Sorry! You must be logged in to read this post. Please sign up for your FREE MY-DSC account here. Login Tags:adult regression syndromeAEautoimmune encephalitisBrian Chicoinecatatonic psychosescatoniachicoinecognitive declinedown syndrome disintegrative disorderDr. Brian ChicoineDSDDimmunoglobulinsimmunotheraphyIVIGNeuropsychologicalregressionregression syndromerituxanrituximab