The framework for studying each of the selected disorders or groups of disorders included an overview of the available epidemiological parameters, a review of the existing knowledge base to support intervention, and projections of the feasibility, cost, and expected impact of proposed interventions. Wherever possible, the committee based its review and recommendations on evidence from a broad range of settings in the developing world; unfortunately, due to the limited available research on most brain disorders in developing countries, they were frequently forced to make qualified extrapolations based on data from the developed world. In most cases, direct correlations appear to exist between developed and developing countries. For example, many proven risk factors for stroke have been established in developed countries (such as hypertension, high-fat and sodium diets, and diabetes), and these risk factors are of growing concern in developing countries. Though extensive data do not exist on prevention methods for controlling or eliminating these risk factors in developing countries, it can be said that such efforts would bear similar reduction in stroke mortality as has been observed in developed countries. In the few instances where correlations might be skewed by differences between developed and developing countries, these limitations are clearly noted.
As one might expect, several observations regarding the impact and outlook for reducing the burden of specific disorders presented in the chapters of Part II mirror comments in Part I that pertain to many or all brain disorders. These points are reiterated in order to build the most complete picture possible of each individual disorder. However, since the discussions of specific brain disorders presented in Part II are ultimately intended to be viewed in the context of the general discussion and strategies that appear in Part I, readers are advised to familiarize themselves with the introductory chapters of this report before proceeding to the chapters in Part II.