Acute pain experience in individuals with autism spectrum disorders: a review

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.

Autistic and Non-autistic Children's Pain Perception is Modulated by Their First-Hand Pain Sensitivity and Theory of Mind

The current study examined whether autistic children's perception of others' pain could be modulated by their first-hand pain sensitivity and theory of mind (ToM). We measured the first-hand pain sensitivity, the rating of others' pain intensity, and the performance in the ToM tasks in 43 5- to 8-year-old autistic and 30 neurotypical children. Our results revealed hyposensitivity to first-hand pain, underestimation of others' pain intensity, as well as difficulties in the False Belief subtasks of ToM in autistic children. Furthermore, we detected an interaction between children's first-hand pain sensitivity and ToM in predicting their perception of others' pain. To be specific, for autistic and NT children with normal or hyper-sensitivity to first-hand pain, better performance on ToM predicted higher ratings for others' pain intensity; while for autistic and NT children with hyposensitivity to first-hand pain, ToM did not predict ratings for others' pain intensity. Our study contributes to the understanding of pain perception in young children and provides implications for clinical practices to improve social understanding in autistic children.

Understanding the impacts of chronic pain on autistic adolescents and effective pain management: a reflexive thematic analysis adolescent-maternal dyadic study

OBJECTIVE

Sensory elements are core features in chronic pain and autism, yet knowledge of the pain experience in autistic adolescents is limited. Little is known regarding how autistic adolescents experience chronic pain, manage their pain and perceive psychological treatment for their chronic pain.

METHODS

Ten autistic adolescents (6 female, 3 male, and 1 self-identified as agender) with chronic pain and their mothers (n = 10) participated in semistructured interviews concerning their perceptions of living with chronic pain. Participants were recruited from U.K. pain management services. According to preference, interviews were conducted individually (n = 10) or dyadically (n = 10 participants across 5 dyads). Data were analyzed using inductive reflexive thematic analysis.

RESULTS

Two themes were generated. Theme 1, "overstimulated and striving for control" described how adolescents' experience of heightened sensitivity enhanced adolescents' levels of anxiety and subsequent pain, illustrating a reciprocal relationship between anxiety, pain, and sensory elements. Theme 2, "not everyone fits the mold" captured how autistic adolescents positioned themselves as distinct from others due to the unique nature of being autistic and living with pain. This sense of difference negatively impacted adolescents' ability to engage with and benefit from the standard treatment for chronic pain.

CONCLUSIONS

Findings suggest that autistic adolescents living with pain experience pain and face barriers to effective pain treatment. Our results identify the need for educational resources to facilitate clinicians to better understand the experience of autistic adolescents living with pain. In turn, such understanding may improve treatment and outcomes in this population.

Mechanisms of pain in aging and age-related conditions: Focus on caregivers

Pain is a complex, subjective experience that can significantly impact quality of life, particularly in aging individuals, by adversely affecting physical and emotional well-being. Whereas acute pain usually serves a protective function, chronic pain is a persistent pathological condition that contributes to functional deficits, cognitive decline, and emotional disturbances in the elderly. Despite substantial progress that has been made in characterizing age-related changes in pain, complete mechanistic details of pain processing mechanisms in the aging patient remain unknown. Pain is particularly under-recognized and under-managed in the elderly, especially among patients with Alzheimer's disease (AD), Alzheimer's disease-related dementias (ADRD), and other age-related conditions. Furthermore, difficulties in assessing pain in patients with AD/ADRD and other age-related conditions may contribute to the familial caregiver burden. The purpose of this article is to discuss the mechanisms and risk factors for chronic pain development and persistence, with a particular focus on age-related changes. Our article also highlights the importance of caregivers working with aging chronic pain patients, and emphasizes the urgent need for increased legislative awareness and improved pain management in these populations to substantially alleviate caregiver burden.

'It seems like a luxury to be able to offer that': Factors influencing the implementation of annual health checks for autistic people in England

LAY ABSTRACT

Autistic people are more likely to have mental and physical health problems than non-autistic people. Annual health checks could reduce these problems by finding and treating them early. Annual health checks are yearly medical appointments where a primary healthcare provider (such as a doctor or nurse) can check things like a patient's weight and heart rate and ask if they have any worries about their health. In this study, we wanted to understand what might encourage primary healthcare providers to use annual health checks with their autistic patients. First, we spoke to 10 autistic people and 11 primary healthcare providers. Using the findings from these conversations, we created an online survey for primary healthcare providers in England. We used the findings from the interviews and survey to help us understand what would encourage primary healthcare providers to offer annual health checks for autistic people. Our participants said that a lack of time and staff would make it hard to provide health checks. To help, they said other members of staff (such as nurses and healthcare assistants) could do the health checks, rather than doctors. They also said parts of the process could be made automatic to save time (e.g. sending automatic reminders). Knowledge about autism was important too (e.g. knowing about the common conditions autistic people have, and how to best support autistic patients). Participants said training on these topics, produced and delivered with autistic people, could encourage them to use annual health checks with their autistic patients.

