Gender, assigned sex at birth, and gender diversity: Windows into diagnostic timing disparities in autism.

LAY ABSTRACT: Later autism diagnosis is associated with risk for mental health problems. Understanding factors related to later autism diagnosis may help reduce mental health risks for autistic people. One characteristic associated with later autism diagnosis is female sex. However, studies often do not distinguish sex assigned at birth and gender identity. Gender diversity may be more common in autistic relative to neurotypical people, and autism is more common in gender-diverse populations. We studied age at autism diagnosis by sex assigned at birth, gender identity, and gender diversity (gender-diverse vs cisgender) status, separately. We studied three separate autistic samples, each of which differed in how they were diagnosed and how they were recruited. The samples included 193 persons (8.0-18.0 years) from a research-recruited academic medical center sample; 1,550 people (1.3-25.4 years) from a clinic-based sample; and 244 people (18.2-30.0 years) from a community-enriched sample. We found significant differences in the clinic-based and community-enriched samples. People assigned female sex at birth were diagnosed with autism significantly later than people assigned male at birth. People of female gender were diagnosed significantly later than people of male gender. Gender-diverse people were diagnosed significantly later than cisgender people. Sex assigned at birth, gender identity, and gender diversity may each show unique relationships with age of autism diagnosis. Differences in how autistic people are diagnosed and recruited are important to consider in studies that examine sex assigned at birth or gender identity. More research into autism diagnosis in adulthood is needed.

Increased anticholinergic medication use in middle-aged and older autistic adults and its associations with self-reported memory difficulties and cognitive decline.

Many commonly used prescription and over-the-counter medicines have potent anticholinergic (AC) effects. Among older adults, AC medications are associated with cognitive impairment and risk for cognitive disorders, including Alzheimer's disease. Collectively, the impact of AC medications is known as anticholinergic cognitive burden (ACB). Because of the high rates of co-occurring medical and psychiatric conditions, autistic adults may have high AC exposure and, thus, may experience elevated ACB. However, no research has characterized AC exposure or examined its associations with cognitive outcomes in autistic adults. Autistic adults (40-83 years) recruited via Simons Powering Autism Research's (SPARK) Research Match service self-reported their medication use (N = 415) and memory complaints (N = 382) at Time (T)1. At T2, 2 years later, a subset of T1 participants (N = 197) self-reported on decline in cognition. Medications were coded using two scales of AC potency. A high proportion (48.2%-62.9%, depending upon the AC potency scale) of autistic adults reported taking at least one medication with AC effects, and 20.5% to 26.5% of autistic adults reported clinically-relevant levels of AC medication (potency ≥3). After controlling for birth-sex, and age, hierarchical linear regression models showed total ACB scores and AC potency values of ≥3 predicted greater memory complaints. Logistic regression models showed that AC medicines at T1 were associated with self-reported cognitive decline at follow-up 2 years later. Understanding AC medications-including potentially earlier AC polypharmacy-and their impacts on cognition (e.g., dementia risk) in autistic adults is warranted.

Self-reported Prospective and Retrospective Memory Among Middle Aged and Older Autistic and Non-autistic People.

OBJECTIVE: Self-reported memory difficulties are common among older adults, but few studies have examined memory problems among autistic middle-aged and older people. The current study examines self-rated prospective (PM) and retrospective (RM) memory difficulties and their associations with age in middle-aged and older autistic and non-autistic people. METHODS: 350 autistic people (58% assigned-female-at-birth; age-range: 40-83 years) and 350 non-autistic adults matched on age, birth-sex and education level were included in the analysis. Participants completed the Prospective and Retrospective Memory Questionnaire (PRMQ) which includes questions about PM vs. RM (memory type), environment-cued vs. self-cued (cue), and short vs. long delay (delay). RESULTS: Autistic people reported significantly more PM and RM difficulties than the comparison group. Both groups reported more difficulties with PM (vs. RM), self-cued (vs. environment-cued), and short (vs. long) delay. No significant interactions were observed. Among autistic people, younger age was associated with reporting more PM and RM difficulties, but this pattern was not observed among non-autistic people. CONCLUSIONS: Autistic people may be at reduced risk for memory problems as they age, compared to their same-age non-autistic peers. Further studies are required to explore the association between self-reported memory challenges and memory task performance among autistic older people.

Extended trajectory of spatial memory errors in typical and atypical development: The role of binding and precision.

