Early development and epilepsy in tuberous sclerosis complex: A prospective longitudinal study

AIM

To characterize early changes in developmental ability, language, and adaptive behaviour in infants diagnosed with tuberous sclerosis complex (TSC), and determine whether clinical features of epilepsy influence this pathway.

METHOD

Prospective, longitudinal data were collected within the Early Development in Tuberous Sclerosis (EDiTS) Study to track development of infants with TSC (n = 32) and typically developing infants (n = 33) between 3 and 24 months of age. Questionnaire and observational measures were used at up to seven timepoints to assess infants' adaptive behaviour, developmental ability, language, and epilepsy.

RESULTS

A significant group by age interaction effect showed that infants with TSC had lower adaptive functioning at 18 to 24 months old (intercept = 88.12, slope estimate = -0.82, p < 0.001) and lower developmental ability scores from 10 months old (intercept = 83.33, slope estimate = -1.44, p < 0.001) compared to typically developing infants. Early epilepsy severity was a significant predictor of these emerging developmental (R2 = 0.35, p = 0.004, 95% confidence interval [CI] -0.08 to -0.01) and adaptive behaviour delays (R2 = 0.34, p = 0.004, 95% CI -0.05 to -0.01]). Lower vocabulary production (intercept = -1.25, slope = -0.12, p < 0.001) and comprehension scores (intercept = 2.39, slope estimate = -0.05, p < 0.001) in infants with TSC at 24 months old were not associated with epilepsy severity.

INTERPRETATION

Divergence of developmental ability and adaptive functioning skills occur in infants with TSC from 10 and 18 months, respectively. Associations between early epilepsy severity and impaired development supports the importance of early intervention to reduce seizure severity.

Is quality of life related to high autistic traits, high ADHD traits and their Interaction? Evidence from a Young-Adult Community-Based twin sample

This study explored whether high autistic traits, high attention deficit hyperactivity disorder (ADHD) traits and their interaction were associated with quality of life (QoL) in a sample of 556 of young-adult twins (Mean age 22 years 5 months, 52% Female). Four participant groups were created: high autistic traits, high ADHD traits, high autistic/ADHD traits, and low ADHD/autistic traits. High autistic traits were associated with lower QoL across domains (physical, psychological, social, and environmental). High ADHD traits associated with lower physical, psychological, and environmental QoL. The interaction of autistic and ADHD traits was not significant in any domain. While mental health difficulties were associated with lower QoL, after accounting for mental health, most relationships between autistic traits, ADHD traits and QoL remained.

Experiences of parents of children with rare neurogenetic conditions during the COVID-19 pandemic: an interpretative phenomenological analysis

BACKGROUND

The Coronavirus disease 2019 (COVID-19) pandemic has impacted parental and child mental health and wellbeing in the UK. This study aimed to explore the experiences of parents of children with rare neurological and neurodevelopmental conditions with a known or suspected genetic cause (neurogenetic) across the first year of the pandemic in the UK.

METHODS

Semi-structured interviews were conducted with 11 parents of children with rare neurogenetic conditions. Parents were recruited via opportunity sampling from the CoIN Study, a longitudinal quantitative study exploring the impact of the pandemic on the mental health and wellbeing of families with rare neurogenetic conditions. Interviews were analysed using Interpretative Phenomenological Analysis.

RESULTS

Four main themes were identified: (1) "A varied impact on child wellbeing: from detrimental to 'no big drama'"; (2) "Parental mental health and wellbeing: impact, changes, and coping"; (3) "'The world had shut its doors and that was that': care and social services during the pandemic"; and (4) "Time and luck: abstract concepts central to parents' perspectives of how they coped during the pandemic". The majority of parents described experiencing an exacerbation of pre-pandemic challenges due to increased uncertainty and a lack of support, with a minority reporting positive effects of the pandemic on family wellbeing.

CONCLUSIONS

These findings offer a unique insight into the experiences parents of children with rare neurogenetic conditions across the first year of the pandemic in the UK. They highlight that the experiences of parents were not pandemic-specific, and will continue to be highly relevant in a non-pandemic context. Future support should to be tailored to the needs of families and implemented across diverse future scenarios to promote coping and positive wellbeing.

Face processing in young adults with autism and ADHD: An event related potentials study

Background

Atypicalities in perception and interpretation of faces and emotional facial expressions have been reported in both autism and attention-deficit/hyperactivity disorder (ADHD) during childhood and adulthood. Investigation of face processing during young adulthood (18 to 25 years), a transition period to full-fledged adulthood, could provide important information on the adult outcomes of autism and ADHD.

Methods

In this study, we investigated event-related potentials (ERPs) related to visual face processing in autism, ADHD, and co-occurring autism and ADHD in a large sample of young adults (N = 566). The groups were based on the Diagnostic Interview for ADHD in Adults 2.0 (DIVA-2) and the Autism Diagnostic Observation Schedule-2 (ADOS-2). We analyzed ERPs from two passive viewing tasks previously used in childhood investigations: (1) upright and inverted faces with direct or averted gaze; (2) faces expressing different emotions.

Results

Across both tasks, we consistently found lower amplitude and longer latency of N170 in participants with autism compared to those without. Longer P1 latencies and smaller P3 amplitudes in response to emotional expressions and longer P3 latencies for upright faces were also characteristic to the autistic group. Those with ADHD had longer N170 latencies, specific to the face-gaze task. Individuals with both autism and ADHD showed additional alterations in gaze modulation and a lack of the face inversion effect indexed by a delayed N170.

Conclusion

Alterations in N170 for autistic young adults is largely consistent with studies on autistic adults, and some studies in autistic children. These findings suggest that there are identifiable and measurable socio-functional atypicalities in young adults with autism.

Epilepsy severity mediates association between mutation type and ADHD symptoms in tuberous sclerosis complex

The association between attention-deficit/hyperactivity disorder (ADHD) and tuberous sclerosis complex (TSC) is widely reported, with support for the role of epilepsy, yet the mechanisms underlying the association across development are unclear. The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of TSC. In Phase 1 of the study, baseline measures of epilepsy, cortical tuber load, and mutation were obtained with 125 children ages 0-16 years. In Phase 2, at an average of 8 years later, ADHD symptoms were measured for 81 of the participants. Structural equation modeling revealed an indirect pathway from genetic mutation, to cortical tuber load, to epileptic spasm severity in infancy, to ADHD symptoms in middle childhood and adolescence, in addition to a pathway linking current seizure severity to ADHD symptoms. Findings were retained when intelligence quotient (IQ) was entered as a correlated factor. The findings support a cascading developmental pathway to ADHD symptoms mediated by early-onset and severe epilepsy in the first 2 years of life. This warrants detailed investigation of seizure characteristics and cognitive and behavioral sequelae associated with ADHD from early in life, to further the understanding of the association between ADHD and early-onset epilepsy across syndromic and non-syndromic populations.

Perinatal adversities in tuberous sclerosis complex: Determinants and neurodevelopmental outcomes

AIM

To examine the association between perinatal adversities and neurodevelopmental outcome in tuberous sclerosis complex (TSC).

