The bidirectional relationship between head injuries and conduct problems: longitudinal modelling of a population-based birth cohort study.

Childhood head injuries and conduct problems increase the risk of aggression and criminality and are well-known correlates. However, the direction and timing of their association and the role of their demographic risk factors remain unclear. This study investigates the bidirectional links between both from 3 to 17 years while revealing common and unique demographic risks. A total of 8,603 participants (50.2% female; 83% White ethnicity) from the Millennium Cohort Study were analysed at 6 timepoints from age 3 to 17. Conduct problems were parent-reported for ages 3 to 17 using the Strengths and Difficulties Questionnaire (SDQ) and head injuries at ages 3 to 14. A cross-lagged path model estimated the longitudinal bidirectional effects between the two whilst salient demographic risks were modelled cumulatively at three ecological levels (child, mother, and household). Conduct problems at age 5 promoted head injuries between 5 and 7 (Z = 0.07; SE = 0.03; 95% CI, 0.02-0.13), and head injuries at ages 7 to 11 promoted conduct problems at age 14 (ß = .0.06; SE = .0.03; 95% CI, 0.01-0.12). Head injuries were associated with direct child-level risk at age 3, whereas conduct problems were associated with direct risks from all ecological levels until 17 years. The findings suggest a sensitive period at 5-11 years for the bidirectional relationship shared between head injuries and conduct problems. They suggest that demographic risks for increased head injuries play an earlier role than they do for conduct problems. Both findings have implications for intervention timing.

Adolescent delinquency following co-occurring childhood head injuries and conduct problem symptoms: findings from a UK longitudinal birth cohort.

Childhood conduct problems and head injuries share a bidirectional association, but how this affects the risk of adolescent delinquency is unknown. Due to their similar underlying mechanisms (i.e. increased impulsivity), this study aims to identify whether their co-occurrence increases the risk of adolescent delinquency. Data was obtained from 11,272 children at age 14 and 10,244 at age 17 years enrolled in the UK Millennium Cohort Study. Conduct problem symptoms (via the Strengths and Difficulties Questionnaire) and head injuries were parent reported from ages 3 to 14 years. Delinquency was self-reported at ages 14 and 17 including substance use, criminality, and antisocial behaviour. Incident rate ratios (IRR) were estimated for delinquency at ages 14 and 17 by childhood conduct problem and head injury status. Co-occurring head injuries and high conduct problem symptoms presented the greatest risk for overall delinquency and substance use at age 14 compared to those with the presence of one or neither (IRRs from 1.20 to 1.60). At age 17, conduct problems (with or without co-occurring head injuries) presented the greatest risk for overall delinquency, substance use, and antisocial behaviour. There was no evidence for an increased risk of delinquency at ages 14 or 17 following a head injury only. Whilst these findings suggest childhood head injuries alone do not increase the risk of adolescent delinquency, when co-occurring alongside high conduct problem symptoms there is a heightened earlier risk. These results provide further insight into adolescent delinquency and the outcomes of co-occurring childhood head injury and conduct problem symptoms.

Linked head injury and conduct problem symptom pathways from early childhood to adolescence and their associated risks: Evidence from the millennium cohort study.

Conduct problems and head injuries increase the risk of delinquency and share a bidirectional association. However, how they link across development is unknown. The present study aimed to identify their linked developmental pathways and associated risk factors. Latent class analysis was modeled from Millennium Cohort Study data (n = 8,600) to identify linked pathways of conduct problem symptoms and head injuries. Head injuries were parent-reported from ages 3 to 14 and conduct problems from ages 3 to 17 using the Strengths and Difficulties Questionnaire (SDQ). Multinomial logistic regression then identified various risk factors associated with pathway membership. Four distinct pathways were identified. Most participants displayed low-level conduct problem symptoms and head injuries (n = 6,422; 74.7%). Three groups were characterized by clinically relevant levels of conduct problem symptoms and high-risk head injuries in childhood (n = 1,422; 16.5%), adolescence (n = 567; 6.6%), or persistent across development (n = 189; 2.2%). These clinically relevant pathways were associated with negative maternal parenting styles. These findings demonstrate how pathways of conduct problem symptoms are uniquely linked with distinct head injury pathways. Suggestions for general preventative intervention targets include early maternal negative parenting styles. Pathway-specific interventions are also required targeting cumulative risk at different ecological levels.

Altered perception-action binding modulates inhibitory control in Gilles de la Tourette syndrome.

BACKGROUND: Gilles de la Tourette Syndrome (GTS) is a multifaceted neuropsychiatric developmental disorder with onset in childhood or adolescence and frequent remissions in early adulthood. A rather new emerging concept of this syndrome suggests that it is a disorder of purposeful actions, in which sensory processes and their relation to motor responses (actions) play a particularly important role. Thus, this syndrome might be conceived as a condition of altered 'perception-action binding'. In the current study, we test this novel concept in the context of inhibitory control. METHODS: We examined N = 35 adolescent GTS patients and N = 39 healthy controls in a Go/Nogo-task manipulating the complexity of sensory information triggering identical actions; i.e. to inhibit a motor response. This was combined with event-related potential recordings, EEG data decomposition and source localization. RESULTS: GTS patients showed worse performance compared to controls and larger performance differences when inhibitory control had to be exerted using unimodal visual compared to bimodal auditory-visual stimuli. This suggests increased binding between bimodal stimuli and responses leading to increased costs of switching between responses instructed by bimodal and those instructed by unimodal stimuli. The neurophysiological data showed that this was related to mechanisms mediating between stimulus evaluation and response selection; i.e. perception-action binding processes in the right inferior parietal cortex (BA40). CONCLUSIONS: Stimulus-action inhibition binding is stronger in GTS patients than healthy controls and affects inhibitory control corroborating the concept suggesting that GTS might be a condition of altered perception-action integration (binding); i.e. a disorder of purposeful actions.

