Retrospective Diagnosis of Dementia Using an Informant Interview Based on the Brief Cognitive Rating Scale

Abstract

The accuracy of a dementia diagnosis by specialist physicians, as verified at an autopsy, is greater than 90% in many series. Donations of brains to the Maritime Brain Tissue Bank (MBTB) by individuals who did not have expert dementia diagnoses before death led us to investigate whether clinical features could also be detected retrospectively. Informants for 36 individuals whose brains were in the MBTB (18 women, mean age = 79 years; pathologic diagnoses: 75% Alzheimer's disease [AD]; 8.4% vascular or mixed dementia) were interviewed by specialist physicians using a semistructured retrospective interview based on the Brief Cognitive Rating Scale (BCRS) (range = 1 [no impairment] to 7 [terminal dementia]). The mean duration of dementia was 8.5 ± 12.8 years based on proxy reports, and most cases suggested severe dementia—(stage 6 [severe] or 7 [terminal])—on the retrospective BCRS (RetroBCRS) before death. A score of 4 or more on the RetroBCRS had 100% sensitivity and specificity in detecting dementia. The RetroBCRS score correlated moderately with duration (.51). In linear and logistic regression models adjusted for age and sex, RetroBCRS staging helped explain 93% of the variation in duration. The accuracy of the retrospective diagnosis of the cause of dementia, compared with autopsy, was 92%. The RetroBCRS used by an expert physician with a reliable informant is a valid method of detecting dementia and determining whether AD was present.

Accuracy of Collateral Source Reports in Very Mild to Mild Dementia of the Alzheimer Type

“…Several standardized instruments for obtaining this information are now available. 7,[13][14][15] Collateral sourcebased methods have been used successfully to detect very mild stages of dementia, 11,16,17 where individual variability often precludes the discrimination of very mild dementia from nondemented aging by cognitive test performance. 9,10 Self-reported memory complaints of older individuals have been found to correlate better with depression than with dementia, whereas the collateral source's report of recent memory change better predicts dementia.…”

“…11,12 Collateral sources provide information about a person's current level of cognitive functioning contrasted with previous levels, as well as the course of cognitive decline. 7,[13][14][15] Collateral sourcebased methods have been used successfully to detect very mild stages of dementia, 11,16,17 where individual variability often precludes the discrimination of very mild dementia from nondemented aging by cognitive test performance. 18 Moderate to good agreement between collateral source reports and objective tests of cognitive performance in moderate dementia has been reported.…”

Clinical Characteristics of Dementia Associated with Argyrophilic Grain Disease

“…Retrospective Dementia Inventory Informant interviews were conducted using an extended version of the Retro Brief Clinical Rating Scale (RetroBCRS) [14] , the Retrospective Dementia Inventory (RDI). The RetroBCRS has proven to be a valid method of retrospectively determining AD in autopsy-confirmed patients [14] . The new RDI was developed to assess the deceased patient's symptoms along 3 axes: (1) activities of daily living (ADL)/behavior, (2) affect and (3) cognition [15] .…”

“…The new RDI was developed to assess the deceased patient's symptoms along 3 axes: (1) activities of daily living (ADL)/behavior, (2) affect and (3) cognition [15] . It comprises 140 questions, of which 117 were taken from the RetroBCRS [14] , 5 from the Clinical Dementia Rating Scale [16] , 4 from the Nurses' Observation Scale for Geriatric Patients [17] , 3 from the Neuropsychiatric Inventory [18] and 11 were newly created questions. The symptom or symptoms queried by each question were identified and allocated to 1 of the 3 axes.…”

The association between late-life cognitive test scores and retrospective informant interview data

“…This may provide a better indication of the subject's cognitive ability, particularly in the period up to their death when they may be cognitively impaired and unable or unwilling to complete testing. In his review, Jorm (2004) comments that it has also been used in prospective studies of dementia to assess cognitive ability in participants who die between assessment waves (Rockwood et al, 1998), and to assess cognitive decline preceding complications such as stroke (Henon et al, 2001), delirium (Cole et al, 2002), or admission to intensive care (Pisani et al, 2003). There is no standard informant interview that is used uniformly across studies.…”