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.     

Intact implicit learning in autism spectrum conditions

Individuals with autism spectrum condition (ASC) have diagnostic impairments in skills that are associated with an implicit acquisition; however, it is not clear whether ASC individuals show specific implicit learning deficits. We compared ASC and typically developing (TD) individuals matched for IQ on five learning tasks: four implicit learning tasks—contextual cueing, serial reaction time, artificial grammar learning, and probabilistic classification learning tasks—that used procedures expressly designed to minimize the use of explicit strategies, and one comparison explicit learning task, paired associates learning. We found implicit learning to be intact in ASC. Beyond no evidence of differences, there was evidence of statistical equivalence between the groups on all the implicit learning tasks. This was not a consequence of compensation by explicit learning ability or IQ. Furthermore, there was no evidence to relate implicit learning to ASC symptomatology. We conclude that implicit mechanisms are preserved in ASC and propose that it is disruption by other atypical processes that impact negatively on the development of skills associated with an implicit acquisition.     

Processing of musical structure by high-functioning adolescents with autism spectrum disorders

Enhanced pitch perception and memory have been cited as evidence of a local processing bias in autism spectrum disorders (ASD). This bias is argued to account for enhanced perceptual functioning (Mottron &; Burack, 2001 Mottron, L. and Burack, J. A. 2001. “Enhanced perceptual functioning in the development of autism”. In The development of autism: Perspectives from theory to research, Edited by: Burack, J. A., Charman, T., Yirmiya, N. and Zelazo, P. R. 131–147. Mahwah, NJ: Lawrence Erlbaum.  [Google Scholar]; Mottron, Dawson, Soulières, Hubert, &; Burack, 2006 Mottron, L., Dawson, M., Soulières, I., Hubert, B. and Burack, J. 2006. Enhanced perceptual functioning in autism: An update, and eight principles of autistic perception. Journal of Autism and Developmental Disorders, 36(1): 27–43. doi:10.1007/s10803-005-0040-7[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and central coherence theories of ASD (Frith, 1989 Frith, U. 1989. Autism: Explaining the enigma, Oxford: United Kingdom: Blackwell.  [Google Scholar]; Happé &; Frith, 2006 Happé, F. and Frith, U. 2006. The weak coherence account: Detail-focused cognitive style in autism spectrum disorders. Journal of Autism and Developmental Disorders, 36(1): 5–25. doi:10.1007/s10803-005-0039-0[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). A local processing bias confers a different cognitive style to individuals with ASD (Happé, 1999 Happé, F. 1999. Autism: Cognitive deficit or cognitive style?. Trends in Cognitive Sciences, 3(6): 216–222. doi:10.1016/S1364-6613(99)01318-2[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), which accounts in part for their good visuospatial and visuoconstructive skills. Here, we present analogues in the auditory domain, audiotemporal or audioconstructive processing, which we assess using a novel experimental task: a musical puzzle. This task evaluates the ability of individuals with ASD to process temporal sequences of musical events as well as various elements of musical structure and thus indexes their ability to employ a global processing style. Musical structures created and replicated by children and adolescents with ASD (10–19 years old) and typically developing children and adolescents (7–17 years old) were found to be similar in global coherence. Presenting a musical template for reference increased accuracy equally for both groups, with performance associated to performance IQ and short-term auditory memory. The overall pattern of performance was similar for both groups; some puzzles were easier than others and this was the case for both groups. Task performance was further found to be correlated with the ability to perceive musical emotions, more so for typically developing participants. Findings are discussed in light of the empathizing-systemizing theory of ASD (Baron-Cohen, 2009 Baron-Cohen, S. 2009. Autism: The Empathizing-Systemizing (E-S) Theory. Annals of the New York Academy of Sciences, 1156: 68–80. doi:10.1111/j.1749-6632.2009.04467.x[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and the importance of describing the strengths of individuals with ASD (Happé, 1999 Happé, F. 1999. Autism: Cognitive deficit or cognitive style?. Trends in Cognitive Sciences, 3(6): 216–222. doi:10.1016/S1364-6613(99)01318-2[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Heaton, 2009 Heaton, P. 2009. Assessing musical skills in autistic children who are not savants. Philosophical Transactions of the Royal Society Biological Sciences, 364: 1443–1447. doi:10.1098/rstb.2008.0327[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]).     

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.     

