Current knowledge on motor disorders in children with autism spectrum disorder (ASD)

Motor symptomatology in autism is currently poorly understood, and still not included in the autism spectrum disorder (ASD) diagnostic criteria, although some studies suggest the presence of motor disturbances in this syndrome. We provide here a literature review on early motor symptoms in autism, focusing on studies on psychomotor issues (tone, postural control, manual dexterity, handedness, praxis). The approach adopted in research to study altered motor behaviors is generally global and there is no detailed semiology of the motor or neuromotor disorders observed in people with ASD. This global approach does not enable understanding of the neuro-developmental mechanisms involved in ASD. Identification of clinical neuro-psychomotor profiles in reference to a standard would help to better understand the origin and the nature of the disorders encountered in ASD, and would thus give new directions for treatment.     

Parent-child interaction during the first year of life in infants at elevated likelihood of autism spectrum disorder

Autism spectrum disorder (ASD) likely emerges from a complex interaction between pre-existing neurodevelopmental vulnerabilities and the environment. The interaction with parents forms a key aspect of an infant’s social environment, but few prospective studies of infants at elevated likelihood (EL) for ASD (who have an older sibling with ASD) have examined parent-child interactions in the first year of life. As part of a European multisite network, parent-child dyads of free play were observed at 5 months (62 EL infants, 47 infants at typical likelihood (TL)) and 10 months (101 EL siblings, 77 TL siblings). The newly-developed Parent-Infant/Toddler Coding of Interaction (PInTCI) scheme was used, focusing on global characteristics of infant and parent behaviors. Coders were blind to participant information. Linear mixed model analyses showed no significant group differences in infant or parent behaviors at 5 or 10 months of age (all ps≥0.09, d≤0.36), controlling for infant’s sex and age, and parental educational level. However, without adjustments, EL infants showed fewer and less clear initiations at 10 months than TL infants (p = 0.02, d = 0.44), but statistical significance was lost after controlling for parental education (p = 0.09, d = 0.36), which tended to be lower in the EL group. Consistent with previous literature focusing on parent-infant dyads, our findings suggest that differences between EL and TL dyads may only be subtle during the first year of life. We discuss possible explanations and implications for future developmental studies.     

Infant motor skill predicts later expressive language and autism spectrum disorder diagnosis

Motor difficulties may be an early Autism Spectrum Disorder (ASD) risk indicator and may predict subsequent expressive language skills. Further understanding of motor functioning in the first year of life in children with ASD is needed. We examined motor skills in 6-month-olds (n = 140) at high and low familial risk for ASD using the Peabody Developmental Motor Scales (Grasping, Visual-Motor Integration, and Stationary subscales). In Study 1, motor skill at 6 months predicted ASD status at 24–36 months; ASD was associated with poorer infant motor skills. In Study 2, motor skill at 6 months predicted expressive language at 30 and 36 months. Findings provide evidence that vulnerability in motor function early in development is present in ASD. Findings highlight the importance of developmental monitoring in high-risk infants and possible cascading effects of early disruption in motor development.     

Olfaction in autism spectrum disorders: A systematic review

Olfactory function is a well-known early biomarker for neurodegeneration and neural functioning in the adult population, being supported by a number of brain structures that could be dysfunctioning in neurodegenerative processes. Evidence has suggested that atypical sensory and, particularly, olfactory processing is present in several neurodevelopmental conditions, including autism spectrum disorders (ASDs). In this paper, we present data obtained by a systematic literature review, conducted according to PRISMA guidelines, regarding the possible association between olfaction and ASDs, and analyze them critically in order to evaluate the occurrence of olfactory impairment in ASDs, as well as the possible usefulness of olfactory evaluation in such conditions. The results obtained in this analysis suggested a possible involvement of olfactory impairment in ASDs, underlining the importance of olfactory evaluation in the clinical assessment of ASDs. This assessment could be potentially included as a complementary evaluation in the diagnostic protocol of the condition. Methods for study selection and inclusion criteria were specified in advance and documented in PROSPERO protocol #CRD42014013939.     