Spatial reconstruction, a method for evaluating how individuals remember the placement of objects, has traditionally been evaluated through the aggregate estimation of placement errors. However, this approach may obscure the nature of task errors. Specifically, recent data has suggested the importance of examining the precision of responses, as well as absolute performance on item-context bindings. In contrast to traditional analysis approaches based on the distance between the target and the reconstructed item, in this study we further explored three types of errors (swap error, global error, and local distance) that may all contribute to the distance, with particular emphasis on swap errors and local distance due to their associations with item-context bindings and memory precision, respectively. We examined these errors in children aged 3-18 years, making comparisons between children with typical development (TD) and children with Down syndrome (DS), a population with known memory challenges. As expected, older children outperformed younger children in terms of overall memory accuracy. Of importance is that we measured uneven maturational trajectories of memory abilities across the various error types. Specifically, both remembered locations (irrespective of object identity) and swap errors (object-location binding errors) align with the overall memory accuracy. Memory precision, as measured by local distance in simpler set size 2 trials, mirrored overall memory accuracy. However, for more complex set size 3 trials, local distance remained stable before age 8 and showed age-related change thereafter. The group with DS showed reduced precision compared to a TD matched group, and measures of precision, and to a lesser extent binding errors, correlated with standard neuropsychological outcomes. Overall, our study contributed to a fine-grained understanding of developing spatial memory ability in a large sample of typical developing children and a memory impaired population. These findings contribute to a growing body of research examining precision as a key factor in memory performance.

Sexual Minority Identities in Autistic Adults: Diversity and Associations with Mental Health Symptoms and Subjective Quality of Life.

Background: Although disparities in mental health and subjective quality of life (QoL) have been reported for autistic adults, reasons for these disparities are poorly understood. A potential factor in these disparities is exposure to social stressors related to minority status (i.e., minority stress), including stigma and discrimination. Autistic individuals are more likely than nonautistic individuals to be from groups with other minority identities, including sexual minorities (i.e., sexual orientations such as asexual, bisexual, gay). However, to date, few studies have examined whether sexual minority autistic adults experience diminished mental health relative to heterosexual autistic adults, and no research has examined subjective QoL for sexual minority compared with heterosexual autistic adults. Methods: Participants were 651 autistic adults aged 18.5 to 83.3 years recruited through Simons Powering Autism Research's Research Match. All participants resided in the United States. Participants completed surveys online, including measures of anxious and depressive symptomatology, perceived stress, and subjective QoL. Participants reported their sexual orientation and other sociodemographic variables. Results: A large proportion of autistic adults reported a sexual minority identity (41.2%), and a diversity of sexual identities was reported. Sexual minority autistic adults reported poorer mental health and lower subjective QoL across all assessed domains relative to heterosexual autistic adults. Conclusion: Understanding factors that may be associated with poorer mental health and decreased subjective QoL in autistic adults is critical and has been identified as a research priority by autistic stakeholders. The findings reported here underscore the need to examine mental health and subjective QoL disparities among autistic individuals within a societal context, taking into consideration the potential of intersecting minority identities and increased social stressors, as these added stressors may increase risks for poorer outcomes.

