Quantified electroencephalographic changes in Parkinson's disease with and without dementia

We examined the presence of quantified electroencephalographic (qEEG) differences between Parkinson's disease (PD) patients with and without dementia, and a group of age-comparable normal controls. While there were no significant differences in relative power in any of the qEEG bands between PD patients without dementia and normal controls, PD patients showed a significantly greater reactivity in the alpha band. On the other hand, PD patients with dementia showed significantly less alpha and more theta relative power than both the normal control and the PD without dementia groups. When PD patients with dementia were compared with a group of patients with Alzheimer's disease (AD) and a similar severity of dementia, no significant between-group differences were found in any of the qEEG bands. In conclusion, while our study demonstrated no significant qEEG differences between non-demented PD patients and normal controls, PD patients with dementia showed qEEG changes similar to those observed in patients with AD.