METHOD

The Tuberous Sclerosis 2000 study is a prospective, longitudinal UK study of TSC. In phase 1, mutation type, TSC family history, tuber characteristics, presence of cardiac rhabdomyomas, seizure characteristics, and intellectual ability were assessed in 125 children affected with TSC (64 females, 61 males; median age 39mo, range 4-254). In phase 2, 88 participants (49 females, 39 males; median age 148mo, range 93-323) were assessed for neurodevelopmental outcomes including intellectual ability, autism spectrum disorder, and attention-deficit/hyperactivity disorder. Perinatal histories of 88 participants with TSC and 80 unaffected siblings were collected retrospectively using the Obstetric Enquiry Schedule and coded with a modified Gillberg Optimality Scale to measure levels of perinatal adversity. Data were analysed using Mann-Whitney U tests, Spearman's rank correlation, and linear regression with robust standard errors.

RESULTS

Children with familial TSC experienced significantly greater perinatal adversity than unaffected siblings. Perinatal adversity was higher in children with TSC-affected mothers than those with unaffected mothers. There was no significant association between perinatal adversities and neurodevelopmental outcomes after controlling for confounders.

INTERPRETATION

Maternal TSC is a significant marker of elevated perinatal risk in addition to risks incurred by fetal genotype. Pregnancies complicated by maternal or fetal TSC require higher vigilance, and mechanisms underlying increased perinatal adversity require further research.

WHAT THIS PAPER ADDS

Higher perinatal adversity is associated with familial tuberous sclerosis complex (TSC). Maternal TSC was associated with higher frequencies of several perinatal risk markers. Paternal TSC was not associated with higher levels of perinatal adversity. Perinatal adversity levels in TSC1 and TSC2 subgroups did not differ significantly. Perinatal adversities were not associated with neurodevelopmental outcomes.

White matter disruptions related to inattention and autism spectrum symptoms in tuberous sclerosis complex

Tuberous sclerosis complex is a rare genetic multisystem condition that is associated with a high prevalence of neurodevelopmental disorders such as autism and attention-deficit/hyperactivity disorder. The underlying neural mechanisms of the emergence of these symptom domains in tuberous sclerosis complex remain unclear. Here, we use fixel-based analysis of diffusion-weighted imaging, which allows for the differentiation between multiple fibre populations within a voxel, to compare white matter properties in 16 participants with tuberous sclerosis complex (aged 11-19) and 12 age and sex matched control participants. We further tested associations between white matter alterations and autism and inattention symptoms as well as cognitive ability in participants with tuberous sclerosis complex. Compared to controls, participants with tuberous sclerosis complex showed reduced fibre density cross-section (FDC) in the dorsal branch of right superior longitudinal fasciculus and bilateral inferior longitudinal fasciculus, reduced fibre density (FD) in bilateral tapetum, and reduced fibre cross-section (FC) in the ventral branch of right superior longitudinal fasciculus. In participants with tuberous sclerosis complex, the extent of FDC reductions in right superior longitudinal fasciculus was significantly associated with autism traits (social communication difficulties and restricted, repetitive behaviours), whereas FDC reductions in right inferior longitudinal fasciculus were associated with inattention. The observed white matter alterations were unrelated to cognitive ability. Our findings shed light on the fibre-specific biophysical properties of white matter alterations in tuberous sclerosis complex and suggest that these regional changes are selectively associated with the severity of neurodevelopmental symptoms.

Understanding the nature of face processing in early autism: A prospective study

Dimensional approaches to psychopathology interrogate the core neurocognitive domains interacting at the individual level to shape diagnostic symptoms. Embedding this approach in prospective longitudinal studies could transform our understanding of the mechanisms underlying neurodevelopmental disorders. Such designs require us to move beyond traditional group comparisons and determine which domain-specific alterations apply at the level of the individual, and whether they vary across distinct phenotypic subgroups. As a proof of principle, this study examines how the domain of face processing contributes to the emergence of autism spectrum disorder (ASD). We used an event-related potentials (ERPs) task in a cohort of 8-month-old infants with (n = 148) and without (n = 68) an older sibling with ASD, and combined traditional case-control comparisons with machine-learning techniques for prediction of social traits and ASD diagnosis at 36 months, and Bayesian hierarchical clustering for stratification into subgroups. A broad profile of alterations in the time-course of neural processing of faces in infancy was predictive of later ASD, with a strong convergence in ERP features predicting social traits and diagnosis. We identified two main subgroups in ASD, defined by distinct patterns of neural responses to faces, which differed on later sensory sensitivity. Taken together, our findings suggest that individual differences between infants contribute to the diffuse pattern of alterations predictive of ASD in the first year of life. Moving from group-level comparisons to pattern recognition and stratification can help to understand and reduce heterogeneity in clinical cohorts, and improve our understanding of the mechanisms that lead to later neurodevelopmental outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Alpha oscillatory activity during attentional control in children with Autism Spectrum Disorder (ASD), Attention-Deficit/Hyperactivity Disorder (ADHD), and ASD+ADHD

BACKGROUND

Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) share impairments in top-down and bottom-up modulation of attention. However, it is not yet well understood if co-occurrence of ASD and ADHD reflects a distinct or additive profile of attention deficits. We aimed to characterise alpha oscillatory activity (stimulus-locked alpha desynchronisation and prestimulus alpha) as an index of integration of top-down and bottom-up attentional processes in ASD and ADHD.

METHODS

Children with ASD, ADHD, comorbid ASD+ADHD, and typically-developing children completed a fixed-choice reaction-time task ('Fast task') while neurophysiological activity was recorded. Outcome measures were derived from source-decomposed neurophysiological data. Main measures of interest were prestimulus alpha power and alpha desynchronisation (difference between poststimulus and prestimulus alpha). Poststimulus activity linked to attention allocation (P1, P3), attentional control (N2), and cognitive control (theta synchronisation, 100-600 ms) was also examined. ANOVA was used to test differences across diagnostics groups on these measures. Spearman's correlations were used to investigate the relationship between attentional control processes (alpha oscillations), central executive functions (theta synchronisation), early visual processing (P1), and behavioural performance.

RESULTS

Children with ADHD (ADHD and ASD+ADHD) showed attenuated alpha desynchronisation, indicating poor integration of top-down and bottom-up attentional processes. Children with ADHD showed reduced N2 and P3 amplitudes, while children with ASD (ASD and ASD+ADHD) showed greater N2 amplitude, indicating atypical attentional control and attention allocation across ASD and ADHD. In the ASD group, prestimulus alpha and theta synchronisation were negatively correlated, and alpha desynchronisation and theta synchronisation were positively correlated, suggesting an atypical association between attentional control processes and executive functions.

CONCLUSIONS

ASD and ADHD are associated with disorder-specific impairments, while children with ASD+ADHD overall presented an additive profile with attentional deficits of both disorders. Importantly, these findings may inform the improvement of transdiagnostic procedures and optimisation of personalised intervention approaches.

