The differential diagnosis of autism spectrum disorder in adults

INTRODUCTION

Diagnosing autism spectrum disorder (ASD) in adults is challenging due to its heterogeneity and symptom overlap with other conditions. Making an accurate diagnosis can be difficult and overwhelming but is vital for proper accommodations and interventions while avoiding unproductive or harmful treatments.

AREAS COVERED

The authors have based their review on a comprehensive literature search using PubMed, PsycINFO, and Google Scholar to identify relevant recommendations, diagnostic tools, and common differential diagnoses for adults with ASD. A clinical framework is provided based on the DSM-5 criteria, starting with an evaluation of childhood symptom onset and persistent manifestations of the core criteria - social and communication impairment, along with restricted, repetitive behaviors. Conditions with overlapping presentations, including personality disorders, anxiety, depression, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, and schizophrenia, are discussed, as well as challenges in differentiating these from ASD.

EXPERT OPINION

Many factors complicate diagnosing ASD in adults - such as skewed public perception or misinformation spread on social media. Existing tools frequently miss subtle or atypical presentations, particularly in underdiagnosed groups like women and older adults. Promising advances in machine learning and artificial intelligence will hopefully improve diagnostic precision in the future. Up-to-date clinician training and large-scale research remain paramount for refining adult ASD diagnosis.

Identification and support of autistic individuals within the UK Criminal Justice System: a practical approach based upon professional consensus with input from lived experience

BACKGROUND

Autism spectrum disorder (hereafter referred to as autism) is characterised by difficulties with (i) social communication, social interaction, and (ii) restricted and repetitive interests and behaviours. Estimates of autism prevalence within the criminal justice system (CJS) vary considerably, but there is evidence to suggest that the condition can be missed or misidentified within this population. Autism has implications for an individual's journey through the CJS, from police questioning and engagement in court proceedings through to risk assessment, formulation, therapeutic approaches, engagement with support services, and long-term social and legal outcomes.

METHODS

This consensus based on professional opinion with input from lived experience aims to provide general principles for consideration by United Kingdom (UK) CJS personnel when working with autistic individuals, focusing on autistic offenders and those suspected of offences. Principles may be transferable to countries beyond the UK. Multidisciplinary professionals and two service users were approached for their input to address the effective identification and support strategies for autistic individuals within the CJS.

RESULTS

The authors provide a consensus statement including recommendations on the general principles of effective identification, and support strategies for autistic individuals across different levels of the CJS.

CONCLUSION

Greater attention needs to be given to this population as they navigate the CJS.

Revising the Pragmatics Profile using a modified Delphi methodology to meet the assessment needs of current speech-language therapists

BACKGROUND

Non-standardized assessment tools are preferred when assessing communication of individuals with developmental disabilities. Currently, there are limited tools available for assessing this population. Informant report tools such as the Pragmatics Profile (PP) of Everyday Communication Skills are beneficial in gathering a representative view of an individual's communication. However, the PP is out of print and outdated, requiring revisions to meet contemporary assessment needs of speech-language therapists (SLTs).

AIMS

To seek consensus from an international panel regarding revising the Pragmatic Profile by (1) updating language and terminology, and (2) development of an online tool.

METHODS & PROCEDURES

A total of 13 experienced SLTs and researchers in the disability field participated in a modified Delphi study including an initial online meeting followed by an anonymous four-round survey. Participants reviewed the relevance and wording of questions in the original preschool, school-age and adult versions to create a single combined version of the PP. In each Delphi round, the level of consensus was calculated and qualitative comments were analysed using thematic analysis.

OUTCOMES & RESULTS

A revised online version of the PP was created including 64 questions. Qualitative analysis illuminated key concepts in the creation of a revised form including the need for plain and age-neutral language, which is inclusive of all communication modalities and physical impairments, and identifies behaviours that have the potential to be communicative acts. Using conditional logic, users are navigated to the appropriate questions based on the intentionality level of the individual rather than their age.

CONCLUSIONS & IMPLICATIONS

This study resulted in the revision of a valued assessment tool appropriate for current disability service provision that identifies communication along the continuum of intentionality rather than age.

