How do children with autism spectrum disorders express pain? Pain. 2013;154:2007-2013. [PMID: 24040973 DOI: 10.1016/j.pain.2013.06.011]

Social Determinants and Consequences of Pain: Toward Multilevel, Intersectional, and Life Course Perspectives

Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain remain rarely addressed in the context of pain prevention and management. In this review, we aim to 1) examine the broad scope of social determinants and consequences of pain and their interactions across multiple levels of organization, and 2) provide a framework synthesizing existing concepts and potential areas for future work on social aspects of pain, drawing upon socioecological, intersectional, and life course approaches. Integrating interdisciplinary theory and evidence, we outline pathways through which multilevel social factors and pain may affect each other over time. We also provide a brief summary of intrapersonal aspects of pain, which are thought to operate at the interface between individuals and the social context. Progressing from micro- to macrolevel factors, we illustrate how social determinants of pain can directly or indirectly contribute to pain experiences, expression, risk, prognosis, and impact across populations. We consider 1) at the interpersonal level, the roles of social comparison, social relatedness, social support, social exclusion, empathy, and interpersonal conflict; 2) at the group or community level, the roles of intimacy groups, task groups, social categories, and loose associations; and 3) at the societal level, the roles of political, economic, and cultural systems, as well as their policies and practices. We present examples of multilevel consequences of pain across these levels and discuss opportunities to reduce the burden and inequities of pain by expanding multilevel social approaches in pain research and practice. PERSPECTIVE: Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain are often unclearly defined, hindering their use in pain prevention, management, and research. We summarize the scope of social aspects of pain and provide a framework synthesizing existing concepts and potential areas for future work.

Anterior cingulate cortex-related functional hyperconnectivity underlies sensory hypersensitivity in Grin2b-mutant mice

Sensory abnormalities are observed in ~90% of individuals with autism spectrum disorders (ASD), but the underlying mechanisms are poorly understood. GluN2B, an NMDA receptor subunit that regulates long-term depression and circuit refinement during brain development, has been strongly implicated in ASD, but whether GRIN2B mutations lead to sensory abnormalities remains unclear. Here, we report that Grin2b-mutant mice show behavioral sensory hypersensitivity and brain hyperconnectivity associated with the anterior cingulate cortex (ACC). Grin2b-mutant mice with a patient-derived C456Y mutation (Grin2bC456Y/+) show sensory hypersensitivity to mechanical, thermal, and electrical stimuli through supraspinal mechanisms. c-fos and functional magnetic resonance imaging indicate that the ACC is hyperactive and hyperconnected with other brain regions under baseline and stimulation conditions. ACC pyramidal neurons show increased excitatory synaptic transmission. Chemogenetic inhibition of ACC pyramidal neurons normalizes ACC hyperconnectivity and sensory hypersensitivity. These results suggest that GluN2B critically regulates ASD-related cortical connectivity and sensory brain functions.

[Pain assessment for children and adolescents with autism spectrum disorders (ASD): A systematic review]

OBJECTIVE

Pain in children and adolescents with autism spectrum disorders remains underdiagnosed due to their inherent communication difficulties. The goal of this review is to identify the most suitable methods for assessing pain in this population and for evaluating the specific perceptions of, or behavioural reactions to, pain whilst considering disorder severity and specifiers (with or without accompanying intellectual impairment, with or without accompanying language impairment).

METHOD

A systematic review and analysis of the international literature was conducted.

RESULTS

Fourteen studies were selected. No difference was found in pain-related behaviours based on the age or gender of children or adolescents with autism. Three studies showed pain-related behaviours in autism spectrum disorders to be similar to control groups. Other studies showed specific behavioural responses in autism spectrum disorders with a longer physiological and behavioural recovery time associated with an episode of acute pain in this population. Similarly, the three studies that focused on sensory perceptions of pain all showed differences in the autism spectrum disorders population compared to control groups. In hospital or daily life contexts, studies essentially showed idiosyncratic expressions, hypervigilance, motor agitation, negative emotional reactions, or vocalizations. Regarding the association of autism severity with hyposensitivity to pain, the results remain unclear even when language disorders or intellectual disabilities are also present (in conjunction with autism). The Non-Communicative Children Pain Checklist and its translation into French and Italian showed good internal validity and was used by almost half of the studies in hetero-assessment, mostly by parents. Studies recommend the inclusion of parents in the assessment in order to optimise the evaluation process. Similarly, analysis of parent/child/caregiver interviews from the studies highlights the importance of personalizing pain assessment of children and adolescents, taking into account subject-specific characteristics, pathology, and context.

CONCLUSION

An integrative and personalized approach to pain assessment appears to be the most appropriate for enhancing the understanding and detection of pain in individuals with autism spectrum disorders. This approach aligns well with a care setting where a nominated professional with a good expertise in autism is responsible for pain assessment. Given the complexity of identifying pain in individuals with autism, further qualitative studies, in conjunction with new pain exploration technologies, are considered necessary as well as a more extensive categorization of the population studies.

Individualized Numeric Rating Scale to Assess Pain in Critically Ill Children With Neurodevelopmental Disabilities

BACKGROUND

Pain is a significant burden for children with neurodevelopmental disabilities but is difficult for clinicians to identify. No pain assessment tools for children with neurodevelopmental disabilities have been validated for use in pediatric intensive care units. The Individualized Numeric Rating Scale (INRS) is an adapted 0-to-10 rating that includes parents' input on their child's pain indicators.

OBJECTIVES

To evaluate the reliability, validity, and feasibility and acceptability of use of the INRS for assessing pain in critically ill children with neurodevelopmental disabilities.

METHODS

This observational study enrolled critically ill patients with neurodevelopmental disabilities aged 3 to 17 years in 2 pediatric intensive care units at a children's hospital using a prospective repeated-measures cohort design. Structured parent interviews were used to populate each patient's INRS. Bedside nurses assessed pain using the INRS throughout the study. The research team completed independent INRS ratings using video clips. Participating parents and nurses completed feasibility and acceptability surveys. Psychometric properties of the INRS and survey responses were evaluated with appropriate statistical methods.

RESULTS

For 481 paired INRS pain ratings in 34 patients, interrater reliability between nurse and research team ratings was moderate (weighted κ = 0.56). Parents said that creating the INRS was easy, made them feel more involved in care, and helped them communicate with nurses.

CONCLUSIONS

The INRS has adequate measurement properties for assessing pain in critically ill children with neurodevelopmental disabilities. It furthers goals of patient- and family-centered care but may have implementation barriers.

