Anosognosia in Alzheimer disease: Prevalence, associated factors, and influence on disease progression

Anosognosia is a frequent symptom in Alzheimer disease (AD). The objective of this article is to describe prevalence of this condition at time of diagnosis and analyse any predisposing factors and their influence on disease progression.

Observational, prospective, and analytical multi-centre study in an outpatient setting. Patients recently diagnosed with AD (NINCDS-ADRDA criteria) were included. Each patient underwent two cognitive, functional, and neuropsychiatric assessments separated by an interval of 18 months. The Clinical Insight Rating Scale was employed as a measure of anosognosia (CIR, scored 0-8). Progression was defined as an increase in the Clinical Dementia Rating Scale-sum of boxes of more than 2.5 points. The predictor variables were analysed using binary logistic regression.

The study included 127 patients, and 94 completed both assessments. Of the total, 31.5% displayed severe anosognosia (CIR 7-8); 39.4%, altered level of consciousness (CIR 3-6); and 29.1%, normal awareness (CIR 0-2). The median baseline CIR in this cohort was 4 (Q1-Q3: 1-7), and at 18 months, 6 (Q1-Q3: 3-8), P<.001. Advanced age (odds ratio (OR) 2.43; CI 95%:1.14-5.19), lower educational level (OR 2.15; CI 95%:1.01-4.58), and more marked neuropsychiatric symptoms (OR 2.66; CI 95%:1.23-5.74) were predictor variables of anosognosia. Baseline CIR was similar in the groups with and without significant clinical progression.

The large majority of patients with AD at the time of diagnosis showed significant anosognosia, and this condition was associated with advanced age, lower educational level, and more marked behavioural symptoms. Our results did not show that anosognosia had an effect on the initial clinical progression of AD after diagnosis.