Cognitive deficits, by definition, should not appear within a year from MS onset (1-year rule), otherwise DLB diagnosis should be considered [115]. Over years, about 26% of PD patients will present mild cognitive impairment (MCI) features. PD-MCI is mainly associated with “subcortical” deficits (i.e., executive and attentional), but also visuospatial, praxis, language, and memory impairment can be present [116]. Dementia also appears in PD in up to 80% of cases, typically in advanced stages, and is associated with increased mortality [117].