Why is this an important issue?: Autistic people are at risk for mental health problems, such as depression and anxiety, and report lower quality of life. Autistic people are more likely than nonautistic people to identify as a sexual minority. Sexual minority identities are sexual orientations other than heterosexual, such as asexual, bisexual, or gay. Sexual minority persons are also at risk for mental health problems and lower quality of life. Autistic people who are sexual minorities may have even higher risk of mental health problems and lower quality of life. What was the purpose of this study?: There is little research on mental health and quality of life in persons who are both autistic and identify as a sexual minority. Sexual minority autistic adults may be exposed to more minority-related stress than heterosexual autistic adults. People who belong to minority groups face added stress created by society. This added stress is referred to as minority stress, which includes things such as discrimination, rejection, or violence. Minority stress could increase risk for poor outcomes. We compared heterosexual and sexual minority autistic adults to see if having more than one minority identity (an autistic identity and a sexual minority identity) was associated with mental health or subjective quality of life. Subjective quality of life refers to how a person feels about parts of their life, such as their physical and psychological health or their living arrangements. What did the researchers do?: We asked 651 autistic adults living in the United States to complete surveys online. Participants rated their anxiety, depression, and everyday stress; answered questions about their subjective quality of life; and reported their sexual orientation, sex assigned at birth, and gender identity. We compared sexual minority with heterosexual autistic adults to see if they differed for mental health or subjective quality-of-life ratings. What were the results of the study?: A total of 41.2% of autistic adults reported a sexual minority identity. Autistic adults reported a diversity of sexual orientations, including asexual, bisexual, gay, and pansexual. Sexual minority autistic adults reported more depression, anxiety, and stress compared with heterosexual autistic adults. Sexual minority autistic adults reported poorer subjective quality of life across different areas of their lives compared with heterosexual autistic adults. Sexual minority autistic adults reported having less energy and more physical pain than heterosexual autistic adults. Sexual minority autistic adults also reported feeling more negative emotions and having problems with thinking/concentration. Sexual minority autistic adults reported more concerns about things such as having health care and transportation and greater worries about feeling safe in their homes and neighborhoods. Finally, sexual minority autistic adults were more likely to report that they faced barriers in their everyday lives (such as sensory sensitivities making it hard to grocery shop). What are the potential weaknesses in the study?: Although we found significant differences between sexual minority and heterosexual autistic groups, other factors likely play a role in these results. For example, we know that not having enough social support can contribute to worse mental health and quality of life. Measuring other such factors is needed in future studies. How will these findings help autistic adults now or in the future?: These findings highlight the need for more awareness of sexual minority identities in autistic adults. Understanding factors that may contribute to worse mental health and quality of life for autistic adults can help us improve well-being for all autistic people.

Predictors of sleep quality for autistic people across adulthood.

Poor sleep can have a significant impact on physical health and well-being. Sleep problems are common among autistic children, but less is known about sleep across the autistic adult lifespan. Autistic adults (n = 730, aged 18-78 years) were recruited via Simons Powering Autism Research for Knowledge Research Match. Participants completed online surveys asking about demographics, health problems, social support, symptoms of anxiety and depression, and overall and specific aspects of sleep quality. Regression analyses explored the variables associated with sleep quality. Physical health, assigned female sex at birth and self-reported anxiety symptoms significantly contributed to models for all aspects of sleep. Perceived stress contributed to models of overall and subjective sleep quality, and daytime dysfunction. Depression symptoms did not contribute significantly to any of the models of sleep quality. However, utilizing government support mechanisms (such as social security) contributed to the model of sleep efficiency. Age contributed little to models of sleep quality, whereas perceived stress and psychotropic medication use contributed to some but not all aspects of sleep. Sleep quality is poor for autistic people across the adult lifespan. Given known impacts of poor sleep on health, cognition and quality of life, attention should be paid to sleep and its possible everyday effects for autistic people of all ages.

Cardiovascular disease risk factors in autistic adults: The impact of sleep quality and antipsychotic medication use.

Approximately 40% of American adults are affected by cardiovascular disease (CVD) risk factors (e.g., high blood pressure, high cholesterol, diabetes, and overweight or obesity), and risk among autistic adults may be even higher. Mechanisms underlying the high prevalence of CVD risk factors in autistic people may include known correlates of CVD risk factors in other groups, including high levels of perceived stress, poor sleep quality, and antipsychotic medication use. A sample of 545 autistic adults without intellectual disability aged 18+ were recruited through the Simons Foundation Powering Autism Research, Research Match. Multiple linear regression models examined the association between key independent variables (self-reported perceived stress, sleep quality, and antipsychotic medication use) and CVD risk factors, controlling for demographic variables (age, sex assigned at birth, race, low-income status, autistic traits). Overall, 73.2% of autistic adults in our sample had an overweight/obesity classification, 45.3% had high cholesterol, 39.4% had high blood pressure, and 10.3% had diabetes. Older age, male sex assigned at birth, and poorer sleep quality were associated with a higher number of CVD risk factors. Using antipsychotic medications was associated with an increased likelihood of having diabetes. Poorer sleep quality was associated with an increased likelihood of having an overweight/obesity classification. Self-reported CVD risk factors are highly prevalent among autistic adults. Both improving sleep quality and closely monitoring CVD risk factors among autistic adults who use antipsychotic medications have the potential to reduce risk for CVD.

Vocational Outcomes in ASD: An Examination of Work Readiness Skills as well as Barriers and Facilitators to Employment Identified by Autistic Adults.

