The heterogeneity of anosognosia for memory impairment in Alzheimer's disease: A review of the literature and a proposed model

Assessing anosognosia: a critical review

“…In this sample the severity of amnesia, as assessed by means of the Rivermead Behavioural Memory Test (RBMT-3; Wilson et al, 2008) correlated positively with the degree of anosognosia (r= .40 ; p<.05). This finding is in line with one of the three types of anosognosia for amnesia identified by Agnew and Morris (1998) as mnemonic anosognosia. According to these authors, mnemonic anosognosia would be directly caused by amnesia per se, which would prevent a correct updating of the patient's semantic personal knowledge with information about memory failures.…”

“…Lack of awareness of memory deficits in dementia has also been sketched in cognitive models. For instance, Hannesdottir and Morris (2007; See also Agnew & Morris, 1998) distinguished between a form of anosognosia secondary to memory or executive dysfunction, and primary anosognosia, which affects the system of self-awareness directly.…”

“…According to these authors, mnemonic anosognosia would be directly caused by amnesia per se, which would prevent a correct updating of the patient's semantic personal knowledge with information about memory failures. It would be therefore interesting to challenge this diagnosis by exploring whether similar patients would show anosognosia for other possible deficits and, if so, by considering other explanations that may contemplate a common mechanism, such as an impairment of the Conscious Awareness System (CAS), also identified by Hannesdottir and Morris as primary anosognosia (see also Agnew & Morris, 1998).…”

Two aspects of impaired consciousness in Alzheimer's disease

“…The parietal associative cortex related to a discrepancy score in AD may be involved in selfreferential processes or may subserve the ''thirdperson'' knowledge that AD patients have of themselves (Tulving, 1993;Agnew and Morris, 1998;Klein et al, 2003). Accordingly, the right inferior parietal cortex was activated when volunteers had to recall whether an adjective had initially been characterized as fitting their personality (Lou et al, 2004).…”

“…All those parameters may be viewed as confounding factors, that contribute to, but do not yet explain, anosognosia in dementia. Moreover, they show that different dimensions exist in anosognosia (Agnew and Morris, 1998).…”