Language lateralization in children using functional transcranial Doppler sonography

AIM Language lateralization with functional transcranial Doppler sonography (fTCD) and lexical word generation has been shown to have high concordance with the Wada test and functional magnetic resonance imaging in adults. We evaluated a nonlexical paradigm to determine language dominance in children. METHOD In 23 right-handed children (12 females, 11 males; age range 6-11y; mean age 8y 4mo, SD 1y 7mo) and in 22 adolescents (14 females, 8 males; age range 12-18y; mean age 14y 8mo, SD 2y 5 mo) cerebral blood flow velocity (CBFV) was measured in both middle cerebral arteries during picture description and in adolescents additionally during lexical word generation. For each individual/paradigm a lateralization index (LI; side difference in CBFV during mental activity) and its standard error of the mean (SEM; representing variability of the LI throughout task repetition) were computed. RESULTS Fourteen of 23 children (mean LI=0.74, SD 4.22; SEM 1.05, SD 0.51) and 14 of 21 adolescents (LI=2.35, SD 4.65; SEM 1.09, SD 0.61) showed left hemispheric dominance during picture description compared with 20 of 21 adolescents during word generation (LI=3.72 SD 1.93; SEM 0.99, SD 0.41). Indicated by similarity in mean SEM, variability of the LI throughout task repetition did not differ between age groups or paradigms. INTERPRETATION Functional TCD proved to be well tolerated in children, with similar data quality as in adolescents. However, the picture description paradigm failed to show left hemispheric dominance in a substantial number of participants. This emphasizes the need to evaluate further paradigms for fTCD language lateralization in children.