Preparation and motor potentials in chronic tic and Tourette syndromes

Many studies have found that people with tic disorder show more difficulty when inhibiting an automated than a controlled response. Furthermore, although normal motor threshold and excitability are present, but reduced or impaired, motor inhibition seems manifest in patients with tic. In order to localize this inhibition impairment in tic disorder the present study examine two response-locked ERPs: the Bereitschaft (preparation BP) and the motor potentials (MP). The simple tic group showed faster BP latency and smaller amplitude than control and complex tic group and did not show a corresponding change in values with practice or with automated or controlled condition. The MP amplitudes revealed that whereas both controls and complex tic disorder showed a decrease in amplitude during control condition for both blocks, simple tic showed larger amplitude. Our ERP results are in agreement with RT results of a previous study. The explanation could lie with modulation in motor excitation inhibition circuits and seems worse in simple tics where the movements are more automatic and nonvoluntary.     

Psychopathological Profile in Children with Chronic Tic Disorder and Co-existing ADHD: Additive Effects

The nature of the co-occurrence of chronic tic disorders (CTD) and attention deficit hyperactivity disorder (ADHD) is unclear. Especially in the field of psychopathology, the relationship of CTD and ADHD remains to be clarified. Thus, the aim of the present chart review study was to specify the contribution of CTD and/or ADHD to the psychopathological profile of the comorbid group (CTD+ADHD). The psychopathological profiles of four large groups (CTD-only (n=112), CTD+ADHD (n=82), ADHD-only (n=129), controls (n=144)) were measured by the eight subscales of the Child Behavior Checklist (CBCL) and analyzed by a 2×2 factorial design followed by contrasts. There were main effects of ADHD diagnosis on all but one subscale of the CBCL (Somatic Complaints). For CTD diagnosis, main effects were found for Attention Problems, Anxious/Depressed, Thought Problems, Social Problems and Somatic Complaints. The only interaction effect was seen for Somatic Complaints. While CTD and ADHD were both related to internalizing psychopathology of children in the CTD+ADHD group, ADHD had the largest effect on externalizing psychopathology in the comorbid group. At the level of psychopathology, an additive model for the co-occurrence of CTD and ADHD is strongly supported. In the comorbid group (CTD+ADHD), the ADHD diagnosis shows the strongest relation to externalizing psychopathology.     

Evaluation of a cognitive-behavioural program for the management of chronic tic and habit disorders

The aim was to evaluate the efficacy of a manualized cognitive-behavioural program based on habit reversal for the management of chronic tic disorder (CTD) and habit disorder (HD). Forty-seven CTD and 43 HD received a 4-month treatment program. Thirty-eight (22 CTD, 16 HD) were placed on a waitlist control group, which subsequently received treatment. The treatment approach combined awareness training, relaxation (including modification of a tension-producing style of action), and habit-reversal training, with more general cognitive restructuring of anticipations linked to ticcing. Sixty-five percent of completers reported between 75 and 100% control over the tic. At 2-year follow-up, 52% rated 75-100% control. There were also significant changes post-treatment in measures of self-esteem, anxiety, depression and style of planning action. Successful tic/habit modification was associated in CTD and HD groups with successful change in style of planning action. There were no consistent differences in any outcome measures between CTD and HD groups.     

Impulsive responses in children with conduct disorder and borderline intellectual functioning.

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual "go" signal is presented on the screen. In a second condition the "go" signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the "go" signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

Impulsive Responses In Children with Conduct Disorder and Borderline Intellectual Functioning

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual “go” signal is presented on the screen. In a second condition the “go” signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the “go” signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

I: Effect of delayed auditory feedback on speech and keytapping

The effects of delayed auditory feedback (DAF) on the performance of simple speech and keytapping tasks were compared. In the first experiment, each of the fourteen young adult subjects was asked to repeat the speech sound “b” in groups of three sounds. The subject heard his undelayed speech sounds through earphones. Under the delay condition, the speech sounds were delayed 244 millisec. before being returned to the subject's earphones. In the second experiment, each of the same subjects was asked to tap on a key in groups of three taps. The subjects heard an undelayed click through earphones each time they tapped on the key. Under the delay condition, the clicks were delayed 244 millisec. before being returned to the earphones. Graphic recordings were made of the time and intensity characteristics of tapping under both conditions.

The changes which occurred in speech and keytapping under DAF were qualitatively the same and consisted of increases in intensity and unit-to-unit time of both taps and speech sounds. When performing under DAF, the subjects also exhibited a tendency to repeat more sounds or to tap more times than had been requested. The percentage of change in intensity and time characteristics for speech and keytapping performances which occurred under DAF were not significantly different for the two motor systems. The amount of change in speech performance under DAF did not correlate significantly with the amount of change in keytapping performance.     

