We investigated the efficacy of donepezil for mild cognitive impairment in Parkinson’s disease (PD-MCI). This was a prospective, non-randomized, open-label, two-arm study. Eighty PD-MCI patients were assigned to either a treatment or control group. The treatment group received donepezil for 48 weeks. The primary outcome measures were the Korean version of Mini-Mental State Exam and Montreal Cognitive Assessment scores. Secondary outcome measures were the Clinical Dementia Rating, Unified Parkinson’s Disease Rating Scale part III, Clinical Global Impression scores. Progression of dementia was assessed at 48-week. Comprehensive neuropsychological tests and electroencephalography (EEG) were performed at baseline and after 48 weeks. The spectral power ratio of the theta to beta2 band (TB2R) in the electroencephalogram was analyzed. There was no significant difference in the primary and secondary outcome measures between the two groups. However, the treatment group showed a significant decrease in TB2R at bilateral frontotemporoparietal channels compared to the control group. Although we could not demonstrate improvements in the cognitive functions, donepezil treatment had a modulatory effect on the EEG in PD-MCI patients. EEG might be a sensitive biomarker for detecting changes in PD-MCI after donepezil treatment.

Background Early screening biomarker has been required to discriminate higher risk of progressive subgroup in subjective cognitive decline(SCD) at preclinical stage. Study purpose was to identify quantitative EEG patterns among different condition of amnestic SCD Method From 6 dementia clinics in Korea, we enrolled participants aged over 60 years with complaining of persistent cognitive decline, performance range of 7% to 50% of the verbal memory tests and over 7% of the rest subtests of comprehensive neuropsychological battery. Both 18F‐Florbetaben brain amyloid‐beta PET and genetic test for APOE ε4 allele were conducted. EEG was measured at 19 channels of international 10‐20 system under resting state, and spectrum power and power ratio were calculated. Source cortical activity was mathematically estimated by standardized low resolution brain electromagnetic tomography(sLORETA) Result 120 SCD subjects (male 53, female 67) were included. Amyloid PET(+) was 25 (20.8%) and APOE ε4 allele (+) was 26(21.6%) independently. Amyloid PET (+) SCD had higher frequency of APOE e4 (48%) compared to amyloid PET (‐) SCD (14%). We selected 67 amyloid PET (‐) SCD older than 65 years to escape age differences between 2 groups. Amyloid PET (+) SCD showed significant increase of relative theta power at left frontotemporal(Fp1, F7, T5), both occipital(O1,2) and right parietal(P4) channels. Similarly, significant enhancement of theta was observed at left superior and transverse temporal, fusiform and cuneus at sLORETA in amyloid PET (+) SCD. Among amyloid PET (+) SCD, APOE ε4 (+) subgroup showed significant increase of theta/beta ratio at both superior frontal and anterior cingulate, right parietal and occipital area Conclusion Amnestic SCD with amyloid (+) showed relative enhancement of slow wave in resting EEG, which have been similarly reported about amnestic MCI or AD dementia. QEEG could be tentative biomarker to screen AD or to predict progressiveness of SCD at preclinical stage. Longitudinal study and development of single quantitative index of QEEG to evaluate individual subject will be needed to confirm its clinical significance.