with significantly poorer accuracy during acquisition of the sequence, indicative of impaired habit-learning. There were no interactions between the TS and ADHD factors, indicating young people with TS + ADHD showed both TS- and ADHD-related atypicalities in habit-learning.     

Enhanced saccadic control in young people with Tourette syndrome despite slowed pro‐saccades

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics. Tics are repetitive and uncontrolled behaviours that have been associated with basal ganglia dysfunction. We investigated saccadic eye movements in a group of young people with TS but without co‐morbid ADHD. Participants performed two tasks. One required them to perform only pro‐saccade responses (pure pro‐saccade task). The other involved shifting, unpredictably, between executing pro‐ and anti‐saccades (mixed saccade task). We show that in the mixing saccade task, the TS group makes significantly fewer errors than an age‐matched control group, while responding equally fast. By contrast, on the pure pro‐saccade task, the TS group were shown to be significantly slower to initiate and to complete the saccades (longer movement duration and decreased peak velocity) than controls, while movement amplitude and direction accuracy were not different. These findings demonstrate enhanced shifting ability despite slower reflexive responding in TS and are discussed with respect to a disorder‐related adaptation for increased cognitive regulation of behaviour.     

Motor excitability during movement preparation in Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by the occurrence of motor and vocal tics. TS has been linked to the impaired operation of cortical‐striatal‐thalamic‐cortical circuits that give rise to hyper‐excitability of cortical motor areas, which may be exacerbated by dysfunctional intra‐cortical inhibitory mechanisms. That said, many individuals gain control over their tics during adolescence and it has been suggested that this increased control arises as a result of the development of mechanisms that operate to suppress corticospinal excitability (CSE) ahead of volitional movements. Here we used single‐pulse transcranial magnetic stimulation (TMS) in conjunction with a manual Go/NoGo task to investigate alterations in CSE ahead of volitional movements in a group of adolescents with TS (N = 10). Our study demonstrated that CSE, as measured by TMS‐induced motor‐evoked potentials (MEPs), was significantly reduced in the TS group in the period immediately preceding a finger movement. More specifically, we show that individuals with TS, unlike their age‐matched controls, do not exhibit the predicted increase in mean MEP amplitude and decrease in MEP variability that immediately precede the execution of volitional movements in typically developing young adults. Finally, we report that the magnitude of the rise in MEP amplitude across the movement preparation period in TS is significantly negatively correlated with clinical measures of motor tic severity, suggesting that individuals with severe motor tics are least able to modulate motor cortical excitability.     

Preliminary evidence for reduced posterror reaction time slowing in hyperactive/inattentive preschool children

Background: Attention deficit/hyperactivity disorder (ADHD) has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in posterror slowing. Method: A computerized two-choice RT task was administered to an ethnically diverse sample of preschool-aged children classified as either “control” (n = 120) or “hyperactive/inattentive” (HI; n = 148) using parent- and teacher-rated ADHD symptoms. Analyses were conducted to determine whether HI preschoolers exhibit a deficit in this self-regulatory ability. Results: HI children exhibited reduced posterror slowing relative to controls on the trials selected for analysis. Supplementary analyses indicated that this may have been due to a reduced proportion of trials following errors on which HI children slowed rather than due to a reduction in the absolute magnitude of slowing on all trials following errors. Conclusions: High levels of ADHD symptoms in preschoolers may be associated with a deficit in error processing as indicated by posterror slowing. The results of supplementary analyses suggest that this deficit is perhaps more a result of failures to perceive errors than of difficulties with executive control.     

Attention bias for social threat in youth with tic disorders: Links with tic severity and social anxiety

Many individuals with Tourette syndrome and chronic tic disorders (TS/CTDs) report poor social functioning and comorbid social anxiety. Yet limited research has investigated the role of cognitive factors that highlight social threats in youth with TS/CTD, and whether these biases underlie tic severity and co-occurring social anxiety. This study examined whether selective attention to social threat is enhanced young people with TS/CTDs compared to healthy controls, and whether attention biases are associated with tic severity and social anxiety. Twenty seven young people with TS/CTDs and 25 matched control participants completed an experimental measure of attention bias toward/away from threat stimuli. A clinician-rated interview measuring tic severity/impairment (YGTSS Total Score) and questionnaire measures of social anxiety were completed by participants and their parents. Young people with TS/CTD showed an attention bias to social threat words (relative to benign words) compared to controls but no such bias for social threat faces. Attention bias for social threat words was associated with increasing YGTSS Total Score and parent-reported social anxiety in the TS/CTDs group. Mediation analysis revealed a significant indirect path between YGTSS Total Score and social anxiety, via attention to social threat. Tentatively, these associations appeared to be driven by impairment rather than tic severity scores. Preliminary data suggests that youth with TS/CTD have enhanced attention to threat, compared to controls, and this is associated with impairment and social anxiety. Attention to threat could offer a cognitive mechanism connecting impairment and social anxiety, and so be a valuable trans-diagnostic treatment target.     