Systematic Review and Meta-analysis: The Science of Early-Life Precursors and Interventions for Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To evaluate which early neurocognitive and behavioral precursors are associated with the development of attention-deficit/hyperactivity disorder (ADHD) and whether these are currently targeted in early interventions.

METHOD

We conducted 2 systematic reviews and meta-analyses of empirical studies to examine the following: (1) early-life (0-5 years) neurocognitive and behavioral precursors associated with familial likelihood for ADHD, an early ADHD diagnosis/elevated ADHD symptoms, and/or the presence of later-childhood ADHD; and (2) interventions delivered to children aged 0 to 5 years targeting the identified precursors or measuring these as outcomes. Standardized mean differences (Hedges' g) and pre-post-treatment change scores (SMD) were computed.

RESULTS

A total of 149 studies (165,095 participants) investigating 8 neurocognitive and behavioral domains met inclusion criteria for part 1. Multi-level random-effects meta-analyses on 136 studies revealed significant associations between ADHD and poorer cognitive (g = -0.46 [95% CIs: -0.59, -0.33]), motor (g = -0.35 [CIs: -0.48, -0.21]) and language (g = -0.43 [CIs: -0.66, -0.19]) development, social (g = 0.23 [CIs: 0.03, 0.43]) and emotional (g = 0.46 [CIs: 0.33, 0.58]) difficulties, early regulatory (g = 0.30 [CIs: 0.18, 0.43]) and sleep (g = 0.29 [CIs: 0.14, 0.44]) problems, sensory atypicalities (g = 0.52 [CIs: 0.16, 0.88]), elevated activity levels (g = 0.54 [CIs: 0.37, 0.72]), and executive function difficulties (g = 0.34 [CIs: 0.05, 0.64] to -0.87 [CIs: -1.35, -0.40]). A total of 32 trials (28 randomized, 4 nonrandomized, 3,848 participants) testing early interventions that targeted the identified precursors met inclusion criteria for part 2. Multi-level random-effects meta-analyses on 22 studies revealed significant intervention-related improvements in ADHD symptoms (SMD = 0.43 [CIs: 0.22, 0.64]) and working memory (SMD = 0.37 [CIs: 0.06, 0.69]).

CONCLUSION

Children aged 0 to 5 years with current or later-emerging ADHD are likely to experience difficulties in multiple neurocognitive/behavioral functions. Early interventions show some effectiveness in reducing ADHD symptoms, but their effects on neurocognitive/behavioral difficulties require further study.

Oscillatory neural network alterations in young people with tuberous sclerosis complex and associations with co-occurring symptoms of autism spectrum disorder and attention-deficit/hyperactivity disorder

Tuberous sclerosis complex (TSC) is a genetic disorder caused by mutations on the TSC1/TSC2 genes, which result in alterations in molecular signalling pathways involved in neurogenesis and hamartomas in the brain and other organs. TSC carries a high risk for autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), although the reasons for this are unclear. One proposal is that TSC-related alterations in molecular signalling during neurogenesis lead to atypical development of neural networks, which are involved in the occurrence of ASD and ADHD in TSC. We investigated this proposal in young people with TSC who have been studied longitudinally since their diagnosis in childhood. Electroencephalography (EEG) was used to examine oscillatory connectivity in functional neural networks and local and global network organisation during three tasks (resting-state, attentional and inhibitory control Go/Nogo task, upright and inverted face processing task) in participants with TSC (n = 48) compared to an age- and sex-matched group of typically developing Controls (n = 20). Compared to Controls, the TSC group showed hypoconnected neural networks in the alpha frequency during the resting-state and in the theta and alpha frequencies during the Go/Nogo task (P ≤ .008), as well as reduced local network organisation in the theta and alpha frequencies during the Go/Nogo task (F = 3.95, P = .010). There were no significant group differences in network metrics during the face processing task. Increased connectivity in the hypoconnected alpha-range resting-state network was associated with greater ASD and inattentive ADHD symptoms (rho≥.40, P ≤ .036). Reduced local network organisation in the theta-range during the Go/Nogo task was significantly associated with higher hyperactive/impulsive ADHD symptoms (rho = -.43, P = .041). These findings suggest that TSC is associated with widespread hypoconnectivity in neural networks and support the proposal that altered network function may be involved in the co-occurrence of ASD and ADHD in TSC.

A systematic review and meta-analysis of altered electrophysiological markers of performance monitoring in Obsessive-Compulsive Disorder (OCD), Gilles de la Tourette Syndrome (GTS), Attention-Deficit/Hyperactivity disorder (ADHD) and Autism

Altered performance monitoring is implicated in obsessive-compulsive disorder (OCD), Gilles de la Tourette syndrome (GTS), attention-deficit/hyperactivity disorder (ADHD) and autism. We conducted a systematic review and meta-analysis of electrophysiological correlates of performance monitoring (error-related negativity, ERN; error positivity, Pe; feedback-related negativity, FRN; feedback-P3) in individuals with OCD, GTS, ADHD or autism compared to control participants, or associations between correlates and symptoms/traits of these conditions. Meta-analyses on 97 studies (5890 participants) showed increased ERN in OCD (Hedge's g = 0.54[CIs:0.44,0.65]) and GTS (g = 0.99[CIs:0.05,1.93]). OCD also showed increased Pe (g = 0.51[CIs:0.21,0.81]) and FRN (g = 0.50[CIs:0.26,0.73]). ADHD and autism showed reduced ERN (ADHD: g=-0.47[CIs:-0.67,-0.26]; autism: g=-0.61[CIs:-1.10,-0.13]). ADHD also showed reduced Pe (g=-0.50[CIs:-0.69,-0.32]). These findings suggest overlap in electrophysiological markers of performance monitoring alterations in four common neurodevelopmental conditions, with increased amplitudes of the markers in OCD and GTS and decreased amplitudes in ADHD and autism. Implications of these findings in terms of shared and distinct performance monitoring alterations across these neurodevelopmental conditions are discussed. PROSPERO pre-registration code: CRD42019134612.

Pharmacological approaches of ADHD

Abstract Body

Adults with ADHD describe self-medicating with cannabis. A small number of psychiatrists in the US prescribe cannabis medication for ADHD, despite there being no evidence from trials. The EMA-C trial (Experimental Medicine in ADHD-Cannabinoids) was a pilot randomised placebo-controlled experimental study of a cannabinoid medication, Sativex Oromucosal Spray, in 30 adults with ADHD. The primary outcome was cognitive performance and activity level using the QbTest. Secondary outcomes included ADHD and emotional lability (EL) symptoms. From 17.07.14-18.06.15, 30 participants were randomly assigned to the active (n=15) or placebo (n=15) group. For the primary outcome, no significant difference was found in the intent-to-treat analysis although the overall pattern of scores was such that the active group usually had scores that were better than the placebo group (Est=-0.17,95%CI-0.40-0.07, p=0.16, n=15/11 active/placebo). For secondary outcomes Sativex was associated with a nominally significant improvement in hyperactivity/impulsivity (p=0.03) and a cognitive measure of inhibition (p=0.05), and a trend towards improvement for inattention (p=0.10) and EL (p=0.11). Per-protocol effects were higher. Results did not meet significance following adjustment for multiple testing. One serious (muscular seizures/spasms) and three mild adverse events occurred in the active group and one serious (cardiovascular problems) adverse event in the placebo group. Adults with ADHD may represent a subgroup of individuals who experience a reduction of symptoms and no cognitive impairments following cannabinoid use. While not definitive, this study provides preliminary evidence supporting the self-medication theory of cannabis use in ADHD and the need for further studies of the endocannabinoid system in ADHD.

