What is the difference between mild cognitive impairment and Parkinson's dementia?

A fellow caregiver asked...

What is the difference between mild cognitive impairment and Parkinson's dementia?

Expert Answer

Graham A. Glass, MD, is the co-founder of PEAK Neurology and Sleep Medicine, LLC with multiple locations across Alaska. Previously, he was deputy director of the San Francisco Parkinson's Disease Research, Education, and Clinical Care Center PADRECC and assistant clinical professor of neurology at the University of California, San Francisco (UCSF). Glass received his medical degree from the University of Texas Health Sciences Center at the San Antonio School of Medicine and completed his neurology residency at Tufts-New England Medical Center. He subsequently completed a fellowship in movement disorders at the Mayo Clinic.

Mild cognitive impairment implies that a patient is not normal in one or more "domains" of memory, but is not severly struggling in these areas to a degree that it impacts day to day function badly. PD with dementia is thought to be more severe and often patients with PDD (Parkinsons Disease with Dementia) can have hallucinations, confusion, difficulty with visuo-spacial skills (getting one's leg in the right hole of the pants etc.) and or problems with executive function (making good decisions etc). In some cases, we think that MCI may preceed PDD, but this is not always the case.