Altered gamma-band electrophysiological activity in individuals with autism spectrum disorder (ASD) is well documented, and analogous gamma-band alterations are recapitulated in several preclinical murine models relevant to ASD. Such gamma-band activity is hypothesized to underlie local circuit processes. Gamma-band cross-frequency coupling (CFC), a related though distinct metric, interrogates local neural circuit signal integration. Several recent studies have observed perturbed gamma-band CFC in individuals with ASD, although the direction of change remains unresolved. It also remains unclear whether murine models relevant to ASD recapitulate this altered gamma-band CFC. As such, this study examined whether mice with parvalbumin (PV) cell-specific ablation of NMDA-R1 (PVcre/NR1fl/fl) demonstrated altered gamma-band CFC as compared with their control littermates (PVcre/NR1+/+-mice that do not have the PV cell-specific ablation of NMDA-R1). Ten mice of each genotype had 4 min of “resting” electroencephalography recorded and analyzed. First, resting electrophysiological power was parsed into the canonical frequency bands and genotype-related differences were subsequently explored so as to provide context for the subsequent CFC analyses. PVcre/NR1fl/fl mice exhibited an increase in resting power specific to the high gamma-band, but not other frequency bands, as compared with PVcre/NR1+/+. CFC analyses then examined both the standard magnitude (strength) of CFC and the novel metric PhaseMax-which denotes the phase of the lower frequency signal at which the peak higher frequency signal power occurred. PVcre/NR1fl/fl mice exhibited altered PhaseMax, but not strength, of gamma-band CFC as compared with PVcre/NR1+/+ mice. As such, this study suggests a potential novel metric to explore when studying neuropsychiatric disorders.
Keywords: ASD; cross-frequency coupling; gamma; phase; phase-amplitude coupling.
While genes with an excess of de novo mutations (DNMs) have been identified in children with neurodevelopmental disorders (NDDs), few studies focus on DNM patterns where the sex of affected children is examined separately. We considered ∼8,825 sequenced parent-child trios (n ∼26,475 individuals) and identify 54 genes with a DNM enrichment in males (n = 18), females (n = 17), or overlapping in both the male and female subsets (n = 19). A replication cohort of 18,778 sequenced parent-child trios (n = 56,334 individuals) confirms 25 genes (n = 3 in males, n = 7 in females, n = 15 in both male and female subsets). As expected, we observe significant enrichment on the X chromosome for females but also find autosomal genes with potential sex bias (females, CDK13, ITPR1; males, CHD8, MBD5, SYNGAP1); 6.5% of females harbor a DNM in a female-enriched gene, whereas 2.7% of males have a DNM in a male-enriched gene. Sex-biased genes are enriched in transcriptional processes and chromatin binding, primarily reside in the nucleus of cells, and have brain expression. By downsampling, we find that DNM gene discovery is greatest when studying affected females. Finally, directly comparing de novo allele counts in NDD-affected males and females identifies one replicated genome-wide significant gene (DDX3X) with locus-specific enrichment in females. Our sex-based DNM enrichment analysis identifies candidate NDD genes differentially affecting males and females and indicates that the study of females with NDDs leads to greater gene discovery consistent with the female-protective effect.
Keywords: X chromosome; autism; female protective effect; intellectual disability; neurodevelopmental disorder; sex bias
Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characterized by sociocommunicative impairments. Growing consensus indicates that neurobehavioral abnormalities require explanation in terms of interconnected networks. Despite theoretical speculations about increased local and reduced distal connectivity, links between local and distal functional connectivity have not been systematically investigated in ASDs. Specifically, it remains open whether hypothesized local overconnectivity may reflect isolated versus overly integrative processing. Resting state functional MRI data from 57 children and adolescents with ASDs and 51 typically developing (TD) participants were included. In regional homogeneity (ReHo) analyses, pericalcarine visual cortex was found be locally overconnected (ASD > TD). Using this region as seed in whole-brain analyses, we observed overconnectivity in distal regions, specifically middle frontal gyri, for an ASD subgroup identified through k-means clustering. While in this subgroup local occipital to distal frontal overconnectivity was associated with greater symptom severity, a second subgroup showed the opposite pattern of connectivity and symptom severity correlations. Our findings suggest that increased local connectivity in ASDs is region-specific and may be partially associated with more integrative long-distance connectivity. Results also highlight the need to test for subtypes, as differential patterns of brain-behavior links were observed in two distinct subgroups of our ASD cohort.
Keywords: autism; frontal cortex; functional connectivity MRI; local connectivity; visual cortex.