Five‐year outcomes of ADHD diagnosed in adulthood

There is a dearth of long‐term follow‐up studies of adults diagnosed with ADHD. Here, the aim was to evaluate long‐term outcomes in a group of ADHD patients diagnosed in adulthood and receiving routine psychiatric health care. Adults diagnosed with any type of ADHD (n = 52) and healthy controls (n = 73) were assessed at baseline and at a 5‐year follow‐up, using Global Assessment of Functioning (GAF), Clinical Global Impression (CGI), Brown ADD Scale (BADDS) and Adult ADHD Self‐Report Scale (ASRS). A multivariate regression method was used to identify factors predicting 5‐year outcomes, including baseline ratings, medication intensity, comorbidity, intelligence quotient (IQ), age, and sex. After 5 years, ADHD patients reported fewer and/or less severe symptoms compared to baseline, but remained at clinically significant symptom levels and with functional deficits. Baseline self‐reports of ADHD symptoms predicted their own 5‐year outcome and low baseline functioning level predicted improved global functioning at follow‐up. Factors previously reported to predict short‐term outcomes (i.e., medication, comorbidity, IQ, age, and sex) did not anticipate long‐term outcomes in present study.     

Women are more sensitive than men to prior trial events on the Stop‐signal task

Sexual dimorphism in the brain and cognition is a topic of widespread interest. Many studies of sex differences have focused on visuospatial and verbal abilities, but few studies have investigated sex differences in executive functions. We examined two key components of executive function – response inhibition and response monitoring – in healthy men (n = 285) and women (n = 346) performing the Stop‐signal task. In this task, participants are required to make a key press to a stimulus, unless a tone is presented at some delay following the initial stimulus presentation; on these infrequent trials, participants are instructed to inhibit their planned response. Response inhibition was assessed with an estimate of the latency needed to inhibit a response (stop‐signal reaction time), and response monitoring was measured by calculating the degree to which participants adjusted their reaction times based on the immediately preceding trial (e.g., speeding following correct trials and slowing following errors). There were no sex differences in overall accuracy or response inhibition, but women showed greater sensitivity to trial history. Women sped up more than men following correct ‘Go’ trials, and slowed down more than men following errors. These small but statistically significant effects (Cohen's d = 0.25–0.3) suggest more flexible adjustments in speed–accuracy trade‐offs in women and greater cognitive flexibility associated with the responsive control of action.     

Attentional Performance in Children and Adolescents with Tic Disorder and Co-Occurring Attention-Deficit/Hyperactivity Disorder: New Insights from a 2 × 2 Factorial Design Study

The aim of the present study was to investigate the effect of both tic disorder (TD) and attention-deficit/hyperactivity disorder (ADHD) on attentional functions. N = 96 children and adolescents participated in the study, including n = 21 subjects with TD, n = 23 subjects with ADHD, n = 25 subjects with TD+ADHD, and n = 27 controls. Attentional performance was tested based on four computerized attention tasks (sustained attention, divided attention, go/nogo and set shifting). The effect of TD as well as ADHD on attentional performance was tested using a 2 × 2 factorial approach. A diagnosis of TD had no negative impact on attentional functions but was associated with improved performance in the set shifting task. By contrast, regardless of a diagnosis of TD, subjects with ADHD were found to perform worse in the sustained attention, divided attention and go/nogo task. No interaction effect between the factors TD and ADHD was revealed for any of the attention measures. Our results add to findings from other areas of research, showing that in subjects with TD and ADHD, ADHD psychopathology is often the main source of impairment, whereas a diagnosis of TD has little or no impact on neuropsychological performance in most cases and even seems to be associated with adaptive mechanisms.     

