Comparison of 2 Informant Questionnaire Screening Tools for Dementia and Mild Cognitive Impairment

Abstract

Background Dementia and mild cognitive impairment (MCI) are under-recognized in community settings. This may be due in part to the lack of brief dementia screening tools available to clinicians. We compared two brief, informant-based screening tests: the AD8 and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) in a community-based neurology practice in the Midwestern United States Methods We examined 186 consecutive patients (44 controls, 13 with MCI, and 129 with dementia). Receiver operator characteristic curves were used to examine the ability of AD8 and IQCODE to discriminate between controls and MCI or dementia. Sensitivity, specificity, predictive values, and likelihood ratios were reported. Results AD8 differentiated healthy controls from MCI (p<.001) or dementia (p<.001), as well as MCI from dementia (p=.008). The IQCODE differentiated controls and MCI from dementia (both p<.001), and between controls and MCI (p=.002). Both AD8 (AUC = 0.953, 95% CI: 0.92–0.99) and IQCODE (AUC = 0.930, 95% CI: 0.88–0.97) provided discrimination between controls and patients with dementia; however the AD8 had superior sensitivity detecting dementia (99.2%) and MCI (100%) compared to the IQCODE (79.1% for dementia, 46.1% for MCI) with non-overlapping confidence intervals. Using published cut-offs (AD8 ≥ 2, IQCODE ≥ 3.4), only one case of dementia was missed with the AD8 while the IQCODE failed to detect dementia in 27 individuals. The AD8 detected MCI in all 13 individuals while the IQCODE misclassified 7 individuals. Conclusion Both the AD8 and IQCODE were able to detect dementia in a community setting. The AD8, however, was more successful than IQCODE in detecting MCI. If simple and efficient screening for early cognitive impairment is the goal, particularly in the early stages (e.g., for prevention trials or public screening), the combination of an informant interview (the AD8) and a brief performance measure could be considered as they meet the basic requirements of the Personalized Prevention Plan for Medicare beneficiaries.

Screening for Dementia in Older Adults: Comparison of Mini-Mental State Examination, Mini-Cog, Clock Drawing Test and AD8

“…For the Mini-Cog analysis, the optimal algorithm had the following three rules: (i) subjects recalling none of the words were classified as having dementia, (ii) those recalling all three words were classified as without dementia, and (iii) those with intermediate word recall (1–2) were classified based on the CDT(abnormal = having dementia, normal = without dementia) [14]. For the CDT evaluation in the present work, the results were evaluated by scoring from 1 point (perfect) to6 points (not at all representation of a clock), a score less than 4was considered as dementia.TheAD8 had 8 yes/no questions and took 2 to 3 minutes to complete [22], and a score of AD8 above 1 was considered as dementia [14]. …”

An Informant-Based Simple Questionnaire for Language Assessment in Neurodegenerative Disorders

“…Lastly, we wanted to address an important problem, which is that commonly used informant-based questionnaires for the screening of dementia or mild cognitive impairment from normal elderly, including CDR, AD8, and IQCODE, lack or have few questions regarding language dysfunction [6, 26-28]. We provided a simple informant-based language questionnaire for the clinical assessment of individuals with or without dementia.…”

Detection of Dementia

“…In a comparison of the AD8 and the IQCODE, both were able to detect the presence of cognitive impairment in community settings and were highly correlated with brief assessments of cognitive ability (MMSE, Mini-Cog, Clock Drawing, and Animal Naming) that are commonly used in community settings [ 71 ]. Both the AD8 and IQCODE differentiated cognitively normal from individuals with dementia, however, the AD8 was better than the IQCODE in detecting MCI [ 71 ]. While the IQCODE covers two aspects of memory (acquisition of new information and retrieval of existing knowledge) and two aspects of intelligence (verbal and performance), the AD8 contains items that relate to memory, problem-solving abilities, orientation, and daily activities.…”

“…The rating scale was designed to refl ect cognitive improvement as well as cognitive decline, to allow for the questionnaire to be used in treatment trials and following acute illnesses [ 70 ]. In a comparison of the AD8 and the IQCODE, both were able to detect the presence of cognitive impairment in community settings and were highly correlated with brief assessments of cognitive ability (MMSE, Mini-Cog, Clock Drawing, and Animal Naming) that are commonly used in community settings [ 71 ]. Both the AD8 and IQCODE differentiated cognitively normal from individuals with dementia, however, the AD8 was better than the IQCODE in detecting MCI [ 71 ].…”