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Summary of Advances Cover 2010

Summary of Advances

In Autism Spectrum Disorder Research


Question 1: Diagnosis - When Should I Be Concerned?

Implementing developmental screening and referrals: lessons learned from a national project.
King TM, Tandon SD, Macias MM, Healy JA, Duncan PM, Swigonski NL, Skipper SM, Lipkin PH. Pediatrics. 2010 Feb;125(2):350-60.

In 2006, the American Academy of Pediatrics (AAP) issued guidelines on developmental surveillance and screening that included the recommendation that all children be screened for developmental delays at 9, 18, and 24 or 30 months of age. In addition, children who were identified as being at risk should be referred for a detailed evaluation by a specialist and enrolled in early intervention services. In an effort to improve the adoption of their guidelines, the AAP simultaneously launched a project to assess how well the guidelines were being implemented in 17 diverse clinical settings. The study found that while most pediatricians conducted the regular developmental screenings recommended by the AAP, there could be significant improvement in the issuing and tracking of referrals for children who fail screens. Based on patient records from the monitored sites, the practices were successful in screening over 85 percent of patients who returned for appointments at the recommended ages. In phone interviews, individuals working at the practices reported that the high rate of screening was accomplished by delegating responsibilities among staff and actively monitoring whether screens had taken place. However, several sites had difficulty consistently screening children during busy periods or after periods of staff turnover. Many practices also had difficulty issuing and tracking referrals for children who were deemed to be at risk for developmental delays – 39 percent of children who failed screens never received the recommended referrals to a specialist and an early intervention program. When tracking did take place, the clinicians found that many parents had not followed through with the referrals. Based on the project, the authors conclude that more focus should be placed on the referral process and communicating with families about the reasons for the referrals.

Consensus statement: Chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies.
Miller DT, Adam MP, Aradhya S, Biesecker LG, Brothman AR, Carter NP, Church DM, Crolla JA, Eichler EE, Epstein CJ, Faucett WA, Feuk L, Friedman JM, Hamosh A, Jackson L, Kaminsky EB, Kok K, Krantz ID, Kuhn RM, Lee C, Ostell JM, Rosenberg C, Scherer SW, Spinner NB, Stavropoulos DJ, Tepperberg JH, Thorland EC, Vermeesch JR, Waggoner DJ, Watson MS, Martin CL, Ledbetter DH. Am J Hum Genet. 2010 May 14;86(5):749-64.

An international consortium of geneticists recommended that chromosomal microarray assessment (CMA) be used as the standard genetic test for diagnosing people with unexplained developmental or intellectual delay, autism spectrum disorders, or birth defects. Previously, a test developed in the 1970s called G-banded karyotyping was the standard assessment used, but a literature review conducted by the consortium showed that CMA has greater sensitivity, resulting in a greater likelihood of diagnosis (3% diagnosis rate using G-banded karyotyping compared to 15 – 20% using CMA). This is primarily because CMA has greater sensitivity for submicroscopic deletions and insertions of DNA known as copy number variations. Researchers were able to develop CMA after the Human Genome Project was completed in 2000, and it has become a commonly ordered test for patients with developmental concerns. However, formal best practice guidelines had yet to be issued recommending CMA as a first-tier diagnostic test. The consortium concluded that CMA should be used in place of G-banded karyotyping as the genetic test for patients with unexplained developmental or intellectual delay, autism spectrum disorder, or birth defects. G-banded karyotyping should only be used by those who have obvious chromosomal syndromes such as Down syndrome, a family history of chromosomal rearrangement, or a history of multiple miscarriages.

Automated vocal analysis of naturalistic recordings from children with autism, language delay, and typical development.
Oller DK, Niyogi P, Gray S, Richards JA, Gilkerson J, Xu D, Yapanel U, Warren SF. Proc Natl Acad Sci U S A. 2010 Jul 27;107(30):13354-9.

Researchers have developed technology assessing patterns of vocalization that can distinguish children with ASD from others with a relatively high degree of accuracy. Using a lightweight recording device clipped to clothing, researchers captured 1,486 day-long recordings from children diagnosed with ASD, language delay, and those who were developing typically. The children in the study ranged from 10 months to 4 years of age. Investigators created a program that analyzes patterns of speech (or the cooing and babbling that precedes speech) and is able to distinguish children with ASD from their typically developing peers with 86 percent accuracy. Of those with developmental disorders, children with ASD were reliably distinguished from children with language delay with 70 percent accuracy. Vocalizations were assessed using 12 separate parameters but investigators found that the most important factor for identification was the child's ability to produce clear syllables through quick movements of the jaw and tongue. The authors discuss the potential for using automated analysis as a convenient and objective addition to diagnostic tests for ASD and language delay. Ultimately, vocal analysis could help to decrease the average age of diagnosis for children with ASD (reported to be about 4½ to 5½ years of age in the United States), allowing children to start interventions earlier. Future efforts will focus on fine-tuning the technology to better differentiate between different subgroups of language disorders.

A prospective study of the emergence of early behavioral signs of autism. Ozonoff S, Iosif AM, Baguio F, Cook IC, Hill MM, Hutman T, Rogers SJ, Rozga A, Sangha S, Sigman M, Steinfeld MB, Young GS. J Am Acad Child Adolesc Psychiatry. 2010 Mar;49(3):256-66.e1-2.

The study found that children with ASD generally do not show signs of the disorder at six months of age but that a plateauing or loss of social skills is evident by the time they reach their first birthday. The finding suggests that behavioral symptoms of autism are not present at birth as hypothesized by the man who first identified ASD, Dr. Leo Kanner, but instead emerge after six months of age in most instances. The authors of the study note that there may be some cases where behavioral signs of ASD are present at six months of age or earlier but that this pattern of onset is probably less common than originally thought. The researchers reached these conclusions by comparing the social behavior of 25 infants who were ultimately diagnosed with ASD to that of 25 typically developing infants. Researchers observed the children at 6, 12, 18, 24, and 36 months of age and coded the frequency of specific types of social communication behavior (e.g., gazing at faces, social smiling, vocalizations directed at a listener, etc.). The children showed no difference in social behavior at 6 months of age but by 12 months, the majority of children with ASD had failed to gain new social skills or had lost previously acquired ones. Notably, the majority of children with ASD showed a gradual loss of specific social skills, particularly between 6 and 18 months of age. However, this subtle regression in development went unnoticed by most parents. This demonstrates a critical flaw in retrospective studies of onset using parent report. The authors note that the traditional models of autism (early onset of symptoms or dramatic regression after typical development) may not adequately portray how ASD emerges and suggest that additional models may need to be developed. Alternately, the onset of symptoms may be better represented by a continuum based on the amount and timing of regression.

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