WHAT THIS PAPER ADDS

What is already known on this subject Non-standardized tools are appropriate when assessing communication of individuals with developmental disabilities. However, there are limited published tools suitable for this population with several of them out of print, making it difficult to conduct a holistic assessment. What this study adds to the existing knowledge This study resulted in the creation of an online PP based on experts' opinion. The revised PP modified the primary focus of the tool from age- to skill-based whereby questions are targeted according to intentionality level. Revisions included plain language, and inclusion of all communication modalities and physical impairments via a series of prompts to ensure that the information provided by informants is accurate and relevant. What are the potential or actual clinical implications of this work? The revised PP adds to the toolkit of an SLT working with individuals with a developmental disability and allows for accurate reporting of functional communication. Guided by experts' opinion, the revised PP is likely to be highly valued in the increasingly technological world in which we live.

Screening for autism spectrum disorder in deaf adults with intellectual disability: Feasibility and accuracy of two autism screening instruments

BACKGROUND

There is a lack of autism screening instruments for deaf or hard of hearing (DHH) adults with intellectual disability.

AIMS

This study examined the diagnostic validity of the Pervasive Developmental Disorder in Mental Retardation Scale and the Diagnostic Behavioral Assessment for autism spectrum disorder - Revised in this rare population.

METHODS AND PARTICIPANTS

56 DHH adults with intellectual disability living in three specialized therapeutic communities were examined, 9 of whom met criteria for autism.

OUTCOMES AND RESULTS

With minimal adaptions regarding item interpretation, both tools showed good diagnostic and high convergent validity. Items probing for difficulties in reciprocal social interaction and restricted interests were discriminant between individuals with and without autism.

CONCLUSION

These data suggest that both autism screening tools are feasible and psychometrically sound when used with appropriate adaptations for DHH adults with intellectual disability.

Usefulness of current autism diagnostic or screening assessment tools in adults with intellectual disability (ID): systematic review of literature

Purpose

The purpose of the study is to identify and ascertain if there were any validated tools for diagnosing or screening autism spectrum disorder in adults with ID. The estimated prevalence of intellectual disability (ID) in the general population is about 10.37/1,000 population (Maulik et al., 2011). In total, 1 out of 4 individuals with ID suffers from an autism spectrum disorder (ASD) (Sappok et al., 2010). Early diagnosis and support for ASD is key to having a good quality of life. The diagnosis of ASD in people with an ID presents its own challenges and it is likely under-identification of ASD amongst adults with ID by about 20% to 30% (Emerson and Baines, 2010).

Design/methodology/approach

Studies were selected based on the following criteria: studies that reported either screening or diagnostic tools for ASD, participants had an ID i.e. a mean IQ of <70, adults i.e. participants were >18 years of age at the time of entry to the study and articles reported either sensitivity, specificity or area under the curve. Relevant studies that were published up to January 2020 were identified from EMBASE, PsychINFO, CINAHL and PubMed. In total, 75 papers were identified of which 15 papers met the criteria.

Findings

The screening or diagnostic tools currently in use is dependant on the degree of ID. A number of the tools had good psychometric properties and utility when used in people with specific degrees of ID or when used in combination with another screening or diagnostic tool. The authors could not identify a diagnostic tool that could be used across all levels of severity of ID unless used in combination. Hence, concluded that there is a need for a diagnostic tool with good psychometric properties for the assessment of ASD in adults with all degree of ID within a reasonable time period without the need for an additional tool to be used in conjunction.

Originality/value

Currently, the “gold standard” for diagnosing ASD is a lengthy and time-consuming process carried out by trained multi-disciplinary team members who assess historical, behavioural and parent/carer report to arrive at a diagnosis. There are a number of tools that have been developed to aid diagnosis. However, it is important to identify the tools that can optimise the procedures and are also time-efficient.