Little is known about work readiness skills among autistic adults. This study sought to address this by examining work readiness skills and their relation to vocational outcomes among 281 autistic young adults. It also examined perceived barriers and facilitators to employment as articulated by a subset of autistic adults. Results revealed a variegated work readiness profile. Stronger work readiness skills (particularly work style/adaptability) were associated with more favorable vocational outcomes. Autistic participants articulated both barriers and facilitators to employment related to the autism phenotype, job search/work readiness, and workplace education. These findings indicate the need for research on phenotype-driven vocational rehabilitation strategies as well as workplace psychoeducation/accommodations to support vocational outcomes for autistic adults.

Co-occurring ADHD symptoms in autistic adults are associated with less independence in daily living activities and lower subjective quality of life.

LAY ABSTRACT: Outcomes for autistic adults are generally poor, including activities of daily living and self-ratings of quality of life. Co-occurring psychiatric conditions contribute to these poor outcomes. Attention-deficit/hyperactivity disorder is one of the most common co-occurring conditions in autistic individuals. However, we know little about the association between attention-deficit/hyperactivity disorder symptoms and outcomes in autistic adults. A total of 724 autistic adults (18-83 years; 58% female) recruited from the Simons Foundation Powering Autism Research participant registry completed questionnaires on demographics, co-occurring psychiatric conditions, activities of daily living, and subjective quality of life. Autistic adults who rated themselves as having more attention-deficit/hyperactivity disorder symptoms also rated themselves as having less independence in activities of daily living and a lower quality of life. This is the first study to show these relationships in autistic adults. These findings highlight that additional research and better supports for co-occurring attention-deficit/hyperactivity disorder symptoms may be critical to improving independence and quality of life for autistic adults.

Increased perceived stress is negatively associated with activities of daily living and subjective quality of life in younger, middle, and older autistic adults.

Few studies have examined self-reported perceived stress in autistic adults. Existing studies have included relatively small, predominantly male samples and have not included older autistic adults. Using a large autistic sample (N = 713), enriched for individuals designated female at birth (59.3%), and spanning younger, middle, and older adulthood, we examined perceived stress and its associations with independence in activities of daily living and subjective quality of life (QoL). Perceived stress for autistic adults designated male or female at birth was compared to their same birth-sex counterparts in a general population sample. In addition, within the autistic sample, effects of sex designated at birth, age, and their interaction were examined. Regression modeling examined associations between perceived stress and independence in activities of daily living and domains of subjective QoL in autistic adults, after controlling for age, sex designated at birth, and household income. Autistic adults reported significantly greater perceived stress than a general population comparison sample. Relative to autistic adults designated male at birth, those designated female at birth demonstrated significantly elevated perceived stress. Perceived stress contributed significantly to all regression models, with greater perceived stress associated with less independence in activities of daily living, and poorer subjective QoL across all domains-Physical, Psychological, Social, Environment, and Autism-related QoL. Findings are contextualized within the literature documenting that autistic individuals experience elevated underemployment and unemployment, heightened rates of adverse life events, and increased exposure to minority stress. LAY SUMMARY: This study looked at self-reported perceived stress in a large sample of autistic adults. Autistic adults reported more perceived stress than non-autistic adults. Autistic individuals designated female at birth reported higher stress than autistic individuals designated male at birth. In autistic adults, greater perceived stress is related to less independence in activities of daily living and poorer subjective quality of life.

Variegation of autism related traits across seven neurogenetic disorders.

Gene dosage disorders (GDDs) constitute a major class of genetic risks for psychopathology, but there is considerable debate regarding the extent to which different GDDs induce different psychopathology profiles. The current research speaks to this debate by compiling and analyzing dimensional measures of several autism-related traits (ARTs) across seven diverse GDDs. The sample included 350 individuals with one of 7 GDDs, as well as reference idiopathic autism spectrum disorder (ASD; n = 74) and typically developing control (TD; n = 171) groups. The GDDs were: Down, Williams-Beuren, and Smith-Magenis (DS, WS, SMS) syndromes, and varying sex chromosome aneuploidies ("plusX", "plusXX", "plusY", "plusXY"). The Social Responsiveness Scale (SRS-2) was used to measure ARTs at different levels of granularity-item, subscale, and total. General linear models were used to examine ART profiles in GDDs, and machine learning was used to predict genotype from SRS-2 subscales and items. These analyses were completed with and without covariation for cognitive impairment. Twelve of all possible 21 pairwise GDD group contrasts showed significantly different ART profiles (7/21 when co-varying for IQ, all Bonferroni-corrected). Prominent GDD-ART associations in post hoc analyses included relatively preserved social motivation in WS and relatively low levels of repetitive behaviors in plusX. Machine learning revealed that GDD group could be predicted with plausible accuracy (~60-80%) even after controlling for IQ. GDD effects on ARTs are influenced by GDD subtype and ART dimension. This observation has consequences for mechanistic, clinical, and translational aspects of psychiatric neurogenetics.