The role of the school psychologist in the inclusive education of school-age children with autism spectrum disorders

Two independent trends are impacting school psychologists with regard to their involvement in the education of students with autism spectrum disorders (ASDs): increasing prevalence estimates of ASDs and an emphasis on the inclusion of students with special needs in regular education classrooms. In light of these trends and growing awareness of the need for evidence-based practices in the field, school psychologists can expect to be involved in the educational programming of students with ASDs and should be knowledgeable about empirically supported strategies relevant to inclusive education of these children. The purpose of this review is to familiarize school psychologists with currently available intervention techniques by describing each strategy and outlining the degree of empirical support for each. Strategies for managing disruptive behaviors, promoting learning, and facilitating social integration are reviewed.     

言语行为的关系框架理论视角:孤独症谱系障碍的新探索

语言功能异常是孤独症谱系障碍(ASD)的典型症状之一。1957年,斯金纳从行为学角度提出"言语行为",认为人们获得表达和理解语言的能力与学会走路、跳舞等行为的原理相同。2001年,海斯等人在斯金纳的基础上提出关于人类语言和认知的新视角——关系框架理论(Relational Frame Theory,RFT),澄清了语言的推衍性实质,认为言语行为是将一个刺激与其他刺激建立关系框架的过程。研究表明基于RFT的多范例训练可以提升ASD患者的推衍关系反应水平,且推衍关系反应与语言和认知功能的发展高相关。未来RFT的研究可以探索如何通过推衍关系反应训练修复ASD患者的语言和认知功能缺陷。     

Explaining the theory of mind deficit in autism spectrum disorder

The theory of mind (ToM) deficit associated with autism has been a central topic in the debate about the modularity of the mind. Most involved in the debate about the explanation of the ToM deficit have failed to notice that autism’s status as a spectrum disorder has implications about which explanation is more plausible. In this paper, I argue that the shift from viewing autism as a unified syndrome to a spectrum disorder increases the plausibility of the explanation of the ToM deficit that appeals to a domain-specific, higher-level ToM module. First, I discuss what it means to consider autism as a spectrum rather than as a unified disorder. Second, I argue for the plausibility of the modular explanation on the basis that autism is better considered as a spectrum disorder. Third, I respond to a potential challenge to my account from Philip Gerrans and Valerie Stone’s recent work (Gerrans, Biol Philos 17:305–321, 2002; Stone and Gerrans, Trends Cogn Sci 10:3–4, 2006a; Soc Neurosci 1:309–319, 2006b; Gerrans and Stone, Br J Philos Sci 59:121–141, 2008).     

High cognitive sensitivity to activational effects of testosterone in parents of offspring with autism spectrum disorders

The existence of mild forms of autistic-like characteristics in parents of children with autism spectrum disorders (ASDs) has been defined as a broader autistic phenotype (BAP). Excessive prenatal exposure to testosterone (T) seems to play a role in its development. The aims of this study were to characterize whether ASD parents show masculinized brains or high T prenatal exposure compared to a normative population, using cognitive questionnaires, and also to examine the T level changes in response to different cognitive tasks. ASD parents were found to present higher autistic and lower empathic trait scores than controls. They also have higher T levels and magnitude of T response to cognitive tasks. Specific correlation patterns between masculinized brain types and T levels were observed only in ASD parents. Thus, it seems that first-degree relatives of people with ASD have high T levels during task performance, which, in turn, produce slight cognitive masculinization. Our findings should be considered for understanding the role of androgens in the etiology of ASD. Nevertheless, the masculinization parameters described throughout the study are subtle and require further analysis.     

Parental reflective functioning and theory of mind acquisition: A developmental perspective

This study investigated theory of mind (ToM) development in 83 children aged 3–5 years and its associations with parental reflective functioning (PRF), using a multidimensional and developmental approach. Results showed that ToM dimensions (i.e., affective, belief-desire, and cognitive) gradually increased with age. All dimensions of PRF (i.e., prementalizing modes, certainty about mental states, and interest and curiosity in mental states) were associated with ToM dimensions, with different dimensions being differentially related to ToM, including age-related effects.     

Metacognition of agency and theory of mind in adults with high functioning autism

We investigated metacognition of agency in adults with high functioning autism or Asperger Syndrome (HFA/AS) using a computer task in which participants moved the mouse to get the cursor to touch the downward moving X’s and avoid the O’s. They were then asked to make judgments of performance and judgments of agency. Objective control was either undistorted, or distorted by adding turbulence (i.e., random noise) or a time Lag between the mouse and cursor movements. Participants with HFA/AS used sensorimotor cues available in the turbulence and lag conditions to a lesser extent than control participants in making their judgments of agency. Furthermore, the failure to use these internal diagnostic cues to their own agency was correlated with decrements in a theory of mind task. These findings suggest that a reduced sensitivity to veridical internal cues about the sense of agency is related to mentalizing impairments in autism.     

