Diagnosis of Autism Spectrum Disorder After Age 5 in Children Evaluated Longitudinally Since Infancy

Abstract

Objective: The diagnosis of autism spectrum disorder (ASD) has been found to be remarkably stable but few studies have followed children not initially diagnosed with ASD beyond age 3 to examine late or delayed diagnoses. The current study used a prospective familial-risk design to identify children who had undergone multiple comprehensive assessments in preschool and were determined to be ASD-negative, only to meet criteria for ASD when tested in middle childhood. Method: Data were pooled across three research teams studying later-born siblings of children with ASD. Fourteen children met inclusion criteria for the Late Diagnosed group and were compared to a large sample of high- and low-risk siblings from the same sites who had ASD or typical development (TD) outcomes at age 3. Results: As a group, the Late Diagnosed children scored between the TD and ASD groups on most measures administered at age 3 and differed significantly from the ASD group on most measures. However, there was significant heterogeneity among the Late Diagnosed cases. Seven showed very little evidence of ASD in preschool, while seven demonstrated subtle, subthreshold symptomatology. Conclusion: Some children with ASD may present with a subtle phenotype early in life or show a prolonged time course of symptom development. This emphasizes the need for screening and surveillance schedules that extend past 36 months and continued evaluation of any child who presents with atypical early development and/or high-risk status. The findings also shed light on reasons why the mean age of ASD diagnosis remains over 4 years.

Mapping Early Symptom Trajectories in Autism Spectrum Disorder: Lessons and Challenges for Clinical Practice and Science

“…The Worsening group had average non-verbal ability (NVIQ = 101) but considerably lower verbal ability (VIQ = 75) at baseline and both were higher than in the Moderately-improving and Severe-persistent groups. This is similar to the pattern reported in children with a later onset or emergence of ASD symptoms seen in familial high-risk sibling studies, both across a similar early preschool timeframe as in the present study 3 and in those who receive an ASD diagnosis in mid-childhood but did not when assessed at age 3 years 4,5,6 . One notable feature of the Worsening group was that despite having increasing ASD symptoms they showed considerable improvements in language and communication skills and adaptive abilities over time.…”

Autism spectrum disorder

“…This change recognizes the developmental nature of autism, wherein for some individuals, clear manifestation of autism might not be apparent until mid-childhood, adolescence or even adulthood. In addition, late diagnosis (that is, diagnosis beyond early childhood) can occur even in those who received intensive early monitoring 132 . In addition, the DSM-5 criteria supports the use of specifiers that can denote those with a dual diagnoses, such as individuals with ASD and ADHD or other psychiatric disorders, as well genetic conditions such as fragile X syndrome or down syndrome.…”

Look duration at the face as a developmental endophenotype: elucidating pathways to autism and ADHD

“…Although endophenotypes can be present when the clinical symptoms are not, one requirement is that they are linked to a clinical condition. However, a critical point emerging from studies of infants with elevated likelihood of ASD is that developmental trajectories are dynamic and children show different profiles of the nature and timing of symptom development (Ozonoff et al, 2018). Thus, it may be that an endophenotype is stable/state independent, but the symptom profile that it is related to changes over developmental time.…”

“…At the group level, early signs of emerging symptomatology can be robustly identified by two years of age (Ozonoff et al, 2015). However, in some cases clinical manifestations might not emerge until age five years (Ozonoff et al, 2018). Moreover, the effect of genetic factors on ASD and ADHD traits, though present across childhood, becomes stronger with age (Stergiakouli et al, 2017).…”