Cluster analysis of autism spectrum disorder symptomatology: Qualitatively distinct subtypes or quantitative degrees of severity of a single disorder?

Profiling clinical heterogeneity in Autism Spectrum Disorder at time of children's diagnosis: A cluster analysis from the ELENA cohort

BACKGROUND

Autism Spectrum Disorder (ASD) encompass a heterogeneous group of neurodevelopmental conditions characterized by deficits in social communication and repetitive behaviors. The rising prevalence of ASD highlights the urgent need for effective diagnostic and intervention strategies. However, the significant clinical, cognitive and etiological heterogeneity within ASD populations poses substantial challenges to these efforts.

AIMS

This study aimed to identify distinct ASD subtypes at time of diagnosis within the ELENA cohort by incorporating not only DSM-5 criteria but also measures of adaptive functioning and behavioral problems.

MATERIAL AND METHODS

Data from 458 children and adolescents with ASD were analyzed using hierarchical agglomerative clustering. Variables included autistic symptoms, intellectual quotient, adaptive behavior and behavioral problems. Clusters were identified based on these parameters, and post-hoc analyses were conducted to assess statistically significant differences in sex and age among the four clusters using Chi-square test and Student's t-tests.

RESULTS

Four distinct clusters were identified from the analysis: (1) High Autistic Symptom Severity with Lowest Behavioral Problems, (2) High Autistic Symptom Severity with High Behavioral Problems, (3) Low Autistic Symptom Severity with Highest Behavioral Problems and (4) Low Autistic Symptom Severity with low behavioral problems, while significant age differences were observed across clusters, no significant sex differences were found.

DISCUSSION

These clusters exhibited significant variability in adaptive functioning and behavioral problems, suggesting that DSM-5 criteria alone do not fully capture the complexity of ASD. The findings underscore the importance of incorporating measures of adaptive functioning and behavioral problems into ASD assessments and interventions. Future research should aim to validate these clusters in larger and more diverse populations and explore the integration of genetic and neuroimaging data to further refine the characterization of ASD subtypes. Additionally, longitudinal studies are needed to assess the stability and clinical relevance of these subtypes over time.

TRIAL REGISTRATION NUMBER

NCT02625116.

Profiles of nonverbal skills used by young pre-verbal children with autism on the ADOS-2: Relation to screening disposition and outcomes

Autistic individuals exhibit differences in their use and understanding of nonverbal communication; however, individual patterns of nonverbal strengths and challenges vary significantly. This heterogeneity can complicate the diagnostic and screening processes and can result in delayed or missed diagnoses. In this study, we characterize various profiles of nonverbal communication skills among 215 pre-verbal children with autism (Mage = 36.27 months, range = 18-70) and explore how these profiles are related to screening outcomes, diagnostic certainty, and developmental and behavioral features. We conducted a latent class analysis of nine items assessing nonverbal communication skills from the Toddler Module and Module 1 of the Autism Diagnostic Observation Schedule, 2nd Edition. Five nonverbal profiles were identified that differentiated children based on the form, function, and frequency of their nonverbal communication skills. Furthermore, screening outcomes and clinician certainty in autism diagnosis varied by nonverbal profile. False negative screening outcomes based on parent report were highest for children who used a range of nonverbal skills but with limited frequency or consistency. Clinicians, on the other hand, tended to have high certainty in an autism diagnosis for children with this profile, and instead rated their lowest certainty in diagnosing children who demonstrated consistent integration of eye contact with their nonverbal communication. The profiles identified in this study could be clinically useful in helping to identify children at highest likelihood of being overlooked during the screening or diagnostic processes, providing an opportunity to improve early identification and intervention for autism.

Global Sensory Features are Linked to Executive and Attentional Impairments in Autism Spectrum Disorders

Sensory features, executive and attentional impairments are frequently reported in individuals with autism spectrum disorders (ASD). However, little is known about their complex relationships. In this study, we aim to examine the executive and attentional difficulties related to distinct sensory profiles. We identified sensory profiles with a Latent Profile Analysis (LPA) based on scores on the Short Sensory Profile (SSP) questionnaire in 95 children with ASD aged 6 to 17 years. Executive and attention functions were assessed using the Behavior Rating Inventory of Executive Functions (BRIEF) questionnaire and Attention-Deficit Hyperactivity Disorder Rating Scale (ADHD-RS). A three-cluster solution based on raw SSP scores identified a "high'', a "medium" and a "low'' SSP profile. We found a significant relationship between executive functions, attentional skills and the global severity of sensory features, reinforcing findings of previous studies in the literature. A two-cluster solution based on normalized SSP (i.e. equalized for the global severity) identified distinct sensory profiles, mainly discriminated by the score of underresponsive/seeks sensation. We found no significant difference between these two clusters for the BRIEF and ADHD-RS related scores. Our study suggests that the heterogeneity of sensory features in ASD may not be explained by differences in executive and attention functions. Future studies are needed to refine the link between sensory features and executive functions in autism.