Pain communication in children with autism spectrum disorder: A scoping review

Children with autism spectrum disorder (ASD) experience social interaction and communication challenges and often display repetitive, restricted patterns of behavior, activities, and interests. The concept of pain is regarded as one of the most complex human stressors due to its subjective and personal nature and the influences of multiple internal and external factors. Due to the complexity of this disorder, it remains concerning how children with ASD communicate their pain and how observers (i.e., parents, carers, and health care practitioners) respond to these children's pain communication. This scoping review aimed to identify how children with ASD communicate or express their pain. Ten studies met the inclusion criteria for further data extraction. Through reflexive thematic analysis, two main themes were identified: verbal and nonverbal responses used by children with ASD to communicate their pain that could influence pain assessment and management strategies. This review highlighted that children with ASD utilized various verbal and nonverbal methods to communicate their pain experiences and that these methods differed compared to children without disabilities. Furthermore, this review emphasizes the importance of holistic pain assessment strategies as well as additional pictorial support for children with ASD. This review recommends that future research should focus on understanding how the inclusion of different stakeholders in pain assessment for children with ASD, can contribute to holistic pain assessment.

Pain assessment in autism: updating the ethical and methodological challenges through a state-of-the-art review

Sensory features of autism include hypo- or hyper-reactivity to pain; however, previous studies on pain in autism lead to conflicting results. Here, we present the state of the art and the methodological challenges concerning pain perception in autism, focusing on studies that used standardized protocol as Quantitative Sensory Testing (QST) to measure perception. Despite there are still scant evidences found with the use of QST, they have challenged the presumed hyposensitivity to pain in autisms, which emerged from parents' reports. Both, peripheral and central mechanisms, have been found involved in typical features of perception in autism. Nonetheless, evidences with controlled protocols are still scarce, and even scarcer are studies focused on children. Overall, complex ethical challenges have to be overcome in order to collect subjective and objective measures from autistic children. With heterogeneous neurodevelopmental features, or intellectual disability, novel or modified protocols are needed.

Perspectives on pain in Down syndrome

Down syndrome (DS) or trisomy 21 is a genetic condition often accompanied by chronic pain caused by congenital abnormalities and/or conditions, such as osteoarthritis, recurrent infections, and leukemia. Although DS patients are more susceptible to chronic pain as compared to the general population, the pain experience in these individuals may vary, attributed to the heterogenous structural and functional differences in the central nervous system, which might result in abnormal pain sensory information transduction, transmission, modulation, and perception. We tried to elaborate on some key questions and possible explanations in this review. Further clarification of the mechanisms underlying such abnormal conditions induced by the structural and functional differences is needed to help pain management in DS patients.

Examining the latent structure and correlates of sensory reactivity in autism: a multi-site integrative data analysis by the autism sensory research consortium

BACKGROUND

Differences in responding to sensory stimuli, including sensory hyperreactivity (HYPER), hyporeactivity (HYPO), and sensory seeking (SEEK) have been observed in autistic individuals across sensory modalities, but few studies have examined the structure of these "supra-modal" traits in the autistic population.

METHODS

Leveraging a combined sample of 3868 autistic youth drawn from 12 distinct data sources (ages 3-18 years and representing the full range of cognitive ability), the current study used modern psychometric and meta-analytic techniques to interrogate the latent structure and correlates of caregiver-reported HYPER, HYPO, and SEEK within and across sensory modalities. Bifactor statistical indices were used to both evaluate the strength of a "general response pattern" factor for each supra-modal construct and determine the added value of "modality-specific response pattern" scores (e.g., Visual HYPER). Bayesian random-effects integrative data analysis models were used to examine the clinical and demographic correlates of all interpretable HYPER, HYPO, and SEEK (sub)constructs.

RESULTS

All modality-specific HYPER subconstructs could be reliably and validly measured, whereas certain modality-specific HYPO and SEEK subconstructs were psychometrically inadequate when measured using existing items. Bifactor analyses supported the validity of a supra-modal HYPER construct (ωH = .800) but not a supra-modal HYPO construct (ωH = .653), and supra-modal SEEK models suggested a more limited version of the construct that excluded some sensory modalities (ωH = .800; 4/7 modalities). Modality-specific subscales demonstrated significant added value for all response patterns. Meta-analytic correlations varied by construct, although sensory features tended to correlate most with other domains of core autism features and co-occurring psychiatric symptoms (with general HYPER and speech HYPO demonstrating the largest numbers of practically significant correlations).

LIMITATIONS

Conclusions may not be generalizable beyond the specific pool of items used in the current study, which was limited to caregiver report of observable behaviors and excluded multisensory items that reflect many "real-world" sensory experiences.

CONCLUSION

Of the three sensory response patterns, only HYPER demonstrated sufficient evidence for valid interpretation at the supra-modal level, whereas supra-modal HYPO/SEEK constructs demonstrated substantial psychometric limitations. For clinicians and researchers seeking to characterize sensory reactivity in autism, modality-specific response pattern scores may represent viable alternatives that overcome many of these limitations.

The impact of COVID-19 pandemic on emotional and behavioral problems of children with autism spectrum disorder and developmental delay aged 1-6 years in China

Introduction

The COVID-19 pandemic outbreak have caused increased levels of emotional and behavioral problems, particularly among people with pre-existing mental health conditions. Young individuals with autism spectrum disorders (ASD) and developmental delay (DD) are particularly at risk due to their vulnerability. The purpose of this study was to look into the different effects of the COVID-19 pandemic on 1-6-year-old children with ASD and DD.

Methods

Parents and guardians of children with ASD completed an online survey that included questions about their children's socio-demographics characteristics, the effects of the COVID-19 outbreak on their health, and what they needed in order to deal with the conditions of the pandemic.

Results

This study compared 4,138 children with ASD to 711 children with DD. Children with ASD had a higher risk of having more emotional and behavioral problems than children with DD (OR 1.38, 95% CI 1.12-1.70). Compared to parent-oriented rehabilitation at home, discontinuing rehabilitation had a higher likelihood of negative emotional and behavioral change (OR 1.67, 95% CI 1.41-1.98). Having teachers' online support had a higher likelihood of negative emotional and behavioral change for ASD children (OR 1.26, 95% CI 1.03-1.54).

Conclusions

This article provided evidence that children with developmental disabilities, particularly ASD, were at risk for a variety of challenges to their emotional functioning during the COVID-19 period, and that online support was not an ideal way for children with ASD to receive effective educational intervention in China.

Consensus recommendations on altered sensory functioning in Phelan-McDermid syndrome

Altered sensory functioning is often observed in individuals with SHANK3 related Phelan-McDermid syndrome (PMS). Compared to typically developing individuals and individuals with an autism spectrum disorder, it has been suggested that there are distinctive features of sensory functioning in PMS. More hyporeactivity symptoms and less hyperreactivity and sensory seeking behaviour are seen, particularly in the auditory domain. Hypersensitivity to touch, possible overheating or turning red easily and reduced pain response are often seen. In this paper the current literature on sensory functioning in PMS is reviewed and recommendations for caregivers, based on consensus within the European PMS consortium, are given.

