Summary of Advances
In Autism Spectrum Disorder Research
Age at autism spectrum disorder (ASD) diagnosis by race, ethnicity, and primary household language among children with special health care needs, United States, 2009–2010
Jo H, Schieve LA, Rice CE, Yeargin-Allsopp M, Tian LH, Blumberg SJ, Kogan MD, Boyle CA. Matern Child Health J. 2015 Aug;19(8):1687-97. [PMID: 25701197]
In the US age of ASD diagnosis is decreasing; however, there is limited evidence about discrepancies between race/ethnicities in age of diagnosis even though non-Hispanic-white children are still more likely than either black or Hispanic children to be diagnosed with ASD. To determine if there are differences in the timing of ASD diagnosis across different racial and ethnic groups, the researchers in this study identified 2,729 children from 3 to 17 years of age with a diagnosis of ASD using the 2009–2010 National Survey of Children with Special Health Care Needs (NSCSHCN)(a telephone survey conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention). The 2,729 children were divided into four groups: white (and not Hispanic), black (and not Hispanic), Hispanic who speak mainly English at home, and Hispanic who speak mainly a language other than English at home. Researchers then compared ASD rates, age at diagnosis, and the percentage of children with later ASD diagnoses (defined as at 5 years of age or older) across these groups..
Although the researchers found that the average age of ASD diagnosis was similar across the racial, ethnic, and primary household language groups for children in the study who were 3 to 4 years of age at the time of the study, they did identify some differences in age at first diagnosis across these groups for children who were 5 years of age or older at the time of the study—mainly in cases of less severe, or mild or moderate, ASD. Specifically, they found that two groups of children 5 to 17 years of age with less severe ASD—white children and English-speaking Hispanic children—had a higher prevalence (15.3 and 14.1 per 1,000, respectively) of ASD and a higher proportion (50.8% and 43.5%, respectively) of later diagnoses than black children (10.4 per 1,000 and 33.5%) and Hispanic children who do not speak English (5.2 per 1,000 and 18.0%). However, these results may not be truly indicative of a higher prevalence of ASD in these groups. Rather, it may indicate that the black children and the non-English-speaking Hispanic children are under-represented in the study sample or that they are getting screened and diagnosed with ASD less often than the white and Hispanic English-speaking children. This is consistent with previous research that has found that black and Hispanic children may have reduced access to mental health care and that children of Hispanic immigrants (measured in this study as non-English speaking households) may have additional cultural and language barriers that reduce their access to health care. This study highlights that cultural and language differences should be considered when providing care and that education about the detection and importance of early identification of ASD is needed for both parents and health care professionals.
Diagnostic stability in young children at risk for autism spectrum disorder: a baby siblings research consortium study
Ozonoff S, Young GS, Landa RJ, Brian J, Bryson S, Charman T, Chawarska K, Macari SL, Messinger D, Stone WL, Zwaigenbaum L, Iosif AM. J Child Psychol Psychiatry. 2015 Sep;56(9):988-98. [PMID: 25921776]
Although previous research has shown that a clinical diagnosis of ASD made before a child reaches 3 years of age is not likely to change over time, a critical need remains to better understand whether an early diagnosis in children who have a family risk of developing ASD also remains stable. Such an understanding is especially important because American Academy of Pediatrics (AAP) guidelines call for more intensive surveillance and screening for this high-risk group of children, which provides an opportunity for earlier intervention and treatment. This study looked at whether a diagnosis of ASD that was made at 18 and 24 months of age in infants with a family risk for ASD remained the same at 36 months of age. It also explored the differences between children who were correctly and incorrectly diagnosed at 18 and 24 months.
The study involved the analysis of data contributed by seven sites in the Baby Siblings Research Consortium (BSRC)—an international network that gathers data from individually funded research sites to study the development of infants with a family risk for ASD. BSRC contributed data for 418 infants, all of whom had older biological siblings with ASD. Each site used standard diagnosis procedures to make the diagnosis of “ASD” or “Not ASD” at 18, 24, and 36 months for each of the infants. Statistical analyses found that when a child was diagnosed as having ASD at 18 months of age, 93% of the time that diagnosis was confirmed at 24 months and 36 months of age. Also, children who were first diagnosed as having ASD at 24 months (but not at 18 months) of age were confirmed to have ASD 82% of the time at 36 months of age. These high levels of stability indicate that when ASD is identified at 18 or 24 months, the diagnosis is not likely to change—and intervention should begin as soon as possible.
These findings support the AAP guidelines for more intensive surveillance for children at high risk for ASD and provide reassurance that early screening, assessment, and referral to services for these children is needed. The study authors also suggest that the AAP guidelines may need to go even further, because the results showed that rescreening children in high-risk groups (siblings of children with ASD and children with developmental delays) at 3 years of age will identify some children whose ASD symptoms were not apparent earlier. Some implications of this finding are that screening may need to be repeated many times in the first years of life, and beyond 24 months, and that follow-up should continue for children who show early signs of social and communication difficulties, even if they are not diagnosed with ASD when they are first assessed.