There are two established electroencephalogram (EEG) indices that putatively relate to anxiety symptoms: a) the error-related negativity (ERN), which reflects endogenous threat sensitivity, and b) resting-state EEG relative right frontal activity (rRFA), which relates to approach/withdrawal motivation. We examined these indices conjointly to better elucidate differential mechanisms underlying the common anxiety phenotype in youth with autism spectrum disorder (ASD), in relation to subjective reports of symptomatology and treatment response. EEG was recorded from 53 youth with ASD who participated in a 10-week social skills intervention (SSI). More negative ERN related to higher self-reported social anxiety symptoms at baseline, and predicted improvements in self-reported social anxiety symptoms following SSI. Although rRFA did not relate to anxiety symptoms at baseline, more rRFA predicted improvement in parent-reported anxiety domains but worsening in self-reported anxiety symptoms. This study provides evidence for unique neural mechanisms of anxiety symptoms and changes in anxiety after SSI in youth with ASD.
Keywords: Anxiety; Autism spectrum disorder; Electroencephalogram (EEG); Error-related negativity (ERN); Hemispheric asymmetry.
Autistic self-advocates, family members, and community organizations have called for greater emphasis on enhancing quality of life (QoL) for people with autism. Doing this is critical to understand how QoL unfolds across the life course and to clarify whether gender affects QoL, health, and functioning for people with autism. The purpose of this study was to curate and test a lifespan QoL measurement tool using freely available and well-constructed National Institutes of Health Parent-Reported Outcomes Measurement Information System (PROMIS). To develop the PROMIS Autism Battery-Lifespan (PAB-L), we identified PROMIS scales relevant for autism, reviewed each item, consulted with a panel of autism experts, and elicited feedback from autistic people and family members. This battery provides a comprehensive portrait of QoL for children ages 5-13 (through parent proxy), teens 14-17 (parent proxy and self-report), and adults 18-65 (self-report) with autism compared to the general population. Participants and parent informants (N = 912) recruited through a children’s hospital and nationwide U.S. autism research registry completed the PAB-L online. Results indicate that compared to general population norms, people with autism of all ages (or their proxies) reported less desirable outcomes and lower QoL across all domains. Women and girls experienced greater challenges in some areas compared to men and boys with autism. The PAB-L appears to be a feasible and acceptable method for assessing patient-reported outcomes and QoL for autistic people across the life course. Autism Res 2020, 13: 970-987. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We developed a survey to measure the quality of life of children, teens, and adults with autism using free National Institutes of Health PROMIS questionnaires. People with autism and family members rated the PROMIS Autism Battery-Lifespan as useful and important. Some reported a good quality of life, while many reported that their lives were not going as well as they wanted. Women and girls reported more challenges in some areas of life than men and boys.
Keywords: adults; life course; life span/lifespan; patient-reported outcomes; quality of life; sex/gender; women with autism.
Early intervention is important for preschoolers on the autism spectrum, but little is known about early intervention classrooms in the community. This study found that children with better language skills and lower autism severity have more verbal interactions with their classmates, especially in classrooms with typically developing peers (inclusion settings). Findings suggest that natural language sampling is a useful method for characterizing autistic children and their early intervention settings. In addition, natural language sampling may have important implications for understanding individual opportunities for development in community early intervention settings.
Keywords: autism spectrum disorders; communication and language; early intervention; education services; environmental factors; pre-school children.
Background: Concerns have been raised that scores on standard measures of autism spectrum disorder (ASD) symptoms may differ as a function of sex. However, these findings are hindered by small female samples studied thus far. The current study evaluated if, after accounting for age, IQ, and language level, sex affects ASD severity estimates from diagnostic measures among children with ASD.
Methods: Data were obtained from eight sources comprising 27 sites. Linear mixed-effects models, including a random effect for site, were fit for 10 outcomes (Autism Diagnostic Observation Schedule [ADOS] domain-level calibrated severity scores, Autism Diagnostic Interview-Revised [ADI-R] raw scores by age-based algorithm, and raw scores from the two indices on the Social Responsiveness Scale [SRS]). Sex was added to the models after controlling for age, NVIQ, and an indicator for language level.
Results: Sex significantly improved model fit for half of the outcomes, but least square mean differences were generally negligible (effect sizes [ES] < 0.20), increasing to small to moderate in adolescence (ES < 0.40). Boys received more severe RRB scores than girls on both the ADOS and ADI-R (age 4 + algorithm), and girls received more severe scores than boys on both SRS indices, which emerged in adolescence.
Conclusions: This study combined several available databases to create the largest sample of girls with ASD diagnoses. We found minimal differences due to sex beyond other known influences on ASD severity indicators. This may suggest that, among children who ultimately receive a clinical ASD diagnosis, severity estimates do not systematically differ to such an extent that sex-specific scoring procedures would be necessary. However, given the limitations inherent in clinically ascertained samples, future research must address questions about systematic sex differences among children or adults who do not receive clinical diagnoses of ASD. Moreover, while the current study helps resolve questions about widely used diagnostic instruments, we could not address sex differences in phenotypic aspects outside of these scores.
Keywords: Sex differences; autism spectrum disorder; restricted and repetitive behavior; social impairment.