The study aims to diagnose MM2- type cortical and thalamic (MM2C and MM2T) sCJD (sporadic Creutzfeld-Jakob disease) at the initial stage using the new criteria.

The researchers took the results of subjects with the disorder in Japan between Apr 1999 and Sep 2019. This included 254 subjects with confirmed prion disorders, which includes 9 MM2C and 10 MM2T subjects. The study also took 607 subjects with non-prion disorders.

The study using conventional criteria showed 4 out of 9 subjects with MM2C and 7 out of 10 subjects with MM2T without a diagnosis. The subjects with MM2C showed slow progress of the disorder and distribution of the hyperintensity lesions, compared to other types. The researchers then used the new criteria, the diagnostic specificity and sensitivity to identify the probable MM2C cases from other types. The diagnostic probability was 77.8% for distinguishing it from other types of sCJD and 98.5% for distinguishing from non-prion disease controls. MM2T cases did not show characteristic features to develop a new diagnostic criterion.

The new criteria, high specificity and sensitivity are more likely to diagnose subjects with MM2C at an early stage. However, those criteria did not prove effective in diagnosing subjects with MM2T.