Functional transcranial Doppler sonography (fTCD) is a simple and non-invasive ultrasound technique which can be used to assess the lateralization of cognitive functions, especially language, and is suitable for use with children.
Bishop, D. V. M., Badcock, N. A., Holt, G. Assessment of Cerebral Lateralization in Children using Functional Transcranial Doppler Ultrasound (fTCD). J. Vis. Exp. (43), e2161, doi:10.3791/2161 (2010).