Targeting Shank3 deficiency and paresthesia in autism spectrum disorder: A brief review

Autism spectrum disorder (ASD) includes a group of multifactorial neurodevelopmental disorders characterized by impaired social communication, social interaction, and repetitive behaviors. Several studies have shown an association between cases of ASD and mutations in the genes of SH3 and multiple ankyrin repeat domain protein 3 (SHANK3). These genes encode many cell adhesion molecules, scaffold proteins, and proteins involved in synaptic transcription, protein synthesis, and degradation. They have a profound impact on all aspects of synaptic transmission and plasticity, including synapse formation and degeneration, suggesting that the pathogenesis of ASD may be partially attributable to synaptic dysfunction. In this review, we summarize the mechanism of synapses related to Shank3 in ASD. We also discuss the molecular, cellular, and functional studies of experimental models of ASD and current autism treatment methods targeting related proteins.

Correlation and predictive ability of sensory characteristics and social interaction in children with autism spectrum disorder

Background

Individuals with autism spectrum disorder (ASD) often have different social characteristics and particular sensory processing patterns, and these sensory behaviors may affect their social functioning. The objective of our study is to investigate the sensory profiles of children with ASD and their association with social behavior. Specifically, we aim to identify the predictive role of sensory processing in social functioning.

Methods

The Short Sensory Profile (SSP) was utilized to analyze sensory differences between ASD children and their peers. The Social Responsiveness Scale (SRS) and other clinical scales were employed to assess the social functioning of children with ASD. Additionally, the predictive ability of sensory perception on social performance was discussed using random forest and support vector machine (SVM) models.

Results

The SSP scores of ASD children were lower than those of the control group, and there was a significant negative correlation between SSP scores and clinical scale scores (P < 0.05). The random forest and SVM models, using all the features, showed higher sensitivity, while the random forest model with 7-feature factors had the highest specificity. The area under the receiver operating characteristic (ROC) curve (AUC) for all the models was higher than 0.8.

Conclusion

Autistic children in our study have different patterns of sensory processing than their peers, which are significantly related to their patterns of social functioning. Sensory features can serve as a good predictor of social functioning in individuals with ASD.

Unique Pain Responses in Different Etiological Subgroups of Intellectual and Developmental Disabilities

We studied whether there exist variations in pain responses between different intellectual and developmental disability (IDD) etiologies. Self-reports and facial expressions (Facial Action Coding System = FACS) were recorded during experimental pressure stimuli and compared among 31 individuals with IDD-13 with cerebral palsy (CP), nine with Down syndrome (DS), nine with unspecified origin (UIDD)-and among 15 typically developing controls (TDCs). The CP and DS groups had higher pain ratings and FACS scores compared to the UIDD and TDC groups, and steeper stimulus-response functions. The DS group exhibited the most diverse facial expressions. There were variations in the foci of facial expressions between groups. It appears that different IDD etiologies display distinct pain responses.

The Current View on the Paradox of Pain in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, which affects 1 in 44 children and may cause severe disabilities. Besides socio-communicational difficulties and repetitive behaviors, ASD also presents as atypical sensorimotor function and pain reactivity. While chronic pain is a frequent co-morbidity in autism, pain management in this population is often insufficient because of difficulties in pain evaluation, worsening their prognosis and perhaps driving higher mortality rates. Previous observations have tended to oversimplify the experience of pain in autism as being insensitive to painful stimuli. Various findings in the past 15 years have challenged and complicated this dogma. However, a relatively small number of studies investigates the physiological correlates of pain reactivity in ASD. We explore the possibility that atypical pain perception in people with ASD is mediated by alterations in pain perception, transmission, expression and modulation, and through interactions between these processes. These complex interactions may account for the great variability and sometimes contradictory findings from the studies. A growing body of evidence is challenging the idea of alterations in pain processing in ASD due to a single factor, and calls for an integrative view. We propose a model of the pain cycle that includes the interplay between the molecular and neurophysiological pathways of pain processing and it conscious appraisal that may interfere with pain reactivity and coping in autism. The role of social factors in pain-induced response is also discussed. Pain assessment in clinical care is mostly based on subjective rather than objective measures. This review clarifies the strong need for a consistent methodology, and describes innovative tools to cope with the heterogeneity of pain expression in ASD, enabling individualized assessment. Multiple measures, including self-reporting, informant reporting, clinician-assessed, and purely physiological metrics may provide more consistent results. An integrative view on the regulation of the pain cycle offers a more robust framework to characterize the experience of pain in autism.

"When I'm in Pain, Everything Is Overwhelming": Implications of Pain in Adults With Autism on Their Daily Living and Participation

Pain sensation in autism spectrum disorder (ASD) has been a growing research field in the last two decades. Existing pain research has focused on pain sensitivity, suggesting either hyposensitivity or hypersensitivity to pain in individuals with ASD. However, research about other aspects of pain experience is scarce. Moreover, most pain-related research in ASD focused on quantitative measures, such as neuroimaging or parental reports. Instead, this paper aimed to illuminate the various aspects of pain experience as perceived by adults with ASD. Its descriptive qualitative research design incorporated semi-structured interviews and deductive thematic analysis. This phenomenological approach captured the subjective pain experience through the lens of people with ASD. Four primary themes emerged from the data: (a) physical pain experience, including the sequence of pain sensitivity, pain awareness, pain-related emotional aspects, and pain communication; (b) direct and indirect coping strategies; (c) function and participation outcomes; and (d) suggestions for Healthcare Providers. The findings echo the crucial role of pain awareness and communication in the pain experience of people with ASD. These two factors have been reported as profoundly influencing coping strategies, function, and participation. The results emphasize the need to expand the exploration of pain in this population, calling for greater understanding, and listening to this population's unique pain profiles and experiences to promote better-suited evaluation, diagnosis, and intervention in pain conditions.