Early screening of autism spectrum disorder: recommendations for practice and research
Zwaigenbaum L, Bauman ML, Fein D, Pierce K, Buie T, Davis PA, Newschaffer C, Robins DL, Wetherby A, Choueiri R, Kasari C, Stone WL, Yirmiya N, Estes A, Hansen RL, McPartland JC, Natowicz MR, Carter A, Granpeesheh D, Mailloux Z, Smith Roley S, Wagner S. Pediatrics. 2015 Oct;136 Suppl 1:S41-59. [PMID: 26430169]
Early screening of children for ASD can be helpful to both children and their families because it enables earlier diagnosis and intervention. In 2009, the American Academy of Pediatrics (AAP) issued a recommendation that pediatricians routinely screen all children for ASD at 18 and 24 months of age using an appropriate screening tool. However, in many parts of the United States, physicians are not meeting this recommendation for ASD screening. It is believed that the debate over whether there is enough evidence to support the value of early screening for ASD of all children may be contributing to the slow uptake of the AAP recommendation into clinical practice. It was within this context that an international working group of clinical practitioners and researchers with expertise in ASD and developmental disabilities met in October 2010. Their aim was to conduct an updated review of the literature that would inform the development of their recommendations for ASD screening best practices, and to discuss ways to increase the adoption of widespread early screening. The group reviewed the evidence base represented by the scientific literature over time (through 2013) and reached agreement on recommendations that addressed the following question: “How can we optimize developmental course and outcomes through ASD screening programs for children aged <24 months?”
The group’s recommendations listed below focus on the usefulness of screening all children for ASD at 18 and 24 months of age and emphasize the importance of using the results of the screening to immediately refer children for evaluation if indicated, so that they may begin receiving intervention as soon as possible. Importantly, the findings indicate that an ASD diagnosis in children aged 24 months and older usually remains stable (unchanged) over time, and the group also identifies priorities for future research in ASD screening. The recommendations of the working group are as follows:
Statement 1: Evidence supports the usefulness of ASD-specific screening at 18 and 24 months. ASD screening before 24 months may be associated with higher false-positive rates than screening at .24 months but may still be informative.
Statement 2: The evidence indicates that siblings of children with ASD are at elevated risk for ASD and other developmental disorders and thus should receive intensified surveillance.
Statement 3: Children identified through ASD-specific screening should be immediately referred for diagnostic/developmental evaluation and appropriate intervention.
Statement 4: The long-term stability of ASD diagnosis in children aged <24 months is well established. Emerging datasuggest that ASD diagnoses in substantial proportions of children diagnosed before age 24 months are also stable, although further research is needed, particularly in the context of early screening.
Statement 5: Further attention to potential barriers to ASD-specific screening in the health care system is needed.
Statement 6: Methodologically rigorous research in ASD-specific screening should be a high priority.
Statement 7: Additional priorities for future research include studies that:
- Examine how broadband and ASD-specific tools can be used in a complementary fashion to maximize both sensitivity and specificity of early screening, perhaps in the context of multistage screening, in which a wide net is cast initially and false-positives are winnowed out in successive assessments;
- Evaluate screening strategies by using randomized experimental designs;
- Consider additional outcome metrics for screening: potential financial savings to society; unintended effects (e.g., family stress);
- Examine whether computer technology can improve screening accuracy;
- Examine the effectiveness of repeating screening for ASD;
- Evaluate how belief systems affect screening uptake and outcomes; and
- Examine potential screening strategies that include measurement of biomarkers.
Early identification of autism spectrum disorder: recommendations for practice and research
Zwaigenbaum L, Bauman ML, Stone WL, Yirmiya N, Estes A, Hansen RL, McPartland JC, Natowicz MR, Choueiri R, Fein D, Kasari C, Pierce K, Buie T, Carter A, Davis PA, Granpeesheh D, Mailloux Z, Newschaffer C, Robins D, Roley SS, Wagner S, Wetherby A. Pediatrics. 2015 Oct;136 Suppl 1:S10-40. [PMID: 26430168]
Identifying children with ASD early helps to ensure that they receive treatment earlier, which leads to better long-term outcomes. It also would help reduce the average age of ASD diagnosis in the United States of 4 to 5 years, which seems to persist even though parents generally report their first concerns before their child is 18 to 24 months old. To address these concerns, an international panel of clinical practitioners and researchers met to complete an updated literature review on the advances that have been made in understanding the early development and identification of ASD in recent years. The group reached agreement on the development of recommendations based on current evidence gathered through an extensive review of the literature that addressed the following question: “What are the earliest signs and symptoms of ASD in children 24 months and younger that can be used for early identification?”
The recommendations presented below were designed to help guide clinicians and researchers in their work related to the early identification of ASD. They include a focus on the wide range of clinical characteristics seen in ASD; on the availability of evidence about behavioral risk markers, or indicators, of ASD at different ages; on the need for caution when drawing conclusions about early risk markers of ASD from certain studies; and on being cautious when generalizing findings from studies of high-risk infants. They also emphasize the importance of including diverse samples in research about these early markers and provide direction for future efforts.
The recommendations of the panel were as follows:
Statement 1: Evidence indicates substantial heterogeneity in the presentation and natural history of clinical features associated with ASDs. This heterogeneity has ramifications for the interpretation of research literature as well as for clinical practice.
Statement 2: There is evidence that reduced levels of social attention and social communication, as well as increased repetitive behavior with objects, are early markers of ASD between 12 and 24 months of age. Additional potential markers include abnormal body movements and temperament dysregulation.
Statement 3: Reliable behavioral markers for ASD in children aged <12 months have not yet been consistently identified.
Statement 4: Developmental trajectories may also serve as risk indicators of ASD.
Statement 5: Caution should be exercised in drawing conclusions about early risk markers of ASD from studies that do not include individual-level outcome data.
Statement 6: Caution should be exercised in generalizing findings from studies of high-risk infants.
Statement 7: Research about early markers of ASD should include diverse high- and low-risk samples.
Statement 8: Future efforts should aim to identify: 1) early markers that can be measured in routine clinical practice, involving direct observation and parental report; 2) early biological processes measurable concurrently with, or before, overt behavioral markers; and 3) combined approaches.