The Alzheimer's questionnaire: a proof of concept study for a new informant-based dementia assessment (original) (raw)
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An Informant Questionnaire for Detecting Alzheimer's Disease: Are Some Items Better Than Others?
Journal of the International Neuropsychological Society, 2011
A decline in everyday cognitive functioning is important for diagnosing dementia. Informant questionnaires, such as the informant questionnaire on cognitive decline in the elderly (IQCODE), are used to measure this. Previously, conflicting results on the IQCODEs ability to discriminate between Alzheimer's disease (AD), mild cognitive impairment (MCI), and cognitively healthy elderly were found. We aim to investigate whether specific groups of items are more useful than others in discriminating between these patient groups. Informants of 180 AD, 59 MCI, and 89 patients with subjective memory complaints (SMC) completed the IQCODE. To investigate the grouping of questionnaire items, we used a two-dimensional graded response model (GRM).The association between IQCODE, age, gender, education, and diagnosis was modeled using structural equation modeling. The GRM with two groups of items fitted better than the unidimensional model. However, the high correlation between the dimensions (r5.90) suggested unidimensionality. The structural model showed that the IQCODE was able to differentiate between all patient groups. The IQCODE can be considered as unidimensional and as a useful addition to diagnostic screening in a memory clinic setting, as it was able to distinguish between AD, MCI, and SMC and was not influenced by gender or education. (JINS, 2011, 17, 674-681)
The combination of cognitive testing and an informant questionnaire in screening for dementia
Age and Ageing, 2003
Aim: a cognitive test and an informant report questionnaire were used together to investigate whether their combined use could improve the accuracy of detecting dementia in a memory clinic, compared with either test used alone. Method: the subjects were 323 patients assessed at a memory clinic. The Mini-Mental State Examination and the short form of the Informant Questionnaire on Cognitive Decline in the Elderly were used. A method of combining the test scores developed by Mackinnon and Mulligan [Am J Psychiatry 1998; 155: 1529-35] was used. Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised criteria. Results: logistic regression analysis showed that the combination of the Mini-Mental State Examination and the Informant Questionnaire on Cognitive Decline in the Elderly produced a slightly more accurate prediction of dementia caseness than either test used alone. Using receiver operating characteristic analysis the performance of the combination of the tests according to a weighted sum rule was compared with the performance of either test used alone. This way of combining the tests resulted in a more accurate screening for dementia than when the Informant Questionnaire on Cognitive Decline in the Elderly was used alone. The area under the receiver operating characteristic curve for the Mini-Mental State Examination combined with the Informant Questionnaire on Cognitive Decline in the Elderly was 0.89 compared with 0.82 for the Informant Questionnaire on Cognitive Decline in the Elderly alone (chisquare = 10.63; P = 0.0011). However, there was no improvement in screening performance when the combination of Mini-Mental State Examination and Informant Questionnaire on Cognitive Decline in the Elderly was compared with the Mini-Mental State Examination used alone (area under the receiver operating characteristic curve = 0.89 versus 0.86; chi-square = 3.54; P = 0.060). Conclusion: the combination of cognitive testing and an informant report according to a weighted sum rule in this population did not result in any advantage over the use of the Mini-Mental State Examination alone. The mixed results of this study contrast with those of Mackinnon and Mulligan.
Validation and diagnostic accuracy of the Alzheimer's questionnaire
Age and Ageing, 2012
Background: accurately identifying individuals with cognitive impairment is difficult. Given the time constraints that many clinicians face, assessment of cognitive status is often not undertaken. The intent of this study is to determine the diagnostic accuracy of the Alzheimer's questionnaire (AQ) in identifying individuals with mild cognitive impairment (MCI) and AD. Methods: utilising a case-control design, 300 [100 AD, 100 MCI, 100 cognitively normal (CN)] older adults between the ages of 53 and 93 from a neurology practice and a brain donation programme had the AQ administered to an informant. Diagnostic accuracy was assessed through receiver-operating characteristic analysis, which yielded sensitivity, specificity and area under the curve (AUC). Results: the AQ demonstrated high sensitivity and specificity for detecting )]; [91.00 (83.60-65.80)] and AD [99.00 (94.60-100.00)]; [96.00 (90.10-98.90)]. AUC values also indicated high diagnostic accuracy for both MCI [0.95 (0.91-0.97)] and AD [0.99 (0.96-1.00)]. Internal consistency of the AQ was also high (Cronbach's alpha = 0.89).
