Neuropsychiatric Symptoms in Amnestic Mild Cognitive Impairment: Increased Risk and Faster Progression to Dementia

Johanne      Somme; Manuel      Fernandez-Martínez; Ana      Molano; Juan      Jose Zarranz

doi:10.2174/1567205011310010012

Abstract

Introduction. Neuropsychiatric symptoms (NPS) are common in mild cognitive impairment (MCI) but its role as a predictive factor for the progression to dementia is still not clear. The objective of this study is to identify NPS that predict the progression from amnestic MCI (a-MCI) to dementia using an easy to administer screening tool for NPS. Material and Methods. 132 patients with a-MCI were assessed for NPS by the Neuropsychiatric Inventory (NPI) and followed to detect progression to dementia. Results. The mean follow-up time was 3.5±2.9 years and rate of progression to dementia 28.8%. Two items of NPI were found to be independent risk factors for progression, nighttime behavioural disturbance (hazard ratio(HR)=2.2, 95%CI=1.10-4.43), anxiety (HR=2.5, 95%CI=1.01-6.20) and apathy (HR=2.2, 95%CI=1.003-4.820). The risk of progression increased with higher score on NPI (HR=1.046 per point, 95%CI=1.019- 1.073), and with a higher number of items of NPI affected (HR=3.6 per item, 95%CI=2.0-6.4). Faster progression to dementia was observed in patients with either nighttime behavioural disturbance, apathy or anxiety (4.6 vs. 8.3 years, 5.3 vs. 8.4 years and 3.0 vs. 7.7 years respectively, p<0.01) as well as in those with a higher number of items affected (no items = 9.2 years, 1-3 items = 6.6 years and >3 items = 2.9 years, p<0.001). Conclusions. Assessing a broad spectrum of NPS can help identify patients with a-MCI presenting a higher risk for progression to dementia. This can be useful to select patients for closer follow-up, clinical trials and future therapeutic interventions.

Keywords: Alzheimer’s disease, anxiety, apathy, dementia, mild cognitive impairment, neuropsychiatric inventory, neuropsychiatric symptoms, progression