Neurocognitive Performance in Children with ADHD and OCD

Attention-deficit/hyperactivity Disorder (ADHD) and obsessive–compulsive disorder (OCD) have both been linked to dysfunction in the cortico-striato-thalamo-cortical circuitry (CSTCC). However, the exact nature of neurocognitive deficits remains to be investigated in both disorders. We applied two neuropsychological tasks that tap into different functions associated with the CSTCC, namely a serial reaction time (SRT) task, developed to assess implicit sequence learning, and a delay aversion (DA) task in order to assess abnormal motivational processes. The performance data of boys with ADHD (n = 20), OCD (n = 20) and healthy controls (n = 25), all aged 10–18 years, were compared. Subjects with ADHD less frequently chose the larger, more delayed reward compared to those with OCD and controls, while subjects with OCD showed impaired implicit learning. In contrast, the ADHD group was unimpaired in their implicit learning behavior and the OCD group was not characterized by a DA style. Within the OCD-group, severity of obsessions was associated with implicit learning deficits and impulsive symptoms with DA in the ADHD-group. This double dissociation highlights the distinct cognitive dysfunctions associated with ADHD and OCD and might possibly point to different neural abnormalities in both disorders.     

Efficacy of a Photovoice‐based video as an online mental illness anti‐stigma intervention and the role of empathy in audience response: A randomized controlled trial

This study examined the efficacy of a Photovoice‐based video as a novel online anti‐stigma video in reducing mental illness stigma, as well as the role of empathic concern in stigma reduction. Photovoice is a grassroots process by which members of a marginalized group, such as people with a mental illness, document and convey their experience; in this study’s context, the experience of living with a mental illness and the stigma associated with this experience. Canadian undergraduate university students (n = 303; average age = 21) were randomly assigned to view either a Photovoice‐based anti‐stigma intervention video (n = 156) or a control video (n = 147). Compared to the control condition, the Photovoice‐based video was efficacious in reducing mental illness stigma, including reduced fear and anger toward people with a mental illness, decreased perceptions of dangerousness, and decreased desired social distance. In addition, the intervention was efficacious in maintaining reduced desired social distance relative to the control at 1‐month post‐intervention. Finally, empathic concern was found to mediate the relationship between the Photovoice‐based video and reduced mental illness stigma, suggesting that one way the intervention reduced mental illness stigma was by eliciting empathy in the viewer.     

Common mechanisms of executive attention underlie executive function and effortful control in children

Executive Function (EF) and Effortful Control (EC) have traditionally been viewed as distinct constructs related to cognition and temperament during development. More recently, EF and EC have been implicated in top‐down self‐regulation ‐ the goal‐directed control of cognition, emotion, and behavior. We propose that executive attention, a limited‐capacity attentional resource subserving goal‐directed cognition and behavior, is the common cognitive mechanism underlying the self‐regulatory capacities captured by EF and EC. We addressed three related questions: (a) Do behavioral ratings of EF and EC represent the same self‐regulation construct? (b) Is this self‐regulation construct explained by a common executive attention factor as measured by performance on cognitive tasks? and (c) Does the executive attention factor explain additional variance in attention deficit hyperactivity disorder (ADHD) problems to behavioral ratings of self‐regulation? Measures of performance on complex span, general intelligence, and response inhibition tasks were obtained from 136 preadolescent children (M = 11 years, 10 months, SD = 8 months), along with self‐ and parent‐reported EC, and parent‐reported EF, and ADHD problems. Results from structural equation modeling demonstrated that behavioral ratings of EF and EC measured the same self‐regulation construct. Cognitive tasks measured a common executive attention factor that significantly explained 30% of the variance in behavioral ratings of self‐regulation. Executive attention failed to significantly explain additional variance in ADHD problems beyond that explained by behavioral ratings of self‐regulation. These findings raise questions about the utility of task‐based cognitive measures in research and clinical assessment of self‐regulation and psychopathology in developmental samples.     

Cross-lateralisation in children with attention-deficit/hyperactivity disorder and motor skill performance

Cross-lateralisation and increased motor difficulties have been reported in children with attention-deficit/hyperactivity disorder (ADHD). Nevertheless, the question of how crossed (i.e. mixed preference) or uncrossed (i.e. same side preference) lateralisation impacts motor performance in children with ADHD has yet to be examined. In this study, previously validated observational measures of hand and foot preference were used to identify right-handed children with ADHD who display cross- (n = 29) and uncross-lateralisation (n = 31). An uncross-lateralised typically developing (TD) group (n = 32) was also identified, and included as a control. Motor performance was assessed with seven valid and reliable fine and gross motor tasks performed with both preferred and non-preferred limbs. Group, task and sex-related effects were examined. Findings revealed that male (but not female) cross-lateralised children with ADHD performed significantly worse, respectively, in two of the fine motor tasks (spiral tracing [p < .01], and dot filling [p < .05]). Results suggest that cross-lateralised hand and foot preference may affect complex motor skills in male children with ADHD. Furthermore, characteristics of ADHD may manifest differently in male and female children. Findings highlight the importance of considering both hand and foot preference when targeting motor interventions for children with ADHD.     

