Reflective consciousness in degenerative dementia: The ReCoDe study [Coscienza riflessiva nelle demenze degenerative: Lo studio ReCoDe]

Objective: The clinical picture of Alzheimer's disease (AD) and other forms of degenerative dementia is characterized by cognitive and neuropsychological dysfunction and progressive loss of reflective consciousness (RC), sometimes referred to as self-awareness. However, limited knowledge is currently available concerning the specific pattern of impairment in RC in different stages and subtypes of dementia. The aim of this study was to investigate RC in a population of patients with degenerative dementia, with special attention being focused on the relationship between alteration of RC and the natural history/neuropsychiatric profile of the disease. Methods: A total of 103 outpatients attending the Dementia Clinic, Department of Neurology, Amedeo Avogadro University, Novara, and the Dementia Clinic, S. Andrea Hospital, Vercelli, Italy, have been recruited. Inclusion criteria were: 1. diagnosis of mild or moderate degenerative dementia according to DSM-IV and NINCDS/ADRDA criteria, and 2. age-corrected mini-mental state examination (MMSE) > 10. All patients underwent a comprehensive neuropsychological examination and neuropsychiatric assessment for behavioural and psychological signs and symptoms of dementia (BPSD). RC was indexed in each subject using the 14-item Self-Consciousness Questionnaire (SCQ). Results: Four groups of patients were studied: 57 patients with Alzheimer's disease (AD); 18 with frontotemporal dementia (FTD); 8 with dementia with Lewy bodies (DLB); 18 with mixed dementia (MD). The four groups did not differ in terms of clinical severity (CDR scores) and cognitive dysfunction (MMSE scores) (Tab. I). However, patients with FTD scored significantly lower (p < 0.05) than other dementia groups on the SCQ (especially questions on moral judgement, introspection, metacognition, and self-evaluation of the affective state), whilst patients with AD showed marked deficits in awareness of identity and self evaluation of affect (Fig. 1). Overall SCQ scores correlated significantly (p < 0.01) with the frontal function tests (Frontal Assessment Battery, FAB; Middelheim Frontality Score, MFS), but did not show any correlation with other clinical characteristics, including affective disorders as assessed using the Cornell Scale for Depression in Dementia (CSDD) (Tab. II). Conclusions: Overall, RC is more severely affected in patients with FTD than in patients with other forms of degenerative dementia, regardless of the degree of cognitive deficit. With respect to RC domains, FTD seems to be characterised by selective deficit in moral and self judgements, as predicted by predominant involvement of the frontal lobe; on the other hand, patients with AD show a predominant impairment in awareness of identity and self evaluation of affect, consistent with the early involvement of the posteromedial parietal regions, which are part of the "default mode" of the conscious resting state, and are thought to subserve self processing and first-person perspective taking.