A cohort study to identify predictors for the clinical progression to mild cognitive impairment or dementia from subjective cognitive decline: Neuroimaging / Multi‐modal comparisons. (7th December 2020) - Yang, Dong Won
Abstract: Background: Subjective cognitive decline(SCD) has been considered as at risk state to progress to mild cognitive impairment(MCI) or Alzheimer's disease(AD) dementia. The purpose of this study is to set up cohort and to identify risk factors for the progression to MCI or dementia from amnestic SCD Method: We enrolled subjects aged 60 years or older complaining of persistent cognitive decline. To include higher risk SCD patients with rapidly progression, subjects needs to have 7% to 50% of the verbal memory and over 7% of the rest subtests of comprehensive neuropsychological battery. We named this state of SCD as an amnestic SCD. Brain magnetic resonance imaging (MRI) volumetry, visual and standardized uptake value ratio (SUVR) analysis of 18F‐Florbetaben brain amyloid‐beta Positron Emission Tomography (PET) were. Blood amyloid oligomerization was measured by the Multimer Detection System‐Oligomeric Aβ (MDS‐OAβ) method. Quantitative EEG were also analyzed. Sleep time and physical activity were collected with wearable device (Fitbit alta). Gait speed, body mass index, and muscle strength were measured. Result: We analyzed 120 SCD subjects (male 53, female 67). Mean age and education were 70.9 and 11.2 years. 25 (20.8%) showed amyloid positive PET and 26(21.6%) had APOE ε4 allele. Positive amyloid PET SCD had higher frequency of APOE ε4 (48%) compared to amyloid negative SCD (14%). Positive amyloid PET SCD also had lower delayed verbal memory score and lower frontal inferior, anterior, medial and lateral temporal and lateral parietal regional brain volume ratio. Power spectral analysis of EEG showed increased relative theta /alpha ratio in the bilateral frontal regions. sLORETA showed increased theta spectrum in the left superior temporal, transverse temporal and fusiform area in amyloid positive SCD. MDS‐OAβ was positive in 55.1% which was not associated with SUVR value of amyloid PET. Conclusion: Amnestic SCD with amyloid PET positive showed higher APOE ε4 allele, lower regional brain volume in AD related areas, lower verbal memory score and higher relative theta/alpha ratio in the frontal area. Longitudinal follow‐up for the next 3 years will identify risk factors for the progression to MCI or dementia and clinical significance of blood MDS‐OAβ value.