高风险婴儿前瞻性纵向研究与孤独症谱系障碍早期识别

孤独症谱系障碍(Autism Spectrum Disorder, ASD)早期识别有助于早期诊断和早期干预的实施, 对于改善ASD儿童发育结果至关重要。高风险前瞻性纵向研究以高风险婴儿(ASD儿童的年幼同胞, 入组年龄小于12个月)作为主要研究对象, 通过对ASD高风险婴儿(24至36个月之间诊断为ASD的高风险婴儿)的早期发育轨迹的描绘和核心症状早期表现的识别, 为ASD早期识别提供了重要依据。未来可以增加被试数量、延长观察时间并密集观察时间点、关注伴发障碍、综合考虑遗传、环境和文化因素影响, 并结合早期干预研究进行深入探索。未来在中国开展相关研究具有重要的科学价值和临床意义。     

孤独症儿童动作发展障碍的神经机制

动作发展障碍(Developmental motor disorders)是孤独症谱系障碍的常见特征。通过系统回顾孤独症儿童动作发展障碍的神经科学研究, 发现γ-氨基丁酸和5-羟色胺浓度的改变及γ-氨基丁酸相关蛋白和Shank蛋白的表达异常不仅会损害中枢神经系统的发育, 而且还能导致突触兴奋性与抑制性失衡, 进而改变孤独症儿童小脑和大脑皮层运动区的功能连接。孤独症儿童小脑、基底神经节和胼胝体结构的改变对全脑的连通性产生了负面影响。神经生化机制和脑结构的异常共同导致了脑功能的异常, 最终造成孤独症儿童的动作发展障碍。此外, 动作发展障碍与孤独症核心症状共同的神经基础主要包括镜像神经元系统紊乱, 丘脑、基底神经节和小脑异常以及SLC7A5和PTEN 基因突变。未来研究需要关注与运动密切相关的其他神经递质, 如乙酰胆碱和多巴胺; 探索动作发展障碍神经网络的动态机制及其形成; 剖析该障碍的神经机制和自闭症核心症状神经机制的相互作用。     

Associations between gross motor and communicative development in at-risk infants

Infants’ advances in locomotion relate to advances in communicative development. However, little is known about these relations in infants at risk for delays in these domains and whether they may extend to earlier achievements in gross motor development in infancy. We examined whether advances in sitting and prone locomotion are related to communicative development in infants who have an older sibling with autism spectrum disorder (ASD) and are at risk for motor and communication delays (heightened-risk; HR). We conducted a longitudinal study with 37 HR infants who did not receive an ASD diagnosis at 36 months. Infants were observed monthly between the ages of 5 and 14 months. We assessed gross motor development using the Alberta Infant Motor Scales (AIMS) and recorded ages of onset of verbal and nonverbal communicative behaviors. Results indicated increased presence of early gross motor delay from 5 to 10 months. In addition, there were positive relations between sitting and gesture and babble onset and between prone development and gesture onset. Thus, links between gross motor development and communication extend to at-risk development and provide a starting point for future research on potential cascading consequences of motor advances on communication development.     

Children with autism spectrum disorder are more trusting than typically developing children

The current study examined whether children with autism spectrum disorder (ASD) had an indiscriminate trust bias whereby they would believe any information provided by an unfamiliar adult with whom they had no interactive history. Young school-aged children with ASD and their age- and ability-matched typically developing (TD) peers participated in a simple hide-and-seek game. In the game, an experimenter with whom the children had no previous interactive history pointed to or left a marker on a box to indicate the whereabouts of a hidden reward. Results showed that although young school-aged ASD children did not blindly trust any information provided by the unfamiliar adult, they appeared to be more trusting in the adult informant than did their age- and ability-matched TD children.     

