Two dimensions of anosognosia in patients with Alzheimer's disease: Reliability and validity of the Japanese version of the Anosognosia Questionnaire for Dementia (AQ‐D)

Abstract

Although a number of studies have examined anosognosia of cognitive deficits in patients with Alzheimer's disease (AD), not much is known about the anosognosia of behavioral symptoms in AD. The aims of the present study were to establish a Japanese version of the Anosognosia Questionnaire-Dementia (AQ-D) and to examine its factor structure, reliability and validity, and to identify the effects of various variables on the AQ-D. Factor structure, internal consistency, testretest reliability and concurrent validity of the Japanese version of the AQ-D were analyzed. Multiple regression was then done using the results of the AQ-D as dependent variables and entering all relevant predictor variables. Both the internal consistency and the test-retest reliability of the AQ-D were excellent. Factor analysis indicated four factors: anosognosia of basic and instrumental activities of daily living; that of episodic memory and orientation; that of disinhibited behaviors; and that of apathy and depression. The first two factors were regarded as anosognosia of cognitive deficits and were associated with Mini-Mental State Examination scores, while the latter two factors were regarded as anosognosia of behavioral symptoms and were associated with the Neuropsychiatric Inventory (NPI) score. A dissociation between the two domains of anosognosia was confirmed, namely of cognitive deficits and of behavioral symptoms using the Japanese version of the AQ-D. The knowledge that various factors may have different effects on different domains of anosognosia in patients with AD may serve as useful information for clinicians assessing anosognosia in AD.

The Italian Validation of the Anosognosia Questionnaire for Dementia in Alzheimer’s Disease

“…25 Good internal and external reliabilities of the scale and a satisfactory concurrent validity were confirmed with the following 4 factors originally identified by Starkstein and colleagues: (1) IADL, (2) bADL, (3) apathy, and (4) depression and disinhibition. The 2-point discrepancy cutoff in at least 4 IADL items provides a good level of specificity and sensitivity to the scale.…”

“…Finally, we calculated the congruence coefficients for the components after varimax rotation between the present study and the results of the previous validations. 21,25 A receiver-operating characteristics (ROC) curve was constructed (referring to the clinical diagnosis of presence or absence of anosognosia-Reed's score !2) to analyze sensitivity and specificity for the possible scores on the AQ-D items concerning the IADL domain. This was done in order to identify clinically significant anosognosia and confirm the original cutoff 21 in the Italian population.…”

“…The range of these overestimations is 1 to 7 and correlates with depression (r ¼ .252, P ¼ .007). Anosognosic patients also occasionally overestimate their deficits but only in a few situations (19.15%, 9 of 47, range: 1-3), in particular with regard to items involving behavior factors (items [23][24][25][26][27][28][29][30].…”

“…The exploratory principal component analysis as well as the examination of scree plot confirmed the data of previous validations. 21,25 Four factors in this study explain the 62.6% of variance in the data (1) IADL, corresponding to anosognosia for memory and executive functions deficit, (2) bADL, (3) depression and apathy, and (4) disinhibited behavior.…”

Evaluation of Anosognosia in Alzheimer's Disease Using the Symptoms of Early Dementia-11 Questionnaire (SED-11Q)

“…For external validation of the SED-11Q, we used the standardized questionnaire of anosognosia, the Japanese version of the Anosognosia Questionnaire for Dementia (AQ-D) [20,21], which contains questions about the awareness of deficits in intellectual functioning (22 items), and mood and behavior domains (8 items). Each item of the AQ-D was evaluated on a 0-3 scale: never (0 points), sometimes (1 point), usually (2 points), or always (3 points).…”