Developing a consensus research definition for profound autism using a modified Delphi method.

Almost everyone who took part was based in the United States: only 8 respondents came from Canada, Europe, Asia Pacific, and the Middle East or Africa combined. Diagnosis and access to services vary between countries, so the wording may not travel. Only 2 respondents identified as autistic, and the survey collected little about them beyond their role and region, so you cannot tell how far the views represent the wider community. No IQ cut-off reached the agreed bar, and the panel split on the youngest age at which the term should apply (74% backed age 5, below the threshold), so two central parts of the definition rest on the committee's judgement rather than on consensus. The participant numbers are reported inconsistently: the methods describe 76 people taking part in the first round and 70 in the second, while the results section describes 70 first-round responses from 137 invitations and 78 second-round responses. The authors state this is a research definition only and that more guidance is needed before it is used clinically, including for people whose IQ is not tested or cannot be tested and whose verbal ability is unclear. Respondents themselves said they might have answered differently if better measures existed for the difficult areas, such as IQ and the age at which features reliably predict later profound autism.

The work was funded by the National Institutes of Health, the Profound Autism Alliance and the Autism Science Foundation. The Delphi process was guided by an independent facilitator from Triducive Partners Limited, and the steering committee that set the domains, drafted the definition and made the final wording decisions was made up of the paper's own authors. The supplied text names no individual author disclosures.

Do not start applying this definition to your patients. The authors say plainly that it is a research definition and that more guidance is needed before it can be used clinically, including for people whose IQ cannot be tested or whose verbal ability is unclear. Nor was the IQ under 50 criterion agreed: it drew 68% support, below the panel's own bar, and was included as an alternative to minimal speech rather than as a settled cut-off.