This study sought to survey individuals with expertise in neurocognitive regression in persons with DS using the traditional Delphi method in order to create a multi-disciplinary expert guided consensus on the diagnostic work up and criteria for regression in persons with DS. This study may be of benefit for both future research in regression in DS and for clinical guidance in the diagnosis of this condition.Assessment and Diagnosis of Down Syndrome Regression Disorder – International Expert ConsensusSource: Santoro et al.