Early developmental delay in children with autism: A study from a developing country

Early diagnosis is appropriate and important for developmental disorders such as autism spectrum disorder. In many less developed countries, unfortunately, diagnosis of this disorder is delayed. The aim of the present study is to determine whether this disorder can be screened using simple strategies such as comparison of the age of acquisition of motor skills. For this purpose, 124 children with autism were chosen to enter the study, and their parents were asked to retrospectively specify the age of achieving milestones of sitting without support, standing alone and walking alone. Information obtained from the parents was compared with World Health Organization standards. Results indicate that participants (male and female) have significantly delayed age of acquisition of all three skills. Based on this result, it can be suggested that existing standards, as a simple means with low cost and easy availability, can be used for early screening of the disease at a younger age so that treatment can be provided more quickly.     

The mediating role of joint attention in the relationship between motor skills and receptive and expressive language in siblings at risk for autism spectrum disorder

Language problems are highly prevalent in younger siblings of children with autism spectrum disorder (HR-sibs), yet little is known about early predictors. There is growing evidence that motor and language development are linked and this connection might be mediated by joint attention. Developmental changes in motor abilities change how children interact with objects and people (e.g., by showing), which may influence language development. This association has however not yet been studied in HR-sibs. The interrelationship between motor, joint attention and language skills was explored in younger siblings of typically developing children (LR-sibs, N = 31) and HR-sibs (N = 32). In both groups, motor skills (composite of fine and gross motor skills) at 10 months influenced receptive and expressive language at 36 months directly and indirectly through joint attention at 14 months. Group status moderated this direct and indirect effect with mainly significant effects in HR-sibs. This indicates that lower motor skills can have cascading effects on joint attention and language in HR-sibs. Consequently, assessment of early motor skills in HR-sibs might hold promise for early identification of motor difficulties but can also be indicative of language difficulties later in life, especially when difficulties with joint attention are also present.     

Behavioural reactions to an emotion evoking task in infants at increased likelihood for autism spectrum disorder

Infants at increased likelihood for autism spectrum disorder (ASD) exhibit more negative affect and avoidance behaviour than typically developing infants, and children with ASD express fear differently than typically developing peers. We examined behavioural reactions to emotion-evoking stimuli in infants at increased familial likelihood for ASD. Participants included 55 increased likelihood (IL) infants (i.e., siblings of children diagnosed with ASD) and 27 typical likelihood (TL) infants (i.e., no family history of ASD). At 18 months, we showed infants two masks that commonly elicit fearful responses in older children and examined potential behavioural differences in approach, avoidance, ‘freezing’, crying, gaze aversion, and smiling. At 24 months, infants were assessed with the Toddler Module of the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2). Results of video-based coding showed that (1) IL infants exhibited more intense avoidance behaviour than TL infants in response to masks, and (2) intensity of avoidance and duration of freezing were positively correlated with ADOS-2 symptom severity scores. Findings suggest that differences in response to emotion-eliciting stimuli may predict later ASD symptoms. Such behavioural differences may inform early detection and intervention in ASD.     

Task-switching abilities in children with autism spectrum disorder

Task-switching performance is often used as a measure of executive control functions. Various task-switching studies in children with autism spectrum disorder (ASD) found, in contrast to expectations, no impairments in cognitive flexibility. Here, we studied whether the role of memory for arbitrary task rules can explain these findings, and how studying rule memory can help to generally better understand executive control. We designed a novel task-switching paradigm to separate cognitive flexibility from demand on memory for arbitrary rules, and we compared 19 children with ASD (9 to 16 years old) with an age- and IQ-matched control group. Children with ASD had increased difficulty with task switching only when memorizing arbitrary rules was required. When no arbitrary rules needed to be memorized, they performed accurately and quickly. Nevertheless, they showed less distraction from task-irrelevant stimulus features, suggesting that they represented tasks differently from the children in the comparison group. We conclude that children with ASD have a weaker capacity of forming rule representations, which only leads to performance impairment when they need to memorize arbitrary rules. Further, executive control impairments in ASD seem more complex than hitherto hypothesized due to mutual interactions between memory demand and task representations.     

