Implementation of subjective cognitive decline criteria in research studies

Abstract

INTRODUCTION Subjective Cognitive Decline (SCD) manifesting prior to clinical impairment could serve as a target population for early intervention trials in Alzheimer’s disease (AD). A working group, the Subjective Cognitive Decline Initiative (SCD-I), published SCD research criteria in the context of preclinical AD. To successfully apply them, a number of issues regarding assessment and implementation of SCD needed to be addressed. METHODS Members of the SCD-I met to identify and agree upon topics relevant to SCD criteria operationalization in research settings. Initial ideas and recommendations were discussed with other SCD-I working group members and modified accordingly. RESULTS Topics included SCD inclusion and exclusion criteria, together with the informant’s role in defining SCD presence and the impact of demographic factors. DISCUSSION Recommendations for the operationalization of SCD in differing research settings, with the aim of harmonization of SCD measurement across studies are proposed, to enhance comparability and generalizability across studies.

Objective features of subjective cognitive decline in a United States national database

“…One recent report indicated that 34 self-report measures are being used across 19 international studies of SCD [26]. At present, there is no “gold standard” method of SCD assessment [44]. However, the single item used in our study did not allow us to assess SCD severity and it may have restricted our ability to capture complaints in domains other than memory, which can be affected early in non-amnestic types of dementia.…”

Subjective Cognitive Decline, Objective Cognition, and Depression in Older Hispanics Screened for Memory Impairment

“…Future studies would be strengthened by using well-validated SCD instruments specifically designed for Hispanic older adults. It is worth noting however, that there is still no gold standard measure to assess SCD [10], especially for Hispanics living in the United Stated (where research is lacking). As such, we view the current findings as a first attempt to replicate previous findings in non-Hispanic Whites, with hopes of improving the measurement of SCD in Hispanics and non-Hispanic Whites as new validated instruments become available in the near future.…”

“…Additional factors such as personality traits and cultural background might also be related to SCD, but little research has been done outside of non-Hispanic White older adult cohorts [5–7]. The Subjective Cognitive Decline Initiative (SCD-I) Working Group recently published recommendations for the implementation of SCD criteria in research studies and mentioned that “further work is needed to determine whether SCD may manifest differently in different racial or ethnic groups” [10]. As such, it is important for the SCD research field to examine if the relationship between SCD scores, cognitive performance, and symptoms of depression in Hispanics is similar to that previously observed in non-Hispanic Whites.…”

<b><i>APOE</i></b> ε4 Genotype and Cognitive Reserve Effects on the Cognitive Functioning of Healthy Elders

“…SCD was assessed using the Memory failures in everyday life following severe head injury [28] and the Subjective Cognitive Decline Questionnaire (SCD-Q) [29]. Although SCD has been recently included in the preclinical stage of AD [30, 31], its identification in the healthy aging population is essential [32] due to their association with a higher risk of AD [33, 34]. …”