Aims
MBI is characterised by persistent (>6 months), late-life (age>50 years) emergence of neuropsychiatric symptoms before dementia onset. MBI in the presence of MCI is associated with a higher burden of Alzheimer’s neuropathology.1 While prevalence of MBI has been explored in normative Asian populations, we aim to further characterise MBI in an Asian MCI cohort.
Methods
Subjects aged 30-95 years satisfying diagnostic criteria for MCI (Clinical Dementia Rating 0.5) were recruited from an outpatient memory clinic in Singapore as part of a larger ongoing longitudinal study evaluating MCI pathology (SALIENCE - Singapore ALliance towards an Integrated rEsearch platform for NeuroCognitive DisEases). Subjects that were illiterate or diagnosed with psychiatric illness, relevant neurological disorders (ie. Parkinson’s/debilitating stroke), serious systemic disease or cancer were excluded. MBI Checklist was not administered in this cohort, so MBI operational case definition was adapted from Guan et al. utilising physician-rated Neuropsychiatric Inventory at consecutive visits.2 Data from the study with at least 2 visits 6-12 months apart (n=55) were analysed.
Results
12 out of 55 subjects (21.8%) with MCI (age 75.65 ± 6.92, age range 59-92, 54.5% female) met the operationalised criteria for MBI. In the identified MBI participants, the most common subdomains were impulse dyscontrol (41.7%), affective dysregulation (33.3%) and decreased motivation (33.3%).
Conclusions
Our findings are consistent with previous prevalence rates reported in other Asian studies ranging from 13-25%.3-5 Lower Asian prevalence rates compared to worldwide prevalence of ~50%6 warrant further investigation. Impulse dyscontrol and affective dysregulation are consistently the most common MBI subdomains.7