Camouflaging in autism spectrum disorder: Examining the roles of sex, gender identity, and diagnostic timing.

LAY ABSTRACT: Camouflaging in autism spectrum disorder refers to behaviors and/or strategies that mask the presentation of autism spectrum disorder features in social contexts in order to appear "non-autistic" (Attwood, 2007). Camouflaging modifies the behavioral presentation of core autism spectrum disorder features (e.g. social and communication differences), but the underlying autistic profile is unaffected, yielding a mismatch between external observable features and the internal lived experience of autism. Camouflaging could be an important factor in later diagnosis of individuals without co-occurring intellectual disability, especially among those designated female sex at birth. Little research to date has examined how gender identity impacts camouflaging, however. Furthermore, no study has compared groups that differ in diagnostic timing to directly investigate if later-diagnosed individuals show elevated camouflaging relative to those receiving an earlier diagnosis. We used the Camouflaging Autistic Traits Questionnaire subscales (Assimilation, Compensation, and Masking) and investigated the roles of sex, gender identity (gender diverse vs cisgender), and diagnostic timing (childhood/adolescent-diagnosed vs adult-diagnosed), and the interactions of these factors, in autistic adults (N = 502; ages 18-49 years). Main effects of sex, gender identity, and diagnostic timing were revealed. Autistic females reported more camouflaging across all three Camouflaging Autistic Traits Questionnaire subscales compared to males. Gender diverse adults reported elevated camouflaging on the Compensation subscale compared to cisgender adults. Adulthood-diagnosed individuals reported elevated Assimilation and Compensation compared to childhood/adolescence-diagnosed individuals. We discuss how the aspects of camouflaging may have unique implications for later diagnostic timing and for the intersection of neurodiversity and gender diversity.

Patterns of psychopathology and cognition in sex chromosome aneuploidy.

BACKGROUND: Sex chromosome aneuploidies (SCAs) are a collectively common family of genetic disorders that increase the risk for neuropsychiatric and cognitive impairment. Beyond being important medical disorders in their own right, SCAs also offer a unique naturally occurring model for studying X- and Y-chromosome influences on the human brain. However, it remains unclear if (i) different SCAs are associated with different profiles of psychopathology and (ii) the notable interindividual variation in psychopathology is related to co-occurring variation in cognitive ability. METHODS: We examined scores for 11 dimensions of psychopathology [Child/Adult Behavior Checklist (CBCL)] and general cognitive ability [full-scale IQ (FSIQ) from Wechsler tests] in 110 youth with varying SCAs (XXY = 41, XYY = 22, XXX = 27, XXYY = 20) and 131 typically developing controls (XX = 59, XY = 72). RESULTS: All SCAs were associated with elevated CBCL scores across several dimensions of psychopathology (two-sample t tests comparing the euploidic and aneuploidic groups [all |T| > 9, and p < 0.001]). Social and attentional functioning were particularly sensitive to the carriage of a supernumerary Y-chromosome. In particular, the XYY group evidenced significantly more social problems than both extra-X groups (Cohen's d effect size > 0.5, Bonferroni corrected p < .05). There was marked variability in CBCL scores within each SCA group, which generally correlated negatively with IQ, but most strongly so for social and attentional difficulties (standardized ß, - 0.3). These correlations showed subtle differences as a function of the SCA group and CBCL scale. CONCLUSIONS: There is domain-specific variation in psychopathology across SCA groups and domain-specific correlation between psychopathology and IQ within SCAs. These findings (i) help to tailor clinical assessment of this common and impactful family of genetic disorders and (ii) suggest that dosage abnormalities of X- and Y-linked genes impart somewhat distinct profiles of neuropsychiatric risk.

Circadian Sleep-Activity Rhythm across Ages in Down Syndrome.

