Background: Mild The term "cognitive impairment" was first used in the 1980s to describe minor cognitive impairments in the setting of Alzheimer's disease that were not severe enough to be classified as dementia. This idea has only just found application in the field of Parkinson's disease (PD), a condition characterized by cognitive impairments that are prevalent even at the time of diagnosis. Use, definition, evaluation, and predictive significance of this term are all very contentious, however. Here, we take a look back at what is known about motor cognitive impairment (MCI) in PD from an epidemiological standpoint, including contemporary classifications, underlying pathophysiology, detection techniques, monitoring the existence of cognitive involvement in PD, and current debates in this field. Objective: Objectives of this review paper include exploring PD-specific cognitive impairment characteristics, categorizing PD-related cognitive impairment kinds, and analyzing PD-MCI risk factor subgroups. Final thoughts: When trying to comprehend the individual and population-level evolution of PD, PD-MCI plays a significant role as a clinical entity. Longitudinal studies using more sensitive visuospatial assessments should be conducted in the future to track the development of cognitive changes in PD. In addition to neuropsychological testing, multimodal assessments will most certainly start to appear in definitions and biomarkers. In order to stratify diseases and provide individualized treatments, as well as the possibility of early intervention, it is necessary to identify the first phases of cognitive involvement. In the long run, it will help find therapies to stop dementia from progressing in PD by allowing for more