Identifying genetic determinants of inflammatory pain in mice using a large-scale gene-targeted screen

ABSTRACT

Identifying the genetic determinants of pain is a scientific imperative given the magnitude of the global health burden that pain causes. Here, we report a genetic screen for nociception, performed under the auspices of the International Mouse Phenotyping Consortium. A biased set of 110 single-gene knockout mouse strains was screened for 1 or more nociception and hypersensitivity assays, including chemical nociception (formalin) and mechanical and thermal nociception (von Frey filaments and Hargreaves tests, respectively), with or without an inflammatory agent (complete Freund's adjuvant). We identified 13 single-gene knockout strains with altered nocifensive behavior in 1 or more assays. All these novel mouse models are openly available to the scientific community to study gene function. Two of the 13 genes (Gria1 and Htr3a) have been previously reported with nociception-related phenotypes in genetically engineered mouse strains and represent useful benchmarking standards. One of the 13 genes (Cnrip1) is known from human studies to play a role in pain modulation and the knockout mouse reported herein can be used to explore this function further. The remaining 10 genes (Abhd13, Alg6, BC048562, Cgnl1, Cp, Mmp16, Oxa1l, Tecpr2, Trim14, and Trim2) reveal novel pathways involved in nociception and may provide new knowledge to better understand genetic mechanisms of inflammatory pain and to serve as models for therapeutic target validation and drug development.

Improving pain-related communication in children with autism spectrum disorder and intellectual disability

The communication of pain in individuals with co-morbid Autism Spectrum Disorder and intellectual disability (ASD-ID) is largely unexplored. The communication deficits associated with ASD-ID can result in nonverbal behavior such as self-injurious behavior, aggression, irritability, and reduced activity as a means to communicate that pain is present. The objective of this study was to determine whether a behavioral-based educational intervention could increase the pain-related communication of children with ASD-ID who experience pain frequently. Specifically, the study aimed to determine if children with ASD-ID can label the location of their pain or quantify pain severity and request pain relief. The sample included three children with ASD-ID who experienced pain frequently. The intervention utilized educational materials and behavioral reinforcements and the intervention was conducted using a series of case studies. Pain was assessed daily by caregivers using the Non-Communicating Children's Pain Checklist-Postoperative (NCCPC-PV) and the ability of the individual to identify and express pain was recorded using the Wong Baker FACES Pain (WBFPS) Scale. Challenging behavior was recorded based on frequency count. The results indicated that all participants displayed the ability to independently respond to a question about how they were feeling by vocalizing the location of pain or indicating their level of pain on the WBFPS and requesting pain relief. The results suggest a role for behavioral-based educational interventions to promote communication of pain in people with ASD-ID.

Autistic Traits and Empathy for Others' Pain Among the General Population: Test of the Mediating Effects of First-Hand Pain Sensitivity

Autism spectrum disorders (ASD) are characterized by reduced pain empathy-a process that is grounded in first-hand pain perception. Because autistic traits are continuously distributed in the general population, we hypothesized that first-hand pain sensitivity would mediate the link between autistic traits and pain empathy. After controlling for alexithymia, higher autistic traits were associated with lower cognitive and emotional empathy in response to others' pain, as well as lower sensitivity to cold and heat pain (higher cold pain tolerance and lower laser heat pain-intensity ratings). Importantly, pain sensitivity fully mediated the link between autistic traits and pain empathy. These findings highlight the role of atypical first-hand pain sensitivity in the lack of pain empathy observed in people with high autistic traits or ASD.

COVID-19 Pandemic and Impact on Patients with Autism Spectrum Disorder

The COVID-19 infectious disease pandemic has caused significant fear and uncertainty around the world and had significant adverse psychological impact. Children, adolescents and adults with autism spectrum disorder (ASD) are a particularly vulnerable population, impacted by stay-at-home orders, closures at nonessential services, and social distancing standards. This commentary describes various challenges faced by individuals with ASD in the United States including disruptions caused by educational and vocational changes, challenges to home and leisure routines, limited access to behavioral health services and changes in health services delivery due to the pandemic. We highlight the need for ongoing skills development for individuals and development within systems to better respond to needs of the ASD population in future emergencies.

A Systematic Review on the Impact of the Social Confinement on People with Autism Spectrum Disorder and Their Caregivers during the COVID-19 Pandemic

The COVID-19 pandemic had imposed a variety of containment measures on the general population for prolonged periods. Confinement has had, and still has, social, economic, educational, health, and psychological consequences on the entire population.

OBJECTIVE

In this article, a systematic search has been performed based on studies carried out since the beginning of the pandemic, regarding the impact of these containment measures on the autism spectrum disorder (ASD) population and their caregivers.

METHOD

We consulted six databases (i.e., PubMed, Medline, Embase, Scopus, Web of Science, and Science Direct) and selected ten studies that met the inclusion criteria. The chosen studies have been classified according to their theoretical focus, methodology, and target population.

RESULTS

We found an increase in stress and a decrease in psychological well-being among individuals diagnosed with ASD (i.e., parents and caregivers). Additionally, in studies focused on children, youth, and adults with ASD diagnosis, the results are contradictory depending on variables such as age, ASD severity, or type of family structure.

CONCLUSIONS

The results show that the consequences of quarantine and social confinement are quite contradictory and depend on variables such as age, ASD severity, and family features.

Pain Behavior of People with Intellectual and Developmental Disabilities Coded with the New PAIC-15 and Validation of Its Arabic Translation

Pain management necessitates assessment of pain; the gold standard being self-report. Among individuals with intellectual and developmental disabilities (IDD), self-report may be limited and therefore indirect methods for pain assessment are required. A new, internationally agreed upon and user-friendly observational tool was recently published—the Pain Assessment in Impaired Cognition (PAIC-15). The current study’s aims were: to test the use of the PAIC-15 in assessing pain among people with IDD and to translate the PAIC-15 into Arabic for dissemination among Arabic-speaking professionals. Pain behavior following experimental pressure stimuli was analyzed among 30 individuals with IDD and 15 typically developing controls (TDCs). Translation of the PAIC followed the forward–backward approach; and reliability between the two versions and between raters was calculated. Observational scores with the PAIC-15 exhibited a stimulus–response relationship with pressure stimulation. Those of the IDD group were greater than those of the TDC group. The overall agreement between the English and Arabic versions was high (ICC = 0.89); single items exhibited moderate to high agreement levels. Inter-rater reliability was high (ICC = 0.92). Both versions of the PAIC-15 are feasible and reliable tools to record pain behavior in individuals with IDD. Future studies using these tools in clinical settings are warranted.

Mirror therapy for phantom limb pain in moderate intellectual disability. A case report

BACKGROUND

Phantom limb pain (PLP) is a common problem after limb amputation. There is mounting evidence supporting the use of mirror therapy (MT) in the treatment of individuals with PLP. However, there is no research studying the effects of MT on PLP in individuals with intellectual developmental disorders (IDD). The aim of this study was to increase our understanding of MT when used with adults with IDD and PLP through a case study approach.

METHODS

Here, we describe the use of MT with a 53-year-old female with moderate IDD and PLP, related to her left leg being amputated after ulcer complications. The study followed an A-B-A-B design (baseline-treatment-withdrawal of treatment-re-introduction of treatment), lasting 2 years, which included a long-term follow-up.

