Self-Consciousness Deficits in Alzheimer's Disease and Frontotemporal Dementia.

Self-consciousness (SC) is multifaceted and considered to be the consciousness of one's own mental states. The main aim of this paper is to compare SC in patients with Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD). Three groups (control and patient groups) of 23 subjects each were assessed using an SC questionnaire. Both types of dementia clearly induce an alteration of SC. The bvFTD group showed a greater impairment in SC than the AD and control groups. The SC score was strongly associated with frontal functions. The most significantly impaired SC aspects in the bvFTD group were Anosognosia, Introspection, and Moral Judgments. For the AD group, the significantly impaired aspects of SC were Anosognosia and Prospective Memory. The differences in SC between the AD and bvFTD groups were essentially centered on the Anosognosia, Moral Judgments, and Introspection aspects, which were highly impaired in the bvFTD patients. This suggests that SC is related to orbito-frontal functioning and thus, to the default mode network.

Self-Consciousness in Patients with Behavioral Variant Frontotemporal Dementia.

Self-consciousness (SC) is multifaceted and considered to be the consciousness of one's own mental states. The medial prefrontal cortex may play a critical role in SC. The main aim of this paper was to examine SC in patients with behavioral variant frontotemporal dementia, who are characterized more by changes in personal, social, and emotional conduct and loss of insight than by cognitive disturbances. Control and patient groups of 21 subjects each, matched by age, educational level, gender, and nationality were assessed using a SC questionnaire. It measures several aspects: Personal identity, Anosognosia, Affective state, Body representation, Prospective memory, Introspection, and Moral judgments. The most disturbed ones in patients were Anosognosia, Affective state, and Moral judgments, and the least disturbed aspects were awareness of identity and of body representation. No significant correlations were found between the SC score and any clinical or demographical characteristics. The core deficiency of SC in patients was related to behavioral SC aspects, which are more dependent on orbito-frontal functioning.

Apathy in Parkinson's disease: an electrophysiological study.

In Parkinson's disease (PD), apathy (or loss of motivation) is frequent. Nevertheless, the contribution of attentional disorders to its genesis is still not clearly known. We want to determine the relation existing between apathy and attentional disorders by using P300a (or novelty P3) as a marker of the attentional process. The study included 25 patients (13 women and 12 men) with PD for whom we have determined the relationship between automatic attention (represented by P300a) and motor status, apathy, executive dysfunction, mental flexibility, inhibitory control, and depression/anxiety. We have found a correlation between the apathy score and amplitude of novelty P300 during the ON period and also a correlation of the apathy score with a decrease in amplitude of P300 during the OFF period. In a linear regression model, changes in the P300a predicted the severity of apathy independently of any other variable. We concluded firstly that the reduction in amplitude of the P300a wave was a neurophysiological marker of apathy in PD and secondly that apathy led to both dopaminergic denervation (mesolimbic) and nondopaminergic (dorsolateral prefrontal-subcortical) dysfunction.