Disclosure

During this work-RC was a Ph.D. student funded by a grant to PA from Vifor Pharma. PA received funds (consultancy/sponsored talks/research/education) from Shire, Lilly, Novartis, Janssen, PCMScientific, Vifor Pharma, QBTech. Sativex was free from GW Pharm

Attentive brain states in infants with and without later autism

Early difficulties in engaging attentive brain states in social settings could affect learning and have cascading effects on social development. We investigated this possibility using multichannel electroencephalography during a face/non-face paradigm in 8-month-old infants with (FH, n = 91) and without (noFH, n = 40) a family history of autism spectrum disorder (ASD). An event-related potential component reflecting attention engagement, the Nc, was compared between FH infants who received a diagnosis of ASD at 3 years of age (FH-ASD; n = 19), FH infants who did not (FH-noASD; n = 72) and noFH infants (who also did not, hereafter noFH-noASD; n = 40). 'Prototypical' microstates during social attention were extracted from the noFH-noASD group and examined in relation to later categorical and dimensional outcome. Machine-learning was used to identify the microstate features that best predicted ASD and social adaptive skills at three years. Results suggested that whilst measures of brain state timing were related to categorical ASD outcome, brain state strength was related to dimensional measures of social functioning. Specifically, the FH-ASD group showed shorter Nc latency relative to other groups, and duration of the attentive microstate responses to faces was informative for categorical outcome prediction. Reduced Nc amplitude difference between faces with direct gaze and a non-social control stimulus and strength of the attentive microstate to faces contributed to the prediction of dimensional variation in social skills. Taken together, this provides consistent evidence that atypical attention engagement precedes the emergence of difficulties in socialization and indicates that using the spatio-temporal characteristics of whole-brain activation to define brain states in infancy provides an important new approach to understanding of the neurodevelopmental mechanisms that lead to ASD.

Uncovering neurodevelopmental paths to autism spectrum disorder through an integrated analysis of developmental measures and neural sensitivity to faces

BACKGROUND

Autism spectrum disorder (ASD) is highly heterogeneous in its etiology and manifestation. The neurobiological processes underlying ASD development are reflected in multiple features, from behaviour and cognition to brain functioning. An integrated analysis of these features may optimize the identification of these processes.

METHODS

We examined cognitive and adaptive functioning and ASD symptoms between 8 and 36 months in 161 infants at familial high risk for ASD and 71 low-risk controls; we also examined neural sensitivity to eye gaze at 8 months in a subsample of 140 high-risk and 61 low-risk infants. We used linked independent component analysis to extract patterns of variation across domains and development, and we selected the patterns significantly associated with clinical classification at 36 months.

RESULTS

An early process at 8 months, indicating high levels of functioning and low levels of symptoms linked to higher attention to gaze shifts, was reduced in infants who developed ASD. A longitudinal process of increasing functioning and low levels of symptoms was reduced in infants who developed ASD, and another process suggesting a stagnation in cognitive functioning at 24 months was increased in infants who developed ASD.

LIMITATIONS

Although the results showed a clear significant trend relating to clinical classification, we found substantial overlap between groups.

CONCLUSION

We uncovered underlying processes that acted together early in development and were associated with clinical outcomes. Our results highlighted the complexity of emerging ASD, which goes beyond the borders of clinical categories. Future work should integrate genetic data to investigate the specific genetic risks linked to these processes.

Actigraph-Measured Movement Correlates of Attention-Deficit/Hyperactivity Disorder (ADHD) Symptoms in Young People with Tuberous Sclerosis Complex (TSC) with and without Intellectual Disability and Autism Spectrum Disorder (ASD)

Actigraphy, an objective measure of motor activity, reliably indexes increased movement levels in attention-deficit/hyperactivity disorder (ADHD) and may be useful for diagnosis and treatment-monitoring. However, actigraphy has not been examined in complex neurodevelopmental conditions. This study used actigraphy to objectively measure movement levels in individuals with a complex neurodevelopmental genetic disorder, tuberous sclerosis (TSC). Thirty participants with TSC (11–21 years, 20 females, IQ = 35–108) underwent brief (approximately 1 h) daytime actigraph assessment during two settings: movie viewing and cognitive testing. Multiple linear regressions were used to test associations between movement measurements and parent-rated ADHD symptoms. Correlations were used to examine associations between actigraph measures and parent-rated ADHD symptoms and other characteristics of TSC (symptoms of autism spectrum disorder (ASD), intellectual ability (IQ), epilepsy severity, cortical tuber count). Higher movement levels during movies were associated with higher parent-rated ADHD symptoms. Higher ADHD symptoms and actigraph-measured movement levels during movies were positively associated with ASD symptoms and negatively associated with IQ. Inter-individual variability of movement during movies was not associated with parent-rated hyperactivity or IQ but was negatively associated with ASD symptoms. There were no associations with tuber count or epilepsy. Our findings suggest that actigraph-measured movement provides a useful correlate of ADHD in TSC.

Neural and behavioural indices of face processing in siblings of children with autism spectrum disorder (ASD): A longitudinal study from infancy to mid-childhood

Impaired face processing is proposed to play a key role in the early development of autism spectrum disorder (ASD) and to be an endophenotypic trait which indexes genetic risk for the disorder. However, no published work has examined the development of face processing abilities from infancy into the school-age years and how they relate to ASD symptoms in individuals with or at high-risk for ASD. In this novel study we investigated neural and behavioural measures of face processing at age 7 months and again in mid-childhood (age 7 years) as well as social-communication and sensory symptoms in siblings at high (n = 42) and low (n = 35) familial risk for ASD. In mid-childhood, high-risk siblings showed atypical P1 and N170 event-related potential correlates of face processing and, for high-risk boys only, poorer face and object recognition ability compared to low-risk siblings. These neural and behavioural atypicalities were associated with each other and with higher social-communication and sensory symptoms in mid-childhood. Additionally, more atypical neural correlates of object (but not face) processing in infancy were associated with less right-lateralised (more atypical) N170 amplitudes and greater social-communication problems in mid-childhood. The implications for models of face processing in ASD are discussed.

Long-term cognitive outcomes in tuberous sclerosis complex

AIM

To investigate the interdependence between risk factors associated with long-term intellectual development in individuals with tuberous sclerosis complex (TSC).