Decision-making under risk conditions is susceptible to interference by a secondary executive task

Recent research suggests two ways of making decisions: an intuitive and an analytical one. The current study examines whether a secondary executive task interferes with advantageous decision-making in the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps executive functioning. One group of participants performed the original GDT solely, two groups performed either the GDT and a 1-back or a 2-back working memory task as a secondary task simultaneously. Results show that the group which performed the GDT and the secondary task with high executive load (2-back) decided less advantageously than the group which did not perform a secondary executive task. These findings give further evidence for the view that decision-making under risky conditions taps into the rational-analytical system which acts in a serial and not parallel way as performance on the GDT is disturbed by a parallel task that also requires executive resources.     

Modified Comprehensive Behavioral Intervention for Tics: Treating Children With Tic Disorders,Co-Occurring ADHD,and Psychosocial Impairment

Our objective was to evaluate the feasibility and acceptability, and preliminary efficacy of a modified comprehensive behavioral intervention for tics (MCBIT) therapy for youth with chronic tic disorders (CTDs), co-occurring attention-deficit hyperactivity disorder (ADHD), and associated psychosocial impairment. Seventeen youth ages 10–17 with CTD and co-occurring ADHD were randomly assigned to the MCBIT group (n = 9) or to a control group where they received traditional comprehensive behavioral intervention for tics (CBIT) therapy (n = 8). Both groups received ten 55-minute weekly treatment sessions, and two 55-minute biweekly relapse prevention sessions. Sixteen of the 17 participants completed the study, and acceptability ratings in both treatment groups were high with no significant differences in expectation of improvement. The MCBIT and CBIT groups in combination showed significant improvement in tic severity, ADHD symptom severity, and tic-related impairment. Group differences were not significant. The results indicate that MCBIT treatment is feasible and acceptable for youth with CTD and ADHD, and is similarly well tolerated relative to traditional CBIT. Results were not sufficiently superior to recommend MCBIT over CBIT for this population. However, given the demonstrated benefit of behavioral treatments that target co-occurring conditions concurrently, continuing to examine novel behavioral approaches that can target tics and related conditions simultaneously and successfully is recommended.     

Complex nonverbal response inhibition and stopping impulsivity in childhood stuttering

PurposeThe primary purpose of this study was to examine complex nonverbal response inhibition and stopping impulsivity in children who do (CWS) and do not stutter (CWNS).MethodA total of 30 CWS and 30 CWNS between the ages of 3;1 and 6;0 (years; months) performed the Peg-Tapping Task (PTT; Diamond & Taylor, 1996; Luria, 1966), in which children were required to tap a dowel once when an examiner taps twice and vice versa. The main dependent variables were the number of practice trials, response accuracy, response latency for accurate responses, and the number of extra taps (i.e., tapping more than two times).ResultsThe CWS were less accurate and slower on the PTT than the CWNS, with no differences in the number of practice trials. Furthermore, the CWS, especially boys, produced more extra taps than the CWNS.ConclusionsFindings revealed that preschool CWS have weaknesses in complex response inhibition and stopping impulsivity in the nonverbal domain compared to CWNS. Taken together, these findings along with those of previous studies indicate that CWS may have weaknesses in inhibition and impulsivity in the nonverbal domain as well as the verbal domain, suggesting a domain-general weakness.     

An experimental evaluation of tic suppression and the tic rebound effect

Tourette's syndrome (TS) is a neurobiological disorder consisting of motor and vocal tics that are thought to be temporarily suppressible. Many professionals, however, believe that a paradoxical increase in tic frequency (above baseline levels) occurs when efforts to suppress have ceased (i.e., a rebound effect). To date, little research has investigated tic suppression or its effects. This study examined tic frequency during baseline, suppression, and post-suppression conditions using an experimental preparation reported to reliably produce tic suppression in children. Six children with TS and one with chronic tic disorder (CTD) were recorded during baseline and repeated suppression and post-suppression conditions. Tic frequency was significantly lower during suppression as compared to baseline. Although tic frequency during post-suppression was higher than during suppression, it was lower than baseline levels, arguing against a "rebound" effect of tic suppression. Exploratory analyses revealed that scores on the attention problems subscale of the Child Behavior Checklist significantly predicted tic suppressibility. The relationships between age, tic severity, and tic suppressibility were also explored.     

