A revolution for the at-risk

The case for investment in early intervention for neurodevelopmental disorders

Brain adaptation and alternative developmental trajectories

Resilience and adaptation in the face of early genetic or environmental risk has become a major interest in child psychiatry over recent years. However, we still remain far from an understanding of how developing human brains as a whole adapt to the diffuse and widespread atypical synaptic function that may be characteristic of some common developmental disorders. The first part of this paper discusses four types of whole-brain adaptation in the face of early risk: redundancy, reorganization, niche construction, and adjustment of developmental rate. The second part of the paper applies these adaptation processes specifically to autism. We speculate that key features of autism may be the end result of processes of early brain adaptation, rather than the direct consequences of ongoing neural pathology

Annual research review: Infant development, autism, and ADHD – early pathways to emerging disorders

- Background: Autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) are two of the most common neurodevelopmental disorders, with a high degree of co-occurrence. - Methods: Prospective longitudinal studies of infants who later meet criteria for ASD or ADHD offer the opportunity to determine whether the two disorders share developmental pathways. - Results: Prospective studies of younger siblings of children with autism have revealed a range of infant behavioral and neural markers associated with later diagnosis of ASD. Research on infants with later ADHD is less developed, but emerging evidence reveals a number of relations between infant measures and later symptoms of inattention and hyperactivity. - Conclusions: We review this literature, highlighting points of convergence and divergence in the early pathways to ASD and ADHD

Executive function in the first three years of life: precursors, predictors and patterns

Executive function (EF) underpins the ability to set goals and work towards those goals by co-ordinating thought and action. Its emergence during the first 3 years of life is under-studied, largely due to the limitations that early social, motor and language skills place on performance on traditional EF tasks. Nevertheless, across the fields of cognitive psychology, neuroscience, social development and temperament research, evidence is amassing of meaningful precursors and predictors of EF. This review draws together the evidence, highlighting methodological considerations and areas of theoretical debate, and identifies 4 domains critical to the development of EF: control of attention, self-regulation, processing speed and cognitive flexibility. Individual differences within these domains have clinical significance both in terms of the identification of risk markers for later executive dysfunction and for the target or delivery of early intervention to ameliorate this risk. By the end of the third year, typically-developing infants are able to selectively employ impulse control and cognitive flexibility to achieve goal-directed responses to novel situations

Sex differences in the association between infant markers and later autistic traits

BACKGROUND: Although it is well established that the prevalence of autism spectrum disorder (ASD) is higher in males than females, there is relatively little understanding of the underlying mechanisms and their developmental time course. Sex-specific protective or risk factors have often been invoked to explain these differences, but such factors are yet to be identified. METHODS: We take a developmental approach, using a prospective sample of 104 infants at high and low familial risk for ASD, to characterise sex differences in infant markers known to predict emerging autism symptoms. We examine three markers previously shown to be associated with later autistic social-communication symptoms: the Autism Observation Scale for Infants (AOSI) total score, attention disengagement speed and gaze following behaviour. Our aim was to test whether sex differences were already present in these markers at 1 year of age, which would suggest sex-specific mechanisms of risk or protection. RESULTS: While no sex differences were found in any of the three markers investigated, we found sex differences in their relationship to 3-year autism traits; all three markers significantly predicted later autism traits only in the boys. CONCLUSIONS: Previously identified ‘early autism markers’ were associated with later autism symptoms only in boys. This suggests that there may be additional moderating risk or protective factors which remain to be identified. Our findings have important implications for prospective studies in terms of directly testing for the moderating effect of sex on emerging autistic traits

Ethical dimensions of translational developmental neuroscience research in autism

Background Since the 1990s, increasing research has been devoted to the identification of biomarkers for autism to help attain more objective diagnosis; enable early prediction of prognosis; and guide individualized intervention options. Early studies focused on the identification of genetic variants associated with autism, but more recently, research has expanded to investigate neurodevelopmental markers. While ethicists have extensively discussed issues around advances in autism genomics, much less ethical scrutiny has focused on research on early neurodevelopment and on the interventions being developed as a result. Objectives We summarize the current state of the science on the identification of early markers for autism and its potential clinical applications, before providing an overview of the ethical issues arising from increasing understanding of children's neurodevelopment in very early life. Results Advances in the understanding of brain and behavioral trajectories preceding later autism diagnosis raise ethical concerns around three themes: (a) New models for understanding autism; (b) Risks and benefits of early identification and intervention; and (c) Communication of early concerns to families. These ethical issues should be further investigated in research conducted in partnership with autistic people and their families. Conclusions This paper highlights the need for ethical scrutiny of early neurodevelopmental research in autism. Scrutiny requires expertise and methods from the basic sciences and bioethics, as well as constructive collaborations among autistic people, their parents, and autism researchers to anticipate early interventions that serve the community's interests and accommodate the varied experiences and preferences of people on the spectrum and their families.</p

Alexithymia in autism: cross-sectional and longitudinal associations with social-communication difficulties, anxiety and depression symptoms