Development of a Social Communication Questionnaire (QSC-ID) for People With Intellectual Disability in a Deaf Sample: A Pilot and Feasibility Study

Background: Social communication (SC) includes the use and interpretation of verbal and non-verbal messages within a social context and thus requires more than knowledge of language. Social communication skills are essential for connecting and engaging with others, and SC deficits are often associated with emotional and behavioral problems. There is a lack of feasible instruments for assessing SC skills in individuals with intellectual disability (ID). Methods: A questionnaire on social communication in adults with ID (QSC-ID) comprising 20 Likert-scaled items was developed and completed on behalf of participants (n = 52) from three Austrian therapeutic living communities for people with ID and deafness by their living- and working-facility key caregivers. The sample of adults with hearing loss was considered ideal for the development of a measure of SC that is not restricted to a specific communication mode or overly related with language skills. Results: The preliminary results showed high construct validity. Correlations were high between SC and language, social skills, and severity of autism spectrum disorder (ASD), moderate between SC and adaptive skills, and non-verbal intelligence and, as expected, low between SC and motor skills. Interrater reliability was found to be good or at least acceptable for all items. Total raw scores were well-distributed over the whole range-Cut-offs based on the 10th and 20th percentile are suggested to identify atypical and borderline SC skills. Caregiver feedback and completeness of data suggest that the questionnaire is highly feasible. Conclusion: Questionnaire on social communication in adults with ID is an easy-to-use caregiver-reported questionnaire for use with individuals with mild to severe forms of ID. Initial testing of validity looks promising. Further validation in populations with typical hearing is required. Due to substantial correlations between SC and structural language skills the calculation of specific SC cut-offs for different levels of linguistic skills should be considered when sufficient data is available.

Improving the Diagnosis of Autism Spectrum Disorder in Fragile X Syndrome by Adapting the Social Communication Questionnaire and the Social Responsiveness Scale-2

We carried out a psychometric assessment of the Social Communication Questionnaire (SCQ) and the Social Responsiveness Scale (SRS-2) in fragile X syndrome (FXS), relative to clinician DSM5-based diagnosis of autism spectrum disorder (ASD) in FXS. This was followed by instrument revisions that included: removal of non-discriminating and/or low face validity items for FXS; use of receiver operating characteristic (ROC) curves to determine optimal cut points for the original and revised measures; an exploratory factor analysis to outline subscales better representing ASD in FXS; and creation of a "triple criteria" diagnosis to better delineate ASD subgroups in FXS. These methods improved the sensitivity and/or specificity of the SCQ and SRS-2, but diagnostic accuracy of ASD remains problematic in FXS.

Diagnosing Autism in Adults with Intellectual Disability: Validation of the DiBAS-R in an Independent Sample

The study assessed the diagnostic validity of the diagnostic behavioral assessment for autism spectrum disorders-revised (DiBAS-R; 19-item screening scale based on ratings by caregivers) in a clinical sample of 381 adults with ID. Analysis revealed a sensitivity of 0.82 and a specificity of 0.67 in the overall sample (70.3% agreement). Sensitivity (0.79) and specificity (0.84) were balanced in individuals with mild to moderate ID (83.3% agreement), while specificity was lower in individuals with severe to profound ID (sensitivity: 0.83, specificity: 0.34, 51% agreement). The level of ID as well as its interaction with ASD explained a significant proportion of the variance in the DiBAS-R scores. The DiBAS-R is an adequate screening tool, especially in individuals with mild to moderate ID.

Psychometric properties of questionnaires and diagnostic measures for autism spectrum disorders in adults: A systematic review

Accurately diagnosing autism spectrum disorders in adulthood can be challenging. Structured questionnaires and diagnostic measures are frequently used to assist case recognition and diagnosis. This study reviewed research evidence on structured questionnaires and diagnostic measures published since the National Institute for Health and Care Excellence evidence update. The Cochrane library, Medline, Embase and PsycINFO were searched. In all, 20 studies met inclusion criteria. Sensitivity and specificity of structured questionnaires were best for individuals with previously confirmed autism spectrum disorder diagnoses and reduced in participants referred for diagnostic assessments, with discrimination of autism spectrum disorder from mental health conditions especially limited. For adults with intellectual disability, diagnostic accuracy increased when a combination of structured questionnaires were used. Evidence suggests some utility of diagnostic measures in identifying autism spectrum disorder among clinic referrals, although specificity for diagnosis was relatively low. In mental health settings, the use of a single structured questionnaire is unlikely to accurately identify adults without autism spectrum disorder or differentiate autism spectrum disorder from mental health conditions. This is important as adults seeking an autism spectrum disorder diagnostic assessment are likely to have co-existing mental health conditions. Robust autism spectrum disorder assessment tools specifically for use in adult diagnostic health services in the presence of co-occurring mental health and neurodevelopmental disorders are a research priority.