METHOD

The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of individuals with TSC. In phase 1 of the study, baseline measures of intellectual ability, epilepsy, cortical tuber load, and mutation were obtained for 125 children (63 females, 62 males; median age=39mo). In phase 2, at an average of 8 years later, intellectual abilities were estimated for 88 participants with TSC and 35 unaffected siblings. Structural equation modelling was used to determine the risk pathways from genetic mutation through to IQ at phase 2.

RESULTS

Intellectual disability was present in 57% of individuals with TSC. Individuals without intellectual disability had significantly lower mean IQ compared to unaffected siblings, supporting specific genetic factors associated with intellectual impairment. Individuals with TSC who had a slower gain in IQ from infancy to middle childhood were younger at seizure onset and had increased infant seizure severity. Structural equation modelling indicated indirect pathways from genetic mutation, to tuber count, to seizure severity in infancy, through to IQ in middle childhood and adolescence.

INTERPRETATION

Early-onset and severe epilepsy in the first 2 years of life are associated with increased risk of long-term intellectual disability in individuals with TSC, emphasizing the importance of early and effective treatment or prevention of epilepsy.

WHAT THIS PAPER ADDS

Intellectual disability was present in 57% of individuals with tuberous sclerosis complex (TSC). Those with TSC without intellectual disability had significantly lower mean IQ compared to unaffected siblings. Earlier onset and greater severity of seizures in the first 2 years were observed in individuals with a slower gain in intellectual ability. Risk pathways through seizures in the first 2 years predict long-term cognitive outcomes in individuals with TSC.

No evidence of associations between ADHD and event-related brain potentials from a continuous performance task in a population-based sample of adolescent twins

We investigated key event-related brain potential markers (ERPs) derived from a flanked continuous performance task (CPT) and whether these would show phenotypic associations with ADHD (attention-deficit/hyperactivity disorder) in a population-based sample. We further explored whether there was preliminary evidence that such ERPs could also index genetic risk for ADHD (depending on finding phenotypic associations). Sixty-seven male-only twin pairs (N = 134; aged 12–15) from a subsample of the Twins’ Early Development Study, concordant and discordant for ADHD symptoms, performed the flanked CPT (or CPT-OX) while electroencephalography (EEG) was recorded. ERPs were obtained for cue (P3, CNV or contingency negative variation), go (P3, N2) and nogo trials (P3, N2). We found no phenotypic associations between CPT-derived ERPs and ADHD—the sizes of the estimated phenotypic correlations were nonsignificant and very small (r’s = -.11 to .04). Twin-model fitting analyses using structural equation modelling provided preliminary evidence that some of the ERPs were heritable (with the most robust effect for go-P3 latency), but there was limited evidence of any genetic associations between ERPs and ADHD, although with the caveat that our sample was small and hence had limited power. Overall, unlike in previous research, there was no evidence of phenotypic (nor preliminary evidence for genetic) associations between ADHD and CPT-derived ERPs in this study. Hence, it may be currently premature for genetic analyses of ADHD to be guided by CPT-derived ERP parameters (unlike alternative cognitive-neurophysiological approaches which may be more promising). Further research with better-powered, population-based, genetically-informative and cross-disorder samples are required, which could be facilitated by emerging mobile EEG technologies.

Corrigendum: Characterizing the Interplay Between Autism Spectrum Disorder and Comorbid Medical Conditions: An Integrative Review

[This corrects the article DOI: 10.3389/fpsyt.2018.00751.].

Oscillatory neural networks underlying resting-state, attentional control and social cognition task conditions in children with ASD, ADHD and ASD+ADHD

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are common and impairing neurodevelopmental disorders that frequently co-occur. The neurobiological mechanisms involved in ASD and ADHD are not fully understood. However, alterations in large-scale neural networks have been proposed as core deficits in both ASD and ADHD and may help to disentangle the neurobiological basis of these disorders and their co-occurrence. In this study, we examined similarities and differences in large-scale oscillatory neural networks between boys aged 8-13 years with ASD (n = 19), ADHD (n = 18), ASD + ADHD (n = 29) and typical development (Controls, n = 26). Oscillatory neural networks were computed using graph-theoretical methods from electroencephalographic (EEG) data collected during an eyes-open resting-state and attentional control and social cognition tasks in which we previously reported disorder-specific atypicalities in oscillatory power and event-related potentials (ERPs). We found that children with ASD showed significant hypoconnectivity in large-scale networks during all three task conditions compared to children without ASD. In contrast, children with ADHD showed significant hyperconnectivity in large-scale networks during the attentional control and social cognition tasks, but not during the resting-state, compared to children without ADHD. Children with co-occurring ASD + ADHD did not differ from children with ASD when paired with this group and vice versa when paired with the ADHD group, indicating that these children showed both ASD-like hypoconnectivity and ADHD-like hyperconnectivity. Our findings suggest that ASD and ADHD are associated with distinct alterations in large-scale oscillatory networks, and these atypicalities present together in children with both disorders. These alterations appear to be task-independent in ASD but task-related in ADHD, and may underlie other neurocognitive atypicalities in these disorders.

Secular changes in severity of intellectual disability in tuberous sclerosis complex: A reflection of improved identification and treatment of epileptic spasms?

Tuberous sclerosis complex (TSC) is a multisystem genetic disorder caused by mutations in TSC1 or TSC2. Epilepsy occurs in 80%-90% of affected individuals during their lifetime, and up to one-third of children with TSC will develop epileptic (infantile) spasms, for which vigabatrin has been shown to be particularly effective. Epilepsy severity and epileptic spasms are consistent markers of risk for the development of intellectual impairment in TSC. Although previous studies demonstrate a bimodal distribution of intellectual ability in TSC, recent findings suggest a unimodal distribution, which may reflect a change in IQ distribution over time. We compared 3 large historical UK cohorts of TSC (n = 331) that show varied distributions of intellectual ability, first ruling out differences in study methodology. Later-born individuals had a higher frequency of reported spasms and higher likelihood of vigabatrin administration, but were less likely to have profound intellectual impairment, compared to the earlier-born individuals. Our findings suggest that epileptic spasms went undetected in the older patients and therefore were not treated, leading to a higher occurrence of profound impairment, whereas the later born cohort had better access to treatment. These findings support the importance of early identification and treatment of seizures in TSC.

Characterizing the Interplay Between Autism Spectrum Disorder and Comorbid Medical Conditions: An Integrative Review

Co-occurring medical disorders and associated physiological abnormalities in individuals with autism spectrum disorder (ASD) may provide insight into causal pathways or underlying biological mechanisms. Here, we review medical conditions that have been repeatedly highlighted as sharing the strongest associations with ASD-epilepsy, sleep, as well as gastrointestinal and immune functioning. We describe within each condition their prevalence, associations with behavior, and evidence for successful treatment. We additionally discuss research aiming to uncover potential aetiological mechanisms. We then consider the potential interaction between each group of conditions and ASD and, based on the available evidence, propose a model that integrates these medical comorbidities in relation to potential shared aetiological mechanisms. Future research should aim to systematically examine the interactions between these physiological systems, rather than considering these in isolation, using robust and sensitive biomarkers across an individual's development. A consideration of the overlap between medical conditions and ASD may aid in defining biological subtypes within ASD and in the development of specific targeted interventions.

