Functional Remission and Diagnostic Overshadowing in Early Regressive Autism: A Longitudinal Case Study Following a Naturopathic Intervention

This dataset accompanies a longitudinal single-case study investigating the developmental trajectory of a child with early regressive autism following the implementation of an individualized Complex Naturopathic Intervention (CNI), protocolized as the Katia Dolle Method®. The case documents the evolution of an 18-month-old male presenting with socio-communicative regression and suspected autism spectrum disorder (ASD), who underwent a 24-month multimodal intervention combining trophological modifications, parental coaching, and targeted naturopathic supplementation. Outcome measures include longitudinal ATEC scores, external neuropsychological assessments, biological markers, and qualitative caregiver-reported observations. A substantial reduction in symptom severity was observed, with ATEC scores decreasing from 56 at baseline to 10 after 24 months, corresponding to a transition from moderate symptomatology to a subclinical range . The study further documents an acute regression episode associated with discontinuation of dietary guidelines, followed by rapid recovery upon reinstatement of the intervention, supporting the dynamic relationship between biological homeostasis and behavioral regulation. A notable methodological finding is the discrepancy between blinded and non-blinded external assessments, illustrating a phenomenon consistent with diagnostic overshadowing and functional masking in neurodevelopmental disorders . This case contributes to the emerging body of literature exploring integrative and systems-based approaches to ASD, highlighting the potential role of gut–brain axis modulation and individualized, adaptive interventions in achieving functional remission (optimal outcome). Keywords: autism spectrum disorder, regressive autism, functional remission, diagnostic overshadowing, gut–brain axis, naturopathic intervention, case study, integrative medicine