**3. History of EIBI**

The history of this early intervention approach to autism has been well documented over the last three decades. For example, Matson and Smith (2008) trace the origins of this ap‐ proach in autism treatment to what they refer to as a "seminal paper" (p.61) published as early as 1973 by Lovaas, Koegel, Simmons, and Long (1973). Matson and Smith argue that this paper demonstrated a visionary conceptual framework for early intervention with ASD.

*"The true significance of the study was the authors' efforts to formulate an overarching treatment of children with autism on a multitude of behaviours including self-stimulation/stereotypies, echolalia, appropriate verbal behaviour, social behaviour, appropri‐ ate play, intelligence quotient (IQ), and adaptive behaviour"* (Matson & Smith, 2008, pp. 61-62).

Trends in EIBI, to this day, are based on this original template involving the delivery of idio‐ syncratic treatment packages constituting evidence-based behavioural interventions to tar‐ get core symptoms as well as expansive groups of behaviours. Numerous studies have been published since this seminal paper in 1973 examining EIBI outcomes in autism. One of the most distinguished and considered published papers which resulted in the acclamation of EIBI involved that of Lovaas (1987). This well-reviewed study which reported an average difference of 31 points on IQ test scores between the ASD treatment group and control group, and classified nine of 19 (47%) participants as having achieved recovery (defined as post-intervention IQ in the normal range). To this current day, the findings of this study have caused much debate among researchers with criticisms focusing on particular meth‐ odological limitations (see for example, Gresham and MacMillan 1998; Short & Mesibov, 1989). We will return to this study in a later section.

To date, a substantial number of studies have been conducted and published to demonstrate the effectiveness of EIBI in autism treatment. Moreover, six illustrative review papers and one "mega-analysis" (a combination of all of the data into one single analysis) have been published (see below), each providing somewhat varying angles in exploring the outcomes. Steady growing rates of publications on the findings of EIBI in autism have been evidenced and concise descriptions of methodology have appeared to improve in most recent years, particularly with respect to the inclusion of control–no treatment groups and random as‐ signment of participants across experimental conditions.

The current chapter will provide a synopsis of EIBI studies published between 1987-2012. Systematic searches were conducted using the following databases: Scopus, Psychology & Behavioral Sciences Collection, and PsycINFO

The searches were carried out using the terms "early intensive behavioural intervention AND autism", and "intensive behavioural intervention AND autism". The inclusion criteria were largely in line with those of Reichow (2012). Studies were reviewed if they included a treatment group who received EIBI and an alternate-treatment control group who received either no treatment, a different treatment or EIBI provided at different intensity levels. Only studies including children with ASD were reviewed. Each study was required to involve original research that was written in English and published in a peer reviewed journal. In the interest of clarity we grouped published investigations under the following headings: Studies published before 2000 (4 studies), studies published from 2000-2010 (12 studies) and studies published between 2011-2012 (5 studies). We provide a summary of factors associat‐ ed with each published paper including intake characteristics of participants, outcome measures employed, specific treatment characteristics and group differences following inter‐ vention. The following sections provide a synopsis of all studies identified.