Cannabinoids in attention-deficit/hyperactivity disorder: A randomised-controlled trial

Adults with ADHD describe self-medicating with cannabis, with some reporting a preference for cannabis over ADHD medications. A small number of psychiatrists in the US prescribe cannabis medication for ADHD, despite there being no evidence from randomised controlled studies. The EMA-C trial (Experimental Medicine in ADHD-Cannabinoids) was a pilot randomised placebo-controlled experimental study of a cannabinoid medication, Sativex Oromucosal Spray, in 30 adults with ADHD. The primary outcome was cognitive performance and activity level using the QbTest. Secondary outcomes included ADHD and emotional lability (EL) symptoms. From 17.07.14 to 18.06.15, 30 participants were randomly assigned to the active (n=15) or placebo (n=15) group. For the primary outcome, no significant difference was found in the ITT analysis although the overall pattern of scores was such that the active group usually had scores that were better than the placebo group (Est=-0.17, 95%CI-0.40 to 0.07, p=0.16, n=15/11 active/placebo). For secondary outcomes Sativex was associated with a nominally significant improvement in hyperactivity/impulsivity (p=0.03) and a cognitive measure of inhibition (p=0.05), and a trend towards improvement for inattention (p=0.10) and EL (p=0.11). Per-protocol effects were higher. Results did not meet significance following adjustment for multiple testing. One serious (muscular seizures/spasms) and three mild adverse events occurred in the active group and one serious (cardiovascular problems) adverse event in the placebo group. Adults with ADHD may represent a subgroup of individuals who experience a reduction of symptoms and no cognitive impairments following cannabinoid use. While not definitive, this study provides preliminary evidence supporting the self-medication theory of cannabis use in ADHD and the need for further studies of the endocannabinoid system in ADHD.

Callous-unemotional traits moderate executive function in children with ASD and ADHD: A pilot event-related potential study

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Children with ASD and ADHD show varied and heterogeneous executive function (EF) profiles.

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Typical or enhanced EF has been demonstrated in individuals with callous-unemotional (CU) traits.

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We investigated the effect of CU traits on event-related potential (ERP) responses during a cued continuous performance test (CPT-OX) in children with ASD, ADHD and co-occurring ASD + ADHD.

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Children with ASD and high CU traits showed better conflict monitoring compared to children with ASD and low CU traits.

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Increased CU traits may be associated with cognitive strengths in children with ASD.

Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are associated with varied executive function (EF) difficulties. Callous-unemotional (CU) traits, a proposed antecedent of adult psychopathy, are often associated with intact or enhanced EF. Here we test whether CU traits may therefore modulate EF in ASD and ADHD, in which EF is typically impaired. We collected CU traits and measured event-related potentials (ERPs) that index EF during a cued-continuous performance test (CPT-OX) in boys with ASD, ADHD, comorbid ASD + ADHD and typical controls. We examined attentional orienting at cues (Cue-P3), inhibitory processing at non-targets (NoGo-P3) and conflict monitoring between target and non-target trials (Go-N2 vs. NoGo-N2). In children with ASD, higher CU traits were associated with an enhanced increase in N2 amplitude in NoGo trials compared to Go trials, which suggests relatively superior conflict monitoring and a potential cognitive strength associated with CU traits. The results emphasise the importance of considering the effects of co-occurring traits in the assessment of heterogeneity of EF profiles in neurodevelopmental disorders.

Response time variability under slow and fast-incentive conditions in children with ASD, ADHD and ASD+ADHD

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) show significant behavioural and genetic overlap. Both ADHD and ASD are characterised by poor performance on a range of cognitive tasks. In particular, increased response time variability (RTV) is a promising indicator of risk for both ADHD and ASD. However, it is not clear whether different indices of RTV and changes to RTV according to task conditions are able to discriminate between the two disorders.

METHODS

Children with ASD (n = 19), ADHD (n = 18), ASD + ADHD (n = 29) and typically developing controls (TDC; n = 26) performed a four-choice RT task with slow-baseline and fast-incentive conditions. Performance was characterised by mean RT (MRT), standard deviation of RT (SD-RT), coefficient of variation (CV) and ex-Gaussian distribution measures of Mu, Sigma and Tau.

RESULTS

In the slow-baseline condition, categorical diagnoses and trait measures converged to indicate that children with ADHD-only and ASD + ADHD demonstrated increased MRT, SD-RT, CV and Tau compared to TDC and ASD-only. Importantly, greater improvement in MRT, SD-RT and Tau was demonstrated in ADHD and ASD + ADHD from slow-baseline to fast-incentive conditions compared to TDC and ASD-only.

CONCLUSIONS

Slower and more variable RTs are markers of ADHD compared to ASD and typically developing controls during slow and less rewarding conditions. Energetic factors and rewards improve task performance to a greater extent in children with ADHD compared to children with ASD. These findings suggest that RTV can be distinguished in ASD, ADHD and ASD + ADHD based on the indices of variability used and the conditions in which they are elicited. Further work identifying neural processes underlying increased RTV is warranted, in order to elucidate disorder-specific and disorder-convergent aetiological pathways.

Immune signatures and disorder-specific patterns in a cross-disorder gene expression analysis

BACKGROUND

Recent studies point to overlap between neuropsychiatric disorders in symptomatology and genetic aetiology.

AIMS

To systematically investigate genomics overlap between childhood and adult attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD) and major depressive disorder (MDD).

METHOD

Analysis of whole-genome blood gene expression and genetic risk scores of 318 individuals. Participants included individuals affected with adult ADHD (n = 93), childhood ADHD (n = 17), MDD (n = 63), ASD (n = 51), childhood dual diagnosis of ADHD-ASD (n = 16) and healthy controls (n = 78).

RESULTS

Weighted gene co-expression analysis results reveal disorder-specific signatures for childhood ADHD and MDD, and also highlight two immune-related gene co-expression modules correlating inversely with MDD and adult ADHD disease status. We find no significant relationship between polygenic risk scores and gene expression signatures.

CONCLUSIONS

Our results reveal disorder overlap and specificity at the genetic and gene expression level. They suggest new pathways contributing to distinct pathophysiology in psychiatric disorders and shed light on potential shared genomic risk factors.

Early developmental pathways to autism spectrum disorder in tuberous sclerosis complex

Purpose

– Tuberous sclerosis complex (TSC) is a genetic disorder with a high prevalence of autism spectrum disorder (ASD), yet no single genetic, neurological or neurophysiological risk marker is necessary or sufficient to increase risk for ASD. This paper aims to discuss the utility of adopting a developmental perspective.

Design/methodology/approach

– The increasing number of TSC infants presenting with abnormalities prenatally provides a unique opportunity to study risk pathways to ASD from birth. Here, the authors review findings to date that support the investigation of infants with TSC to further our understanding of typical and atypical development.

