The Prevalence of Rapid Eye Movement Sleep Behavior Disorder in Amyloid Positron Emission Tomography Positive Alzheimer's Disease

ABSTRACT

OBJECTIVES@#Rapid eye movement (REM) sleep behavior disorder (RBD) is well known as a prodromal symptom of neurodegenerative disease, especially α-synucleinopathy. In the previous literature, it has been reported the incidence rate of RBD in Alzheimer's disease (AD) is about 10%. This incidence rate is relatively low, if we consider that nearly half of AD patients also have Lewy body pathology. The objective of this study is to determine the incidence rate of RBD among patients with AD, confirmed by amyloid positron emission tomography (PET) image.@*METHODS@#We enrolled 57 patients with clinically probable AD patients who identified AD pathology in amyloid PET scan. RBD was evaluated with REM sleep behavior disorder questionnaire-Korean vesion (RBDQ-KR), which validated the RBD screening questionnaire as Korean version to confirm RBD. Detailed neuropsychological tests were measured using the Seoul Neuropsychological Screening Battery (SNSB).@*RESULTS@#We analyzed RBDQ-KR data collected from 57 AD patients. Dementia due to AD was 36 patients (63.2%) and mild cognitive impairment (MCI) due to AD was 21 (36.8%). AD with RBD was 14 (24.6%). Among these, AD dementia with RBD was 13 (36.1%), and MCI due to AD with RBD was 1 (4.8%). There were no significant differences in cognitive function between the patients with or without RBD, evaluated by detailed neuropsychological test.@*CONCLUSIONS@#In this study, the incidence of RBD in AD was not rare; therefore, if the patient shows symptoms of RBD, we should not rule out AD.