Background: Alexithymia (difficulties identifying and describing emotion) is a transdiagnostic trait implicated in social-emotional and mental health problems in the general population. Many autistic individuals experience significant social-communication difficulties and elevated anxiety/ depression and alexithymia. Nevertheless, the role of alexithymia in explaining individual variability in the quality/ severity of social-communication difficulties and/ or anxiety and depression symptoms in autism remains poorly understood. Methods: 337 adolescents and adults (autism N=179) were assessed for alexithymia on the Toronto Alexithymia Scale and for social-communication difficulties, anxiety and depression symptoms. 135 individuals (autism N=76) were followed up 12-24-months later. We used regression models to establish cross-sectional and longitudinal associations between alexithymia, social-communication difficulties, anxiety and depression symptoms. Results: Autistic individuals reported significantly higher alexithymia than comparison individuals (p<0.001, r effect size=0.48), with 47.3% of autistic females and 21.0% of autistic males meeting cut-off for clinically relevant alexithymia (score ≥61). Difficulties describing feelings were particularly associated with current self-reported social-communication difficulties (p<0.001, β=0.57, 95% CI [0.44, 0.67]) and predicted later social-communication difficulties (p=0.02, β=0.43, 95% CI [0.07, 0.82]). Difficulties identifying feelings were particularly associated with current anxiety symptom severity (p<0.001, β=0.54, 95% CI [0.41, 0.77]) and predicted later anxiety (p=0.01; β=0.31, 95% CI [0.08, 0.62]). Conclusions: Our findings suggest that difficulties identifying vs. describing emotion are associated with differential clinical outcomes in autism. Psychological therapies targeting emotional awareness may improve social-communication and anxiety symptoms in autism, potentially conferring long-term benefits

Face processing in early development: a systematic review of behavioral studies and considerations in times of COVID-19 pandemic

Human faces are one of the most prominent stimuli in the visual environment of young infants and convey critical information for the development of social cognition. During the COVID-19 pandemic, mask wearing has become a common practice outside the home environment. With masks covering nose and mouth regions, the facial cues available to the infant are impoverished. The impact of these changes on development is unknown but is critical to debates around mask mandates in early childhood settings. As infants grow, they increasingly interact with a broader range of familiar and unfamiliar people outside the home; in these settings, mask wearing could possibly influence social development. In order to generate hypotheses about the effects of mask wearing on infant social development, in the present work, we systematically review N = 129 studies selected based on the most recent PRISMA guidelines providing a state-of-the-art framework of behavioral studies investigating face processing in early infancy. We focused on identifying sensitive periods during which being exposed to specific facial features or to the entire face configuration has been found to be important for the development of perceptive and socio-communicative skills. For perceptive skills, infants gradually learn to analyze the eyes or the gaze direction within the context of the entire face configuration. This contributes to identity recognition as well as emotional expression discrimination. For socio- communicative skills, direct gaze and emotional facial expressions are crucial for attention engagement while eye-gaze cuing is important for joint attention. Moreover, attention to the mouth is particularly relevant for speech learning. We discuss possible implications of the exposure to masked faces for developmental needs and functions. Providing groundwork for further research, we encourage the investigation of the consequences of mask wearing for infants’ perceptive and socio-communicative development, suggesting new directions within the research field

Habitual night waking associates with dynamics of waking cortical theta power in infancy

The implications of the substantial individual differences in infant sleep for early brain development remains unclear. Here, we examined whether night sleep quality relates to daytime brain activity, operationalised through measures of EEG theta power and its dynamic modulation, which have been previously linked to later cognitive development (Braithwaite et al., 2020, Jones et al., 2020). For this longitudinal study 76 typically developing infants were studied (age: 4-14 months, 166 individual study visits) over the course of 6 months with 1, 2, 3, or 4 lab visits. Habitual sleep was measured with a 7-day sleep diary and actigraphy, and the BISQ. 20-channel EEG was recorded while infants watched multiple rounds of videos of women singing nursery rhymes; oscillatory power in the theta band was extracted. Key metrics were average theta across stimuli, and the slope of change in theta within the first novel movie. Both objective and subjective sleep assessment methods showed a relationship between more night waking, and higher overall theta power and reduced dynamic modulation of theta over the course of the novel video stimuli. These results may indicate altered learning and consolidation in infants with more disrupted night sleep, which may have implications for cognitive development

Executive function profiles of preschool children with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder: a systematic review

Background: Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are both associated with differences in Executive Functioning (EF). There is lack of clarity around the specificity or overlap of EF differences in early childhood when both disorders are first emerging. Method: This systematic review aims to delineate preschool EF profiles by examining studies comparing the EF profiles of children with and without ASD or ADHD. Five electronic databases were systematically searched (last search in May 2022) to identify published, quantitative studies of global and specific EF (Inhibition, Shifting, Working Memory, Planning and Attentional Control), comparing children aged 2-6 with a diagnosis of ASD or ADHD to peers without ASD or ADHD. Results: Thirty-one empirical studies (10 ADHD and 21 ASD studies) met criteria for inclusion. EF profiles in preschool ASD were characterised by consistent Shifting, and, in most cases, Inhibition impairments. ADHD studies consistently reported impairments in Inhibition and Planning, and in most cases Working Memory. Findings with regards to sustained Attention and Shifting in ADHD and Working Memory and Planning in ASD were mixed. Conclusions: Overall, current evidence indicates overlap but also some specificity in EF impairments in preschool ASD and ADHD. There were differences in the degree to which individual domains were impaired, with Shifting more consistently impaired in ASD, and Inhibition, Working Memory and Planning in ADHD. Methodological issues and differences in methods of outcome measurement could potentially underlie mixed findings, as informant-based measures revealed more robust EF impairments than laboratory-based tasks