Findings

– Evidence has accumulated from studies of infants at familial risk for ASD (“baby siblings”) to suggest that early markers of ASD are present in the first year of life. The early waves of prospective studies of infants with TSC indicate dynamic changes in developmental trajectories to ASD and are likely to provide insight into cascading effects of brain “insult” early in development. Emerging evidence of phenotypic and biological homology between syndromic and idiopathic cases of ASD supports the notion of a convergence of risk factors on a final common pathway in ASD.

Originality/value

– The delineation of brain-based biomarkers of risk, prediction and treatment response in TSC will be critical in aiding the development of targeted intervention and prevention strategies for those infants at high risk of poorer developmental outcomes.

Autism diagnosis differentiates neurophysiological responses to faces in adults with tuberous sclerosis complex

Background

Autism spectrum disorder (ASD) is a common and highly heritable neurodevelopmental disorder that is likely to be the outcome of complex aetiological mechanisms. One strategy to provide insight is to study ASD within tuberous sclerosis complex (TSC), a rare disorder with a high incidence of ASD, but for which the genetic cause is determined. Individuals with ASD consistently demonstrate face processing impairments, but these have not been examined in adults with TSC using event-related potentials (ERPs) that are able to capture distinct temporal stages of processing.

Methods

For adults with TSC (n = 14), 6 of which had a diagnosis of ASD, and control adults (n = 13) passively viewed upright and inverted human faces with direct or averted gaze, with concurrent EEG recording. Amplitude and latency of the P1 and N170 ERPs were measured.

Results

Individuals with TSC + ASD exhibited longer N170 latencies to faces compared to typical adults. Typical adults and adults with TSC-only exhibited longer N170 latency to inverted versus upright faces, whereas individuals with TSC + ASD did not show latency differences according to face orientation. In addition, individuals with TSC + ASD showed increased N170 latency to averted compared to direct gaze, which was not demonstrated in typical adults. A reduced lateralization was shown for the TSC + ASD groups on P1 and N170 amplitude.

Conclusions

The findings suggest that individuals with TSC + ASD may have similar electrophysiological abnormalities to idiopathic ASD and are suggestive of developmental delay. Identifying brain-based markers of ASD that are similar in TSC and idiopathic cases is likely to help elucidate the risk pathways to ASD.

Electronic supplementary material

The online version of this article (doi:10.1186/s11689-015-9129-2) contains supplementary material, which is available to authorized users.

Intellectual abilities in tuberous sclerosis complex: risk factors and correlates from the Tuberous Sclerosis 2000 Study

BACKGROUND

Tuberous sclerosis complex (TSC) is associated with intellectual disability, but the risk pathways are poorly understood.

METHOD

The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of the natural history of TSC. One hundred and twenty-five UK children age 0-16 years with TSC and born between January 2001 and December 2006 were studied. Intelligence was assessed using standardized measures at ≥2 years of age. The age of onset of epilepsy, the type of seizure disorder, the frequency and duration of seizures, as well as the response to treatment was assessed at interview and by review of medical records. The severity of epilepsy in the early years was estimated using the E-Chess score. Genetic studies identified the mutations and the number of cortical tubers was determined from brain scans.

RESULTS

TSC2 mutations were associated with significantly higher cortical tuber count than TSC1 mutations. The extent of brain involvement, as indexed by cortical tuber count, was associated with an earlier age of onset and severity of epilepsy. In turn, the severity of epilepsy was strongly associated with the degree of intellectual impairment. Structural equation modelling supported a causal pathway from genetic abnormality to cortical tuber count to epilepsy severity to intellectual outcome. Infantile spasms and status epilepticus were important contributors to seizure severity.

CONCLUSIONS

The findings support the proposition that severe, early onset epilepsy may impair intellectual development in TSC and highlight the potential importance of early, prompt and effective treatment or prevention of epilepsy in tuberous sclerosis.

Omega-3 polyunsaturated fatty acid supplementation and cognition: A systematic review and meta-analysis

BACKGROUND

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are promoted as cognitive enhancers with consumption recommended in the general population and those with neurocognitive deficits such as attention deficit hyperactivity disorder (ADHD). However, evidence from randomised placebo-controlled trials is inconclusive.

AIMS

This study aimed to conduct a systematic review and meta-analysis examining the effect of n-3 PUFA supplementation on cognition in healthy populations and those with ADHD and related disorders (RDs).

METHODS

Databases were searched for randomised controlled trials (RCTs) in adults and school-aged children (who were healthy and typically developing (TD) or had ADHD or a related-neurodevelopmental disorder (ADHD+RD) which assessed the effects of n-3 PUFA on cognition.

RESULTS

In the 24 included studies n-3 PUFA supplementation, in the whole sample and the TD and ADHD+RD subgroup, did not show improvements in any of the cognitive performance measures. In those with low n-3 PUFA status, supplementation improved short-term memory.

CONCLUSIONS

There is marginal evidence that n-3 PUFA supplementation effects cognition in those who are n-3 PUFA deficient. However, there is no evidence of an effect in the general population or those with neurodevelopmental disorders. This has important implications given the widespread advertisement and consumption of n-3 PUFA; claims of cognitive benefit should be narrowed.

Attention and inhibition in children with ASD, ADHD and co-morbid ASD + ADHD: an event-related potential study

BACKGROUND

Substantial overlap has been reported between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Deficits in executive function (EF) are characteristic of both disorders but these impairments have not been compared directly across pure and co-morbid cases using event-related potentials (ERPs).

METHOD

Behavioural parameters and ERPs were recorded during a flankered cued-continuous performance test (CPT-OX) administered to 8-13-year-old boys with ASD (n = 19), ADHD (n = 18), co-morbid ASD + ADHD (n = 29) and typically developing controls (TD; n = 26). Preparatory processing (contingent negative variation, CNV) and attentional orienting (Cue-P3) at cues, response execution at targets (Go-P3), inhibitory processing at non-targets (NoGo-P3) and conflict monitoring between target and non-target trials (Go-N2 v. NoGo-N2) were examined.

RESULTS

Categorical diagnoses and quantitative trait measures indicated that participants with ADHD (ADHD/ASD + ADHD) made more omission errors and exhibited increased reaction-time (RT) variability and reduced amplitude of the Cue-P3 and NoGo-P3 compared to TD/ASD participants. Participants with ASD (ASD/ ASD + ADHD) demonstrated reduced N2 enhancement from Go to NoGo trials compared to TD/ADHD participants. Participants with ASD-only displayed enhanced CNV amplitude compared to ASD + ADHD and TD participants.

CONCLUSIONS

Children with ADHD show deficits in attentional orienting and inhibitory control whereas children with ASD show abnormalities in conflict monitoring and response preparation. Children with co-morbid ASD + ADHD present as an additive co-occurrence with deficits of both disorders, although non-additive effects are suggested for response preparation. Measuring ERPs that index attention and inhibition is useful in disentangling cognitive markers of ASD and ADHD and elucidating the basis of co-occurring ASD + ADHD to guide clinical assessment.

