Decrease of event related theta power is more profound in patients with Parkinson's disease dementia in comparison to Alzheimer's disease dementia

Abstract

AbstractBackgroundAlzheimer's disease dementia (ADD) and Parkinson's disease dementia (PDD) are the most common types of dementia. ADD and PDD have different pathophysiology and clinical profile. It is important to understand mechanisms underlying pathophysiology, clinical symptoms, and the electrophysiological differences between these two types of dementia. Event‐related theta responses during cognitive paradimgs are one of the essential biomarkers that could succfesully show cognitive decline in dementia patients (Yener et al.,2007;Güntekin et al.,2020). The aim of the present study was to investigate the Event‐related theta responses during the visual cognitive task in patients with PDD and ADD in order to find the differentiation between these two types of dementia.MethodEEG recordings of 15 patients with ADD, 15 patients with PDD, and matched 15 healthy elderly controls (HC) were performed during the visual oddball paradigm. Event‐related phase‐locking and power analysis were performed for theta frequency band (4‐7 Hz). Repeated measures of ANOVA was used for statistical analysis (p<0.05).ResultThere were significant differences among groups for both event‐related theta phase‐locking (p=0.004) and theta power (p<0.0001). ADD (p<0.005) and PDD (p<0.005) groups had reduced theta phase‐locking in comparison to the HC group (Figure 1). Especially, this reduction was more pronounced in the PDD group. In addition, the PDD group had decreased theta power as compared to the HC (p<0.0001) and ADD (p<0.005) group (Figure 1). Figure 1 shows the grand average of event‐related theta power (upper part) and phase‐locking (lower part) and in HC, ADD and PDD groups.ConclusionThe present study showed decreased event‐related theta responses during the visual oddball paradigm in patients with dementia. Especially, PDD patients had the worst event‐related theta responses. These findings could be interpreted as the visual cognitive processes are more impaired in PDD patients compared to ADD patients.