[Limitations of the Second Consensus Statement on the Diagnosis of Multiple System Atrophy]

The Second Consensus Statement on the Diagnosis of Multiple System Atrophy (MSA), issued in 2008, has unified the concept of MSA and significantly advanced clinical and drug discovery research. However, subsequent developments in research have revealed several critical findings that would affect the diagnostic sensitivity, specificity, and positive predictive value of the consensus statement. In this review, we discuss the limitations of diagnostic sensitivity for early diagnosis; positioning of orthostatic hypotension; diagnostic categories; exclusion criteria such as elderly onset, family history, and dementia; differentiation from progressive supranuclear palsy; and imaging findings of the Second Consensus Statement.