Role of autonomic, nociceptive, and limbic brainstem nuclei in core autism features

Although multiple theories have speculated about the brainstem reticular formation's involvement in autistic behaviors, the in vivo imaging of brainstem nuclei needed to test these theories has proven technologically challenging. Using methods to improve brainstem imaging in children, this study set out to elucidate the role of the autonomic, nociceptive, and limbic brainstem nuclei in the autism features of 145 children (74 autistic children, 6.0-10.9 years). Participants completed an assessment of core autism features and diffusion- and T1-weighted imaging optimized to improve brainstem images. After data reduction via principal component analysis, correlational analyses examined associations among autism features and the microstructural properties of brainstem clusters. Independent replication was performed in 43 adolescents (24 autistic, 13.0-17.9 years). We found specific nuclei, most robustly the parvicellular reticular formation-alpha (PCRtA) and to a lesser degree the lateral parabrachial nucleus (LPB) and ventral tegmental parabrachial pigmented complex (VTA-PBP), to be associated with autism features. The PCRtA and some of the LPB associations were independently found in the replication sample, but the VTA-PBP associations were not. Consistent with theoretical perspectives, the findings suggest that individual differences in pontine reticular formation nuclei contribute to the prominence of autistic features. Specifically, the PCRtA, a nucleus involved in mastication, digestion, and cardio-respiration in animal models, was associated with social communication in children, while the LPB, a pain-network nucleus, was associated with repetitive behaviors. These findings highlight the contributions of key autonomic brainstem nuclei to the expression of core autism features.

Perioperative Management and Outcomes in Patients With Autism Spectrum Disorder: A Retrospective Cohort Study

BACKGROUND

Autism spectrum disorder (ASD) is a neurocognitive disorder characterized by impairments in communication and socialization. There are little data comparing the differences in perioperative outcomes in children with and without ASD. We hypothesized that children with ASD would have higher postoperative pain scores than those without ASD.

METHODS

Pediatric patients undergoing ambulatory tonsillectomy/adenoidectomy, ophthalmological surgery, general surgery, and urologic procedures between 2016 and 2021 were included in this retrospective cohort study. ASD patients, defined by International Classification of Diseases-9/10 codes, were compared to controls utilizing inverse probability of treatment weighting based on surgical category/duration, age, sex, race and ethnicity, anesthetizing location, American Society of Anesthesiology physical status, intraoperative opioid dose, and intraoperative dexmedetomidine dose. The primary outcome was the maximum postanesthesia care unit (PACU) pain score, and secondary outcomes included premedication administration, behavior at induction, PACU opioid administration, postoperative vomiting, emergence delirium, and PACU length of stay.

RESULTS

Three hundred thirty-five children with ASD and 11,551 non-ASD controls were included. Maximum PACU pain scores in the ASD group were not significantly higher than controls (median, 5; interquartile range [IQR], 0-8; ASD versus median, 5; IQR, 0-8 controls; median difference [95% confidence interval {CI}] of 0 [-1.1 to 1.1]; P = .66). There was no significant difference in the use of premedication (96% ASD versus 95% controls; odds ratio [OR], 1.5; [95% CI, 0.9-2.7]; P = .12), but the ASD cohort had significantly higher odds of receiving an intranasal premedication (4.2% ASD versus 1.2% controls; OR, 3.5 [95% CI, 1.8-6.8]; P < .001) and received ketamine significantly more frequently (0.3% ASD versus <0.1% controls; P < .001). Children with ASD were more likely to have parental (4.9% ASD versus 1.0% controls; OR, 5 [95% CI, 2.1-12]; P < .001) and child life specialist (1.3% ASD versus 0.1% controls; OR, 9.9 [95% CI, 2.3-43]; P < .001) presence at induction, but were more likely to have a difficult induction (11% ASD versus 3.4% controls; OR, 3.42 [95% CI, 1.7-6.7]; P < .001). There were no significant differences in postoperative opioid administration, emergence delirium, vomiting, or PACU length of stay between cohorts.

CONCLUSIONS

We found no difference in maximum PACU pain scores in children with ASD compared to a similarly weighted cohort without ASD. Children with ASD had higher odds of a difficult induction despite similar rates of premedication administration, and significantly higher parental and child life specialist presence at induction. These findings highlight the need for future research to develop evidence-based interventions to optimize the perioperative care of this population.

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.

Disturbance of skin sensation and autism spectrum disorder: A bidirectional Mendelian randomization study

BACKGROUND AND AIM

Patients with autism spectrum disorder (ASD) commonly experience aberrant skin sensation sensitivity; however, the causal relationship is not yet clear. This study uses a bidirectional Mendelian randomization (MR) method to explore the relationship between disturbance of skin sensation (DSS) and ASD.

METHODS

Single-nucleotide polymorphisms (SNPs) extracted from the summary data of genome-wide association studies were used as genetic instruments. MR was performed using the inverse-variance-weighted method, with alternate methods (e.g., weighted median, MR-Egger, simple mode, weighted mode, and MR-pleiotropy residual sum and outlier) and multiple sensitivity analyses to assess horizontal pleiotropy and remove outliers.

RESULTS

The results of the analysis using six SNPs as genetic instruments showed that the DSS is associated with an increased risk of ASD (odds ratio = 1.126, 95% confidence interval = 1.029-1.132; p = .010). The results of the sensitivity analyses were robust with no evidence of pleiotropy. The reverse MR analyses showed no causal effects of ASD on DSS.

CONCLUSION

This study's findings suggest that DSS has potential causal effects on ASD, whereas ASD has no effect on DSS. Thus, skin sensitivity may represent a behavioral marker of ASD, by which some populations could be subtyped in the future.

Placebo effects in children with autism spectrum disorder

Placebo responses are frequently observed in research studies and clinical contexts, yet there is limited knowledge about the placebo effect among children with neurodevelopmental disorders. Here, we review the placebo effect in autism spectrum disorder (ASD). Placebo responses are widely evident in ASD clinical trials and could partly operate via so-called placebo-by-proxy, whereby caregivers or clinicians indirectly shape patient outcomes. Understanding the role of placebo effects in ASD may help discern genuine treatment effects from contextual factors in clinical trials. The much less studied nocebo effect, or negative placebo, might contribute to the experience of side effects in ASD treatments but empirical data is missing. Better knowledge about placebo and nocebo mechanisms may contribute to the development of more effective research designs, such as three-armed designs that account for natural history, and improved treatments for ASD symptoms. At a clinical level, deeper knowledge about placebo and nocebo effects may optimize the delivery of care for individuals with ASD in the future. WHAT THIS PAPER ADDS: Placebo responses are evident in autism spectrum disorder (ASD) clinical trials. Placebo responses in ASD are likely dependent on a placebo-by-proxy mechanism.

