[The characteristics of Parkinson's disease with dementia and Alzheimer's disease with impaired cognitive function].

Objective: To analyze the characterization of cognitive function in Parkinson's disease with dementia and Alzheimer's disease.

Methods: Cognitive function was examined in Parkinson's disease with dementia (PDD) patients (n = 30), Alzheimer's disease (AD) patients (n = 30) and healthy elderly control subjects (n = 60). Neuropsychological evaluation contained semantic fluency test, phonemic fluency test, action fluency test, objective and action naming tests.

Results: In PDD group, the score of semantic fluency test is 9.33 ± 2.78, 6.17 ± 1.67 of phonemic fluency test and 7.03 ± 2.34 of action fluency test, it is 6.90 ± 2.47, 7.87 ± 2.01, 8.30 ± 3.17 of AD group. The score of objective and action naming tests is 36.33 ± 3.39, 17.63 ± 2.17 in PDD group, while AD patients is 33.23 ± 3.56 and 22.33 ± 2.37. The verbal fluency tests and naming tests were impaired in PDD and AD patients compared with the healthy elderly control group (P < 0.01), phonemic fluency, action fluency and action naming were more impaired in PDD patients compared with the AD group, while semantic fluency and objective naming were more impaired in AD patients (P < 0.01).

Conclusions: Executive function deficit and naming impairment are found in PDD and AD patients, it shows that PDD is characterized by the addition of cortical dysfunction upon a predominant and progressive fronto-subcortical impairment. There is subcortical dysfunction in AD patients.