Journal of Clinical Epidemiology, 2003
This study sought to determine whether the augmentation of cognitive testing with an informant report questionnaire could improve accuracy in screening for dementia in a community setting. The sample consisted of 646 subjects aged 70-93 years. Cognitive state was assessed using the Mini-Mental State Examination (MMSE). Informants completed the 16-item short form of the Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE). Dementia was diagnosed according to DSM-III-R criteria. Combination of the IQCODE with the MMSE resulted in more accurate prediction of caseness than either test alone. Receiver Operating Characteristic analysis demonstrated the superior screening performance of a logical "or" rule and a weighted sum of scores on the two tests over other methods of combination, replicating previous clinically based research. The findings also suggest that the appropriate combination of existing tests may be a fruitful method of improving screening accuracy in a variety of situations. Ć
International Journal of Geriatric Psychiatry, 1996
The performance characteristics of an informant screening test for senile dementia were evaluated within a community-dwelling sample of 583 elderly persons in the Bordeaux region of France. Receiver operating characteristics analysis indicated that although the test performs less well within this context than within a previous case-control study, it nonetheless retains high discriminability. A specificity of 90% and a sensitivity of 79% for the detection of diagnosed senile dementia were obtained with a cutoff point of 24/25. The discriminability of the test was not affected by level of education. The study demonstrates the necessity of adjusting the cutoff point of dementia screening instruments according to the estimated prevalence rate of dementia in the target population. The potential utility of the instrument as a method of detecting dementia by postal survey and in cross-cultural research is discussed.
Alzheimers & Dementia, 2006
Background: Studies of dementia in populations avoid many of the selection biases in clinical samples but require special evaluation and diagnostic methods to obtain high participation rates. To address this issue, we developed a unique in-home dementia assessment. We assessed validity of these assessments using neuropathologic confirmation of the clinical diagnosis in 3 epidemiologic samples. Methods: Subjects were 175 participants in 3 ongoing studies of dementia. Two were population based and identified dementia by cognitive screening. The third study sought volunteers via advertisements. Dementia evaluations were then conducted at the participants' residences by specially trained nurses and psychometricians. Evaluation results were interpreted, and preliminary diagnoses were assigned by a geropsychiatrist or neurologist and a psychologist. Final diagnoses were assigned by a consensus panel of neurologists, geropsychiatrists, and psychologists. We compared the clinical diagnoses with the gold-standard neuropathologic diagnoses for those participants who subsequently underwent autopsy. Results: Among the demented, the sensitivity of a clinical diagnosis of probable or possible Alzheimer's disease (AD) was 93% across the 3 studies. The rate of overall diagnostic agreement was 81%. Measures of agreement did not differ meaningfully across varying levels of dementia severity. Conclusions: Rates of neuropathologic confirmation for clinical AD diagnoses in these studies were similar to those reported from clinic-based samples. These results support the validity of clinical diagnoses of AD from a structured in-home assessment of community dwelling and institutionalized individuals using relatively economical methods of dementia screening and assessment.
The Alzheimer's disease assessment scale (ADAS): An instrument for early diagnosis of dementia?
International Journal of Geriatric Psychiatry, 1988
With the aim of detecting mild dementias, 94 elderly subjects who had been participating in a long‐term study since 1976 were studied by means of a new diagnostic instrument, the Alzheimer's Disease Assessment Scale (ADAS) (Rosen et al., 1984). Data available from intelligence tests performed during the course of the long‐term study were also analysed.On the basis of an independent clinical assessment, four subjects were rated as clearly demented, seven as possibly demented, and 83 as normal. A comparison of these three groups showed that the subjects classified as demented obtained significantly poorer scores on the ADAS than did the group of normal subjects. The cognitive section of the ADAS distinguished even better between the normal and the clearly demented subjects. On the other hand, there was no indication that the ADAS was specifically sensitive to degenerative types of dementia since the subject with the highest ADAS score was suffering from vascular dementia. There we...
Comparative Analysis of the Alzheimer Questionnaire (AQ) With the CDR Sum of Boxes, MoCA, and MMSE
Alzheimer Disease & Associated Disorders, 2012
The Alzheimer Questionnaire (AQ) has been established as a valid and accurate informant-based screening questionnaire for Alzheimer disease and amnestic mild cognitive impairment. Although the AQ's validity and diagnostic accuracy has been established, its performance in comparison with other instruments has not. Thirty-nine amnestic mild cognitive impairment cases and 34 Alzheimer disease cases were matched on the basis of age, education, and sex to 73 cognitively normal individuals. The sample had a mean age of 82.54 ± 7.77 years and a mean education level of 14.61 ± 2.61 years. The diagnostic accuracy of the CDR Sum of Boxes, Mini Mental State Exam (MMSE), and Montreal Cognitive Assessment (MoCA) were compared with the AQ. The AQ correlated strongly with the CDR Sum of Boxes (r = 0.79) and demonstrated similar diagnostic accuracy with the MoCA and MMSE. These results suggest that the AQ is comparable with other established informant-based and patient-based measures.