Anosognosia in Very Mild Alzheimer’s Disease but Not in Mild Cognitive Impairment

Abstract

Objective: To study awareness of cognitive dysfunction in patients with very mild Alzheimer’s disease (AD) and subjects with mild cognitive impairment (MCI). Methods: A complaint interview covering 13 cognitive domains was administered to 82 AD and 79 MCI patients and their caregivers. The patient groups were comparable according to age and education, and Mini Mental State Examination (MMSE) scores were ≧24 in all cases. The discrepancy between the patients’ and caregivers’ estimations of impairments was taken as a measure of anosognosia. Results: Self-reports of cognitive difficulties were comparable for AD and MCI patients. However, while in comparison to caregivers MCI patients reported significantly more cognitive impairment (p < 0.05), AD patients complained significantly less cognitive dysfunctions (p < 0.001). Conclusions: While most MCI patients tend to overestimate cognitive deficits when compared to their caregiver’s assessment, AD patients in early stages of disease underestimate cognitive dysfunctions. Anosognosia can thus be regarded as a characteristic symptom at a stage of very mild AD (MMSE ≧24) but not MCI. Accordingly, medical history even in mildly affected patients should always include information from both patient and caregiver.

Cognitive complaint in mild cognitive impairment and Alzheimer's disease

“…There was also a remarkable absence of correlation between subjective complaints on memory domains and objective memory performance in AD patients. This finding is consistent with the anosognosia typically reported in AD patients (Farias et al, 2005;Kalbe et al, 2005). Notably, however, the number of AD participants in this study was relatively small (n 5 26) and more statistical power might be required to uncover an association between objective deficits and cognitive complaints in AD.…”

“…However, it is unclear how the cognitive complaint evolves from MCI to AD and within the MCI phase. Whereas some studies have concluded that individuals with MCI and individuals with AD have a similar level of anosognosia (Vogel et al, 2004(Vogel et al, , 2005, others have found that persons with MCI report more cognitive problems (Kalbe et al, 2005) or functional difficulties (Farias et al, 2005) than what is reported by their informant, indicating an overestimation of their deficits. One possibility is that these differences are a function of the phase during which MCI participants were tested: the initial phase could be associated with a higher level of complaint, which would decrease as persons develop more severe deficits and anosognosia.…”

Memory Awareness Profiles Differentiate Mild Cognitive Impairment from Early-Stage Dementia: Evidence from Assessments of Performance Monitoring and Evaluative Judgement

“…This may help to explain the findings from previous research that PwMCI appear to lack awareness but to a lesser extent than PwD [17] and may account for the fact that while some previous studies have identified significant overestimation of functioning among people with MCI [41,42], others have identified considerable heterogeneity in the presentation of awareness in this group [18,19]. PwMCI tend to show normal performance monitoring but impaired evaluative judgement, although the impairment in the latter is less than that seen in PwD.…”

Two aspects of impaired consciousness in Alzheimer's disease

“…Loss of insight may be evaluated by the clinician, on the basis of patient answers to questions probing awareness of cognitive deficits (expert judgment), or by caregivers assessing the frequency of behavioral manifestations of unawareness in everyday life (Derouesne et al, 1999). While most patients with mild cognitive impairment (MCI) tend to overestimate their cognitive deficits when compared to their caregiver's assessment, AD patients in early stages of the disease with similar MMSE scores underestimate their cognitive dysfunction (Kalbe et al, 2005). Accordingly, underestimation of cognitive difficulties (compared to caregiver's assessment) is considered as a risk factor for conversion from MCI to AD (Tabert et al, 2002).…”