Santhanam & Hewitt, 2015

Introduction to Evidence-Based Assessment in Autism Spectrum Disorders (ASD)

  • Authors: Siva Priya Santhanam & Lynne E. Hewitt

  • Institution: Department of Communication Sciences and Disorders, Bowling Green State University, Bowling Green, OH, USA

Abstract

  • Assessment of language and communication in individuals with Autism Spectrum Disorder (ASD) is fundamentally critical for developing and implementing effective interventions and supports. However, there is notably limited comprehensive guidance specifically for conducting communication assessments in individuals with ASD, prompting a crucial need for synthesizing existing research.

  • A systematic scoping review was conducted to identify relevant research articles published between 1995 and 2013. The search strategy employed specific keywords to ensure comprehensive coverage:

    • autism + language + assessment

    • autism + speech + assessment

    • autism + communication + assessment

  • Findings: The review synthesized current evidence, highlighting several key practices:

    • Formal norm- and criterion-referenced tests, even if not specifically designed or normed for ASD populations, can be judiciously and validly used when clinicians are aware of their limitations and interpret results cautiously in the context of ASD characteristics.

    • Language sample analysis (LSA) and structured observational assessments are highly recommended as they provide rich, authentic data, crucial for capturing an individual’s unique profile of strengths and challenges in naturalistic communication contexts.

    • Caregiver reports and interviews are invaluable sources of information, effectively supplementing direct testing by providing ecological validity and insights into daily communication patterns across various environments.

Overview of Autism Spectrum Disorder (ASD)

  • ASD is a complex neurodevelopmental disorder characterized by persistent deficits in social interaction and social communication, as well as restricted, repetitive patterns of behavior, interests, or activities. These characteristics manifest early in development and significantly impair daily functioning.

  • Prevalence: Data from the Centers for Disease Control and Prevention (CDC) in 2012 reported a prevalence rate of 1 in 68 children diagnosed with ASD. This figure has continued to evolve, emphasizing the growing recognition and impact of the disorder.

  • The increasing recognition and diagnosis rates of ASD underscore an urgent and escalating need for the development of highly effective and individualized diagnostic and intervention services.

  • Importance of Assessment: Comprehensive and valid assessments are foundational as they directly inform the design of targeted and effective intervention strategies, which are absolutely essential for improving developmental and functional outcomes for individuals with ASD across their lifespan.

  • Evidence-based practice (EBP) is a cornerstone of effective assessment and intervention. It integrates three essential components (ASHA, 2004):

    • The highest quality empirical evidence from research.

    • The clinical expertise, experience, and judgment of the speech-language pathologist.

    • The values, preferences, and unique circumstances of the client and their family.

Methodology of the Scoping Review

  • The primary aim of this scoping review was to systematically synthesize existing literature concerning evidence-based practices specifically in speech-language assessment for individuals across the autism spectrum. This comprehensive approach sought to map the extent, range, and nature of research activity in this critical area.

  • Literature Search: A thorough search was conducted across multiple prominent electronic databases to ensure broad coverage of the literature from 1995 to 2013:

    • EBSCOhost (including CINAHL Plus with Full Text, ERIC, Medline, PsycINFO)

    • ISI Web of Science

  • Study Selection Criteria: Articles were rigorously screened based on specific inclusion and exclusion criteria to ensure relevance and quality:

    • Inclusion: English language publications that directly addressed speech, language, or social communication assessment for individuals with ASD. Studies focusing on the assessment of theory of mind (the ability to attribute mental states to oneself and others) and general social skills were also included due to their integral role in communication.

    • Exclusion: Studies that focused strictly on the diagnosis or screening for ASD (e.g., studies evaluating diagnostic instruments like the ADOS or ADI-R) were excluded, as the review's focus was on post-diagnosis communication assessment.

  • Final Count: The rigorous selection process yielded a total of 54 relevant articles that met all criteria for inclusion in the review.

Results of the Review
1. Formal Testing

  • Several widely used formal, standardized tests demonstrated some degree of validity and utility in assessing various communication abilities within the ASD population. These tests often provide standardized scores that can track progress or identify areas of significant delay.

  • Noted tests frequently utilized and examined in the literature include:

    • Mullen Scales of Early Learning (MSEL): A comprehensive developmental assessment for children from birth to 68 months, measuring cognitive, motor, and language abilities.

    • Clinical Evaluation of Language Fundamentals (CELF): A widely used battery of tests for assessing receptive and expressive language skills in school-aged children and adolescents.

    • Receptive and Expressive One-Word Vocabulary Tests (ROWPVT, EOWPVT): Measures of receptive and expressive vocabulary knowledge, often used to assess semantic skills.

    • Peabody Picture Vocabulary Test (PPVT): A nonverbal, multiple-choice test designed to assess receptive vocabulary for standard American English in individuals from 2 years 6 months to 90+ years.

  • Concerns: A significant limitation is the lack of autism-specific normative data for many of these formal tests. This limits their ecological validity and interpretability for individuals with ASD, as performance norms are typically derived from neurotypical populations.

