Notwithstanding the apparent formal stability of Icelandic cases, there is evidence that they are experiencing subtle changes in their functions (Barðdal, 2011;Barðdal and Eythórsson, 2003;Eythórsson, 2000).
barðdal argues that an accumulation of small syntatico-semantic shifts has finally resulted in a shift in the Icelandic dative's functions (i.e., 'dative sickness'), possibly triggered by earlier changes in nominatives and accusatives (e.g., 'nominative sickness').