**1. Introduction**

A steady increase in the prevalence of autism across the globe and growing demands for service and support have drawn increasing attention from policy makers, researchers, and practitioners in the field of health care, mental health care, and disability services. A recent systematic review, synthesizing 99 estimates from 71 studies of the prevalence of autism spectrum disorder (ASD) worldwide, suggests that approximately 1% of children are diagnosed with ASD around the world and that the prevalence data in 2012 and 2021 are not much different from a global point of view [1]. However, there are a number of countries (e.g., Australia, France, Korea, and the USA) reporting a noticeable ascending trend of autism prevalence. For instance, in the USA, the prevalence of autism has been rising, and it is rising very rapidly according to the CDC. When the CDC started systemic screening in

2000, the ratio of 8-year-old children with ASD was about 1:166, and it has increased fourfold to 1:44 as of 2020 [2]. In response to the increasing autistic population and huge demands for high-quality service and support, there have been intensifying efforts in researching and developing effective intervention approaches for supporting autistic individuals to improve specific outcomes such as social communication and interaction skills and enhance holistic outcomes like quality of life. Over the last several decades, a wide array of psycho-educational interventions has been developed and researched, leading to the need for a systematic way of determining which of these interventions are most effective for autistic individuals. As such, the field has identified its own methods for identifying what we know as evidence-based practices (EBPs), which are seen as the "gold standard" in the field of autism intervention.

In this chapter, we will discuss current EBPs in the autism intervention literature. We begin with an introduction of the most commonly identified EBPs and a brief summary of some major methodological and ethical concerns of these psych-educational approaches. In the pursuit of potential remedies for addressing these issues and concerns, we introduce Naturalistic Developmental Behavioral Interventions (NDBIs; [3]), as a highly regarded intervention model with a strong evidence base, and potential value-based and culturally adapted evidence-based practices that can help address some of the underlying methodological and ethical concerns in autism interventions and support. We will then delineate both promises and limitations of NDBIs. Lastly, we evaluate the areas in which NDBIs need to be further improved, as well as implications for clinical practice and future research.

#### **2. Evidence-based practices in autism interventions and support**

There is a plethora of research on autism interventions that have been conducted in the last five decades. This research has sought to answer a critical question: how do we effectively support autistic individuals and their families? As a result of this research, the field has been able to identify a set of interventions that have proven to be effective and demonstrated positive outcomes for autistic individuals. The field knows these as evidence-based practices (EBPs). Currently, there are two main groups that have evaluated the extensive literature to determine which interventions and intervention packages qualify as evidence-based practice—the National Standards Project [4] and National Professional Development Center (NPDC) on autism spectrum disorders. Through a thorough literature review, NSP has identified 14 established evidence-based practices and 18 with emerging evidence [4]. The NPDC identified 27 evidence-based practices [5]. Most of these identified EBPs are based on behavioral principles.

Based on the NPDC standards, in order to meet the criteria as an evidence-based practice, there must be positive evidence to support the intervention strategy with at least two high-quality experimental or quasi-experimental group design studies that have been conducted by two different researchers or research groups, or at least five high-quality single-subject design studies conducted by at least three different researchers or research groups, totaling at least 20 participants. A practice could also meet this standard if there is one high-quality randomized or quasi-experimental group design study and a minimum of three high-quality single-subject design studies conducted by at least three different researchers or research groups across all studies [5]. The NSP standards for established evidence-based practices are similar and require either two group designs or four single-subject design studies that have

*Naturalistic Developmental Behavioral Interventions as Value-Based and Culturally Adapted… DOI: http://dx.doi.org/10.5772/intechopen.108124*

a minimum of 12 participants with no conflicting results or a minimum of three group designs of six single-subject designs with a minimum of 18 participants, with no fewer than 10% of studies having conflicting results. Additionally, the NSP has a scoring system for ensuring these studies are of high quality [4].

