Anomalous dominance describes any pattern of cerebral organization of function in which the left hemisphere is not primarily responsible for initiating propositional speech and processing written or spoken language.
Since the left hemisphere primacy for language is typical of most right-handers (who represent the vast majority of the population), it is considered to be the “dominant” pattern of brain organization. Hence, any pattern that differs from this is considered to be anomalous. Most deviations occur in left-handers, approximately 30% of whom exhibit some form of anomalous dominance for language where these functions are organized either primarily in the right hemisphere (“reversed dominance”) or are more bilaterally represented. Although anomalous dominance can occur in right-handers, this is rare and, when present, is often a consequence of some early developmental defect or brain trauma. Other associations that have been...