Across all ages, individuals with Down syndrome (DS) experience high rates of sleep problems as well as cognitive impairments. This study sought to investigate whether circadian rhythm disruption was also experienced by people with DS and whether this kind of sleep disorder may be correlated with cognitive performance. A cross-sectional study of 101 participants (58 with DS, 43 with typical development) included individuals in middle childhood (6-10 years old), adolescence (11-18 years old), and young adulthood (19-26 years old). Sleep and markers of circadian timing and robustness were calculated using actigraphy. Cognitive and behavioral data were gathered via a novel touchscreen battery (A-MAPTM, Arizona Memory Assessment for Preschoolers and Special Populations) and parent questionnaire. Results indicated that children and adolescents with DS slept the same amount as peers with typical development, but significant group differences were seen in phase timing. The circadian robustness markers, interdaily stability and intradaily variability of sleep-wake rhythms, were healthiest for children regardless of diagnostic group and worst for adults with DS. Amplitude of the 24-h activity profile was elevated for all individuals with DS. In analyses of the correlations between sleep quality, rhythms, and cognition in people with DS, interdaily stability was positively correlated with reaction time and negatively correlated with verbal and scene recall, a finding that indicates increased stability may paradoxically correlate with poorer cognitive outcomes. Further, we found no relations with sleep efficiency previously found in preschool and adult samples. Therefore, the current findings suggest that a thorough examination of sleep disorders in DS must take into account age as well as circadian robustness to better understand sleep-cognitive correlations in this group.

Speech Impairments Explain Unique Variance in Adaptive Behavior Skills in Young People With Down Syndrome.

Background Down syndrome (DS) is a disorder characterized by impairments in global cognitive abilities and adaptive function. In addition, individuals with DS demonstrate pronounced speech and language deficits. However, little is known about the linguistic correlates of impaired adaptive functioning in DS. Method Using the Adaptive Behavior Assessment System-Second Edition and the Children's Communication Checklist-Second Edition (CCC-2), this study investigated the unique variance in adaptive skills accounted for by speech and language impairments in individuals with DS (N = 29, M age = 13.46). Results Pearson correlations revealed that a composite of CCC-2 structural language scales, but not pragmatic language scales, was significantly correlated with the Adaptive Behavior Assessment System-Second Edition Global Adaptive Composite, Conceptual, and Practical domains. Further investigation utilizing hierarchical regression analyses identified only the Speech scale on the CCC-2 as contributing unique variance to the prediction of adaptive behavior scores in the Global Adaptive Composite, Conceptual, and Practical domains. Conclusion Speech impairments may serve as flags to identify children with DS who are at risk for adaptive behavior deficits and reinforce the need for speech-language therapies that focus on speech for these individuals. Supplemental Material https://doi.org/10.23641/asha.13231985.

Hypoplasia of cerebellar afferent networks in Down syndrome revealed by DTI-driven tensor based morphometry.

Quantitative magnetic resonance imaging (MRI) investigations of brain anatomy in children and young adults with Down syndrome (DS) are limited, with no diffusion tensor imaging (DTI) studies covering that age range. We used DTI-driven tensor based morphometry (DTBM), a novel technique that extracts morphometric information from diffusion data, to investigate brain anatomy in 15 participants with DS and 15 age- and sex-matched typically developing (TD) controls, ages 6-24 years (mean age ~17 years). DTBM revealed marked hypoplasia of cerebellar afferent systems in DS, including fronto-pontine (middle cerebellar peduncle) and olivo-cerebellar (inferior cerebellar peduncle) connections. Prominent gray matter hypoplasia was observed in medial frontal regions, the inferior olives, and the cerebellum. Very few abnormalities were detected by classical diffusion MRI metrics, such as fractional anisotropy and mean diffusivity. Our results highlight the potential importance of cerebro-cerebellar networks in the clinical manifestations of DS and suggest a role for DTBM in the investigation of other brain disorders involving white matter hypoplasia or atrophy.

Relations between Everyday Executive Functioning and Language in Youth with Down Syndrome and Youth with Autism Spectrum Disorder.

Language and executive functioning are major impairments in many neurodevelopmental disorders, but little is known about the relations between these constructs, particularly using parent-report. Thus, the current research sought to examine relations between executive function and language in two groups - Down syndrome (DS; n=41; Mage = 11.2) and autism spectrum disorder (ASD; n=91; Mage = 7.7). Results were as follows: in DS, executive function predicted pragmatic, but not structural language after covarying for age, sex, and social functioning; in ASD, executive function predicted both. Findings highlight the interrelatedness of language and executive functioning and may have implications for intervention development.