The effect of methylphenidate on very low frequency electroencephalography oscillations in adult ADHD

Altered very low-frequency electroencephalographic (VLF-EEG) activity is an endophenotype of ADHD in children and adolescents. We investigated VLF-EEG case-control differences in adult samples and the effects of methylphenidate (MPH). A longitudinal case-control study was conducted examining the effects of MPH on VLF-EEG (.02-0.2Hz) during a cued continuous performance task. 41 untreated adults with ADHD and 47 controls were assessed, and 21 cases followed up after MPH treatment, with a similar follow-up for 38 controls (mean follow-up=9.4months). Cases had enhanced frontal and parietal VLF-EEG and increased omission errors. In the whole sample, increased parietal VLF-EEG correlated with increased omission errors. After controlling for subthreshold comorbid symptoms, VLF-EEG case-control differences and treatment effects remained. Post-treatment, a time by group interaction emerged; VLF-EEG and omission errors reduced to the same level as controls, with decreased inattentive symptoms in cases. Reduced VLF-EEG following MPH treatment provides preliminary evidence that changes in VLF-EEG may relate to MPH treatment effects on ADHD symptoms; and that VLF-EEG may be an intermediate phenotype of ADHD. Further studies of the treatment effect of MPH in larger controlled studies are required to formally evaluate any causal link between MPH, VLF-EEG and ADHD symptoms.

Neural connectivity abnormalities in autism: insights from the Tuberous Sclerosis model

Autism Spectrum Disorder (ASD) is a behavioral syndrome caused by complex genetic and non-genetic risk factors. It has been proposed that these risk factors lead to alterations in the development and 'wiring' of brain circuits and hence, the emergence of ASD. Although several lines of research lend support to this theory, etiological and clinical heterogeneity, methodological issues and inconsistent findings have led to significant doubts. One of the best established, albeit rare, causes of ASD is the genetic condition Tuberous Sclerosis Complex (TSC), where 40% of individuals develop ASD. A recent study by Peters and Taquet et al. analyzed electroencephalography (EEG) data using graph theory to model neural 'connectivity' in individuals with TSC with and without ASD and cases with 'idiopathic' ASD. TSC cases exhibited global under-connectivity and abnormal network topology, whereas individuals with TSC + ASD demonstrated similar connectivity patterns to those seen in individuals with idiopathic ASD: decreased long- over short-range connectivity. The similarity in connectivity abnormalities in TSC + ASD and ASD suggest a common final pathway and provide further support for 'mis-wired' neural circuitry in ASD. The origins of the connectivity changes, and their role in mediating between the neural and the cognitive/behavioral manifestations, will require further study.Please see related research article here http://www.biomedcentral.com/1741-7015/11/54.

Neurophysiological responses to faces and gaze direction differentiate children with ASD, ADHD and ASD+ADHD

Children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) demonstrate face processing abnormalities that may underlie social impairment. Despite substantial overlap between ASD and ADHD, ERP markers of face and gaze processing have not been directly compared across pure and comorbid cases. Children with ASD (n=19), ADHD (n=18), comorbid ASD+ADHD (n=29) and typically developing (TD) controls (n=26) were presented with upright/inverted faces with direct/averted gaze, with concurrent recording of the P1 and N170 components. While the N170 was predominant in the right hemisphere in TD and ADHD, children with ASD (ASD/ASD+ADHD) showed a bilateral distribution. In addition, children with ASD demonstrated altered response to gaze direction on P1 latency and no sensitivity to gaze direction on midline-N170 amplitude compared to TD and ADHD. In contrast, children with ADHD (ADHD/ASD+ADHD) exhibited a reduced face inversion effect on P1 latency compared to TD and ASD. These findings suggest children with ASD have specific abnormalities in gaze processing and altered neural specialisation, whereas children with ADHD show abnormalities at early visual attention stages. Children with ASD+ADHD are an additive co-occurrence with deficits of both disorders. Elucidating the neural basis of the overlap between ASD and ADHD is likely to inform aetiological investigation and clinical assessment.

Shared genetic influences on ADHD symptoms and very low-frequency EEG activity: a twin study

BACKGROUND

  Attention deficit hyperactivity disorder (ADHD) is a common and highly heritable neurodevelopmental disorder with a complex aetiology. The identification of candidate intermediate phenotypes that are both heritable and genetically linked to ADHD may facilitate the detection of susceptibility genes and elucidate aetiological pathways. Very low-frequency (VLF; <0.5 Hz) electroencephalographic (EEG) activity represents a promising indicator of risk for ADHD, but it currently remains unclear as to whether it is heritable or genetically linked to the disorder.

METHODS

  Direct-current (DC)-EEG was recorded during a cognitive activation condition in 30 monozygotic and dizygotic adolescent twin pairs concordant or discordant for high ADHD symptom scores, and 37 monozygotic and dizygotic matched-control twin pairs with low ADHD symptom scores. Structural equation modelling was used to quantify the genetic and environmental contributions to the phenotypic covariance between ADHD and VLF activity.

RESULTS

  Attention deficit hyperactivity disorder was significantly associated with reduced VLF power during cognitive activation, which suggests reduced synchronization of widespread neuronal activity. Very low-frequency power demonstrated modest heritability (0.31), and the genetic correlation (-0.80) indicated a substantial degree of overlap in genetic influences on ADHD and VLF activity.

CONCLUSIONS

  Altered VLF activity is a potential candidate intermediate phenotype of ADHD, which warrants further investigation of underlying neurobiological and genetic mechanisms.

Patients' experiences of care provided by emergency care practitioners and traditional ambulance practitioners: a survey from the London Ambulance Service

Patients' experiences after receiving care from emergency care practitioners (ECPs) were compared with those after receiving care from traditional ambulance practitioners using a postal questionnaire distributed to 1658 patients in London; 888 responses were received. The responses of patients receiving care from both groups were similar and largely positive. But in two areas ("thoroughness of assessment" and "explaining what would happen next"), the care provided by ECPs was experienced as considerably better. These differences were partly explained by considerably fewer patients from ECPs being conveyed to the emergency department, suggesting that empowering ECPs to explore and explain alternatives to the emergency department improves patient satisfaction.

Qualified nurses' perceptions of the needs of suddenly bereaved family members in the accident and emergency department

This study aimed to identify qualified nurses' perceptions of the helpfulness of selected nursing actions, derived from the literature, in meeting the needs of suddenly bereaved family members in the accident and emergency (A&E) department. The effect of age, length of professional experience and death education received on the respondents' perceptions was examined. The nurse subjects' feelings of preparation for this stressful role were also identified. A self-administered, structured questionnaire using a five-point, Likert-type rating scale and two open-ended questions was developed. A non-randomized, convenience sample of 52 qualified nurses working in three A&E departments in the Greater London Area was used. Analysis of the sample's responses to the 35 nursing actions included revealed that certain activities were ranked lower in terms of their perceived helpfulness, compared to the survivors' perceptions in other studies. All three variables considered had a statistically significant correlation with the perceptions of the sample as measured by the instrument (P < 0.05, using Mann-Whitney U-test). Only 42% of the sample had received any form of death education and 56% felt unprepared for this specialist role.