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.

Shank2 identifies a subset of glycinergic neurons involved in altered nociception in an autism model

BACKGROUND

Autism Spectrum Disorders (ASD) patients experience disturbed nociception in the form of either hyposensitivity to pain or allodynia. A substantial amount of processing of somatosensory and nociceptive stimulus takes place in the dorsal spinal cord. However, many of these circuits are not very well understood in the context of nociceptive processing in ASD.

METHODS

We have used a Shank2^-/- mouse model, which displays a set of phenotypes reminiscent of ASD, and performed behavioural and microscopic analysis to investigate the role of dorsal horn circuitry in nociceptive processing of ASD.

RESULTS

We determined that Shank2^-/- mice display increased sensitivity to formalin pain and thermal preference, but a sensory specific mechanical allodynia. We demonstrate that high levels of Shank2 expression identifies a subpopulation of neurons in murine and human dorsal spinal cord, composed mainly by glycinergic interneurons and that loss of Shank2 causes the decrease in NMDAR in excitatory synapses on these inhibitory interneurons. In fact, in the subacute phase of the formalin test, glycinergic interneurons are strongly activated in wild type (WT) mice but not in Shank2^-/- mice. Consequently, nociception projection neurons in laminae I are activated in larger numbers in Shank2^-/- mice.

LIMITATIONS

Our investigation is limited to male mice, in agreement with the higher representation of ASD in males; therefore, caution should be applied to extrapolate the findings to females. Furthermore, ASD is characterized by extensive genetic diversity and therefore the findings related to Shank2 mutant mice may not necessarily apply to patients with different gene mutations. Since nociceptive phenotypes in ASD range between hyper- and hypo-sensitivity, diverse mutations may affect the circuit in opposite ways.

CONCLUSION

Our findings prove that Shank2 expression identifies a new subset of inhibitory interneurons involved in reducing the transmission of nociceptive stimuli and whose unchecked activation is associated with pain hypersensitivity. We provide evidence that dysfunction in spinal cord pain processing may contribute to the nociceptive phenotypes in ASD.

Experiences of dysmenorrhea and its treatment among allistic and autistic menstruators: a thematic analysis

BACKGROUND

Dysmenorrhea (i.e., period pain) is common and debilitating. Autistic people are known to experience pain differently, yet little is known about the menstrual pain experiences of autistic menstruators relative to non-autistic peers. This study aimed to explore the experience of period pain and treatment uptake for period pain among allistic and autistic populations.

METHODS

This study used a qualitative design and opportunity sampling approach. Thirty-seven participants (of whom 17 were autistic) were interviewed via video-conferencing software using a semi-structured topic guide. Transcriptions of interviews were analysed using Braun and Clarke's Reflexive Thematic Analysis. Data were initially analysed together for common themes. Autistic menstruators' data was subsequently analysed separately to elucidate the unique experiences of this group.

RESULTS

A total of six themes were constructed from the data. Initial analysis determined three themes related to experiences of period pain and treatment uptake in both allistic and autistic menstruators. Social perception of menstruation was discussed, highlighting the normalisation of pain, the taboo nature, and gendered experience of menstruation, contributing to untreated menstrual pain. Issues within menstrual healthcare were also shared, including experiences of ineffective treatment, dismissive interactions, and insufficient menstrual education. Impaired functionality was repeatedly highlighted, with menstruators detailing significant limitations to their usual functioning due to menstrual pain and ineffective treatment. Three further themes were constructed from separate analysis of data from autistic menstruators. Autistic menstruators discussed the impact of menstruation on their sensory experiences and needs, with many identifying overstimulation during menstruation. Social exclusion was discussed as a factor contributing to the experience of menstrual pain and poor treatment uptake. The final theme identified pain communication differences between autistic and allistic menstruators resulting in reports of ineffective treatment and challenges in healthcare interactions.

CONCLUSIONS

Communication differences, sensory aspects, and social factors contributed to the experience of period pain and treatment uptake for autistic menstruators. The perception of menstruation within society was highlighted by allistic and autistic menstruators as influential to their pain experience and engagement with treatment. Functionality was significantly impacted by pain for this sample. The study highlights societal and healthcare factors that could be improved to ensure accessibility of support and treatment for menstrual issues.

Maternal autistic traits and antenatal pain by cross-sectional analysis of the Japan Environment and Children's Study

The aim of cross-sectional study was to investigate whether the presence of autistic traits in pregnant women was positively associated with the prevalence and severity of antenatal pain. We analyzed 89,068 pregnant women from a Japanese national birth cohort cross-sectionally. Autistic traits were assessed using the Japanese version of the Autism-Spectrum Quotient short form (AQ-10-J). Antenatal pain was measured using the SF-8 bodily pain item (SF-8-Pain). Antenatal pain in the second to third trimester during pregnancy was categorized into three groups: without pain, mild pain, and moderate-to-severe pain. Participants were divided into eight groups by AQ-10-J score: seven consecutive scoring groups (scores 0-6), and those above the cut-off (≥ 7) for probable autistic spectrum disorders. Odds ratios (OR) for the prevalence of mild and moderate-to-severe pain were calculated for each AQ-10-J scoring group (reference: without pain group) using multinominal logistic regression analysis. Autistic traits were positively associated with mild and moderate-to-severe pain in a dose-response manner, but the association with moderate-to-severe pain was strongest. Fully-adjusted ORs (95% confidence intervals) for moderate-to-severe pain were: 1.01 (0.91-1.13) for 1 point, 1.13 (1.02-1.25) for 2 points, 1.16 (1.04-1.29) for 3 points, 1.20 (1.07-1.34) for 4 points, 1.23 (1.09-1.40) for 5 points, 1.27 (1.10-1.47) for 6 points, and 1.24 (1.05-1.46) for ≥ 7 points (AQ-10-J cut-off). We identified an association between maternal autistic traits and antenatal pain. Maternal autistic traits may need to be considered when addressing antenatal pain during healthcare for expectant mothers.

