The aim of this study is to standardize Autism Diagnostic Observation Schedule (ADOS) scores within a large sample to approximate an autism severity metric. Using a dataset of 1415 individuals aged 2–16 years with autism spectrum disorders (ASD) or nonspectrum diagnoses, a subset of 1807 assessments from 1118 individuals with ASD were divided into narrow age- and language-cells. Within each cell, severity scores were based on percentiles of raw totals corresponding to each ADOS diagnostic classification. Calibrated severity scores had more uniform distributions across developmental groups and were less influenced by participant demographics than raw totals. This metric should be useful in comparing assessments across modules and time, and identifying trajectories of autism severity for clinical, genetic, and neurobiological research.

Autism Diagnostic Observation Schedule (ADOS) Modules 1-3 item and domain total distributions were reviewed for 1,630 assessments of children aged 14 months to 16 years with an autism spectrum disorder (ASD) or with heterogeneous non-spectrum disorders. Children were divided by language level and age to yield more homogeneous cells. Items were chosen that best differentiated between diagnoses and were arranged into domains on the basis of multi-factor item-response analysis. Reflecting recent research, the revised algorithm now consists of two new domains, Social Affect and Restricted, Repetitive Behaviors (RRB), combined to one score to which thresholds are applied, resulting in generally improved predictive value.

No abstract

Standardized Autism Diagnostic Observation Schedule (ADOS) scores provide a measure of autism severity that is less influenced by child characteristics than raw totals (Gotham et al. in Journal of Autism and Developmental Disorders, 39(5), 693–705 2009). However, these scores combine symptoms from the Social Affect (SA) and Restricted and Repetitive Behaviors (RRB) domains. Separate calibrations of each domain would provide a clearer picture of ASD dimensions. The current study separately calibrated raw totals from the ADOS SA and RRB domains. Standardized domain scores were less influenced by child characteristics than raw domain totals, thereby increasing their utility as indicators of Social-Communication and Repetitive Behavior severity. Calibrated domain scores should facilitate efforts to examine trajectories of ASD symptoms and links between neurobiological and behavioral dimensions.

The Autism Diagnostic Observation Schedule (ADOS; Lord et al., 2000) is widely accepted as a "gold standard" diagnostic instrument, but it is of restricted utility with very young children. The purpose of the current project was to modify the ADOS for use in children under 30 months of age. A modified ADOS, the ADOS Toddler Module (or Module T), was used in 360 evaluations. Participants included 182 children with best estimate diagnoses of ASD, non-spectrum developmental delay or typical development. A final set of protocol and algorithm items was selected based on their ability to discriminate the diagnostic groups. The traditional algorithm "cutoffs" approach yielded high sensitivity and specificity, and a new range of concern approach was proposed.Keywords autism spectrum disorders; diagnosis; ADOS; infants; toddlers Almost ten years ago, the standardization of a revised Autism Diagnostic Observation Schedule (ADOS), a semi-structured assessment for the diagnosis of autism spectrum disorders (ASD) (Lord, Rutter, DiLavore & Risi, 1999) was described. The ADOS has gradually become an integral part of many research and clinical protocols of children suspected of having an autism spectrum disorder (ASD). Due to the growing understanding of symptoms in the first two years of life and the desire of researchers and clinicians to have standardized instruments for use with infants and young toddlers, there is a need for diagnostic tools that are appropriate for very young children. This paper presents a new Toddler Module of the ADOS. The Toddler Module retains the original spirit and many of the original tasks of the ADOS, but is intended for use in children under 30 months of age who have nonverbal mental ages of at least 12 months. The scope of this report is to provide a summary of the new measure, the procedures used to develop it, a description of the standardization sample and relevant psychometrics.In introducing this new module, it is valuable to review the structure of the previously published ADOS. The ADOS evaluates social interaction, communication and play through a series of planned "presses" (Lord et al., 1989) in the context of a naturalistic social interaction. Some of the presses are intended to offer a high level of structure for the participant, while others are intended to provide less structure. All presses, however, afford contexts for both initiations and responses, which are then coded in a standardized manner. An algorithm, which sums the scores of particular items from the measure, yields a classification indicative of autism, ASD or nonspectrum conditions. This classification can then be used by a clinician or researcher as one part of a comprehensive diagnostic process.The first ADOS was introduced in the late 1980s and was intended for children who had a spoken language age equivalent of at least 36 months. A revision was published in 2000 that reflected the need for the measure to be applicable to a wider range of chronological and developmental ages. The 2000 version provided f...