Even with these standards, there have been criticisms of evidence-based practices used with autistic children from both methodological and ethical perspectives (e.g. [6]). These issues identified are not only with the literature base, but also with the practical implications of the use of EBPs in clinical settings. In terms of methodological issues, there have been concerns with both the quality of the review methods for determining the evidence-based interventions for autistic children, as well as issues with the quality of individual study designs and protocols. Specifically, Sandbank et al. [7] identified three major concerns with the reviews of the National Standards Project (NSP) and National Professional Development Center (NPDC) on Autism Spectrum Disorders: the attempt to blend evidence from different research design methodologies (single-subject and group designs) though there is no agreed upon way of doing so, limited information about the extent of intervention effectiveness and for which populations, and the lack of summarizing the effects of any given intervention. In addition to these clear issues with synthesizing the literature on autism interventions, there has been a multitude of common methodological issues that are seen across individual studies. Specifically, critics have expressed concerns over the strong focus on single-subject design versus group design and randomized controlled trials (RCTs) as well as the focus on short-term outcomes, with little attention paid to long-term effects [8]. On a similar note, an additional concern is that there is a lack of focus on adverse outcomes in the literature on autism interventions [9, 10]. Finally, there are concerns about who is conducting the research. This comes with the lack of autistic involvement in autism research, the lack of research on autistic input on evidence-based practices, and the limited social validation measures used in the autism intervention literature [11–13]. Moreover, researchers and research groups who are conducting this intervention literature often fail to identify any potential conflicts of interest (COI), though they are often relevant, calling into question the potential for bias within these studies [14].

Even more concerning than the methodological shortcomings are the ethical concerns that have been voiced by autistic self-advocates in recent years. We have identified a number of ethical concerns that have been brought up regarding the implementation of commonly used evidence-based practices for autistic children. Chief among these concerns are: the unethical history of behavioral intervention, the focus on normalization of autistic recipients, and the emphasis on compliance (a more detailed discussion is provided in a later section regarding limitations of Naturalistic Developmental Behavioral Interventions).

#### **2.1 Naturalistic developmental behavioral interventions**

One example of a manualized EBP approach for autistic children is Naturalistic Developmental Behavioral Interventions (NDBIs; [3, 15]). NDBIs are a set of intervention models that combine behavioral principles with insights from developmental psychology. Intervention models considered as NDBIs include pivotal response treatment (PRT; [16]), Early Start Denver Model (ESDM; [17–19]), Project ImPACT [20], incidental teaching (IT; [21]), enhanced milieu teaching (EMT; [22]), and Joint Attention Symbolic Play Engagement and Regulation (JASPER; [23]). All NDBIs emphasize child-centered learning focused on meeting the child where they are and

using their interests to improve their motivation to learn [3]. NDBIs have built a large evidence base of both single-subject studies and randomized controlled trials, though methodological issues such as publication and detection bias and reliance on parent report measures [7, 24] weaken the evidence base. Nonetheless, a recent meta-analysis still found that NDBIs had the most promising evidence base compared to other interventions for autistic children [7].

Implementation of NDBIs should occur in natural environments, throughout the child's daily routines, at home, or at school. They were originally in part created to combat some of the issues clinicians saw with more typical, structured ABA, such as lack of motivation and generalization [25]. As such, all NDBIs share common components such as following the child's lead, shared control, natural reinforcement, and reinforcing non-perfect attempts. For example, if a child loves cars, playing with toy cars might be used to teach words such as "car," "go," or "fast." The child's interest in cars would thus motivate them to practice such words in a fun, enjoyable environment. It is also important in NDBI implementation to have shared control between children and adults, as opposed to more structured ABA, where the clinician usually directs interactions and has control over the materials [26]. This shared control gives the child agency but also allows the adult the chance to create learning opportunities (for example by holding out the car and asking the child, "what color is this?"). Natural reinforcement is also a hallmark of NDBIs. Natural reinforcement differs from external reinforcement in that the reinforcement is the *natural* consequence of whatever the child just did. For example, if the child wants to play with a car and says, "car," or answers the question about the color of the car, the adult contingently reinforces them with the car (*not* with candy, a sticker, or a token). Lastly, NDBIs encourage clinicians to reinforce *attempts*, as opposed to pushing for fully correct responses. For instance, a child might approximate the word car by saying "cah" or they might say a car is "pink" when it is actually red. By reinforcing these non-perfect attempts, children learn that it is the effort that matters to the adults in their lives.
