Progress in the measurement of laterality and implications for dyslexia research

Much of contemporary laterality research has been motivated by a need to increase the accuracy with which individuals can be classified as left- or right-hemisphere dominant for speech and language. Efforts to improve the classification accuracy of laterality methods have led not only to the refinement of laterality methods but also to the discovery of some of the mechanisms that contribute to asymmetric performance. Despite these advances, laterality methods still do not lead to definitive conclusions about hemispheric specialization in the individual case, and special caution must be used when interpreting results for individual dyslexic children. Event-related measurements of cerebral metabolism, still in the development phase, promise to complement but not replace behavioral laterality methods.