A working taxonomy for describing the sensory differences of autism

BACKGROUND

Individuals on the autism spectrum have been long described to process sensory information differently than neurotypical individuals. While much effort has been leveraged towards characterizing and investigating the neurobiology underlying the sensory differences of autism, there has been a notable lack of consistency in the terms being used to describe the nature of those differences.

MAIN BODY

We argue that inconsistent and interchangeable terminology-use when describing the sensory differences of autism has become problematic beyond mere pedantry and inconvenience. We begin by highlighting popular terms that are currently being used to describe the sensory differences of autism (e.g. "sensitivity", "reactivity" and "responsivity") and discuss why poor nomenclature may hamper efforts towards understanding the aetiology of sensory differences in autism. We then provide a solution to poor terminology-use by proposing a hierarchical taxonomy for describing and referring to various sensory features.

CONCLUSION

Inconsistent terminology-use when describing the sensory features of autism has stifled discussion and scientific understanding of the sensory differences of autism. The hierarchical taxonomy proposed was developed to help resolve lack of clarity when discussing the sensory differences of autism and to place future research targets at appropriate levels of analysis.

Indifference or hypersensitivity? Solving the riddle of the pain profile in individuals with autism

ABSTRACT

Excitatory-inhibitory (E/I) imbalance is a mechanism that underlies autism spectrum disorder, but it is not systematically tested for pain processing. We hypothesized that the pain modulation profile (PMP) in autistic individuals is characterized by less efficient inhibitory processes together with a facilitative state, indicative of a pronociceptive PMP. Fifty-two adults diagnosed with autism and 52 healthy subjects, age matched and sex matched, underwent quantitative sensory testing to assess the function of the (1) pain facilitatory responses to phasic, repetitive, and tonic heat pain stimuli and (2) pain inhibitory processes of habituation and conditioned pain modulation. Anxiety, pain catastrophizing, sensory, and pain sensitivity were self-reported. The autistic group reported significantly higher pain ratings of suprathreshold single ( P = 0.001), repetitive (46°C- P = 0.018; 49°C- P = 0.003; 52°C- P < 0.001), and tonic ( P = 0.013) heat stimuli that were cross correlated ( r = 0.48-0.83; P < 0.001) and associated with sensitivity to daily life pain situations ( r = 0.39-0.45; P < 0.005) but not with psychological distress levels. Hypersensitivity to experimental pain was attributed to greater autism severity and sensory hypersensitivity to daily stimuli. Subjects with autism efficiently inhibited phasic but not tonic heat stimuli during conditioned pain modulation. In conclusion, in line with the E/I imbalance mechanism, autism is associated with a pronociceptive PMP expressed by hypersensitivity to daily stimuli and experimental pain and less-efficient inhibition of tonic pain. The latter is an experimental pain model resembling clinical pain. These results challenge the widely held belief that individuals with autism are indifferent to pain and should raise caregivers' awareness of pain sensitivity in autism.

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.

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 3,868 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 unambiguously supported the validity of a supra-modal HYPER construct (ω H  = .800), whereas a coherent supra-modal HYPO construct was not supported (ω H  = .611), and supra-modal SEEK models suggested a more limited version of the construct that excluded some sensory modalities (ω H  = .799; 4/7 modalities). Within each sensory construct, modality-specific subscales demonstrated substantial added value beyond the supra-modal score. Meta-analytic correlations varied by construct, although sensory features tended to correlate most strongly with other domains of core autism features and co-occurring psychiatric symptoms. Certain subconstructs within the HYPO and SEEK domains were also associated with lower adaptive behavior scores. Limitations: Conclusions may not be generalizable beyond the specific pool of items used in the current study, which was limited to parent-report of observable behaviors and excluded multisensory items that reflect many "real-world" sensory experiences. Conclusion Psychometric issues may limit the degree to which some measures of supra-modal HYPO/SEEK can be interpreted. Depending on the research question at hand, modality-specific response pattern scores may represent a valid alternative method of characterizing sensory reactivity in autism.

Modulation of the thermosensory system by oxytocin

Oxytocin (OT) is a neurohormone involved early in neurodevelopment and is implicated in multiple functions, including sensory modulation. Evidence of such modulation has been observed for different sensory modalities in both healthy and pathological conditions. This review summarizes the pleiotropic modulation that OT can exercise on an often overlooked sensory system: thermosensation. This system allows us to sense temperature variations and compensate for the variation to maintain a stable core body temperature. Oxytocin modulates autonomic and behavioral mechanisms underlying thermoregulation at both central and peripheral levels. Hyposensitivity or hypersensitivity for different sensory modalities, including thermosensitivity, is a common feature in autism spectrum disorder (ASD), recapitulated in several ASD mouse models. These sensory dysregulations occur early in post-natal development and are correlated with dysregulation of the oxytocinergic system. In this study, we discussed the potential link between thermosensory atypia and the dysregulation of the oxytocinergic system in ASD.

