Parent Report of Onset Status: Prospective Versus Retrospective Methods

Background:  Previous studies have demonstrated that parent report of ASD onset status (regression, no regression) is limited and often does not agree with home video evidence (Ozonoff et al 2011) or longitudinal evaluations of behavior in the laboratory setting (Ozonoff et al 2010). Earlier studies often mixed methodologies, comparing prospective data with retrospective parent report. It is therefore difficult to determine whether the poor concordance is due to limitations in parent recall or to differences in data collection methods.

Objectives:  1) To collect both prospective and retrospective parent ratings of their child’s development, and 2) to compare parent ratings to longitudinal expert clinician judgments.

Methods:  Using a prospective longitudinal design, infants at risk for ASD were seen at 6, 9, 12, 15, 18, 24, and 36 months of age. At each visit, both parents and clinicians rated the child’s social-communicative development. At 36 months, parents were interviewed retrospectively with the Autism Diagnostic Interview-Revised (ADI-R) about any loss of skills. Data from all infants with an ASD outcome at 36 months are included in this analysis (n=20). Latent class analysis (LCA) was used to derive onset trajectories for the parent prospective ratings and the clinician longitudinal ratings. Kappa statistics and percent agreement among the methods were calculated.

Results:  The LCA of the clinician ratings demonstrated two trajectories, one with initially low social-communication ratings that were stable over time (i.e., early onset trajectory; 10% of the sample) and one with initially high ratings that declined over time (i.e., regression trajectory; 90% of the sample). The LCA of the parent prospective ratings also demonstrated these two trajectories, with 70% of the sample classified on the regression trajectory. Parent and examiner ratings agreed with each other 60% of the time. In contrast, parent retrospective ratings agreed with their own prospective ratings only 30% of the time (kappa = -0.21; NS) and with clinician ratings only 30% of the time (kappa = -0.06; NS). In all cases, when regression was reported retrospectively by parents on the ADI-R, it was corroborated by prospective ratings (either parent, clinician, or both).

Conclusions:  1) The vast majority of infants who develop ASD demonstrate a regression or declining trajectory of social-communication development, according to prospectively collected data, whether rated by clinicians (90%) or parents (70%). 2) Parents have difficulty reporting on regression retrospectively. Far fewer parents report declining trajectories when asked retrospectively (30%) than prospectively (70%) and their retrospective report contradicts their own prospective report 70% of the time. However, when regression is reported on a retrospective instrument, it is corroborated by prospective data. 3) Obtaining parent ratings of development at well-child pediatric visits, and looking for declines in ratings from previous reports, may be useful as a screening method to help identify children who are developing ASD.