Neuropsychological Profiles in Mild Cognitive Impairment due to Alzheimer's and Parkinson's Diseases.

Background: Neuropsychological comparisons between patients with mild cognitive impairment due to Parkinson's disease (MCI-PD) and Alzheimer's disease (MCI-AD) is mostly based on indirect comparison of patients with these disorders and normal controls (NC). Objective: The focus of this study was to make a direct comparison between patients with these diseases. Methods: The study compared 13 patients with MCI-PD and 19 patients with MCI-AD with similar age, education and gender. The participants were recruited and assessed at the same university clinic with equal methods. Results: The main finding was that on group level, MCI-AD scored significantly poorer on learning and memory tests than MCI-PD, whereas MCI-PD were impaired on 1 of 3 measures of executive functioning. Conclusion: MCI-AD performed poorer learning and memory tests, whereas MCI-PD only scored below the employed cut-off on one single executive test. In general, MCI-PD was noticeably less cognitively impaired than MCI-AD.