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.

Reinforced behavioral variability in the valproate rat model of autism spectrum disorder

Individuals diagnosed with autism spectrum disorder (ASD) tend to display restricted, repetitive behaviors and deficits in social interaction. Rats exposed to valproate (VPA) in utero have been shown to model symptoms of ASD. In previous research, VPA rats engaged in less social interaction and more repetitive responding than controls. The purpose of the present study was to further investigate behavioral variability in the VPA rat model of ASD by testing VPA and control rats in a reinforced-behavioral-variability operant task. In this procedure, rats emitted sequences of lever presses, some of which produced food. During baseline, food was delivered probabilistically, and variability was not required. Next, rats were exposed either to a variability contingency, in which food was only delivered following sequences that differed sufficiently from previous sequences (i.e., variability required), or to a yoked contingency, in which variability was not required. We hypothesized that VPA rats would behave less variably than controls in this task. However, VPA and control rats responded similarly variably when variability was required. Furthermore, VPA rats behaved slightly more variably than controls during baseline and yoked conditions, when variability was not required. These findings contribute to the complex literature surrounding the VPA rat model of ASD.

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.

Autism and chronic ill health: an observational study of symptoms and diagnoses of central sensitivity syndromes in autistic adults

BACKGROUND

Autistic adults, particularly women, are more likely to experience chronic ill health than the general population. Central sensitivity syndromes (CSS) are a group of related conditions that are thought to include an underlying sensitisation of the central nervous system; heightened sensory sensitivity is a common feature. Anecdotal evidence suggests autistic adults may be more prone to developing a CSS. This study aimed to investigate the occurrence of CSS diagnoses and symptoms in autistic adults, and to explore whether CSS symptoms were related to autistic traits, mental health, sensory sensitivity, or gender.

METHODS

The full sample of participants included 973 autistic adults (410 men, 563 women, mean age = 44.6) registered at the Netherlands Autism Register, who completed questionnaires assessing autistic traits, sensory sensitivity, CSS, physical and mental health symptoms. The reliability and validity of the Central Sensitization Inventory (CSI) in an autistic sample was established using exploratory and confirmatory factor analyses. Chi2 analyses, independent t-tests, hierarchical regression and path analysis were used to analyse relationships between CSS symptoms, autistic traits, measures of mental health and wellbeing, sensory sensitivity, age and gender.

RESULTS

21% of participants reported one or more CSS diagnosis, and 60% scored at or above the clinical cut-off for a CSS. Autistic women were more likely to report a CSS diagnosis and experienced more CSS symptoms than men. Sensory sensitivity, anxiety, age and gender were significant predictors of CSS symptoms, with sensory sensitivity and anxiety fully mediating the relationship between autistic traits and CSS symptoms.

LIMITATIONS

Although this study included a large sample of autistic adults, we did not have a control group or a CSS only group. We also could not include a non-binary group due to lack of statistical power.

CONCLUSIONS

CSS diagnoses and symptoms appear to be very common in the autistic population. Increased awareness of an association between autism and central sensitisation should inform clinicians and guide diagnostic practice, particularly for women where CSS are common and autism under recognised.

Exploring a Role for Parental Mental Health in Perception and Reports of Pain on Behalf of Children with Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) have a higher prevalence of pain compared to those without ASD. Pain is a leading cause of morbidity and disability worldwide and may contribute to adverse health outcomes in people with ASD, thus warranting further research on this special population. The present study used data from 1,423 children with ASD and 46,023 children without ASD and their mothers from the combined 2016-2017 National Survey of Children's Health. Mothers reported child pain and ASD status and their own mental health status. Mothers reporting a status of “Fair or Poor” were considered as having maternal mental health conditions (MMHCs) for the purposes of this study. Children with and without ASD who had mothers with MMHCs had higher odds of pain compared to children with mothers without MMHCs. These increased odds did not attenuate as a result of controlling for co-occurring neurological conditions, which have been associated with increased pain in children with ASD. Thus, parent mental health may alter perception and/or reports of pain on behalf of children with and without ASD. Future research should include more detailed assessments of parent mental health and clinical assessments of children in order to explore the role of parent mental health in the experiences of pain and other symptoms present in children with ASD.

The Potential Effect of Na v 1.8 in Autism Spectrum Disorder: Evidence From a Congenital Case With Compound Heterozygous SCN10A Mutations

Apart from the most prominent symptoms in Autism spectrum disorder (ASD), namely deficits in social interaction, communication and repetitive behavior, patients often show abnormal sensory reactivity to environmental stimuli. Especially potentially painful stimuli are reported to be experienced in a different way compared to healthy persons. In our present study, we identified an ASD patient carrying compound heterozygous mutations in the voltage-gated sodium channel (VGSC) Na v 1.8, which is preferentially expressed in sensory neurons. We expressed both mutations, p.I1511M and p.R512∗, in a heterologous expression system and investigated their biophysical properties using patch-clamp recordings. The results of these experiments reveal that the p.R512∗ mutation renders the channel non-functional, while the p.I1511M mutation showed only minor effects on the channel's function. Behavioral experiments in a Na v 1.8 loss-of-function mouse model additionally revealed that Na v 1.8 may play a role in autism-like symptomatology. Our results present Na v 1.8 as a protein potentially involved in ASD pathophysiology and may therefore offer new insights into the genetic basis of this disease.