RESULTS

The data showed that the PLP sensation decreased after the MT treatment, with a raw change of 3.92 points and a 48% decrease in mean pain intensity ratings from pre- to post-treatment.

CONCLUSIONS

This is a unique case-report on the use of MT with an individual with IDD suffering from PLP. The findings show that MT helped to significantly reduce the intensity of the PLP in this patient.

SIGNIFICANCE

This is a case-report that illustrates how mirror therapy can be applied to people with intellectual developmental disorders and phantom limb pain. The results showed that phantom limb pain decreased after the mirror therapy, with a raw change of 3,92 points and a percent change of 48%.

An Australian Cross-Sectional Survey of Parents' Experiences of Emergency Department Visits Among Children with Autism Spectrum Disorder

Parents of children with ASD who had attended an Australian emergency department (ED; n = 421) completed a questionnaire relating to their experiences in the ED, including (1) child's reason for presentation and existing comorbidities, (2) quality of care during the visit (3) child's behaviour during visit, e.g. sensory responses to the ED environment, and disruptive behaviours. Children with comorbid ASD and intellectual disability were more likely to present with gastrointestinal issues and seizures, while those with comorbid ASD and oppositional defiant disorder were more likely to present with self-injury. ED staff awareness of ASD-related issues, including communication and expression of pain, were common difficulties for parents. The ED environment (e.g. lights, sounds, waiting areas), exacerbated child anxiety and led to disruptive behaviour.

Global health disparities in vulnerable populations of psychiatric patients during the COVID-19 pandemic

The coronavirus disease 2019 pandemic affects psychiatric patients disproportionately compared to the general population. In this narrative review, we examine the impact of the pandemic on significant global health disparities affecting vulnerable populations of psychiatric patients: People of diverse ethnic background and color, children with disabilities, sexual and gender minorities, pregnant women, mature adults, and those patients living in urban and rural communities. The identified disparities cause worsened mental health outcomes placing psychiatric patients at higher risk for depression, anxiety and posttraumatic stress disorder symptoms. Those psychiatric patients who are ethnic minorities display barriers to care, including collective trauma and structural racism. Sexual and gender minorities with mental illness face discrimination and limited access to treatment. Pregnant women with psychiatric diagnoses show higher exposure to domestic violence. Children with disabilities face a higher risk of worsening behavior. Mature adults with psychiatric problems show depression due to social isolation. Psychiatric patients who live in urban communities face pollutants and overcrowding compared to those living in rural communities, which face limited access to telehealth services. We suggest that social programs that decrease discrimination, enhance communal resilience, and help overcome systemic barriers of care should be developed to decrease global health disparities in vulnerable population.

Specific Behavioral Responses Rather Than Autonomic Responses Can Indicate and Quantify Acute Pain among Individuals with Intellectual and Developmental Disabilities

Individuals with intellectual and developmental disabilities (IDD) are at a high risk of experiencing pain. Pain management requires assessment, a challenging mission considering the impaired communication skills in IDD. We analyzed subjective and objective responses following calibrated experimental stimuli to determine whether they can differentiate between painful and non-painful states, and adequately quantify pain among individuals with IDD. Eighteen adults with IDD and 21 healthy controls (HC) received experimental pressure stimuli (innocuous, mildly noxious, and moderately noxious). Facial expressions (analyzed with the Facial Action Coding System (FACS)) and autonomic function (heart rate, heart rate variability (HRV), pulse, and galvanic skin response (GSR)) were continuously monitored, and self-reports using a pyramid and a numeric scale were obtained. Significant stimulus-response relationships were observed for the FACS and pyramid scores (but not for the numeric scores), and specific action units could differentiate between the noxious levels among the IDD group. FACS scores of the IDD group were higher and steeper than those of HC. HRV was overall lower among the IDD group, and GSR increased during noxious stimulation in both groups. In conclusion, the facial expressions and self-reports seem to reliably detect and quantify pain among individuals with mild-moderate IDD; their enhanced responses may indicate increased pain sensitivity that requires careful clinical consideration.

From Multisensory Assessment to Functional Interpretation of Social Behavioral Phenotype in Transgenic Mouse Models for Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a common heterogeneous disorder, defined solely by the core behavioral characteristics, including impaired social interaction and restricted and repeated behavior. Although an increasing number of studies have been performed extensively, the neurobiological mechanisms underlying the core symptoms of ASD remain largely unknown. Transgenic mouse models provide a useful tool for evaluating genetic and neuronal mechanisms underlying ASD pathology, which are prerequisites for validating behavioral phenotypes that mimic the core symptoms of human ASD. The purpose of this review is to propose a better strategy for analyzing and interpreting social investigatory behaviors in transgenic mouse models of ASD. Mice are nocturnal, and employ multimodal processing mechanisms for social communicative behaviors, including those that involve olfactory and tactile senses. Most behavioral paradigms that have been developed for measuring a particular ASD-like behavior in mouse models, such as social recognition, preference, and discrimination tests, are based on the evaluation of distance-based investigatory behavior in response to social stimuli. This investigatory behavior in mice is regulated by multimodal processing involving with two different motives: first, an olfactory-based novelty assessment, and second, tactile-based social contact, in a temporally sequential manner. Accurate interpretation of investigatory behavior exhibited by test mice can be achieved by functional analysis of these multimodal, sequential behaviors, which will lead to a better understanding of the specific features of social deficits associated with ASD in transgenic mouse models, at high temporal and spatial resolutions.

Communicating with Youth about Pain: Developmental Considerations

BACKGROUND

Pain experiences can negatively impact children and adolescents, leading to trauma symptoms and nonadherence to important health behaviors. Developmentally-tailored communication strategies may mitigate this risk.

METHODS

This article reviews cognitive and linguistic developmental factors, within the familial and cultural context, that are important to consider when communicating with youth about acute, procedural, and/or chronic pain.

RESULTS

Youth undergoing acute or procedural pain benefit from pain education, truthful information about the procedure, and advance preparation. The use of analogies may be particularly helpful for patient understanding of chronic pain development, maintenance, and treatment. Youth with developmental disabilities may express pain differently than their normative peers, requiring adaptation of communication strategies.

CONCLUSION

Developmentally-tailored pain communication is an important tool for caregivers and healthcare providers that may foster adaptive functioning in youth who experience pain.

Autism and Migraine: An Unexplored Association?

