Operational Determination of Subjective Cognitive Decline, Mild Cognitive Impairment, and Dementia Using Sum of Boxes of the Clinical Dementia Rating Scale.

Yu-Wan Yang,Ray-Chang Tzeng,Cheng-Yu Wei,Kai-Cheng Hsu,Pai-Yi Chiu

doi:10.3389/fnagi.2021.705782

Abstract

Objectives: The Clinical Dementia Rating (CDR) Scale is the gold standard for the staging of dementia due to Alzheimer's disease (AD). However, the application of CDR for the staging of subjective cognitive decline (SCD) and mild cognitive impairment (MCI) in AD remains controversial. This study aimed to use the sum of boxes of the CDR (CDR-SB) plus an SCD single questionnaire to operationally determine the different stages of cognitive impairment (CI) due to AD and non-AD.Methods: This was a two-phase study, and we retrospectively analyzed the Show Chwan Dementia registry database using the data selected from 2015 to 2020. Individuals with normal cognition (NC), SCD, MCI, and mild dementia (MD) due to AD or non-AD with a CDR < 2 were included in the analysis.Results: A total of 6,946 individuals were studied, including 875, 1,009, 1,585, and 3,447 with NC, SCD, MCI, and MD, respectively. The cutoff scores of CDR-SB for NC/SCD, SCD/MCI, and MCI/dementia were 0/0.5, 0.5/1.0, and 2.5/3.0, respectively. The receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) values of the test groups were 0.85, 0.90, and 0.92 for discriminating NC from SCD, SCD from MCI, and MCI from dementia, respectively. Compared with the Cognitive Abilities Screening Instrument or the Montreal Cognitive Assessment, the use of CDR-SB is less influenced by age and education.Conclusion: Our study showed that the operational determination of SCD, MCI, and dementia using the CDR-SB is practical and can be applied in clinical settings and research on CI or dementia.

Highlights

The Clinical Dementia Rating (CDR) Scale is a semi-structured interview and a golden standard protocol for investigating people with dementia of the Alzheimer type or probable Alzheimer’s disease (AD) (Hughes et al, 1982; Morris, 1997)
The pre-dementia phases of AD or other dementia, which include subjective cognitive decline (SCD) and mild cognitive impairment (MCI), have gradually attracted the attention of researchers; robust studies for predicting progression among people in these phases are in full swing (Palmer et al, 2007; Mitchell and Shiri-Feshki, 2009; Snitz et al, 2018; Mazzeo et al, 2019)
The CDR has been used in many clinical trials or studies, its reliability is suboptimal in very mild dementia (VMD) cases with CDR = 0.5 (Rockwood et al, 2000; Schafer et al, 2004; Duara et al, 2010)

Summary

Introduction

The Clinical Dementia Rating (CDR) Scale is a semi-structured interview and a golden standard protocol for investigating people with dementia of the Alzheimer type or probable Alzheimer’s disease (AD) (Hughes et al, 1982; Morris, 1997). Many studies have indicated that non-medical personnel reliably apply the CDR Scale to identify and determine the stage of dementia (McCulla et al, 1989; Chaves et al, 2007). The CDR has been used in many clinical trials or studies, its reliability is suboptimal in very mild dementia (VMD) cases with CDR = 0.5 (Rockwood et al, 2000; Schafer et al, 2004; Duara et al, 2010). The CDR-SB score has a wider dynamic range (0–18) than the CDR (0–3) and can be analyzed as an interval variable

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Discussion

Conclusion