Autism spectrum disorder: advances in evidence-based practice

• Published in: Canadian Medical Association journal (CMAJ) Vol. 186; no. 7; pp. 509 - 519
• Main Authors: Anagnostou, Evdokia, Zwaigenbaum, Lonnie, Szatmari, Peter, Fombonne, Eric, Fernandez, Bridget A., Woodbury-Smith, Marc, Brian, Jessica, Bryson, Susan, Smith, Isabel M., Drmic, Irene, Buchanan, Janet A., Roberts, Wendy, Scherer, Stephen W.
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Inc 15.04.2014; Joule Inc; CMA Impact Inc; CMA Impact, Inc; Canadian Medical Association
• Subjects: Autism; Care and treatment; Child Development Disorders, Pervasive - diagnosis; Child Development Disorders, Pervasive - genetics; Development and progression; Diagnosis; Diagnosis, Differential; Evidence-based medicine; Evidence-Based Practice - methods; Genetic Testing - methods; Humans; Infant; Magnetic Resonance Imaging; Male; Medical diagnosis; Medical treatment; Pediatrics; Pervasive developmental disorders; Review; Systematic review; Canada
• ISSN: 0820-3946; 1488-2329; 1488-2329
• DOI: 10.1503/cmaj.121756

Autism spectrum disorder (ASD) en- compasses wide variation in symptom severity and functional impact. The core features of ASD include impairments in social communication, repetitive behaviours and restricted interests. Not all people with ASD identify their challenges as a disorder. Autism spectrum disorder affects more than 1% of the population,1 and a dramatic increase in its recognition is creating huge demands on health care systems for timely and accurate diagnosis. Health care professionals in many capacities encounter people and their families coping with ASD, and optimal care depends on a large net- work of providers, given the breadth of the associated medical issues. The Autism and Developmental Disabilities Monitoring Network of the US Centers for Dis- ease Control has surveyed ASD among eight- year-olds from up to 14 US centres every two years since 2000. The most recent analysis, which pertains to the 2008 surveillance year,1 estimates the overall prevalence to be 1 in 88 children - almost double the prevalence re- ported in the original cohort. These data cannot distin guish betwe en an increase cause d b y changes in ascertainment and a true increase in prevalence. Global prevalence, as reported in a comprehensive survey of epidemiological reports from 1966 to 2011,2 suggests that autism is still under-recognized, particularly in developing countries. In Canada, a population prevalence of 1% implies that about 67 000 children, aged 3- 20 years have ASD. Boys with ASD outnumber girls by as much as 4:1, but the underlying rea- sons for this difference remain elusive.3 The diagnostic assessment of ASD allows a physician to determine if a child meets the accepted ASD criteria (usually per Diagnostic and Statistical Manual of Mental Disorders [DSM] criteria), identify comorbid medical or genetic syndromes or psychopathology, and identify the patient's treatment needs. Figure 1 shows the typical paths to diagnosis, starting with concerns (including "red flags") raised by parents, teachers, childcare providers, early childhood educators, family physicians or pedia- tricians. Primary care providers then determine whether an assessment is needed for ASD or another developmental issue. A detailed develop- mental history is collected from the parents, and additional information is collected from teachers, early childhood educators and health profession- als. It is essential for the primary care provider to spend time with the child engaged in structured play activities that assess social-emotional relat- edness, the ability of the child to respond to and direct the attention of others, and his or her use of gestures, imitation, imagination and conversa- tion. Multiple prospective and retrospective stud- ies support the recommendations of comprehen- sive reviews and guidelines on diagnosis.18,19