Autism spectrum disorder is characterized by neurological, psychiatric and medical comorbidities—some conditions co-occur so frequently that comorbidity in autism is the rule rather than the exception. The most common autism co-occurring conditions are intellectual disability, language disorders, attention-deficit hyperactivity disorder, epilepsy, gastrointestinal problems, sleep disorders, anxiety, depression, obsessive-compulsive disorder, psychotic disorders, oppositional defiant disorder, and eating disorders. They are well known and studied. Migraine is the most common brain disease in the world, but surprisingly only a few studies investigate the comorbidity between autism and migraine. The aim of this narrative review is to explore the literature reports about the comorbidity between autism and migraine and to investigate the common neurotransmitter, immune, anatomical and genetic abnormalities at the base of these two conditions.

Feasibility of Dried Blood Spots in Children with Behavioral Problems

BACKGROUND

Minimally invasive sampling methods are important to facilitate therapeutic drug monitoring and pharmacokinetic research in children with behavioral problems. This study assessed the feasibility and pain of dried blood spot (DBS) sampling in this population.

METHODS

Repeated DBS sampling was performed in children with autism spectrum disorder (ASD) and severe behavioral problems using antipsychotic drugs, aged between 6 and 18 years. The child, guardian, and DBS performer assessed pain using the numeric rating scale (NRS-11) or 5-face Faces Pain Scale. The influence of age, sex, and the fingerprick performer on the child's pain intensity was analyzed using linear mixed models.

RESULTS

Overall, 247 fingerpricks were performed in 70 children. Seven children refused all DBS sampling. The median (interquartile range) NRS-11 pain scores were 2 (3) rated by children, 3 (2.5) by guardians, and 2 (2) by fingerprick performers. The child's age and sex, and fingerprick performer had no significant influence on pain intensity.

CONCLUSIONS

DBS sampling could be performed in most children with ASD and severe behavioral problems. However, 1 in 5 children refused one or more DBS fingerpricks owing to distress. Most expressed minimal pain (NRS < 4). Repeated sampling with DBS is feasible in children with ASD and severe behavioral problems.

Pain in neuropsychiatry: Insights from animal models

Pain is the most common symptom reported in clinical practice, meaning that it is associated with many pathologies as either the origin or a consequence of other illnesses. Furthermore, pain is a complex emotional and sensorial experience, as the correspondence between pain and body damage varies considerably. While these issues are widely acknowledged in clinical pain research, until recently they have not been extensively considered when exploring animal models, important tools for understanding pain pathophysiology. Interestingly, chronic pain is currently considered a risk factor to suffer psychiatric disorders, mainly stress-related disorders like anxiety and depression. Conversely, pain appears to be altered in many psychiatric disorders, such as depression, anxiety and schizophrenia. Thus, pain and psychiatric disorders have been linked in epidemiological and clinical terms, although the neurobiological mechanisms involved in this pathological bidirectional relationship remain unclear. Here we review the evidence obtained from animal models about the co-morbidity of pain and psychiatric disorders, placing special emphasis on the different dimensions of pain.

Deficiency of SHANK3 isoforms impairs thermal hyperalgesia and dysregulates the expression of postsynaptic proteins in the spinal cord

SHANK3 is one of the scaffolding proteins in the postsynaptic density (PSD). Pain perception and underlying mechanisms were investigated in Shank3 exon 21 deficient (Shank3^△C) mice. Sixty-six mice were attributed according to their genotype to three groups: (1) wild-type (WT), (2) heterozygous Shank3^△C/+, and (3) homozygous Shank3^△C/△C. Complete Freund's adjuvant (CFA) was used to induce inflammatory pain, and thermal hyperalgesia was determined. CFA treatment reduced the thermal threshold in the WT group; groups expressing mutations of Shank3 (^△C/+ and ^△C/△C) had higher thresholds after CFA administration compared to the WT group. Mice with Shank3 mutations (^△C/+ or ^△C/△C) had a lower expression of GluN2A and IP₃R proteins and a higher expression of mGluR5 protein in the PSD compared to WT mice without changes in GluN1, GluN2B, and Homer expression. The crosslinking of Homer-IP₃R, but not Homer-mGluR5, was decreased in the total lysate. Deficit of Shank3 exon 21 may lead to impaired perception of thermal pain in mice under inflammatory conditions. This impairment may result from protein dysregulation in the PSD like downregulation of the GluN2A subunit, which may reduce NMDAR-mediated currents, and/or decreased crosslinking between Homer and IP₃R, which may reduce the release of Ca²⁺ from intracellular stores.

Pain Modulation Mechanisms in ASD Adults

We tested endogenous pain modulation mechanisms in adults with autism spectrum disorders (ASD). Nineteen ASD adults without intellectual disabilities were included, matched with 19 healthy volunteers on the basis of sex and chronological age. An experimental pain model was used to measure excitatory and inhibitory pain mechanisms in a single session. Statistical analyses indicated that endogenous pain modulation mechanisms in ASD group did not differ significantly from those of healthy adults. The pain scores were very disparate in ASD group with a greater range of extreme scores than in control group. Unlike schizophrenic patients, there was no systematic dysfunction of endogenous excitatory pain modulation mechanisms, but the high variability requires to be wise to interpret the results and formulate conclusion.

Mechanisms of Tactile Sensory Phenotypes in Autism: Current Understanding and Future Directions for Research

PURPOSE OF REVIEW

This review aims to summarize the current body of behavioral, physiological, and molecular knowledge concerning tactile sensitivity in autism spectrum disorder (ASD), with a focus on recent studies utilizing rodent models.

RECENT FINDINGS

Mice with mutations in the ASD-related genes, Shank3, Fmr1, UBE3A, and Mecp2, display tactile abnormalities. Some of these abnormalities appear to be caused by mutation-related changes in the PNS, as opposed to changes in the processing of touch stimuli in the CNS, as previously thought. There is also growing evidence suggesting that peripheral mechanisms may contribute to some of the core symptoms and common comorbidities of ASD. Researchers are therefore beginning to assess the therapeutic potential of targeting the PNS in treating some of the core symptoms of ASD. Sensory abnormalities are common in rodent models of ASD. There is growing evidence that sensory hypersensitivity, especially tactile sensitivity, may contribute to social deficits and other autism-related behaviors.

Internalizing Symptoms Mediate the Relation Between Acute Pain and Autism in Adults

Research on pain in autism spectrum disorder (ASD) is in its infancy, with almost nothing known about how individual differences may predicting pain response in ASD. In the present study, 45 adults (28 male, age 22-48 years) with diagnoses of autism and intellectual delay were observed during vaccination or dental cleaning and their pain behaviours coded and measures of autism symptom severity, anxiety, depression and obsessivity taken. Our findings showed that greater autism severity predicted greater pain response which was partially mediated by anxiety and depression. These data suggest that mental health symptoms are important when considering pain response in autism. Mood must therefore be considered in future research on pain in ASD as well as clinical pain management.