The Autism Detection in Early Childhood Tool: Level 2 autism spectrum disorder screening in a NICU Follow-up program

ObjectiveChildren born preterm are at increased risk for autism spectrum disorder (ASD). However, early diagnosis of ASD is challenging because conventional screening Level 1 tools are less reliable in this population. We sought to determine whether the Autism Detection in Early Childhood (ADEC) and Child Behavior Checklist (CBCL) could accurately identify children at risk for ASD in a NICU Follow-up setting and thus facilitate referral for formal ASD evaluation.MethodChildren aged 18–36 months were recruited from a NICU Follow-up program. All children received presumptive diagnoses based on DSM-5 criteria and were screened for ASD risk with the ADEC and CBCL. Children scoring in the “at risk” range on either tool were referred for a full diagnostic ASD evaluation.ResultsSixty-nine patients (median birth weight 1140 g; median gestational age 28 weeks) were included with 18 designated “at risk” for ASD. Nine (13 %) scored “at risk” on the ADEC and 12 (17 %) on the CBCL. Thirteen children underwent diagnostic ASD evaluation with 9 receiving a formal diagnosis of ASD. The ADEC demonstrated the best performance (sensitivity 89 %, specificity 98 %). The CBCL was less sensitive (sensitivity 50 %, specificity 90 %). Requiring elevated scores on both the CBCL and ADEC was specific but not sensitive (sensitivity 33 %, specificity 100 %).ConclusionThe ADEC performed well in identifying children at risk for ASD within this high-risk NICU cohort, adding benefit as an autism-specific screening tool over the CBCL alone.     

Associations between attentional biases to fearful faces and social-emotional development in infants with and without an older sibling with autism

During the first year of life, infants become increasingly attuned to facial emotion, with heightened sensitivity to faces conveying threat observed by age seven months as illustrated through attentional biases (e.g., slower shifting away from fearful faces). Individual differences in these cognitive attentional biases have been discussed in relation to broader social-emotional functioning, and the current study examines these associations in infants with an older sibling with autism spectrum disorder (ASD), a group with an elevated likelihood of a subsequent ASD diagnosis (ELA; n = 33), and a group of infants with no family history of ASD who are at low likelihood of ASD (LLA; n = 24). All infants completed a task measuring disengagement of attention from faces at 12 months (fearful, happy, neutral), and caregivers completed the Infant-Toddler Social and Emotional Assessment at 12, 18, and/or 24 months. For the full sample, greater fear bias in attention disengagement at 12 months related to more internalizing behaviors at 18 months, and this was driven by the LLA infants. When examining groups separately, findings revealed that LLA with a greater fear bias had more difficult behaviors at 12, 18, and 24 months; in contrast, ELA showed the opposite pattern, and this was most pronounced for ELA who later received an ASD diagnosis. These preliminary group-level findings suggest that heightened sensitivity to fearful faces might serve an adaptive function in children who later receive an ASD diagnosis, but in infants with no family history of ASD, increased biases might reflect a marker of social-emotional difficulties.     

Initiation of joint attention and related visual attention processes in infants with autism spectrum disorder: Literature review

Autism spectrum disorder (ASD) represents a group of neurodevelopmental disabilities that can be difficult to identify before the age of 2 or 3 years, the age when the full range of behavioral symptoms has emerged in most cases. Initiation of joint attention is an important developmental function in which impairments are already observable before the second birthday and can predict children’s ASD symptomatology. In the first part of this review, we summarize results pertaining to retrospective studies of initiation of joint attention in children with ASD and prospective studies of infants at high risk for ASD during the first 2 years, when this behavior is becoming more complex in terms of frequency, quality, and variety. We will also discuss the implications of impairments in dyadic engagement, a precursor of joint attention behavior, for the early development of joint attention. Finally, the early development of initiation of joint attention has been related to specific visual attention mechanisms such as social orienting and visual disengagement. In the second part of this review, we provide an overview of the relationship between those visual attention mechanisms and subsequent social-communication impairments. Clinical and research implications of these findings for both early detection and early intervention will be discussed.     

