[Perception of cognitive deficits and behavior disorders in patients with Alzheimer's disease]

Alzheimer's disease (AD) is associated with cognitive decline and, often, the development of behavioural abnormalities. However, patients may have limited insight into the severity and extent of their impairments. This study was designed to investigate agreement between patients and carers on the assessment of cognitive and behavioural symptoms typically associated with AD. Thirty consecutive outpatients meeting criteria for the diagnosis of AD according to DSM-IV and their respective carers were invited to participate in this study. An enlarged version of the questionnaire for dementia-anosognosia (QD) was used to assess cognitive and behavioural symptoms according to patients and carers. Cognitive impairment was further assessed with the mini-mental state examination (MMSE). The mean age of patients and carers was 71.38 (CI=68.23 to 74.53) and 52.48 (CI=47.11 to 57.86) respectively. Sixty and 73.3% of patients and carers were women. The mean MMSE score for patients was 14.93 (CI=12.68 to 17.18). Agreement between patients and carers for all QD items was assessed using weighted Kappa - rates were low and ranged from 0 to 0.67. Only 3 of the 42 QD items were associated with Kappa values greater than 0.40. The overall score for questions assessing cognitive abilities (QD-A) was significantly lower according to the evaluation of patients than that of carers (paired t-test = -4.07, p<0.001). The same pattern was observed for questions assessing behaviour (QD-B)(paired t-test= -2.27, p=0.032). The Spearman correlation between QD-A and MMSE scores was -0.39 and -0.57 according patients and carers respectively. The association between cognitive anosognosia (difference between QD-A according to carers and patients) and MMSE scores was poor (rho= -0.14). In addition, cognitive anosognosia scores of patients with and without significant depressive symptoms was similar (t= -0.40, p=0.698). These results suggest that AD patients have limited insight into the severity and extent of their cognitive and behavioural problems. In addition, our data shows that this lack of awareness is not influenced by the severity of cognitive impairment or the presence of depressive symptoms.