Staging of Lewy-related pathology in dementia

Objective: Lewy-related pathology is the characteristic feature of Parkinson's disease with and without dementia and dementia with Lewy bodies (DLB). There are two neuropathological staging systems for Lewy-related pathology commonly employed today: the staging system for Parkinson-related pathology by Braak et al., and the staging system by the Consortium on DLB. There are also several modified systems based on these two scales. Methods: We applied a total of eight different staging systems for Lewy-related pathology to 36 consecutive demented patients with various dementia disorders. Results: The staging systems varied considerably in number of unclassifiable cases (range 0 - 16 out of 36 cases), while the diagnostic agreement between the systems that were able to classify all or the very majority of cases varied only slightly (weighted kappa 0.86 - 0.92 and Spearman's sigma 0.80 - 1.0). Conclusion: The different staging systems for Lewy-related pathology that exist today vary in staging procedure and proportion of unclassifiable cases. The choice of system may affect the stage of Lewy-related pathology and ultimately final diagnosis.