Subjective Cognitive Impairment Cohort (SCIENCe): study design and first results

Background: We aimed to describe the Subjective Cognitive Impairment Cohort (SCIENCe) study design, to cross-sectionally describe participant characteristics, and to evaluate the SCD-plus criteria. Methods: The SCIENCe is a prospective cohort study of subjective cognitive decline (SCD) patients. Participants undergo extensive assessment, including cerebrospinal fluid collection and optional amyloid positron emission tomography scan, with annual follow-up. The primary outcome measure is clinical progression. Results: Cross-sectional evaluation of the first 151 participants (age 64 +/- 8, 44% female, Mini-Mental State Examination 29 +/- 2) showed that 28 (25%) had preclinical Alzheimer's disease (AD) (amyloid status available n = 114 (75%)), 58 (38%) had subthreshold psychiatry, and 65 (43%) had neither. More severe subjective complaints were associated with worse objective performance. The SCD-plus criteria age >= 60 (OR 7.7 (95% CI 1.7-38.9)) and apolipoprotein E (genotype) e4 (OR 4.8 (95% CI 1.6-15.0)) were associated with preclinical AD. Conclusions: The SCIENCe study confirms that SCD is a heterogeneous group, with preclinical AD and subthreshold psychiatric features. We found a number of SCD-plus criteria to be associated with preclinical AD. Further inclusion and follow-up will address important questions related to SCD.