Reliability and Validity of the Clinical Dementia Rating for Community-Living Elderly Subjects without an Informant

Abstract

Background: The Clinical Dementia Rating (CDR) scale is widely used to assess cognitive impairment in Alzheimer's disease. It requires collateral information from a reliable informant who is not available in many instances. We adapted the original CDR scale for use with elderly subjects without an informant (CDR-NI) and evaluated its reliability and validity for assessing mild cognitive impairment (MCI) and dementia among community-dwelling elderly subjects. Method: At two consecutive visits 1 week apart, nurses trained in CDR assessment interviewed, observed and rated cognitive and functional performance according to a protocol in 90 elderly subjects with suboptimal cognitive performance [Mini-Mental State Examination (MMSE) <26 and/or Montreal Cognitive Assessment (MOCA) <26] and without informants according to a protocol. CDR domains and global scores were assigned after the second visit based upon corroborative information from the subjects' responses to questions, role-play, and observed performance in specifically assigned tasks at home and within the community. Results: The CDR-NI scores (0, 0.5, 1) showed good internal consistency (Crohnbach's a 0.83-0.84), inter-rater reliability (κ 0.77-1.00 for six domains and 0.95 for global rating) and test-retest reliability (κ 0.75-1.00 for six domains and 0.80 for global rating), good agreement (κ 0.79) with the clinical assessment status of MCI (n = 37) and dementia (n = 4) and significant differences in the mean scores for MMSE, MOCA and Instrumental Activities of Daily Living (ANOVA global p < 0.001). Conclusion: Owing to the protocol of the interviews, assessments and structured observations gathered during the two visits, CDR-NI provides valid and reliable assessment of MCI and dementia in community-living elderly subjects without an informant.

Mini Mental State Examination and Logical Memory scores for entry into Alzheimer’s disease trials

“…Specifically, the CDR is standardized for multicenter use, has demonstrated good interrater reliability and criterion validity, and has been shown to predict neuropathology [ 26 ]. In fact, even without an informant, recent work in community-dwelling elderly shows the CDR exhibits strong internal consistency (Cronbach’s α 0.83–0.84) and good interrater reliability (0.95 for global rating) and test-retest reliability (κ = 0.80 for global rating) [ 28 ]. The CDR assesses the extent of a person’s impairment in six domains: memory, orientation, judgment/problem-solving, community affairs, home and hobbies, and personal care.…”

Montreal Cognitive Assessment for Screening Mild Cognitive Impairment: Variations in Test Performance and Scores by Education in Singapore

“…Their CDR values were subsequently evaluated (0.5) [29], and a full neuropsychological assessment with a comprehensive test battery was conducted (Digit Span, Rey Auditory Verbal Learning Test, Story Memory, Brief Visuospatial Memory Test-Revised, Boston Naming Test, Color Trails Tests 1 and 2, and Block Design) as well as a clinical diagnostic workup [including clinical examination, relevant blood measurements, and brain imaging (MRI)]. Individuals were diagnosed with MCI after a consensus review of the clinical diagnostic assessment results by a three-member panel of geriatricians and psychiatrists, based on Petersen's [28] criteria (memory complaint usually corroborated by an informant, objective memory impairment for age, essentially preserved general cognitive function, largely intact functional activities, and not demented).…”

Characteristics of detected and undetected dementia among community‐dwelling older people in Metropolitan Tokyo

“…There were a number of limitations in this study. Some participants did not have an informant, and because of this the diagnosis and clinical history was recorded based only on the information supplied by the participants and their environment. However, according to Nyunt et al . the Clinical Dementia Rating scale for use with elderly subjects without an informant showed validity and reliability among community‐dwelling people with mild cognitive impairment and dementia. Diagnosis was based on a long‐form interview with a psychiatrist, and was not conducted in a clinical setting.…”

“…The final diagnosis was made by the interdisciplinary research meeting in the institution, which included more than two certified psychiatrists. We also used the Clinical Dementia Rating scale, which is a widely used measure . Based on information obtained from the participants, family members (if accessible) and prescriptions (if possible), we clarified whether the participants had received a diagnosis of dementia in a clinical setting.…”