Self-consciousness and Alzheimer's disease

Abstract

Objectives– To propose a neuropsychological study of the various aspects of self‐consciousness (SC) in Alzheimer's disease. Methods– Forty‐five patients with probable mild or moderate AD were included in the study. Severity of their dementia was assessed by the Mini Mental State (MMS). Fourteen questions were prepared to evaluate SC. Results– No significant correlations were found between SC score and educational level, age, and duration of disease. A significant correlation was found between SC score and the severity of dementia, whereas frontal disturbances were just short of the significance threshold. The various aspects of SC were not impaired to the same degree. The most disturbed ones were awareness of cognitive deficiencies, moral judgements and prospective memory. The least disturbed aspects were awareness of identity and of mental representation of the body. Items relating to anosognosia and moral judgements were significantly correlated with the MMS score, whereas affective state, body representation disorders, prospective memory, and capacities for introspection were not related to the severity of the dementia. Consciousness of identity was sound, regardless of MMS score. Conclusions– AD clearly induces an heterogeneous impairment of SC. SC requires a convergence of many neural networks. In AD, neuronal alterations involve many cortical areas and information sent to the associative frontal cortex from memory, language and visuospatial areas is lacking or disturbed. Thus, the sequential order of successive stimuli cannot be maintained by the heteromodal associative cortex (dorsal convexity of the prefrontal cortex), and the supramodal associative cortex (located rostrally in the frontal lobes) is unable to provide reliable monitoring and assessment of simultaneous neural cognitive networks carrying insufficient and inadequate input. The core deficiency in AD patients might be impaired SC equated with the disability to maintain sequential and simultaneous “attention to life”. The Self‐Consciousness Questionnaire, a clinical scale providing multidimensional measurement, indicates that different aspects of consciousness are not correlated with overall cognitive deficiency as determined by the MMSE.

Sense of identity in advanced Alzheimer’s dementia: A cognitive dissociation between sameness and selfhood?

“…It is important to note that, compared with the patients included in our study, the ones assessed by Addis and Tippet were at a less severe stage of AD, as attested by their higher MMSE scores (mean score: 19.8 versus 14.0). As reported in previous studies, AD patients" lack of consciousness about their own deficits seems to be related to the severity of their cognitive impairments (Gil et al, 2001). We can therefore hypothesize that some patients at least may have anosognosia, which could contribute to a relatively positive view of themselves.…”

“…Qualitative approaches based on analyses of verbal interactions involving patients have mainly explored the self as a unitary construct in the context of different models such as the social constructionist model (Sabat and Collins, 1999) or interactionist models of self. On the contrary, quantitative approaches have been designed to measure a specific component of the self such as self-knowledge (Gil et al, 2001), role identities (Cohen-Mansfield et al, 2000), self-recognition (Heman et al, 2005) and the identity component of the self-concept (Addis and Tippett, 2004). Studies of the self in Alzheimer"s disease (AD) are scarce and the methodologies used vary widely.…”

Two aspects of impaired consciousness in Alzheimer's disease

“…Several demographic, clinical, and neuropsychological parameters were proposed to be associated with unawareness for self-cognitive deficits in AD. Lack of awareness of AD patients was correlated to dementia severity in most, but not all studies (Sevush and Leve, 1993;McDaniel et al, 1995;Sevush, 1999;Zanetti et al, 1999;Gil et al, 2001). The relationship between anosognosia and depression remains a matter of discussion (Sevush and Leve, 1993;Cummings et al, 1995).…”

Conscience de Soi, maintien du Soi et identité humaine au cours de la maladie d’Alzheimer

“…Une étude des diverses facettes de la conscience de Soi dans une population de malades Alzheimer [10] avait ainsi pu montrer que s'il y avait bien une atteinte de la Conscience de Soi, cette atteinte n'était pas globale mais composite. Ainsi, les connaissances sémantiques sur leur identité, leur conscience du schéma corporel et même la conscience de leur état affectif étaient moins souvent atteintes que la conscience de leur maladie, leur mémoire du futur (donc leur capacité à faire des projets) et les jugements moraux.…”

“…Mais comme le soulignait déjà Locke [19], cette conscience perceptive est inséparable de la conscience de percevoir. La conscience de Soi rassemble de multiples facettes : conscience de ses perceptions et de ses actions, connaissance du corps, évaluation et estime de Soi, conscience de ses projets (mémoire prospective), conscience morale [10,17]. Tel est pour Locke [19] le socle sur lequel se bâtit l'identité personnelle, le Soi, qui procède d'abord de la prise de conscience qu'a ainsi chaque personne de sa singularité par rapport au monde pensant et agissant qui l'entoure.…”