Differential
regional gray matter volumes in patients with on - line game addiction and professional gamers.
Using the estimated developmental trajectories (eTable 4 and eFigures 1, 2, 3, and 4 in the Supplement), we constructed an index of structural brain development based on an adjusted or normed measure of
regional gray matter volume.
Because human gray matter follows a nonlinear developmental trajectory, we established a reference for typical development in focal brain areas and constructed an index that measured whether
regional gray matter volume was larger or smaller than expected, comparing children with others of the same sex and age.