The temporal relationship between premonitory urges and covert compulsions in patients with obsessive-compulsive disorder.

Recent studies in patients with obsessive-compulsive disorder (OCD) have shown that many compulsions are associated with urges rather than obsessions. Premonitory urges are uncomfortable sensory feelings or a rising inner tension, often likened to the urge to scratch, yawn or blink. We studied premonitory urges preceding mental compulsions in 19 patients with OCD and preceding eye blinks in 16 healthy controls. Urge intensity was assessed continuously over 20 min using a real-time urge intensity monitor; compulsions and blinks were measured as discrete events in a free compulsion/blinking and a compulsion/blink suppression condition. Urge intensity showed an inverted U-shaped relationship (increase then decrease) around compulsions within a time-window of approximately 60 s in patients with OCD and within 13 s around blinks in healthy controls. Urge intensity was higher during compulsion / blink suppression and varied more independently of compulsion execution in patients with OCD. There is a close temporal relationship between premonitory sensations and compulsion execution that changes when compulsions are suppressed, indicating that urge intensity might drive the execution of and is then alleviated by compulsions. Suppression weakens the association between urge intensity and compulsion execution.

Evidence for enhanced multi-component behaviour in Tourette syndrome - an EEG study.

Evidence suggests that Tourette syndrome is characterized by an increase in dopamine transmission and structural as well as functional changes in fronto-striatal circuits that might lead to enhanced multi-component behaviour integration. Behavioural and neurophysiological data regarding multi-component behaviour was collected from 15 patients with Tourette syndrome (mean age = 30.40 ± 11.10) and 15 healthy controls (27.07 ± 5.44), using the stop-change task. In this task, participants are asked to sometimes withhold responses to a Go stimulus (stop cue) and change hands to respond to an alternative Go stimulus (change cue). Different onset asynchronies between stop and change cues were implemented (0 and 300 ms) in order to vary task difficulty. Tourette patients responded more accurately than healthy controls when there was no delay between stop and change stimulus, while there was no difference in the 300 ms delay condition. This performance advantage was reflected in a smaller P3 event related potential. Enhanced multi-component behaviour in Tourette syndrome is likely based on an enhanced ability to integrate information from multiple sources and translate it into an appropriate response sequence. This may be a consequence of chronic tic control in these patients, or a known fronto-striatal networks hyperconnectivity in Tourette syndrome.

Temporal relationship between premonitory urges and tics in Gilles de la Tourette syndrome.

Premonitory urges are a cardinal feature in Tourette syndrome and are commonly viewed as the driving force of tics, building up before and subsiding after the execution of tics. Although the urge-tic interplay is one of the most preeminent features in Tourette syndrome, the temporal relationship between tics and urges has never been examined experimentally, mainly due to the lack of an appropriate assessment tool. We investigated the temporal relationship between urge intensity and tics in 17 Tourette patients and between urge intensity and eye blinks in 16 healthy controls in a free ticcing/blinking condition and a tic/blink suppression condition. For this purpose, an urge assessment tool was developed that allows real-time monitoring and quantification of urge intensity. Compared to free ticcing/blinking, urge intensity was higher during the suppression condition in both Tourette patients and healthy controls, while tics and blinks occurred less frequently. The data show that urge intensity increases prior to tics and decreases after tics in a time window of approximately ±10 sec. Tic suppression had a significant effect on the shape of the urge distribution around tics and led to a decrease in the size of the correlation between urge intensity and tics, indicating that tic suppression led to a de-coupling of tics and urges. In healthy controls, urges to blink were highly associated with eye blink execution, albeit in a narrower time frame (∼±5 sec). Blink suppression had a similar effect on the urge distribution associated with eye blinks as tic suppression had on the urge to tic in Tourette patients. These results corroborate the negative reinforcement model, which proposes that tics are associated with a relief in urges, thereby perpetuating ticcing behaviour. This study also documents similarities and differences between urges to act in healthy controls and urges to tic in Tourette syndrome.

Did I turn off the gas? Reality monitoring of everyday actions.

Failing to remember whether we performed, or merely imagined performing, an everyday action can occasionally be inconvenient, but in some circumstances it can have potentially dangerous consequences. In this fMRI study, we investigated the brain activity patterns, and objective and subjective behavioral measures, associated with recollecting such everyday actions. We used an ecologically valid "reality-monitoring" paradigm in which participants performed, or imagined performing, specified actions with real objects drawn from one of two boxes. Lateral brain areas, including prefrontal cortex, were active when participants recollected both the actions that had been associated with objects and the locations from which they had been drawn, consistent with a general role in source recollection. By contrast, medial prefrontal and motor regions made more specific contributions, with supplementary motor cortex activity being associated with recollection decisions about actions but not locations, and medial prefrontal cortex exhibiting greater activity when remembering performed rather than imagined actions. These results support a theoretical interpretation of reality monitoring that entails the fine-grained discrimination between multiple forms of internally and externally generated information.