CHAPTER 4 - The Right Hemisphere's Contribution to Language: A Review of the Evidence from Brain-Damaged Subjects

Abstract

This chapter discusses the right hemisphere's (RH) contribution to language. The present evidence for RH language processing, when the left hemisphere (LH) is dominant for language, is equivocal. Certain facts have been well established: the RH is capable of mediating language if the LH is damaged early in life. The evidence, such as from Dennis and Whitaker (1977), indicates that the RH is innately less successful than the LH as the language hemisphere, particularly in syntactic processing. It would appear that fairly extensive early LH damage must be sustained before language will switch to the RH, and even then there is the possibility of bilateral language representation, as in the case presented in Ojemann and Whitaker (1978). It is particularly challenging to compare claims that RH lesions affect syntactic processing with claims that the RH is not equal to the LH in syntactic processing ability. Many factors must be considered in this discrepancy such as developmental factors, differences between an early hemispherectomy and late focal lesions, or as-yet-unspecified inhibitory relationships between the hemispheres. There is also good evidence that the RH contributes to many factors of human behavior that play some role in communication.