What follows are a series of abstracts concerning the stability of autism spectrum disorder (ASD) diagnosis, including PDD-NOS. [Emphasis throughout is mine.] Each study concludes that certain children diagnosed with ASD at an early age can later lose the diagnosis.
Diagnostic Stability in Very Young Children with Autism Spectrum Disorders.
1: J Autism Dev Disord. 2007 Oct 9; [Epub ahead of print]
Autism Spectrum Disorders (ASD) diagnosis in very young children may be delayed due to doubts about validity. In this study, 77 children received a diagnostic and developmental evaluation between 16 and 35 months and also between 42 and 82 months. Diagnoses based on clinical judgment, Childhood Autism Rating Scale, and the Autism Diagnostic Observation Schedule were stable over time. Diagnoses made using the Autism Diagnostic Interview were slightly less stable. According to clinical judgment, 15 children (19%) moved off the autism spectrum by the second evaluation; none moved onto the spectrum. Results indicate diagnostic stability at acceptable levels for diagnoses made at age 2. Movement off the spectrum may reflect true improvement based on maturation, intervention, or over-diagnosis at age 2.
Variability in outcome for children with an ASD diagnosis at age 2.
1: J Child Psychol Psychiatry. 2007 Aug;48(8):79
BACKGROUND: Few studies have examined the variability in outcomes of children diagnosed with autism spectrum disorder (ASD) at age 2. Research is needed to understand the children whose symptoms - or diagnoses - change over time. The objectives of this study were to examine the behavioral and diagnostic outcomes of a carefully defined sample of 2-year-old children with ASD, and to identify child and environmental factors that contribute to variability in outcomes at age 4. METHODS: Forty-eight children diagnosed with autism or pervasive developmental disorder not otherwise specified (PDDNOS) at age 2 were followed to age 4. Diagnostic measures included the Autism Diagnostic Observation Schedule - Generic (ADOS-G) and clinical diagnosis at ages 2 and 4, and the ADI-R at age 4. RESULTS: Diagnostic stability for an ASD diagnosis (autism or PDD-NOS) was 63%, and for an autism diagnosis was 68%. Children who failed to meet diagnostic criteria for ASD at follow-up were more likely to: 1) be 30 months or younger at initial evaluation; 2) have milder symptoms of autism, particularly in the social domain; and 3) have higher cognitive scores at age 2. No differences between children with stable and unstable diagnoses were found for amount of intervention services received. Among the children with unstable diagnoses, all but one continued to have developmental disorders, most commonly in the area of language.
CONCLUSIONS: The stability of ASD was lower in the present study than has been reported previously, a finding largely attributable to children who were diagnosed at 30 months or younger. Implications for clinical practice are discussed.
Predictors of Optimal Outcome in Toddlers Diagnosed with Autism Spectrum Disorders Journal
Journal of Autism and Developmental Disorders
Received: 30 October 2006 Accepted: 14 November 2006 Published online: 6 January 2007
Abstract A diagnosis of autism spectrum disorder (ASD) is usually taken to be permanent. In this study, 13 two-year-old children with ASD lost the diagnosis by age 4, at which time they scored within the normal range on standardized measures of cognitive and adaptive functioning. No differences were found in symptom severity, socialization, or communication between children who lost the ASD diagnosis and children who did not, but children with PDD-NOS were significantly more likely than those with full autistic disorder to move off the spectrum. The clearest distinguishing factor was motor skills at age 2. Results support the idea that some toddlers with ASD can lose their diagnosis and suggest that this is difficult to predict.