Disease progression from mild cognitive impairment to dementia for patients with Alzheimer's disease or Lewy body pathology.

Background: The majority of mild cognitive impairment (MCI) patients who converted to dementia in later years have Alzheimer's disease (AD) pathology. The second most common type of dementia is Lewy body (LB) dementia. Objective: In this project, we are interested in identifying the risk factors that predict who will develop AD dementia or LB dementia in later years. Methods: Cox proportional hazards model and machine learning survival methods for interval-censored data were used to identify the risk factors that predict the onset of dementia for MCI patients with AD or LB pathology. Results: We found that orientation, memory, and irritability scores were useful in predicting AD dementia onset, while daily living, depression, and executive function scores were identified as strong predictors in the LB cohort. Conclusions: Different neurocognitive domains were predictive for conversion to dementia from MCI in patients with AD or LB pathology. The depression scale and functional activities were found to be predictive of LB dementia while irritability or lability severity score from Neuropsychiatric Inventory Questionnaire was associated with the onset of AD dementia.