Features that best define the heterogeneity and homogeneity of autism in preschool-age children: A multisite case-control analysis replicated across two independent samples

The heterogeneous nature of children with symptoms of autism spectrum disorder (ASD) makes it difficult to identify risk factors and effective treatment options. We sought to identify behavioral and developmental features that best define the heterogeneity and homogeneity in 2-5-year-old children classified with ASD and subthreshold ASD characteristics. Children were enrolled in a multisite case-control study of ASD. Detailed behavioral and developmental data were gathered by maternal telephone interview, parent-administered questionnaires, child cognitive evaluation, and ASD diagnostic measures. Participants with a positive ASD screen score or prior ASD diagnosis were referred for comprehensive evaluation. Children in the ASD group met study criteria based on this evaluation; children who did not meet study criteria were categorized as having subthreshold ASD characteristics. There were 1480 children classified as ASD (81.6% boys) and 594 children classified as having subthreshold ASD characteristics (70.2% boys) in the sample. Factors associated with dysregulation (e.g., aggression, anxiety/depression, sleep problems) followed by developmental abilities (e.g., expressive and receptive language skills) most contributed to heterogeneity in both groups of children. Atypical sensory response contributed to homogeneity in children classified as ASD but not those with subthreshold characteristics. These findings suggest that dysregulation and developmental abilities are clinical features that can impact functioning in children with ASD and other DD, and that documenting these features in pediatric records may help meet the needs of the individual child. Sensory dysfunction could be considered a core feature of ASD and thus used to inform more targeted screening, evaluation, treatment, and research efforts. LAY SUMMARY: The diverse nature of autism spectrum disorder (ASD) makes it difficult to find risk factors and treatment options. We identified the most dissimilar and most similar symptom(s) in children classified as ASD and as having subthreshold ASD characteristics. Factors associated with dysregulation and developmental abilities contributed to diversity in both groups of children. Sensory dysfunction was the most common symptom in children with ASD but not those with subthreshold characteristics. Findings can inform clinical practice and research.

Sibling Adjustment and Sibling Relationships Associated with Clusters of Needs in Children with Autism: A Novel Methodological Approach

We tested a novel methodological approach to examine associations between characteristics of autistic children and outcomes for siblings. Cluster analysis was used to define five groups of children with autism (n = 168) based on autism symptoms, adaptive behavior, pro-social behavior, and behavior problems. Primary and secondary parent carers, and siblings themselves, reported on sibling relationship quality and psychological adjustment. Siblings of autistic children with a mild symptom profile, high levels of adaptive skills, but high internalizing and externalizing problems had the highest level of these problems themselves and more conflict in their relationship. Siblings of autistic children with the most complex support needs (adaptive skills deficits, severe autism symptoms) reported lower warmth relationships but not elevated internalizing and externalizing problems.

Overlap of anxiety, depression, irritability and aggressiveness in autism spectrum disorder: an exploratory study using cluster analysis

Purpose

This study aims to explore the overlap between symptoms of depression, anxiety, irritability and aggressiveness in autism spectrum disorder (ASD), to measure specific and idiosyncratic emotional responses.

Design/methodology/approach

A total of 42 high functioning adolescents and adults, between 12 and 39 years old, meeting the diagnostic and statistical manual of mental disorders – 5 criteria for ASD were selected from the InFoR Autism cohort. Data were analyzed in an exploratory way using Hill and Smith and K-medoids cluster analysis.

Findings

The authors found an aggregation of anxiety, depression, aggressive behaviors and irritability. Cluster analysis was maximized for two groups with 17 and 25 participants, respectively. The first group was characterized by high levels of symptoms of irritability, aggressiveness, hyperactivity and intermediate levels of anxiety and depression. In the first group, participants had significantly higher levels of autistic symptoms considering the social responsiveness scale and repetitive behavior scale-revised scales (relatives’ reports) suggesting that a particular group of subjects with a high level of ASD specific symptoms may express anxiety and depression in a specific way based on externalizing behaviors in addition to the common mood and anxiety symptoms.

Research limitations/implications

Improved understanding of the aggregation of externalized symptoms with symptoms of anxiety and mood disorders in ASD should lead to a better understanding of the underlying mechanisms related to emotion dysregulation in ASD.

Practical implications

Improved knowledge of the symptoms could lead to enhanced detection of psychiatric comorbidities in ASD.

