Author Contributions: Dr Grossman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Avants and Grossman. Acquisition of data: Khan, McCluskey, and Elman. Analysis and interpretation of data: Avants, Khan, and Grossman. Drafting of the manuscript: Avants, Khan, and Grossman. Critical revision of the manuscript for important intellectual content: Avants, McCluskey, Elman, and Grossman. Statistical analysis: Avants. Obtained funding: Avants. Administrative, technical, and material support: Khan. Study supervision: Grossman.