Behavioral Tests for Mouse Models of Autism: An Argument for the Inclusion of Cerebellum-Controlled Motor Behaviors

Mouse models of Autism Spectrum Disorder (ASD) have been interrogated using a variety of behavioral tests in order to understand the symptoms of ASD. However, the hallmark behaviors that are classically affected in ASD - deficits in social interaction and communication as well as the occurrence of repetitive behaviors - do not have direct murine equivalents. Thus, it is critical to identify the caveats that come with modeling a human disorder in mice. The most commonly used behavioral tests represent complex cognitive processes based on largely unknown brain circuitry. Motor impairments provide an alternative, scientifically rigorous approach to understanding ASD symptoms. Difficulties with motor coordination and learning - seen in both patients and mice - point to an involvement of the cerebellum in ASD pathology. This brain area supports types of motor learning that are conserved throughout vertebrate evolution, allowing for direct comparisons of functional abnormalities between humans with autism and ASD mouse models. Studying simple motor behaviors provides researchers with clearly interpretable results. We describe and evaluate methods used on mouse behavioral assays designed to test for social, communicative, perseverative, anxious, nociceptive, and motor learning abnormalities. We comment on the effectiveness and validity of each test based on how much information its results give, as well as its relevance to ASD, and will argue for an inclusion of cerebellum-supported motor behaviors in the phenotypic description of ASD mouse models. LAY SUMMARY: Mouse models of Autism Spectrum Disorder help us gain insight about ASD symptoms in human patients. However, there are many differences between mice and humans, which makes interpreting behaviors challenging. Here, we discuss a battery of behavioral tests for specific mouse behaviors to explore whether each test does indeed evaluate the intended measure, and whether these tests are useful in learning about ASD.

[Nociception pain and autism]

Autistic subjects frequently display sensory anomalies. Those regarding nociception and its potential outcome, pain, are of crucial interest. Indeed, because of numerous comorbidities, autistic subjects are more often exposed to painful situation. Despite being often considered as less sensitive, experimental studies evaluating this point are failing to reach consensus. Using animal model can help reduce variability and bring, regarding autism, an overview of potential alterations of the nociceptive system at the cellular and molecular level.

A review of decreased sound tolerance in autism: Definitions, phenomenology, and potential mechanisms

Atypical behavioral responses to environmental sounds are common in autistic children and adults, with 50-70 % of this population exhibiting decreased sound tolerance (DST) at some point in their lives. This symptom is a source of significant distress and impairment across the lifespan, contributing to anxiety, challenging behaviors, reduced community participation, and school/workplace difficulties. However, relatively little is known about its phenomenology or neurocognitive underpinnings. The present article synthesizes a large body of literature on the phenomenology and pathophysiology of DST-related conditions to generate a comprehensive theoretical account of DST in autism. Notably, we argue against conceptualizing DST as a unified construct, suggesting that it be separated into three phenomenologically distinct conditions: hyperacusis (the perception of everyday sounds as excessively loud or painful), misophonia (an acquired aversive reaction to specific sounds), and phonophobia (a specific phobia of sound), each responsible for a portion of observed DST behaviors. We further elaborate our framework by proposing preliminary neurocognitive models of hyperacusis, misophonia, and phonophobia that incorporate neurophysiologic findings from studies of autism.

Cancer Care of Children, Adolescents and Adults With Autism Spectrum Disorders: Key Information and Strategies for Oncology Teams

Delivering optimal cancer care to children, adolescents and adults with ASD has recently become a healthcare priority and represents a major challenge for all providers involved. In this review, and after consideration of the available evidence, we concisely deliver key information on this heterogenous group of neurodevelopmental disorders, as well as recommendations and concrete tools for the enhanced oncological care of this vulnerable population of patients.

A mini-review: Bridging the gap between autism spectrum disorder and pain comorbidities

Background

Pain is a complex neurobiological response with a multitude of causes; however, patients with autism spectrum disorder (ASD) often report chronic pain with no known etiology. Recent research has been aimed toward identifying the causal mechanisms of pain in mouse and human models of ASD. In recent years, efforts have been made to better document and explore secondary phenotypes observed in ASD patients in the clinic. As new sequencing studies have become more powered with larger cohorts within ASD, specific genes and their variants are often left uncharacterized or validated. In this review we highlight ASD risk genes often presented with pain comorbidities.

Aims

This mini-review bridges the gap between two fields of literature, neurodevelopmental disorders and pain research. We discuss the importance of the genetic landscape of ASD and its links to pain phenotypes.

Results

Among the numerous genes implicated in ASD, few have been implicated with varying severities of pain comorbidity. Mutations in these genes, such as SCN9A, SHANK3, and CNTNAP2, lead to altered neuronal function that produce different responses to pain, shown in both mouse and human models.

Conclusion

There is a necessity to use new technologies to advance the current understanding of ASD risk genes and their contributions to pain. Secondly, there is a need to power future ASD risk genes associated with pain with their own cohort, because a better understanding is needed of this subpopulation.

An Exploratory Analysis of Predictors of Youth Suicide-Related Behaviors in Autism Spectrum Disorder: Implications for Prevention Science

Although autism spectrum disorder (ASD) is associated with significant mental health concerns, little is known about suicidality, particularly among youth. To address this critical gap in the literature, the current study examined the predictive validity of (1) demographics, (2) core autism symptoms, (3) cognitive abilities and adaptive behavior, (4) comorbid psychopathology, and (5) medical problems, for suicide-related behaviors among autistic youth (N = 481; M_age = 11.56 years). As indices of suicide-related behaviors, parents reported on whether the child had ever (1) talked about killing themselves, and (2) engaged in deliberate self-harm or attempted suicide. These two suicide-related outcomes had distinct clinical correlates, including child age, parental education, restricted and repetitive behaviors, IQ and adaptive behavior, affective and conduct problems, and medical concerns.