Autism characteristics in children with fetal alcohol spectrum disorders

Background: Children with fetal alcohol spectrum disorders (FASD) exhibit difficulties in many cognitive and behavioral domains and also have high comorbidity with other disorders such as attention deficit/hyperactivity disorder (ADHD) and conduct disorder as well as autism. Although the FASD profile is shown to be distinct from ADHD and conduct disorder, far less is known about the commonalities with autism. The current study used a parent-rated questionnaire containing an autism subscale to explore the autistic-like features that children with FASD exhibit. Methods: Studied were 25 children with FASD (age: M = 10.3 years) and 17 normal controls (NCs; age: M = 10.2 years). As part of a larger study, all parents/caregivers completed the Social Skills Improvement System (SSIS; Gresham & Elliot, 2008), which in addition to evaluating social skills and behavior problems globally, includes an Autism subscale. Results: Between-group comparisons showed the FASD group not only scored significantly lower in social skills and significantly higher in behavior problems than the NC group but children with FASD also scored significantly higher on the Autism subscale. Item analysis revealed they showed the most difficulty in terms of social and communicative functioning and the least in repetitive and restrictive behaviors. Conclusion: Current findings signify that FASD and autism share similarities with regard to social and communicative functioning. These findings, which further our knowledge of the FASD phenotype, may be useful in specifying the particular interventions these children need.     

Deeper attentional masking by lateral objects in children with autism

Autism spectrum disorder (ASD) is often associated with a detail-oriented perception and overselective attention in visual tasks, such as visual search and crowding. These results were obtained manipulating exclusively the spatial properties of the stimuli: few is known about the spatio-temporal dynamics of visual processing in ASD. In this study we employed an attentional masking (AM) paradigm comparing children with ASD and IQ-matched typically developing (TD) controls. The AM effect refers to an impaired identification of a target followed by a competitive masking object at different proximities in space and time. We found that ASD and TD groups did not differ in the AM effect provoked by the competitive object displayed in the same position of the target. In contrast, children with ASD showed a deeper and prolonged interference than the TD group when the masking object was displayed in the lateral position. These psychophysical results suggest that the inefficient attentional selection in ASD depends on the spatio-temporal interaction between competitive visual objects. These evidence are discussed in the light of the ASD altered neural connectivity hypothesis and the reentrant theory of perception.     

The accidental transgressor: morally-relevant theory of mind

To test young children’s false belief theory of mind in a morally relevant context, two experiments were conducted. In Experiment 1, children (N = 162) at 3.5, 5.5, and 7.5 years of age were administered three tasks: prototypic moral transgression task, false belief theory of mind task (ToM), and an “accidental transgressor” task, which measured a morally-relevant false belief theory of mind (MoToM). Children who did not pass false belief ToM were more likely to attribute negative intentions to an accidental transgressor than children who passed false belief ToM, and to use moral reasons when blaming the accidental transgressor. In Experiment 2, children (N = 46) who did not pass false belief ToM viewed it as more acceptable to punish the accidental transgressor than did participants who passed false belief ToM. Findings are discussed in light of research on the emergence of moral judgment and theory of mind.     

A broad assessment of theory of mind in adolescence: The complexity of mindreading

The aim of this research was to provide an articulated assessment of several different ToM components, namely first- vs. third-person, egocentric vs. allocentric, and first- vs. second-order ToM, in preadolescence and adolescence. Our expectations for the sample of 80 juveniles that participated in the research were that: (1) ToM abilities would improve with age; (2) participants would perform better at first-person than at third-person tasks; (3) participants would perform better at first-order than at second-order tasks; (4) girls will perform systematically better than boys. We also explored possible differences in performance (5) in the allocentric vs. the egocentric perspectives as well as (6) in the comprehension of different types of mental states, namely desires, beliefs and positive and negative emotions. Overall our expectations were confirmed. Our data confirmed that all ToM aspects we investigated keep maturing during preadolescence and adolescence.     

自闭症谱系障碍的生物基础

自闭症谱系障碍是一组发病于生命早期, 由一系列生理、心理因素引起的神经发育障碍。遗传、脑神经结构、营养素等是自闭症谱系障碍的生物基础的重要来源。个体在孕育早期形成的大脑和机体异常可能是导致自闭症谱系障碍的关键。这种异常在出生后的发育中具体作用于神经活动、脑发育、免疫系统等生理途径。研究者们今后可以尝试横跨不同自闭症谱系障碍亚型、年龄和发育阶段, 开展横向与纵向相结合的大范围研究, 以进一步明确自闭症谱系障碍的生物基础。     

The relationship between joint attention and theory of mind in neurotypical adults

Joint attention (JA) is hypothesized to have a close relationship with developing theory of mind (ToM) capabilities. We tested the co-occurrence of ToM and JA in social interactions between adults with no reported history of psychiatric illness or neurodevelopmental disorders. Participants engaged in an experimental task that encouraged nonverbal communication, including JA, and also ToM activity. We adapted an in-lab variant of experience sampling methods (Bryant et al., 2013) to measure ToM during JA based on participants’ subjective reports of their thoughts while performing the task. This experiment successfully elicited instances of JA in 17/20 dyads. We compared participants’ thought contents during episodes of JA and non-JA. Our results suggest that, in adults, JA and ToM may occur independently.     