Numerosity and rhythmicity in stimulus-response compatibility

When people must respond discriminatively to 1 or 2 stimuli by making 1 or 2 taps of a response key, they initiate the response more rapidly when the correct number of taps matches the number of stimuli (compatible condition) than when it mismatches (incompatible condition; J. O. Miller, S. G. Atkins, & F. Van Nes, 2005). Miller et al. sometimes found an effect of compatibility on response execution time, as reflected in the interresponse intervals between successive taps. The authors report 2 further experiments (N = 8 participants) in which they generalized the numerosity compatibility effects on response-initiation time and interresponse intervals to 2- versus 3-stimulus sequences. In addition, they varied gap length between stimuli to see whether the rhythm of the stimulus would influence that of the response. Weak rhythmicity effects were repeatedly found, but those were too small to suggest a plausible alternative explanation for the numerosity compatibility effect on response-initiation time.     

Randomized controlled trial on the effectiveness of metacognitive therapy and intolerance-of-uncertainty therapy for generalized anxiety disorder

This randomized controlled trial compared the effectiveness of metacognitive therapy (MCT) and intolerance-of-uncertainty therapy (IUT) for generalized anxiety disorder (GAD) in an outpatient context. Patients with GAD (N = 126) consecutively referred to an outpatient treatment center for anxiety disorder were randomly allocated to MCT, IUT, or a delayed treatment (DT) condition. Patients were treated individually for up to 14 sessions. Assessments were conducted before treatment (pretreatment), after the last treatment session (posttreatment), and six months after treatment had ended (follow-up). At posttreatment and follow-up assessments, substantial improvements were observed in both treatment conditions across all outcome variables. Both MCT and IUT, but not DT, produced significant reductions in GAD-specific symptoms with large effect sizes (ranging between 0.94 and 2.39) and high proportions of clinically significant change (ranging between 77% and 95%) on various outcome measures, and the vast majority of the patients (i.e., 91% in the MCT group, and 80% in the IUT group) no longer fulfilled the diagnostic criteria for GAD. Results further indicate that MCT produced better results than IUT. This was evident on most outcome measures, and also reflected in effect sizes and degree of clinical response and recovery.     

Underlying processes in the poor response inhibition of children with Attention-Deficit/Hyperactivity Disorder

This study evaluated the effects of reward, punishment, and reward + punishment on the impulsive responses of ADHD children. The impulsive responses of ADHD and normal control boys (30 per group) were compared during performance of a go/no-go task, administered under reward-only, punishment-only, and reward + punishment conditions. When differences in aggression, anxiety, and IQ between these groups were controlled for, results indicated that the impulsivity levels of the ADHD group were higher than the control group in all three reinforcement conditions. Also, the ADHD group was more impulsive in the reward + punishment condition, compared to the reward-only and punishment-only conditions, and there was no difference between the reward-only and punishment-only conditions. The control groups showed no difference across the three reinforcement conditions. These findings raise the possibility that the poor response inhibition of ADHD children may be related to both a generalized inhibitory deficit and a response modulation deficit.     

Auditory dominance in temporal processing: new evidence from synchronization with simultaneous visual and auditory sequences

Evidence that audition dominates vision in temporal processing has come from perceptual judgment tasks. This study shows that this auditory dominance extends to the largely subconscious processes involved in sensorimotor coordination. Participants tapped their finger in synchrony with auditory and visual sequences containing an event onset shift (EOS), expected to elicit an involuntary phase correction response (PCR), and also tried to detect the EOS. Sequences were presented in unimodal and bimodal conditions, including one in which auditory and visual EOSs of opposite sign coincided. Unimodal results showed greater variability of taps, smaller PCRs, and poorer EOS detection in vision than in audition. In bimodal conditions, variability of taps was similar to that for unimodal auditory sequences, and PCRs depended more on auditory than on visual information, even though attention was always focused on the visual sequences.     

Differential Effects of Two Spelling Procedures on Acquisition,Maintenance and Adaption to Reading

An alternating treatments design was used to assess the effects of a constant time delay (CTD) procedure and a cover-copy-compare (CCC) procedure on three students’ acquisition, subsequent maintenance, and adaptation (i.e., application) of acquired spelling words to reading passages. Students were randomly presented two trials of word lists from their respective curriculum under each condition once daily. Results suggest that both procedures were effective for helping students efficiently acquire spelling words, but the CCC condition resulted in more words learned for all participants, although less pronounced when instructional time was considered. However, the CTD procedure resulted in substantially higher levels of maintenance for Jeremy and Leon, with no significant difference between the two procedures for the Anthony. Adaptation of acquired spelling words to reading was about equal under both conditions for Anthony and Leon, while Jeremy showed higher levels of performance in the CTD procedure. Discussion focuses on discrepant results, matching instructional procedures to specific learning concerns, and directions for future research.     