Accurate empathy of romantic partners increases pain ratings but promotes recovery

Background

Perceived empathy is a commonly used strategy to cope with pain and is crucial for maintaining intimacy in dyadic relationships.

Materials and methods

This study used the cold pressor test to investigate how perceived empathy and relationship type interact with the subjective perception of pain and objective measures of recovery time, using heart rate as an index. One hundred and ninety participants were recruited, including 49 friend dyads and 46 romantic partner dyads. Perceived empathy was manipulated by adopting three levels as the experimental conditions: high, accurate, and low.

Results

In the subjective perception stage, the results showed a significant interaction of relationship type and empathy with pain reporting, indicating that romantic partners reported more pain than friends under the accurate empathy condition. There were no differences between the two groups in the high and low perceived empathy conditions. In the self-recovery stage, the results showed that romantic partners had less pain tolerance than friends in all three perceived empathy conditions. On the other hand, romantic partners recovered faster than friends under the accurate empathy condition, but not under the high and low perceived empathy conditions.

Conclusion

These results suggest that perceived accurate empathy is necessary for romantic relationships when coping with pain. The findings deepen our understanding of the mechanism of perceived empathy, and the ways in which it modulates psychological and physiological responses in a social context.

Self-Injury in Autism Spectrum Disorder and Intellectual Disability: Exploring the Role of Reactivity to Pain and Sensory Input

This paper provides information about the prevalence and topography of self-injurious behavior in children and adults with autism spectrum disorder and intellectual disability. Dominant models regarding the etiology of self-injury in this population are reviewed, with a focus on the role of reactivity to pain and sensory input. Neuroimaging studies are presented and suggestions are offered for future research.

Physiological and Behavioral Responses to Calibrated Noxious Stimuli Among Individuals with Cerebral Palsy and Intellectual Disability

Objective

As individuals with intellectual disability (ID) due to cerebral palsy (CP) are at high risk of experiencing pain, measuring their pain is crucial for adequate treatment. While verbal reports are the gold standard in pain measurements, they may not be sufficient in ID. The aim was to detect behavioral/autonomic responses that may indicate the presence and intensity of pain in individuals with CP and ID, using calibrated stimuli, here for the first time.

Subjects

Thirteen adults with CP and ID (CPID), 15 healthy controls (HC), and 5 adults with CP with no ID (CPNID).

Methods

Subjects received pressure stimuli of various intensities. Self-reports (using a pyramid scale), facial expressions (retrospectively analyzed with Facial Action Coding System = FACS), and autonomic function (heart rate, heart rate variability, pulse, galvanic skin response) were analyzed.

Results

Self-reports and facial expressions but not the autonomic function exhibited stimulus-response relationship to pressure stimulation among all groups. The CPID group had increased pain ratings and facial expressions compared with controls. In addition, the increase in facial expressions along the increase in noxious stimulation was larger than in controls. Freezing in response to pain was frequent in CPID.

Conclusions

1) Individuals with CP and ID have increased responses to pain; 2) facial expressions and self-reports, but not autonomic variables can reliably indicate their pain intensity; 3) the pyramid scale is suitable for self-report in this population. Although facial expressions may replace verbal reports, increased facial expressions at rest among these individuals may mask pain, especially at lower intensities.

Pain Assessment and Treatment in Children With Significant Impairment of the Central Nervous System

Pain is a frequent and significant problem for children with impairment of the central nervous system, with the highest frequency and severity occurring in children with the greatest impairment. Despite the significance of the problem, this population remains vulnerable to underrecognition and undertreatment of pain. Barriers to treatment may include uncertainty in identifying pain along with limited experience and fear with the use of medications for pain treatment. Behavioral pain-assessment tools are reviewed in this clinical report, along with other strategies for monitoring pain after an intervention. Sources of pain in this population include acute-onset pain attributable to tissue injury or inflammation resulting in nociceptive pain, with pain then expected to resolve after treatment directed at the source. Other sources can result in chronic intermittent pain that, for many, occurs on a weekly to daily basis, commonly attributed to gastroesophageal reflux, spasticity, and hip subluxation. Most challenging are pain sources attributable to the impaired central nervous system, requiring empirical medication trials directed at causes that cannot be identified by diagnostic tests, such as central neuropathic pain. Interventions reviewed include integrative therapies and medications, such as gabapentinoids, tricyclic antidepressants, α-agonists, and opioids. This clinical report aims to address, with evidence-based guidance, the inherent challenges with the goal to improve comfort throughout life in this vulnerable group of children.

Initially intact neural responses to pain in autism are diminished during sustained pain

Pain assessments typically depend on self-report of the pain experience. Yet, in individuals with autism spectrum disorders, this can be an unreliable due to communication difficulties. Importantly, observations of behavioral hypo- and hyperresponsivity to pain suggest altered pain sensitivity in autism spectrum disorder. Neuroimaging may provide insight into mechanisms underlying pain behaviors. The neural pain signature reliably responds to painful stimulation and is modulated by other outside regions, affecting the pain experience. In this first functional magnetic resonance imaging study of pain in autism spectrum disorder, we investigated neural responses to pain in 15 adults with autism spectrum disorder relative to a typical comparison group (n = 16). We explored temporal and spatial properties of the neural pain signature and its modulators during sustained heat pain. The two groups had indistinguishable pain ratings and neural pain signature responses during acute pain; yet, we observed strikingly reduced neural pain signature response in autism spectrum disorder during sustained pain and after stimulus offset. The posterior cingulate cortex, a neural pain signature modulating region, mirrored this late signal reduction in autism spectrum disorder. Intact early responses, followed by diminished late responses to sustained pain, may reflect altered pain coping or evaluation in autism spectrum disorder. Evidence of a dichotomous neural response to initial versus protracted pain may clarify the coexistence of both hypo- and hyperresponsiveness to pain in autism spectrum disorder.

Daily living pain assessment in children with autism: Exploratory study

This study aims to broaden knowledge about pain expression and assessment in daily life situations in children with Autism Spectrum Disorder (ASD). The goals are to provide a description of the responses of the GED-DI, the French version of the NCCPC, and to test the internal structure validity of this scale. Thirty five children with ASD were included in this study (mean age=58months; mean developmental age=32months). The French version of the NCCPC was filled in by parents. Descriptive analysis of responses shows that children with ASD express pain through varied and common behaviours, related to different expressive markers (vocal, facial, activity, etc.). Behaviours more specific to the symptomology and disturbances of ASD are also displayed. A four-factor solution (negative emotional reaction, idiosyncratic expression, hyper-vigilance reaction, pain expression) emerges from an exploratory factor analysis that explains 54.4% of the total variance. Correlation coefficients show good psychometric qualities in terms of internal consistency, factorial validity and discriminant validity. This study provides new data about pain expression in daily life situations and shows that the French version of NCCPC adjusted to ASD children is relevant to assess pain in daily life situations.