A comprehensive examination of the memory profile of youth with Down syndrome in comparison to typically developing peers.

Down syndrome (DS) is associated with significant memory deficits beyond overall global cognitive impairment. Although a number of studies have examined memory abilities in adults and teens with DS, very few studies have examined memory abilities in children with DS. Additionally, research has yet to examine prospective memory (i.e., remembering to carry out an action in the future) in youth with DS. Consequently, the current study aimed to comprehensively examine the memory profile, including learning, immediate recall, delayed recall and prospective memory, of youth with DS (n = 22, age M = 11.43) in comparison to typically developing, mental-age (MA) matched children (n = 20, age M = 5.04) Consistent with past research, the results indicated that youth with DS performed significantly below MA-expectations on tasks of immediate verbal recall, learning across trials, and prospective memory, and there was a trend toward youth with DS performing below MA-expectations on delayed recall tasks. However, youth with DS did not differ significantly from MA-matched peers on immediate visual recall, rate of learning across trials, or proportion of items recalled on verbal and visual memory tasks following a delay (i.e., proportion relative to their own recall performance prior to the delay). These results highlight the relative strengths and challenges experienced by youth with DS on different learning and memory tasks. The implications of these findings for educators and caregivers are discussed.

A preliminary examination of brain morphometry in youth with Down syndrome with and without parent-reported sleep difficulties.

BACKGROUND: Down syndrome is associated with poor sleep but little is known about its neural correlates. AIMS: The current research compared brain morphometry in youth with Down syndrome with parent-reported sleep problems (DS-S) to peers with Down syndrome (DS) and typical development (TD) without parent-reported sleep problems matched on age (M = 15.15) and sex ratio (62 % female). METHODS AND PROCEDURES: Magnetic resonance imaging was completed on a 3 T scanner. Participants were stratified into groups based on parent-report: DS-S (n = 17), DS (n = 9), TD (n = 22). Brain morphometry, processed with the FreeSurfer Image Analysis Suite, was compared across groups. In addition, the co-occurrence of medical conditions in the DS groups was examined. OUTCOMES AND RESULTS: Youth with DS-S had reduced total, frontal, parietal, and temporal brain volumes relative to DS and TD peers. They also had higher rates of congenital heart defects than the DS-only group; however, this comorbidity did not appear to account for morphometry differences. CONCLUSIONS AND IMPLICATIONS: Parent-reported sleep problems in DS appear to relate to global and localized volume reductions. These preliminary results have implications for understanding the neural correlates of poor sleep in DS; they also highlight the importance of examining relations between sleep and other medical comorbidities.

A Comprehensive Quantitative Genetic Analysis of Cerebral Surface Area in Youth.

The genetics of cortical arealization in youth is not well understood. In this study, we use a genetically informative sample of 677 typically developing children and adolescents (mean age 12.72 years), high-resolution MRI, and quantitative genetic methodology to address several fundamental questions on the genetics of cerebral surface area. We estimate that >85% of the phenotypic variance in total brain surface area in youth is attributable to additive genetic factors. We also observed pronounced regional variability in the genetic influences on surface area, with the most heritable areas seen in primary visual and visual association cortex. A shared global genetic factor strongly influenced large areas of the frontal and temporal cortex, mirroring regions that are the most evolutionarily novel in humans relative to other primates. In contrast to studies on older populations, we observed statistically significant genetic correlations between measures of surface area and cortical thickness (rG = 0.63), suggestive of overlapping genetic influences between these endophenotypes early in life. Finally, we identified strong and highly asymmetric genetically mediated associations between Full-Scale Intelligence Quotient and left perisylvian surface area, particularly receptive language centers. Our findings suggest that spatially complex and temporally dynamic genetic factors are influencing cerebral surface area in our species.SIGNIFICANCE STATEMENT Over evolution, the human cortex has undergone massive expansion. In humans, patterns of neurodevelopmental expansion mirror evolutionary changes. However, there is a sparsity of information on how genetics impacts surface area maturation. Here, we present a systematic analysis of the genetics of cerebral surface area in youth. We confirm prior research that implicates genetics as the dominant force influencing individual differences in global surface area. We also find evidence that evolutionarily novel brain regions share common genetics, that overlapping genetic factors influence both area and thickness in youth, and the presence of strong genetically mediated associations between intelligence and surface area in language centers. These findings further elucidate the complex role that genetics plays in brain development and function.