Numerosity and Rhythmicity in Stimulus-Response Compatibility

When people must respond discriminatively to 1 or 2 stimuli by making 1 or 2 taps of a response key, they initiate the response more rapidly when the correct number of taps matches the number of stimuli (compatible condition) than when it mismatches (incompatible condition; J. O. Miller, S. G. Atkins, & F. Van Nes, 2005). Miller et al. sometimes found an effect of compatibility on response execution time, as reflected in the interresponse intervals between successive taps. The authors report 2 further experiments (N=8 participants) in which they generalized the numerosity compatibility effects on response-initiation time and interresponse intervals to 2- versus 3-stimulus sequences. In addition, they varied gap length between stimuli to see whether the rhythm of the stimulus would influence that of the response. Weak rhythmicity effects were repeatedly found, but those were too small to suggest a plausible alternative explanation for the numerosity compatibility effect on response-initiation time.     

Self-induced versus reactive triggering of synchronous movements in a deafferented patient and control subjects

The present study investigates the contribution of tactile-kinesthetic information to the timing of movements. The relative timing of simultaneous tapping movements of finger and foot (hand-foot asynchrony) was examined in a simple reaction time task and in discrete self-initiated taps (Experiment 1), and in externally triggered synchronization tapping (Experiment 2). We compared the performance of a deafferented participant (IW) to the performance of two control groups of different ages. The pattern of results in control groups replicates previous findings: Whereas positive hand-foot asynchronies (hand precedes foot) are observed in a simultaneous reaction to an auditory stimulus, hand-foot asynchronies are negative with discrete self-initiated as well as auditorily paced sequences of synchronized finger and foot taps. In the first case, results are explained by a simultaneous triggering of motor commands. In contrast, self-initiated and auditorily paced movements are assumed to be controlled in terms of their afferent consequences, as provided by tactile-kinesthetic information. The performance of the deafferented participant differed from that of healthy participants in some aspects. As expected on the basis of unaffected motor functions, the participant was able to generate finger and foot movements in reaction to an external signal. In spite of the lack of movement-contingent sensory feedback, the deafferented participant showed comparable timing errors in self-initiated and regularly paced tapping as observed in control participants. However, in discrete self-initiated taps IW's hand-foot asynchronies were considerably larger than in control participants, while performance did not differ from that of controls in continuous movement generation. These findings are discussed in terms of an internal generation of the movement's sensory consequences (forward-modeling).     

Planning and timing of finger-tapping sequences with a stressed element

Advance planning and execution-time organization of sequences of five finger taps were studied in four experiments. Intertap intervals were required to be equal. In some experimental conditions, one of the taps had to be stronger than the other four. Serial position of the stressed tap, number of alternative stress positions, and tapping rate were manipulated. Time to initiate the sequence after presentation of a reaction stimulus (RT), intertap intervals, and force of the taps were measured. the different effects of stress production and choosing between alternative stress locations on the RT of fast as compared to slow sequences suggest that a plan was selected and activated for the whole sequence only when it had to be executed at a fast rate. Additional organization of the fast sequences during execution was inferred from the intertap intervals, force patterns, and stress location errors, that were all different from those observed in slow sequences. The effects of stress production on timing are discussed in relation to existing timing models.     

Counting visual and tactile events: The effect of attention on multisensory integration

Irrelevant events in one sensory modality can influence the number of events that are perceived in another modality. Previously, the underlying process of sensory integration was studied in conditions in which participants knew a priori which sensory modality was relevant and which was not. Consequently, (bottom-up) sensory interference and (top-down) selective attention were confounded. We disentangled these effects by measuring the influence of visual flashes on the number of tactile taps that were perceived, and vice versa, in two conditions. In the cue condition, participants were instructed on which modality to report before the bimodal stimulus was presented. In the no-cue condition, they were instructed after stimulus presentation. Participants reported the number of events that they perceived for bimodal combinations of one, two, or three flashes and one, two, or three taps. Our main findings were that (1) in no-cue conditions, the influence of vision on touch was stronger than was the influence of touch on vision; (2) in cue conditions, the integration effects were smaller than those in no-cue conditions; and (3) irrelevant taps were less easily ignored than were irrelevant flashes. This study disentangled previously confounded bottom-up and top-down effects: The bottom-up influence of vision on touch was stronger, but vision was also more easily suppressed by top-down selective attention. We have compared our results qualitatively and quantitatively with recently proposed sensory-integration models.     

Group behavior of rats under schedules of reinforcement

Groups of three rats were placed in a chamber containing one response lever and one water dispenser. A variety of schedule conditions were explored including fixed ratio, extinction, satiation, fixed interval, fixed time, differential reinforcement of low rates, and discrimination learning. Each group was treated as a single unit, with the collective lever responses emitted by the three rats being the main dependent variable. Group responding was found to be controlled by the reinforcement schedules in an orderly and consistent manner. However, the groups often paused less and responded faster than individual rats working under identical conditions.