Developing a Consensus Research Definition for Profound Autism Using a Modified Delphi Method

Background The diagnostic term, autism spectrum disorder, encompasses the full range of impairments associated with the autism spectrum, a significant change from earlier DSM definitions that identified various subtypes of autism. However, the majority of autism-related research and cultural representations in recent years has focused on autistic individuals with strong language and cognitive abilities. In 2021, the administrative term Profound Autism (PA) was proposed by a Lancet Commission to draw attention to autistic people whose impairments require lifelong, round-the-clock care. The definition of PA included a minimum age, an IQ range, nonverbal or minimally verbal skills, and required 24/7 access to an adult to ensure safety. However, researchers are not yet using a consistent definition of PA, based on their interpretation of the Lancet Commission report. Methods To address the need to have studies that use comparable samples and increase clarity in communication and interpretation of results, we carried out a systematic, multi-stage Delphi consensus study with over 70 participants who identified as researchers, caregivers, autistic individuals, and clinicians, to measure consensus on components of a research definition of PA. A series of questions was developed for the primary domains of interest. Results After two rounds of review and voting, 76% of the respondents agreed on a research definition of PA of: adaptive functioning well below age level, requiring adult supervision to ensure physical and mental health, safety and well-being, at least 8 years old, diagnosed with ASD, and having severely impaired cognitive abilities (reflected by IQ score below 50) and/or does not verbally communicate other than single words or fixed phrases predominantly to have their basic needs met. Limitations : Variations in access to measurement tools as well as access to services across the world limits the utility of this definition outside research practices. Conclusions Based on these findings, a new working research definition of profound autism is proposed. This definition will improve specificity in precision medicine treatments for ASD.