Motor excitability is reduced prior to voluntary movements in children and adolescents with Tourette syndrome

Tourette syndrome (TS) is a neuro‐developmental disorder characterized by the occurrence of motor and vocal tics: involuntary, repetitive, stereotyped behaviours that occur with a limited duration, often typically many times in a single day. Previous studies suggest that children and adolescents with TS may undergo compensatory, neuroplastic changes in brain structure and function that help them gain control over their tics. In the current study we used single‐pulse and dual‐site paired‐pulse transcranial magnetic stimulation (TMS), in conjunction with a manual choice reaction time task that induces high levels of inter‐manual conflict, to investigate this conjecture in a group of children and adolescents with TS, but without co‐morbid Attention Deficit Hyperactivity Disorder (ADHD). We found that performance on the behavioural response‐conflict task did not differ between the adolescents with TS and a group of age‐matched typically developing individuals. By contrast, our study demonstrated that cortical excitability, as measured by TMS‐induced motor‐evoked potentials (MEPs), was significantly reduced in the TS group in the period immediately preceding a finger movement. This effect is interpreted as consistent with previous suggestions that the cortical hyper‐excitability that may give rise to tics in TS is actively suppressed by cognitive control mechanisms. Finally, we found no reliable evidence for altered patterns of functional inter‐hemispheric connectivity in TS. These results provide evidence for compensatory brain reorganization that may underlie the increased self‐regulation mechanisms that have been hypothesized to bring about the control of tics during adolescence.     

How Distinctive are ADHD and RD? Results of a Double Dissociation Study

The nature of the comorbidity between Attention-Deficit/Hyperactivity Disorder (ADHD) and Reading Disability (RD) was examined using a double dissociation design. Children were between 8 and 12 years of age and entered into four groups: ADHD only (n = 24), ADHD+RD (n = 29), RD only (n = 41) and normal controls (n = 26). In total, 120 children participated in the study; 38 girls and 82 boys. Both ADHD and RD were associated with impairments in inhibition and lexical decision, although inhibition and lexical decision were more severely impaired in RD than in ADHD. Visuospatial working memory deficits were specific to children with only ADHD. It is concluded that there was overlap on lexical decision and to a lesser extent on inhibition between ADHD and RD. In ADHD, impairments were dependent on IQ, which suggest that the overlap in lexical decision and inhibition is different in origin for ADHD and RD. The ADHD only group was specifically characterized by deficits in visuospatial working memory. Hence, no double dissociation between ADHD and RD was found on executive functioning and lexical decision.     

The Relationship Between Sluggish Cognitive Tempo,Subtypes of Attention-Deficit/Hyperactivity Disorder,and Anxiety Disorders

The objective of the present study was to examine the relationship between sluggish cognitive tempo (SCT), subtypes of attention-deficit/hyperactivity disorder (ADHD), and anxiety disorders (AnxDs). One hundred and forty-one children (90 males, 51 females) aged 7–13 years were assigned to four groups, i.e., referred children with comorbid AnxDs and ADHD (n = 25), ADHD (n = 39), AnxDs (n = 41), and nonreferred controls (n = 36). Furthermore we explored the association between SCT and several neurocognitive measures (reaction time, verbal memory, and spatial memory). Diagnoses were established using Kiddie-SADS P/L. SCT was assessed using a 17-item mother-reported questionnaire. SCT correlated significantly with inattentiveness, regardless of the subtype of ADHD. Furthermore, we found significant differences in the levels of SCT among the four groups, with the highest SCT scores observed in the comorbid group. SCT correlated with variability in spatial memory; in contrast, there was no correlation between SCT and reaction time.     

The style of planning action (STOP) questionnaire in OCD spectrum disorders

This article describes the exploratory and confirmatory validation of an everyday style of planning (STOP) questionnaire in a tic disorder (n = 88), Tourette syndrome (n = 76), body-focused repetitive behaviour group (n = 121), obsessive compulsive disorder (n = 251) and a non-clinical control group (n = 127).Exploratory factor analysis was performed on half of the sample and confirmatory analysis on the other half. A three factor solution accounted for 38% of the variance. The factors were labelled respectively: overcomplication, overpreparation, and overactivity. The internal consistency for the overcomplication score and total score was high and for the other two scales, satisfactory. Test–retest was satisfactory and the subscales discriminated amongst clinical groups, and clinical groups from controls. All subscales became significantly less pathological following cognitive behavioural treatment. Convergent validity showed strong correlations with depression, anxiety and perfectionism but not impulsivity. The study confirms style of action as an important characteristic of obsessive compulsive spectrum disorders. Further analysis of the structure of each factor is warranted.     