Increased pain sensitivity and pain-related anxiety in individuals with autism

INTRODUCTION

Individuals with autism spectrum disorder (ASD) often exhibit differences in pain responsivity. This altered responsivity could be related to ASD-related social communication difficulties, sensory differences, or altered processing of pain stimuli. Previous neuroimaging work suggests altered pain evaluation could contribute to pain-related anxiety in ASD.

OBJECTIVES

We hypothesized that individuals with ASD would report increased pain sensitivity and endorse more pain-related anxiety, compared to typically developing controls.

METHODS

We recruited 43 adults (ASD, n = 24; typically developing, n = 19) for 3 heat pain tasks (applied to the calf). We measured heat pain thresholds using a method of limits approach, a pain-rating curve (7 temperatures between 40 and 48°C, 5 seconds, 5 trials each), and a sustained heat pain task with alternating low (42°C) and high (46°C) temperatures (21 seconds, 6 trials each). Individual differences in pain-related anxiety, fear of pain, situational pain catastrophizing, depressive symptoms, and autism-related social communication were assessed by self-report.

RESULTS

There were no group differences in pain thresholds. For suprathreshold tasks, mean pain ratings were higher in ASD across both the pain-rating curve and the sustained heat pain tasks, but responses in the ASD group were more varied. Pain anxiety (PASS-Total) and pain-related fear (FOP-III-Total) were higher in the ASD group and were positively associated with pain ratings.

CONCLUSIONS

Our results suggest that both sensory and cognitive experiences of pain are heightened and interact reciprocally in adults with ASD. Future studies are needed to evaluate the impact of pain-related anxiety on treatment-seeking and pain behaviors, given higher levels of pain-related anxiety in ASD.

A Quantitative Sensory Testing Approach to Pain in Autism Spectrum Disorders

Sensory abnormalities in autism has been noted clinically, with pain insensitivity as a specified diagnostic criterion. However, there is limited research using psychophysically robust techniques. Thirteen adults with ASD and 13 matched controls completed an established quantitative sensory testing (QST) battery, supplemented with measures of pain tolerance and central modulation. The ASD group showed higher thresholds for light touch detection and mechanical pain. Notably, the ASD group had a greater range of extreme scores (the number of z-scores outside of the 95% CI > 2), dynamic mechanical allodynia and paradoxical heat sensation; phenomena not typically seen in neurotypical individuals. These data support the need for research examining central mechanisms for pain in ASD and greater consideration of individual difference.

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.

Prenatal pregabalin is associated with sex-dependent alterations in some behavioral parameters in valproic acid-induced autism in rat offspring

This study was performed to evaluate the effects of prenatal exposure to pregabalin (PGB) on behavioral changes of rat offspring in an animal model of valproic acid (VPA)-induced autism-like symptoms. Pregnant rats received VPA (600 mg/kg/i.p.) once at 12.5 gestational days for autism-like symptom induction in offspring. After the delivery single male and single female offspring from each mother were randomly selected for behavioral test (anxiety, pain response, pleasure, and motor function) at 60th day adulthood (n = 7). Offspring received prenatal PGB (15 & 30 mg/kg/i.p.) during gestational days 9.5 to 15.5 either alone or in combination with VPA (PGB15, PGB30, PGB15 + VPA, and PGB30 + VPA). Control offspring received normal saline during the same period. The result showed that prenatal VPA exposure was associated with autism-like behaviors in rat offspring. PGB treatment during the gestational period revealed significant reduction in sucrose preference test and anxiety in elevated plus maze and open field test in offspring. Also, PGB treatments exhibited a dose-dependent increase in pain threshold in prenatally VPA exposed rats in tail-flick and hot plate test. Also, there was a sex-related significant impairment in motor function in beam balance and open field test, and male rats were affected more than females. However, no significant sex differences in sucrose preference and pain sensitivity were observed in prenatal PGB-treated rat offspring. In conclusion, prenatal exposure to VPA increased the risk of autism-like behaviors in the offspring rats, and PGB treatment during the gestational period was associated with some beneficial effects, including anxiety reduction and motor impairment in autism-like symptoms in rat offspring.

Using phecode analysis to characterize co-occurring medical conditions in autism spectrum disorder

LAY ABSTRACT

People with autism spectrum disorder often have a number of other medical conditions in addition to autism. These can range from constipation to epilepsy. This study uses medical record data to understand how frequently and how long people with autism have to be seen by a medical professional for these other medical conditions. This study confirmed that people with autism often have a number of other medical conditions and that they have to go see a medical professional about those conditions often. We also looked to see if children diagnosed with autism after age 5 years might have different medical conditions compared to children diagnosed earlier. Children diagnosed later had more conditions like asthma, hearing loss, and mood disorders. This work describes how much medical care people with autism get for different medical conditions and the burden of seeking additional medical care for people with autism and their families.

Sex dependent alterations of resveratrol on social behaviors and nociceptive reactivity in VPA-induced autistic-like model in rats

INTRODUCTION

The present study was designed to clarify the effects of resveratrol (RSV) on social behavioral alterations and nociceptive reactivity in valproic acid (VPA)-induced autistic-like model in female and male rats.

METHODS

Pregnant Wistar rats were randomly divided in five groups. Animals received saline, DMSO, VPA, RSV and RSV + VPA. VPA was administered (600 mg/kg, i. p.) on embryonic day 12.5 (E12.5) and pretreatment by resveratrol (3.6 mg/kg, s. c.) was applied on E6.5 until E18.5. All offspring were weaned on postnatal day 21 and the experiments were done in male and female rats on day 60. Social interaction, hot plate and tail flick tests were set out to assess social deficits and pain threshold, respectively. Sociability index (SI), Social novelty index (SNI) and latency time were calculated as the standard indices of social behaviors and pain threshold, respectively.

