Early Intervention Charts as a Resource for Autism Surveillance and Research in the US

Autism and autism spectrum disorders (ASDs) have become a focus of strong interest in many different sectors because of the striking rise in incidence and prevalence rates during the past decade. Two reports from late 2009 placed the prevalence at approximately 1 % of children.^1,2 These high rates are disturbing because of the relative severity of this developmental disability. As the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR) nomenclature reflects, the pervasive developmental disorders affect nearly all systems of learning and development – including the triad of social interaction, communication and repetitive behaviours symptom domains³ – and present along a continuum of severity. Intellectual disability and/or mental retardation frequently co-occur and thus individuals require a high level of life-long support. Even without intellectual disability and with relatively mild symptoms, support needs remain high for learning, social and behavioural adjustment, and transition to higher education and the workplace. Therefore, concerns arise owing to the potential long-term impact upon children and families, as well as the significant long-term costs for early intervention (EI), educational, healthcare and social support systems.

It is important to establish valid and reliable strategies for ascertaining prevalence rates of ASD for surveillance purposes, from both public health planning and research perspectives.^4,5 There has in fact been a surge in epidemiological research, in an attempt to document rising rates and understand their origins from a research perspective, as well as to establish efficient and relatively low-cost surveillance strategies to address public health goals. The growing number of prevalence studies enables a broad examination of the interplay between methodological choices and incidence and prevalence outcomes.^6–9

In this article, we describe the potential use, in the US, of EI charts, which are widely available, as a cost-effective resource for ASD surveillance. The EI system has been operational in the US since the early to mid-1990s. Although there is variability in some features of EI programmes according to location, federal law has driven practice, creating a high degree of consistency in administration and applications across US states. Many central features of the EI programmes create opportunity for:

• population sampling;
• case ascertainment;
• tracking the course of the condition as children age; and
• monitoring treatment and/or intervention effects.

The first two issues, sampling and case ascertainment, are interrelated in that methods for each ideally maximise the likelihood that as many cases as possible are counted in the sample or catchment area. Relatively exhaustive sampling is accomplished more easily in countries where public health policies ensure that all children are seen for well-child visits at specific ages.^10,11 Similarly, many countries with a socialised medicine model have a combination of public-access healthcare and registries specifically for birth conditions and disabilities.^9,12,13

By contrast, in the US, where developmental screening is not universal and condition-specific registries are not widely used, case finding can be labour-intensive and inefficient; many different agencies need to be consulted and voluntary cooperation is required from administrators, practitioners and families.

The US federal mandate for a ‘single point of entry’ for families into the EI programme has arguably created a quasi-registry. The particular agency that is the ‘lead agency’ for first referral and programme administration varies, but, nonetheless, referrals and records are concentrated in one location. In addition, several related features of the EI system are intended to ensure that as many qualified children as possible are enrolled into the EI programme; this helps to ‘capture’ as many cases as possible for surveillance purposes. First, the law allows for self-referral; in other words, families can access EI evaluations and services without referral from a physician or other party, which removes one important access barrier. Second, the EI programmes are mandated with ‘child find’ as well as providing evaluation and intervention services; in other words, they are obligated to locate as many children as possible who qualify to receive services. Finally, the EI services are free or of low cost to the family and, in many areas, the services are extensive and high quality, further encouraging maximal use by all children with disabilities.