A systematic review of physiological reactivity to stimuli in autism

OBJECTIVE

The prevalence of abnormal behavioural responses to a variety of stimuli among individuals with autism has led researchers to examine whether physiological reactivity (PR) is typical in this population. This article reviewed studies assessing PR to sensory, social and emotional, and stressor stimuli in individuals with autism.

METHODS

Systematic searches of electronic databases identified 57 studies that met our inclusion criteria. Studies were analysed to determine: (a) participant characteristics; (b) physiological measures used; (c) PR to sensory, social and emotional or stressor stimuli; (d) the relation between PR and behavioural or psychological variables and (e) baseline physiological activity. A novel measure of methodological quality suitable for use with non-randomized, non-interventional, psychophysiological studies was also developed and applied.

RESULTS

Individuals with autism were found to respond differently than typically developing controls in 78.6%, 66.7% and 71.4% of sensory, social and emotional, and stressor stimulus classes, respectively. However, this extant literature is characterized by variable and inconsistent findings, which do not appear to be accounted for by varying methodological quality, making it difficult to determine what specific factors differentiate individuals with autism who present with atypical PR from those who do not.

CONCLUSIONS

Despite this uncertainty, individual differences in PR are clearly present in autism, suggesting additional research is needed to determine the variables relating to PR among those with ASD and to examine the possible existence of physiological subtype responders in the population.

SHANK3 Deficiency Impairs Heat Hyperalgesia and TRPV1 Signaling in Primary Sensory Neurons

Abnormal pain sensitivity is commonly associated with autism spectrum disorders (ASDs) and affects the life quality of ASD individuals. SHANK3 deficiency was implicated in ASD and pain dysregulation. Here, we report functional expression of SHANK3 in mouse dorsal root ganglion (DRG) sensory neurons and spinal cord presynaptic terminals. Homozygous and heterozygous Shank3 complete knockout (Δe4-22) results in impaired heat hyperalgesia in inflammatory and neuropathic pain. Specific deletion of Shank3 in Nav1.8-expressing sensory neurons also impairs heat hyperalgesia in homozygous and heterozygous mice. SHANK3 interacts with transient receptor potential subtype V1 (TRPV1) via Proline-rich region and regulates TRPV1 surface expression. Furthermore, capsaicin-induced spontaneous pain, inward currents in DRG neurons, and synaptic currents in spinal cord neurons are all reduced after Shank3 haploinsufficiency. Finally, partial knockdown of SHANK3 expression in human DRG neurons abrogates TRPV1 function. Our findings reveal a peripheral mechanism of SHANK3, which may underlie pain deficits in SHANK3-related ASDs.

Neonatal inflammatory pain and systemic inflammatory responses as possible environmental factors in the development of autism spectrum disorder of juvenile rats

Background

Autism spectrum disorder (ASD) affects many children and juveniles. The pathogenesis of ASD is not well understood. Environmental factors may play important roles in the development of ASD. We examined a possible relationship of inflammatory pain in neonates and the development of ASD in juveniles.

Methods

Acute inflammation pain was induced by 5 % formalin (5 μl/day) subcutaneous injection into two hindpaws of postnatal day 3 to 5 (P3–P5) rat pups. Western blot, immunohistochemical, and behavioral examinations were performed at different time points after the insult.

Results

Formalin injection caused acute and chronic inflammatory responses including transient local edema, increased levels of inflammatory cytokines, TNF-α, and IL-1β in the blood as well as in the brain, and increased microglia in the brain. One day after the pain insult, there was significant cell death in the cortex and hippocampus. Two weeks later, although the hindpaw local reaction subsided, impaired axonal growth and demyelization were seen in the brain of P21 juvenile rats. The number of bromodeoxyuridine (BrdU) and doublecortin (DCX) double-positive cells in the hippocampal dentate gyrus of P21 rats was significantly lower than that in controls, indicating reduced neurogenesis. In the P21 rat’s brain of the formalin group, the expression of autism-related gene neurexin 1 (NRXN1), fragile X mental retardation 1 (FMR1), and oxytocin was significantly downregulated, consistent with the gene alteration in ASD. Juvenile rats in the formalin group showed hyperalgesia, repetitive behaviors, abnormal locomotion, sleep disorder, and distinct deficits in social memory and social activities. These alterations in neuroinflammatory reactions, gene expression, and behaviors were more evident in male than in female rats. Importantly, an anti-inflammation treatment using indomethacin (10 mg/kg, i.p.) at the time of formalin injections suppressed inflammatory responses and neuronal cell death and prevented alterations in ASD-related genes and the development of abnormal behaviors.

Conclusions

These novel observations indicate that severe inflammatory pain in neonates and persistent inflammatory reactions may predispose premature infants to development delays and psychiatric disorders including ASD. The prevention of pain stimuli and prompt treatments of inflammation during development appear vitally important in disrupting possible evolution of ASD syndromes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0575-x) contains supplementary material, which is available to authorized users.

Reduced acute nociception and chronic pain in Shank2-/- mice

Autism spectrum disorder is a debilitating mental illness and social issue. Autism spectrum disorder patients suffer from social isolation, cognitive deficits, compulsive behavior, and sensory deficits, including hyposensitivity to pain. However, recent studies argued that autism spectrum disorder patients show physiological pain response and, in some cases, even extremely intense pain response to harmless stimulation. Recently, Shank gene family was reported as one of the genetic risk factors of autism spectrum disorder. Thus, in this study, we used Shank2^−/− (Shank2 knock-out, KO) mice to investigate the controversial pain sensitivity issue and found that Shank2 KO mice showed reduced tactile perception and analgesia to chronic pain.

Validity of the Child Facial Coding System for the Assessment of Acute Pain in Children With Cerebral Palsy

The purpose of the current study was to examine the concurrent and discriminant validity of the Child Facial Coding System for children with cerebral palsy. Eighty-five children (mean = 8.35 years, SD = 4.72 years) were videotaped during a passive joint stretch with their physiotherapist and during 3 time segments: baseline, passive joint stretch, and recovery. Children's pain responses were rated from videotape using the Numerical Rating Scale and Child Facial Coding System. Results indicated that Child Facial Coding System scores during the passive joint stretch significantly correlated with Numerical Rating Scale scores (r = .72, P < .01). Child Facial Coding System scores were also significantly higher during the passive joint stretch than the baseline and recovery segments (P < .001). Facial activity was not significantly correlated with the developmental measures. These findings suggest that the Child Facial Coding System is a valid method of identifying pain in children with cerebral palsy.