Lonnie Zwaigenbaum1,2, Eric Duku3, Eric Fombonne4, Peter Szatmari5,6, Isabel M Smith7,8, Susan E Bryson7,8, Pat Mirenda9, Tracy Vaillancourt10, Joanne Volden11, Stelios Georgiades3, Wendy Roberts12, Teresa Bennett3, Mayada Elsabbagh13, Charlotte Waddell14, Mandy Steiman15, Rebecca Simon15, Ruth Bruno15. 1. Department of Pediatrics, University of Alberta, Edmonton, Alberta. 2. Pediatric Division, Glenrose Rehabilitation Hospital, Edmonton, Alberta. 3. Offord Centre for Child Studies and McMaster Autism Research Team, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario. 4. Departments of Psychiatry, Pediatrics and Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon, USA. 5. Department of Psychiatry, University of Toronto, Toronto, Ontario. 6. Department of Psychiatry, Hospital for Sick Children and Centre for Addiction and Mental Health, Toronto, Ontario. 7. Autism Research Centre, IWK Health Centre, Halifax, Nova Scotia. 8. Departments of Pediatrics, Psychology and Neurosciences, Dalhousie University, Halifax, Nova Scotia. 9. Departments of Educational and Counselling Psychology and Special Education, University of British Columbia, Vancouver, British Columbia. 10. Counselling Psychology, Faculty of Education, University of Ottawa, Ottawa, Ontario. 11. Department of Communication Sciences and Disorders, University of Alberta, Edmonton, Alberta. 12. Integrated Services for Autism and Neurodevelopmental Disorders, Toronto, Ontario. 13. Montreal Neurological Institute, McGill University, Montreal, Quebec. 14. Faculty of Health Sciences, Children's Health Policy Centre, Simon Fraser University, Vancouver, British Columbia. 15. Department of Psychiatry, McGill University, Montreal, Quebec.
Abstract
BACKGROUND: Early diagnosis of autism spectrum disorder (ASD) is essential in most Canadian jurisdictions to access interventions that improve long-term child outcomes. Our main objective was to identify factors associated with timing of ASD diagnosis in five provinces across Canada. METHODS: Factors influencing age of diagnosis were assessed in the analyses of an inception cohort of children diagnosed with ASD between ages 2 and 5 years. We examined bivariate associations and using a series of multiple variable regression models, evaluated the unique contributions of developmental functioning, ASD symptoms and demographic variables. Children with known genetic abnormalities, or severe sensory or motor impairments interfering with assessment were excluded. RESULTS: Participants were 421 children (84.6% boys). The mean age of diagnosis was 38.2 months (SD=8.7), an average of 19 months after parents identified initial concerns. Factors associated with later diagnosis included more advanced language and cognitive skills, and higher levels of restricted repetitive behaviour symptoms. Child sex and family demographics were not associated with age of diagnosis. In regression analyses, language and cognitive skills accounted for 6.8% of variance in age of diagnosis and ASD symptoms contributed an additional 5.5%. Provincial site accounted for 4.0% of variance in age of diagnosis, independent of developmental skills and ASD symptoms. INTERPRETATION: Diagnosis of ASD occurred, on average, 19 months after parents' initial concerns. Language and cognitive skills, symptom severity and provincial site accounted for variation in age of ASD diagnosis in this Canadian cohort. Variable presentation across the developmental continuum must be considered in planning assessment services to ensure timely ASD diagnosis so that outcomes can be improved. Policy and practice leadership is also needed to reduce interprovincial variability.
BACKGROUND: Early diagnosis of autism spectrum disorder (ASD) is essential in most Canadian jurisdictions to access interventions that improve long-term child outcomes. Our main objective was to identify factors associated with timing of ASD diagnosis in five provinces across Canada. METHODS: Factors influencing age of diagnosis were assessed in the analyses of an inception cohort of children diagnosed with ASD between ages 2 and 5 years. We examined bivariate associations and using a series of multiple variable regression models, evaluated the unique contributions of developmental functioning, ASD symptoms and demographic variables. Children with known genetic abnormalities, or severe sensory or motor impairments interfering with assessment were excluded. RESULTS: Participants were 421 children (84.6% boys). The mean age of diagnosis was 38.2 months (SD=8.7), an average of 19 months after parents identified initial concerns. Factors associated with later diagnosis included more advanced language and cognitive skills, and higher levels of restricted repetitive behaviour symptoms. Child sex and family demographics were not associated with age of diagnosis. In regression analyses, language and cognitive skills accounted for 6.8% of variance in age of diagnosis and ASD symptoms contributed an additional 5.5%. Provincial site accounted for 4.0% of variance in age of diagnosis, independent of developmental skills and ASD symptoms. INTERPRETATION: Diagnosis of ASD occurred, on average, 19 months after parents' initial concerns. Language and cognitive skills, symptom severity and provincial site accounted for variation in age of ASD diagnosis in this Canadian cohort. Variable presentation across the developmental continuum must be considered in planning assessment services to ensure timely ASD diagnosis so that outcomes can be improved. Policy and practice leadership is also needed to reduce interprovincial variability.
Entities:
Keywords:
autism spectrum disorder; cognitive development; early diagnosis; language development
Authors: Isabel M Smith; Charlotte Waddell; Wendy J Ungar; Jeffrey den Otter; Patricia Murray; Francine Vezina; Barbara D'Entremont; Helen E Flanagan; Nancy Garon Journal: Paediatr Child Health Date: 2020-09-20 Impact factor: 2.253
Authors: Mark Rodgers; David Marshall; Mark Simmonds; Ann Le Couteur; Mousumi Biswas; Kath Wright; Dheeraj Rai; Stephen Palmer; Lesley Stewart; Robert Hodgson Journal: Health Technol Assess Date: 2020-07 Impact factor: 4.014