Originality/value

The study was based on a transdiagnostic approach of psychiatric symptoms in individuals with ASD. Aggregation and clustering analysis was used to explore naive patterns of these psychiatric symptoms.

Subgroups of Children with Autism Spectrum Disorder without Intellectual Disability: A Longitudinal Examination of Executive and Socio-Adaptive Behaviors in Adolescence

Within the autistic spectrum, there is remarkable variability in the etiology, presentation, and treatment response. This prospective study was designed to identify, through cluster analysis, subgroups of individuals with ASD without intellectual disability (ID) based on the severity of the core symptoms in childhood. The secondary aim was to explore whether these subgroups and a group with typical development (TD) differ in cognitive, adaptive, and social aspects measured in adolescence. The sample at baseline was comprised of 52 children with ASD without ID and 37 children with TD, aged 7-11. Among the ASD group, three clusters were identified. Cluster 1 (40%), 'high severity', presented high symptom severity on the DSM-5 criteria and the Social Communication Questionnaire. Cluster 2 (34%) showed 'moderate severity' on most of the scores. Cluster 3 (25%) corresponded to 'low severity', showing moderate social impairment and low restrictive, repetitive patterns of behavior, interests and activities. At 5-year follow-up, 45 adolescents with ASD without ID and 27 adolescents with TD were assessed. All clusters had significantly more difficulties in EF, ToM, socialization and adaptive behavior compared to TD. Social and adaptive trajectories between the ASD subgroups were relatively different; Cluster 3 showed poorer socialization and daily living skills than the other two subgroups. These findings highlight the importance of fully assessing social, cognitive, and adaptive profiles to develop care plans tailored to specific needs.

Validation strategies for subtypes in psychiatry: A systematic review of research on autism spectrum disorder

Heterogeneity within autism spectrum disorder (ASD) is recognized as a challenge to both biological and psychological research, as well as clinical practice. To reduce unexplained heterogeneity, subtyping techniques are often used to establish more homogeneous subtypes based on metrics of similarity and dissimilarity between people. We review the ASD literature to create a systematic overview of the subtyping procedures and subtype validation techniques that are used in this field. We conducted a systematic review of 156 articles (2001-June 2020) that subtyped participants (range N of studies = 17-20,658), of which some or all had an ASD diagnosis. We found a large diversity in (parametric and non-parametric) methods and (biological, psychological, demographic) variables used to establish subtypes. The majority of studies validated their subtype results using variables that were measured concurrently, but were not included in the subtyping procedure. Other investigations into subtypes' validity were rarer. In order to advance clinical research and the theoretical and clinical usefulness of identified subtypes, we propose a structured approach and present the SUbtyping VAlidation Checklist (SUVAC), a checklist for validating subtyping results.

Muscle dysmorphia: A systematic and meta-analytic review of the literature to assess diagnostic validity

OBJECTIVE

Although muscle dysmorphia (MD) is a new addition to DSM-5 as a specifier of body dysmorphic disorder (BDD), previous studies have treated MD as a stand-alone diagnosis. We aimed to assess the validity of MD as a stand-alone diagnosis via systematic and meta-analytic review of MD literature using both Robins and Guze criteria and additional criteria from Kendler.

METHOD

We performed a systematic search of ProQuest, PsycInfo, and PubMed databases for the period of January 1993 to October 2019 resulting in 40 papers to examine Robins and Guze's criteria (clinical picture) as well as those added by Kendler (antecedent validators; concurrent validators; predictive validators).

RESULTS

We identified two distinct symptomatic presentations of MD using cluster analysis, a behavioral type and cognitive/behavioral type. For examining the concurrent validators, quantitative meta-analyses differentiated MD populations from controls; however, results were inconclusive in delineating MD from existing disorders. For assessing antecedent and predictive validators, the symptomatic profiles, treatment response, and familial links for MD were similar to those for BDD and for eating disorders.

DISCUSSION

We found preliminary support for MD as a clinically valid presentation, but insufficient evidence to determine whether it is best categorized as a specifier of BDD or unique psychiatric condition.

Clinical Profile of Autism Spectrum Disorder in a Pediatric Population from Northern Mexico

Autism spectrum disorder (ASD) is a neurodevelopmental condition classified based on needs of support, in order to address impairments in the areas of social communication and restricted and repetitive behavior. The aim of this work is to describe the main clinical features of the ASD severity levels in a group of Mexican pediatric patients. The results show firstly that this condition was more frequent in males than females. Secondly, an inverse relationship was found between the intellectual coefficient and the level of severity of the disorder. Thirdly, deficits in social reciprocity and communication were more evident in Level 3, than in Levels 1 and 2, while the difference was less evident in restricted and repetitive patterns of behavior.

From bedside to bench and back: Translating ASD models

Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.