P arkinson disease is a progressive neurodegenerative disorder that is pathologically defined by degeneration of the dopaminergic neurons in the substantia nigra and development of Lewy bodies in the residual dopaminergic neurons. Pathologic changes may be detected up to 20 years before the onset of motor symptoms, and are accompanied by a clinical prodrome of nonspecific symptoms such as hypos...

Mild cognitive impairment (MCI) was defined by Petersen et al. (1999) as progressive memory loss, a prodrome of Alzheimer's disease. MCI is a well-established entity that can be both a diagnosis in medical practice and a valid target of Alzheimer's prevention therapy. More recently MCI has expanded to include other cognitive domains with other potential causes: amnestic MCI, multiple domains MC...