Concerns with the new biological research criteria for synucleinopathy

[...]we find the SynNeurGe criteria more appropriate than NSD-ISS, because SynNeurGe includes Parkinson's disease without synucleinopathy. [...]the NSD-ISS proposes a system based on six stages, five of which are based on when motor or non-motor symptoms appear, whereas the SynNeurGe criteria only assess the presence of symptoms, but without considering their functional impact.1,2 We have proposed a simple classification of Parkinson's' disease based on four axes (motor, non-motor, cognition, and dependency [MNCD]) and five stages.3 Analogous to the TNM staging system used in oncology and with the virtues of the Hoehn and Yahr scale in terms of simplicity,4 we have shown that the MNCD staging system also correlates with disease severity and patients' quality of life.5 The MNCD is intended to be a simple tool to identify key symptoms and presentations in Parkinson's disease and monitor disease progression that could be correlated with biological classification data. DS-G has received grants from the Spanish Ministry of Economy and Competitiveness (reference number PI16/01575) co-founded by Instituto de Salud Carlos III for the project titled “Non-motor progression and impact on quality of life in Parkinson's disease”; and has received payments or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Abbvie, UCB Pharma, Lundbeck, KRKA, Zambon, Bial, Italfarmaco, Teva, Archímedes, Esteve, Stada, and Merz.