Co‐Occurring Trajectory of Mothers’ Substance Use and Psychological Control and Children's Behavior Problems: The Effects of a Family Systems Intervention

This study examined the effects of a family systems therapy (Ecologically‐Based Family Therapy [EBFT]) on the co‐occurring trajectory of mothers’ substance use and psychological control, and its association with children's problem behaviors. Participants included 183 mothers with a substance use disorder who had at least one biological child in their care. Mothers were randomly assigned to one of the three intervention conditions: EBFT—home, n = 62; EBFT—office, n = 61; or Women's Health Education, n = 60. Participants were assessed at baseline, 3, 6, 12, and 18 months post‐baseline. A dual‐trajectory class growth analysis identified three groups of mothers in regard to their change trajectories. The majority of the mothers exhibited a synchronous decrease in substance use and psychological control (n = 107). In all, 46 mothers exhibited a synchronous increase in substance use and psychological control. For the remaining 30 mothers, substance use and psychological control remained stable. Mothers in the family therapy condition were more likely to show reduced substance use and psychological control compared to mothers in the control condition. Moreover, children with mothers who showed decreased substance use and psychological control exhibited lower levels of problem behaviors compared to children with mothers showing increased substance use and psychological control. The findings provide evidence for the effectiveness of family systems therapy, EBFT, in treating mothers’ substance use, improving parenting behaviors, and subsequently improving child behavioral outcomes.     

The impact of a stress induction task on tic frequencies in youth with Tourette Syndrome

Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by motor and vocal tics. Tic fluctuations are common and thought to be attributable in part, to contextual variables. Stress is one such variable, but its effects and mechanism of action are poorly understood. The current study measured the effects of a stress induction task on tic frequencies during periods of suppression and non-suppression of tics. Ten youth with TS between the ages of 9 and 17 were exposed to four conditions in random sequence: free-to-tic baseline (BL), reinforced tic suppression (SUP), reinforced tic suppression plus a stress induction task (SUP + STRESS), and a stress induction task alone (STRESS). Tic frequencies did not differ during STRESS and BL. Tic frequencies were greater in SUP + STRESS than SUP. Stress may impact tics through disrupting suppression efforts. Clinically, results suggest that interventions designed to improve tic inhibition in the presence of acute stressors may be beneficial.     

Parallels Between Action‐Object Mapping and Word‐Object Mapping in Young Children

Across a series of four experiments with 3‐ to 4‐year‐olds we demonstrate how cognitive mechanisms supporting noun learning extend to the mapping of actions to objects. In Experiment 1 (n = 61) the demonstration of a novel action led children to select a novel, rather than a familiar object. In Experiment 2 (n = 78) children exhibited long‐term retention of novel action‐object mappings and extended these actions to other category members. In Experiment 3 (n = 60) we showed that children formed an accurate sensorimotor record of the novel action. In Experiment 4 (n = 54) we demonstrate limits on the types of actions mapped to novel objects. Overall these data suggest that certain aspects of noun mapping share common processing with action mapping and support a domain‐general account of word learning.     

Errors on a computer task and subclinical symptoms of attention‐deficit/hyperactivity disorder (ADHD)

Previous reports have found increased error rate for children with attention‐deficit/hyperactivity disorder (ADHD ) on response time (RT ) computer tasks. Here we attempt the conceptual replication and extension of two studies that examined error rate in a general population of children (N = 203). Study 1 followed Johnstone and Galletta but considered associations between scores on a dimensional measure of ADHD symptoms (rather than comparing those with or without an ADHD diagnosis) and the frequency of commission and omission errors. Study 2 followed Shiels, Tamm & Epstein and examined post‐error adjustment in the same group of children as for Study 1. Study 1 did not replicate previous findings of no increase in errors of commission in those with higher ADHD symptoms (Johnstone & Galletta). Instead, we found that younger children with lower ADHD symptoms were more likely to make commission errors, while omission errors did not vary with age. Study 2 replicated the previous finding of less RT slowing in children with more ADHD symptoms, extending this finding to a general population of children. Namely, as ADHD symptoms increase, RT slowing is less likely, putting children with higher ADHD symptoms at risk of additional errors. Overall, we extend previous ADHD research to typically developing children with ADHD symptoms.