Decreased awareness of cognitive deficits in patients with mild dementia of the Alzheimer type

Abstract

Objective To study the unawareness of cognitive deficits in patients with mild dementia of Alzheimer type (DAT). Design Retrospective study. We surveyed the medical records of outpatients meeting the NINCDS–ADRDA criteria for probable DAT who were able to complete the Cognitive Difficulties Scale (CDS) and had a close informant relative (IR) who could complete the family form of the same questionnaire. Setting A department of neurology in a general teaching hospital. Subjects Eighty‐eight patients, aged 73.2±8.6 years with a mean MMSE score of 22.5±3.2. Fifty‐two of the 88 patients had a follow‐up examination after a mean interval of 21 months. Methods Awareness of cognitive deficits was mainly assessed as the difference between the scores on the CDS completed by the IR and the patient (Index of Unawareness, IU). Two secondary assessments of unawareness were performed: (1) an assessment by the clinician on the basis of the patient's answers to questions probing the awareness of memory deficits; (2) an evaluation by the IR of the frequency of behavioural manifestations of unawareness in everyday life. SPECT was performed in 78 patients to study the relationship between unawareness and the topography of perfusion deficits. Results Awareness of the cognitive deficits varied greatly between patients, according to the assessment method used and the stage of progression of the disease. Most patients with mild DAT were cognitively aware of their cognitive deficits but failed to appraise their severity and their consequences in everyday life. Decreased awareness was positively correlated with age and perfusion deficits in the frontal regions and negatively with the anxious symptomatology. However, the main correlate of unawareness was apathy. Conclusion The nature of unawareness of cognitive deficits appeared to be more dimensional than categorical. In patients with mild dementia, decreased awareness appeared to be more related to affective disturbances, especially to emotional deficit or apathy, than to cognitive deficits. Copyright © 1999 John Wiley & Sons, Ltd.

Patterns and persistence of behavioural and psychological symptoms in those with cognitive impairment: the importance of apathy

“…In addition, apathy can increase caregiver burden (Hart et al 2003;Kaufer et al 1998;Pang et al 2002;Thomas et al 2001). Apathy may also reduce quality of life of the patient (Samus et al 2005); although it has been suggested that apathy may not be a concern to the patient themselves and has been associated with lack of awareness in dementia (Aalten et al 2006;Derouesne et al 1999). …”

Two aspects of impaired consciousness in Alzheimer's disease

“…Selfrating of cognitive deficits is also proposed as an index of cognitive unawareness, because AD patients report cognitive impairment that they frequently do not find particularly abnormal for their age (Cummings et al, 1995). 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).…”

“…Studies relating anosognosia to brain activity have shown a decrease of right lateral frontal and parietal activity in AD patients with anosognosia (Leys et al, 1989;Starkstein et al, 1995;Derouesne et al, 1999). In a theoretical model, the ''conscious awareness system'' was suggested to depend on inferior parietal and posterior cingulate cortex (McGlynn and Schacter, 1989).…”

Consciência da doença na demência: resultados preliminares em pacientes com doença de Alzheimer leve e moderada

“…Este relato preliminar aponta para uma diferença significativa na consciência da doença entre os grupos CDR 1 e CDR 2, achado este que corrobora p e s q u i s a s 6,8,13,20 sobre o grau de consciência da d o e n ç a e a evolução clínica. Assim, a consciência da doença diminui na medida em que a doença progride.…”

“…Isto é consistente com o fato de os indivíduos estarem conscientes de determinadas perdas, mas não de outras, ou então, perceberem os déficits, mas não as suas conseqüências 6,20 . Um estudo 13 encontrou correlação positiva entre consciência da doença e idade, mais precisamente com o início tardio da doença. Em nosso estudo a correlação encontrada siderada parcialmente comprometida.…”