RESULTS

The results indicated that systemic intraperitoneal administration of VPA (600 mg/kg) significantly decreased SI and SNI in social interaction test (SIT) especially in male rats, indicating the social impairments caused by VPA. RSV (3.6 mg/kg, s. c.) reversed VPA-induced social deficits in male rats, but not in female group. VPA administration resulted in significant increase in latency time in the hot plate and tail flick tests in male rats, whereas it had no such dramatic effect in females. RSV administration in combination with VPA had no significant effect on latency time compared to the valproic acid group in male rats. It is important to note that RSV by itself had no significant effect on SI, SNI and latency time in female and male rats.

CONCLUSION

It can be concluded that valproic acid produces autistic-like behaviors and increases pain threshold in male rats which may be ameliorated at least in part by resveratrol administration. Further studies are needed to elucidate the molecular mechanisms involved in valproic acid and resveratrol-induced effects.

Effects of EEG examination and ABA-therapy on resting-state EEG in children with low-functioning autism

Objective

We aimed to study the effects of EEG examination and ABA-therapy on resting-state EEG in children with low-functioning autism and tactile defensiveness.

Methods

We have performed this study with three cohorts of preschoolers: children with autistic spectrum disorder (ASD) who needed applied behavior analysis (ABA) therapy due to their tactile defensiveness; children with ASD who didn't need ABA therapy; and the control group of healthy children. Number of microstates was determined in the initial and final parts of the resting-state EEGs.

Results and conclusions

Children with higher tactile defensiveness for the most part had specific EEG microstates associated with unpleasant emotions and senses. The EEG microstates of children with ASD who did not need ABA therapy, had more similarities with the EEG microstates of typically developing children except for temporary changes. Meanwhile, the children with tactile defensiveness demonstrated typical patterns of EEG microstates from start to finish of the procedure.

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.

Assessing pain in children with autism spectrum disorders: findings from a preliminary validation study

AIMS

Assessing pain in children with autism spectrum disorders (ASDs) can be extremely challenging, since many cannot self-report pain. This study aims to test the validity of the Non-Communicating Children's Pain Checklist - Revised (NCCPC-R) in identifying pain in children and adolescents affected by ASDs.

MATERIALS AND METHODS

A two-phase validation study based on (a) the translation and cultural adaptation of the NCCPC-R to Italian and to ASD-specific needs and context; and (b) the validation of a modified, 32-item version of the NCCPC-R. In all, 141 carers of children aged 6-16 years with ASDs were asked to recall an in-pain episode and a not-in-pain episode of their child and to rate on a 3-point scale (0 = not at all, 3 = very often) each behaviour included in the tool. Internal consistency (Cronbach's α), explorative and confirmative factorial structure, as well as concurrent and discriminant validity, were all assessed.

RESULTS

Confirmatory factor analysis established the revised version of the NCCPC-R for children with ASDs (named = NCCPC-R_ASD ), formed from 10 of the original 30 items categorised into three factors ('Changing in mood', 'Increasing in tension' and 'Alerting reaction') to have an acceptable level of reliability. The tool was internally consistent (α = 0.741 during in-pain episodes, α = 0.790 during not-in-pain episodes) and was able to discriminate between in-pain episodes (13.36 out of 40; CI 95% 12.34-14.39) and not-in-pain episodes (7.84 out of 40; CI 95% 6.86-8.82, p < 0.001).

CONCLUSIONS

These results provide preliminary evidence that the 10-item version of the NCCPC-R_ASD is a reliable and valid tool for assessing pain in children with ASD.

Neural Correlates of Cardiac Interoceptive Focus Across Development: Implications for Social Symptoms in Autism Spectrum Disorder

Interoception involves the processing of sensory information relevant to physiological functioning and is integral to building self-awareness, emotional states, and modulating social behaviors. With the role of interoception in emotional processing and social functioning, there is growing interest in characterizing interoception in autism spectrum disorder (ASD), yet, there are mixed results regarding cardiac interoceptive accuracy in ASD. In this study, we explored the neural basis of cardiac interoception using an fMRI heartbeat-counting task in order to assess neural correlates of primary interoception. We predicted that interoceptive-specific response in the insula, a "hub" for interoception, would be related to ASD symptomatology. We investigated the relationship of insula responses during cardiac interoceptive focus and a self/caregiver-reported autism-related symptom scale (Social Responsiveness Scale-2 (SRS)). Participants included 46 individuals with autism spectrum disorder (ASD) (age 8-54, mean = 19.43 ± 10.68 years) and 54 individuals with typical development for comparison (TC, age 8-53, mean = 21.43 ± 10.41 years). We found no significant difference in cardiac interoceptive accuracy or neural response to cardiac interoception focus in ASD. Several insula subdivisions had a curvilinear relationship to age, peaking in early adulthood. Interoceptive-specific insula response was associated with adult self-report SRS scores; this association differed by diagnostic group and was not present for caregiver-reported scores. This work suggests that (a) there is no global deficit in cardiac interoception in ASD, but integrating interoceptive cues with social information may distinguish individuals with ASD, and (b) there is a developmental trajectory for interoceptive processing in the insula that may be relevant for socio-emotional health. Autism Res 2020, 13: 908-920. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We use internal sensory information from the body, such as signals from the heart, to understand our emotional response to the external world. We measured how accurately people with autism feel their heartbeat and how the brain responds to this type of information. We found no differences between the autism and comparison groups in how the brain senses heartbeats, or in how accurately people feel their heartbeats. However, for people with autism, brain responses while sensing heartbeats were related to social difficulties. This work suggests people with autism may use internal and external information in a different way.