We performed diffusion tensor imaging in 15 DD subjects (age, 61.1 ¡À 20.9 months) and 15 age-matched typically developing (TD) children (age, 68.4 ¡À 19.2 months). With diffusion tensor imaging color-coded orientation maps, we quantified the fraction of fibers in the perisylvian region that are oriented in anteroposterior (AP) and mediolateral (ML) directions, and their ratio (AP/ML) was calculated.
The AP/ML ratio was more sensitive than tractography in characterizing perisylvian regional abnormalities in DD children. The AP/ML ratio of the left perisylvian region was significantly lower in DD children compared with TD children (P = .03). The ML component of bilateral perisylvian regions was significantly higher in DD children compared with TD children (P = .01 [left] and P = .004 [right]). No significant difference was found in the AP component in the two groups. A significant negative correlation of the left ML component with Vineland communication skills was observed (r = ?0.657, P = .011).
The AP/ML ratio appears to be a sensitive indicator of regional white matter architectural abnormalities in the perisylvian region of DD children.