Development and implementation of microsimulation models of neurological conditions

As part of a program of the first National Population Health Study of Neurological Conditions launched in 2009, a series of microsimulation models of neurological conditions (called POHEM-Neurological meta-model) was developed to project health and economic impacts of seven neurological conditions (NCs)-Alzheimer's disease and other dementias, cerebral palsy, epilepsy, multiple sclerosis, Parkinson's disease, traumatic brain injury, and traumatic spinal cord injury-over a 20-year horizon. The common framework of the seven models allows for dynamic, continuous-time, discrete-event simulation of synthetic large populations in which persons are subject to the risk of developing the NC under study and are assigned a value of functional health and a probability of receiving a caregiver and of entering long-term care. Calculations for transitions are done every year over the life course, and costs are accumulated throughout the life of the synthetic person. The need to reconcile empirical estimates of incidence and mortality with prevalence required implementation of "cure" parameters for two of the NCs. The POHEM-Neurological meta-model integrates the latest Canadian microdata on neurological conditions and satisfies most criteria for validation of microsimulation models, including conceptualization, computer implementation, assessment of output plausibility, and comparison with external data. Limitations include an absence of risk factors and the lack of uncertainty measures. The POHEM-Neurological meta-model has been useful for projections of health and economic impacts of NCs on persons affected and their caregivers, and allows for comparison of specific scenarios to the base case.