Behavioural symptoms in patients with Alzheimer's disease and their association with cognitive impairment

BACKGROUND: Behavioural and psychological symptoms of dementia (BPSD) are non-cognitive symptoms commonly associated to Alzheimer's disease (AD). The characterization of the clinical profile of AD patients might help to better understand disease evolution and to improve diagnosis and treatment. Thus, the aim of the present study is to describe the clinical profile of AD patients, and to correlate the presence of BPSD with the severity of the disease. METHODS: A cross-sectional, observational and multicenter study was conducted at 115 centres in Spain. Patients suffering from AD with higher and lower BPSD scores (ADAS-Noncog score 26-50 and ≤25, respectively) were included. Demographic and clinical data were collected, and dementia severity was assessed by the Mini Mental State Examination (MMSE) [mild 27-21, moderate 20-11, severe ≤10]. The use of ADAS-Noncog in clinical practice was also explored. RESULTS: A total of 1014 patients (463 with higher and 551 with lower BPSD scores) were included (mean age 77 ± 7 years, 65% women). Almost all patients (90%) had BPSD at inclusion, 17% of which reported psychotic outbreaks. The most prevalent symptoms were lack of concentration (56%), tremors (56%), depression (44%), lack of cooperation (36%), and delusions (32%). Patients with higher BPSD scores showed a significantly higher prevalence of psychotic symptoms (delusions, hallucinations, and delirium) and tremors, while emotional symptoms (tearfulness and apathy) predominated in patients with lower BPSD scores. MMSE and ADAS-Noncog scores were negatively associated (p = 0.0284), suggesting a correlation between cognitive impairment and BPSD. Lack of concentration and appetite change significantly correlated with MMSE (p = 0.0472 and p = 0.0346, respectively). Rivastigmine and donepezil were the first choice therapies in mild to moderate dementia. ADAS-Noncog was generally considered better or similar to other scales (82%), and 68% of the investigators were willing to use it in the future. CONCLUSIONS: Our study shows that patients with AD have a high prevalence of noncognitive symptoms, and that cognitive impairment and BPSD are correlated. Therefore, ADAS-Noncog is a useful evaluation tool.