Early and persistent motor difficulties in infants at-risk of developing autism spectrum disorder: A prospective study

Analyses were conducted in order to investigate motor development in younger siblings of children diagnosed with autism spectrum disorder (ASD). Infants at familial risk and low risk of developing ASD were tested longitudinally between the ages of 7 and 36 months. Data were analysed from motor scales on the Mullen Scales of Early Learning and the Vineland Adaptive Behaviour Scales at each age point. Significantly lower motor scores in at-risk infants were evident from the age of 7 months compared to the low-risk group. Infants who were later diagnosed with ASD demonstrated significantly poorer Fine Motor skills at 36 months than at-risk infants without any developmental difficulties. In addition, Gross Motor scores were highly correlated across the two measures for low-risk infants and infants who later developed ASD. Early motor difficulties may be an early indicator of a number of neurodevelopmental disorders, including ASD.     

More consistent,yet less sensitive: Interval timing in autism spectrum disorders

Even though phenomenological observations and anecdotal reports suggest atypical time processing in individuals with an autism spectrum disorder (ASD), very few psychophysical studies have investigated interval timing, and the obtained results are contradictory. The present study aimed to clarify which timing processes function atypically in ASD and whether they are related to the ASD diagnostic profile. Visual, auditory, and cross-modal interval timing was assessed in 18 individuals with ASD using a repeated standards version of the temporal generalization task. The use of two different standard durations (600 and 1,000 ms) allowed for an assessment of the scalar property of interval timing in ASD, a fundamental characteristic of interval timing. The ASD group showed clearer adherence to the scalar property of interval timing than the control group. In addition, both groups showed the normal effect that auditory stimuli had longer subjective durations than visual ones. Yet, signal detection analysis showed that the sensitivity of temporal discrimination was reduced in the ASD group across modalities, in particular for auditory standards. Moreover, response criteria in the ASD group were related to symptom strength in the communication domain. The findings suggest that temporal intervals are fundamentally processed in the same way in ASD and TD, but with reduced sensitivity for temporal interval differences in ASD. Individuals with ASD may show a more conservative response strategy due to generally decreased sensitivity for the perception of time intervals.     

Task instructions and implicit theory of mind

It has been hypothesized that humans are able to track other’s mental states efficiently and without being conscious of doing so using their implicit theory of mind (iToM) system. However, while iToM appears to operate unconsciously recent work suggests it does draw on executive attentional resources ( Schneider, Lam, Bayliss, & Dux, 2012) bringing into question whether iToM is engaged efficiently. Here, we examined other aspects relating to automatic processing: The extent to which the operation of iToM is controllable and how it is influenced by behavioral intentions. This was implemented by assessing how task instructions affect eye-movement patterns in a Sally–Anne false-belief task. One group of subjects was given no task instructions (No Instructions), another overtly judged the location of a ball a protagonist interacted with (Ball Tracking) and a third indicated the location consistent with the actor’s belief about the ball’s location (Belief Tracking). Despite different task goals, all groups’ eye-movement patterns were consistent with belief analysis, and the No Instructions and Ball Tracking groups reported no explicit mentalizing when debriefed. These findings represent definitive evidence that humans implicitly track the belief states of others in an uncontrollable and unintentional manner.     

Reflexively mindblind: Using theory of mind to interpret behavior requires effortful attention

People commonly interpret others’ behavior in terms of the actors’ underlying beliefs, knowledge, or other mental states, thereby using their “theory of mind.” Two experiments suggest that using one’s theory of mind is a relatively effortful process. In both experiments, people reflexively used their own knowledge and beliefs to follow a speaker’s instruction, but only effortfully used their theory of mind to take into account a speaker’s intention to interpret those instructions. In Experiment 1, people with lower working memory capacity were less effective than people with larger working memory capacity in applying their theory of mind to interpret behavior. In Experiment 2, an attention-demanding secondary task reduced people’s ability to apply their theory of mind. People appear to be reflexively mindblind, interpreting behavior in terms of the actor’s mental states only to the extent that they have the cognitive resources to do so.