2. Parent-report Instruments

  • Parent-report instruments emerged as highly effective and valuable measures, leveraging caregivers' extensive knowledge of their child's communication behaviors across various settings.

  • Measures found to be effective: Two prominent instruments frequently cited for their reliability and validity include:

    • MacArthur–Bates Communicative Development Inventory (MB-CDI): This inventory, available in various age ranges, demonstrated reliability and validity across multiple studies, providing detailed information on early vocabulary and grammatical development, and communicative gestures.

    • Children’s Communication Checklist (CCC-2): Valid for screening and identifying communication deficits, particularly in pragmatic language, the CCC-2 offers insights into subtle difficulties in social communication that might be missed by direct testing.

3. Observational Assessments

  • The review provided strong support for the utility of observational assessments, emphasizing their ability to capture authentic communication behaviors in naturalistic or semi-structured contexts.

  • Support for observational assessments: Findings suggest that using structured observational protocols, such as those involving play-based interactions or specific social probes, can yield invaluable insights into an individual's communicative intents, engagement, and social reciprocity that formal tests may not capture.

  • Practical applications: These assessments are particularly useful for evaluating complex communication acts, including assessing narrative skills (e.g., coherence, story grammar) and the range and frequency of communicative intents (e.g., requesting, commenting).

4. Language Sample Analysis

  • Language Sample Analysis (LSA), especially when focused on narrative assessments, provides highly critical and nuanced insights into an individual's morphology, syntax, and pragmatics in spontaneous speech.

  • Common metrics utilized for language sampling include:

    • Mean length of utterance (MLU): A widely used measure of expressive language complexity, typically calculated by averaging the number of morphemes per utterance. A higher MLU often correlates with greater linguistic proficiency. (e.g., MLU = \frac{\text{Total number of morphemes}}{\text{Total number of utterances}}).

    • Index of Productive Syntax (IPSYN): A more refined measure that evaluates the range and complexity of grammatical forms used, providing a detailed profile of an individual's syntactic development.

Summary of Assessment Domains

  • The areas most frequently assessed in individuals with ASD, reflecting key challenges in the disorder, typically include:

    • Pragmatics and social communication skills, encompassing aspects like joint attention, turn-taking, topic maintenance, and understanding nonverbal cues.

    • Morphosyntax and vocabulary, analyzing grammatical structures, sentence complexity, and breadth of lexicon.

    • Receptive vs. expressive language skills, differentiating between understanding and producing language.

Challenges in Assessment of Communication in ASD

  • Diversity of Needs: Individuals with ASD present with highly heterogeneous profiles, encompassing a wide range of cognitive, linguistic, and social abilities. This diversity necessitates highly individualized and tailored assessment approaches, making a one-size-fits-all battery ineffective.

  • Lack of Normative Data: There is limited specific guidance and normative data concerning typical social and pragmatic language development trajectories across different ages within the ASD population. This deficit significantly exacerbates challenges in accurately identifying delays or atypical patterns, as comparisons to neurotypical norms may not always be appropriate.

  • Test Limitations: Many existing standardized tests do not adequately sample or account for the unique communication characteristics and behaviors often exhibited by individuals with ASD. This can lead to inaccurate results, either underestimating or overestimating abilities, thereby affecting the validity and clinical utility of these instruments for this population.

Ethical and Practical Implications

  • Inadequate or inappropriate assessment can have severe ethical and practical ramifications, potentially impeding individuals with ASD from accessing essential services and interventions. This highlights a critical need for the continued development and stringent validation of autism-specific assessment protocols.

  • The strategic use of dynamic assessments, which involve a test-teach-retest approach, can be particularly supportive for language acquisition and development, especially for nonverbal or minimally verbal children with ASD. These assessments focus on learning potential rather than just current performance.

Conclusion

  • Assessment methodologies in Autism Spectrum Disorder require a multifaceted and integrated approach, judiciously blending formal standardized testing, naturalistic observational methods, and invaluable caregiver reports. This comprehensive strategy provides a more holistic and accurate picture of an individual's communication profile.

  • While the literature indicates a growing consensus on several robust assessment practices, there remains a pressing need for further rigorous research dedicated to developing and refining even more powerful and robust assessment protocols. These protocols must be capable of accurately supporting individuals across the entire spectrum of ASD, accounting for their varied developmental trajectories and unique communication needs.

References (Selected)

  • Barbaro, J. & Dissanayake, C. (2012). Developmental profiles of infants and toddlers with autism spectrum disorders. Journal of Autism and Developmental Disorders.

  • Bruckner, C. et al. (2007). Validity of the MCDI-I receptive vocabulary scale. Journal of Speech, Language, and Hearing Research.

  • Doswell, J. et al. (2014). A scoping review of scoping reviews. Research Synthesis Methods, 5, 371-385.

  • Tager-Flusberg, H. et al. (2009). Recommended measures for evaluating spoken language development. Journal of Speech, Language, and Hearing Research.