A validation exercise on the new consensus criteria for multiple system atrophy.

The revised (new) consensus clinical diagnostic criteria for multiple system atrophy (MSA) were published in 2008. To validate these criteria, we utilized the same cohort that we reported previously, which included 59 patients with a clinical diagnosis of MSA that was confirmed neuropathologically in 51 of them at the Queen Square Brain Bank for Neurological Disorders. At the first clinic visit, sensitivity with new consensus possible category was higher, and PPV marginally higher, than for clinical diagnosis and old consensus possible category. New consensus probable category showed marginally higher sensitivity than, and the same PPV as, old consensus probable category. At the last clinic visit, new consensus possible category had exactly the same sensitivity and only marginally higher PPV compared with old consensus possible category. New consensus probable category showed the same sensitivity and PPV as old consensus probable category. Our data indicate that in this case material the new consensus criteria for possible MSA could improve diagnostic accuracy at first neurological evaluation compared with the old consensus criteria. Prospective clinicopathological validation studies of the new consensus criteria, particularly incorporating in vivo structural and functional imaging results, are required to extend the current findings.