Research suggests that restricted and repetitive behaviors (RRBs) can be subdivided into repetitive sensory motor (RSM) and insistence on Sameness (IS) behaviors. However, because the majority of previous studies have used the Autism Diagnostic Interview-Revised (ADI-R), it is not clear whether these subcategories reflect the actual organization of RRBs in ASD. Using data from the Simons Simplex Collection (n=1825), we examined the association between scores on the ADI-R and the Repetitive Behavior Scale-Revised (RBS-R). Analyses supported the construct validity of RSM and IS subcategories. As in previous studies, IS behaviors showed no relationship with IQ. These findings support the continued use of RRB subcategories, particularly IS behaviors, as a means of creating more behaviorally homogeneous subgroups of children with ASD.

Context Clinical best estimate diagnoses of specific autism spectrum disorders (autistic disorder, pervasive developmental disorder-not otherwise specified, Asperger’s disorder) have been used as the diagnostic gold standard, even when information from standardized instruments is available. Objective To determine if the relationships between behavioral phenotypes and clinical diagnoses of different autism spectrum disorders vary across 12 university-based sites. Design Multi-site observational study collecting clinical phenotype data (diagnostic, developmental and demographic) for genetic research. Classification trees were employed to identify characteristics that predicted diagnosis across and within sites. Setting Participants were recruited through 12 university-based autism service providers into a genetic study of autism. Participants 2102 probands (1814 males) between 4 and 18 years of age (M age=8.93, SD=3.5 years) who met autism spectrum criteria on the Autism Diagnostic Interview–Revised and Autism Diagnostic Observation Schedule and had a clinical diagnosis of an autism spectrum disorder. Main Outcome Measures Best estimate clinical diagnoses predicted by standardized scores from diagnostic, cognitive, and behavioral measures. Results Though distributions of scores on standardized measures were similar across sites, significant site differences emerged in best estimate clinical diagnoses of specific autism spectrum disorders. Relationships between clinical diagnoses and standardized scores, particularly verbal IQ, language level and core diagnostic features, varied across sites in weighting of information and cut-offs. Conclusions Clinical distinctions among categorical diagnostic subtypes of autism spectrum disorders were not reliable even across sites with well-documented fidelity using standardized diagnostic instruments. Results support the move from existing sub-groupings of autism spectrum disorders to dimensional descriptions of core features of social affect and fixated, repetitive behaviors, together with characteristics such as language level and cognitive function.

Background The Social Responsiveness Scale (SRS) is a parent-completed screening questionnaire often used to measure ASD severity. Although child characteristics are known to influence scores from other ASD-symptom measures, as well as parent-questionnaires more broadly, there has been limited consideration of how non-ASD-specific factors may affect interpretation of SRS scores. Previous studies have explored effects of behavior problems on SRS specificity, but have not addressed influences on the use of the SRS as a quantitative measure of ASD-symptoms. Method Raw scores (SRS-Raw) from parent-completed SRS were analyzed for 2,368 probands with ASD and 1,913 unaffected siblings. Regression analyses were used to assess associations between SRS scores and demographic, language, cognitive, and behavior measures. Results For probands, higher SRS-Raw were associated with greater non-ASD behavior problems, higher age, and more impaired language and cognitive skills, as well as scores from other parent report measures of social development and ASD-symptoms. For unaffected siblings, having more behavior problems predicted higher SRS-Raw; male gender, younger age and poorer adaptive social and expressive communication skills also showed small, but significant effects. Conclusions When using the SRS as a quantitative phenotype measure, the influence of behavior problems, age, and expressive language or cognitive level on scores must be considered. If effects of non-ASD-specific factors are not addressed, SRS scores are more appropriately interpreted as indicating general levels of impairment, than as severity of ASD-specific symptoms or social impairment. Further research is needed to consider how these factors influence the SRS’ sensitivity and specificity in large, clinical samples including individuals with disorders other than ASD.