Objectives: To explore the timing and acuity of language and social losses in young children with autism, and to determine if physical illnesses/medical conditions or psychosocial stressors were associated with the developmental regressions.
Methods: Parents of 185 children (146 autism, 39 PDD-NOS) with a mean age 53 months (range 21-153 months) were interviewed using the Autism Diagnostic Interview-Revised [ADI-R; a Toddler version of the ADI was administered for children under age 48 months (n=93)]. For this study, regression was defined as loss of at least 5 words and/or a significant loss of social engagement/responsiveness (score of 2 on ADI-R). Acuity of loss was explored through a question on the Early Development Questionnaire (EDQ; Ozonoff et al., 2005), “Was your child’s loss of skills gradual or sudden? Please describe.” Potential relationships with physical illnesses or psychosocial stressors were explored through answers to open-ended questions on the Early Development Questionnaire.
Results: Twelve of 185 children met criteria for language loss only, 30 children met criteria for social engagement/responsiveness loss only, and 38 met criteria for loss in both areas. Mean age of language loss was 20.7 months (SD = 6.7, range = 12-42), and mean age of loss of social engagement was 18.8 months (SD =6.3, range, 10-51 months).
Among the 80 cases with significant regression, parents of 26 children indicated physical illness/medical issues may have been related to loss of skills, and 21 responses indicated an associated psychosocial stressor (in 7 of these cases, both illness and psychosocial stressors were reported). However, only 8 reports clearly indicated a sudden loss of skills. Five of the 8 cases with sudden loss included both loss of language loss and social engagement/responsiveness. Two of the sudden loss cases were reported to be associated with a physical illness/medical issue and 3 were reported to be associated with a psychosocial stressor (with 1 reported to have both).
Conclusions: Most regression was reported to have been gradual in onset, making it difficult to identify illnesses or events that may have precipitated the developmental losses. Although a causal relationship can only be determined by prospective study of at-risk children, further clues to the nature, timing and events associated with regression may be provided by examination of the children’s medical records, which is currently underway.