A threat-detection advantage in those with autism spectrum disorders

Identifying threatening expressions is a significant social perceptual skill. Individuals with autism spectrum disorders (ASD) are impaired in social interaction, show deficits in face and emotion processing, show amygdala abnormalities and display a disadvantage in the perception of social threat. According to the anger superiority hypothesis, angry faces capture attention faster than happy faces in individuals with a history of typical development [Hansen, C. H., & Hansen, R. D. (1988). Finding the face in the crowd: An anger superiority effect. Journal of Personality and Social Psychology, 54(6), 917–924]. We tested threat detection abilities in ASD using a facial visual search paradigm. Participants were asked to detect an angry or happy face image in an array of distracter faces. A threat-detection advantage was apparent in both groups: participants showed faster and more accurate detection of threatening over friendly faces. Participants with ASD showed similar reaction time, but decreased overall accuracy compared to controls. This provides evidence for less robust, but intact or learned implicit processing of basic emotions in ASD.     

Early processing of emotional faces in children with autism: An event-related potential study

Social deficits are one of the most striking manifestations of autism spectrum disorders (ASDs). Among these social deficits, the recognition and understanding of emotional facial expressions has been widely reported to be affected in ASDs. We investigated emotional face processing in children with and without autism using event-related potentials (ERPs). High-functioning children with autism (n = 15, mean age = 10.5 ± 3.3 years) completed an implicit emotional task while visual ERPs were recorded. Two groups of typically developing children (chronological age-matched and verbal equivalent age-matched [both ns = 15, mean age = 7.7 ± 3.8 years]) also participated in this study. The early ERP responses to faces (P1 and N170) were delayed, and the P1 was smaller in children with autism than in typically developing children of the same chronological age, revealing that the first stages of emotional face processing are affected in autism. However, when matched by verbal equivalent age, only P1 amplitude remained affected in autism. Our results suggest that the emotional and facial processing difficulties in autism could start from atypicalities in visual perceptual processes involving rapid feedback to primary visual areas and subsequent holistic processing.     

A temporally sustained implicit theory of mind deficit in autism spectrum disorders

Eye movements during false-belief tasks can reveal an individual’s capacity to implicitly monitor others’ mental states (theory of mind – ToM). It has been suggested, based on the results of a single-trial-experiment, that this ability is impaired in those with a high-functioning autism spectrum disorder (ASD), despite neurotypical-like performance on explicit ToM measures. However, given there are known attention differences and visual hypersensitivities in ASD it is important to establish whether such impairments are evident over time. In addition, investigating implicit ToM using a repeated trial approach allows an assessment of whether learning processes can reduce the ASD impairment in this ability, as is the case with explicit ToM. Here we investigated the temporal profile of implicit ToM in individuals with ASD and a control group. Despite similar performance on explicit ToM measures, ASD-diagnosed individuals showed no evidence of implicit false-belief tracking even over a one-hour period and many trials, whereas control participants did. These findings demonstrate that the systems involved in implicit and explicit ToM are distinct and hint that impaired implicit false-belief tracking may play an important role in ASD. Further, they indicate that learning processes do not alleviate this impairment across the presentation of multiple trials.     

Conversation,responsibility, and autism spectrum disorder

In this paper, I present a challenge for Michael McKenna’s conversational theory of moral responsibility. On his view, to be a responsible agent is to be able to engage in a type of moral conversation. I argue that individuals with autism spectrum disorder present a considerable problem for the conversational theory because empirical evidence on the disorder seems to suggest that there are individuals in the world who meet all of the conditions for responsible agency that the theory lays out but who are nevertheless not responsible agents. Attending to the moral psychology of such individuals will, I think, help shed light on an important gap in the conversational theory.