Objective: The classical view of hemispheric specialization considers the left hemisphere as the dominant one with respect to language abilities including grammatical information. Recent research, however, has demonstrated that the right hemisphere language system is more richly endowed than previously assumed. The present research examines the linguistic and cognitive abilities of right and left brain-damaged patients in order to provide more insight into the language competence in the two hemispheres.
Method: In this study, which was a descriptive-analytical and case-control research, 10 right hemisphere-damaged patients, 10 left hemisphere-damaged patients, and 10 normal controls were tested. The subjects were selected based on particular criteria and their functions were assessed using verbal fluency, similarities, digit span and word insertion. The independent variables in this study consisted of age, sex, education, and the presence and localization of damage; and the dependent variables were the scores of the subjects on each of the administered tests.
Results: Results showed that in the verbal fluency test, the difference in performance in both groups of patients was meaningful, whereas their performance in the similarities and digit span tests did not differ significantly. The results of the insertion task showed that the right hemisphere-damaged subjects performed worse on the shift than on the non-shift items. However, the left hemisphere-damaged patients, did not exhibit any difference with respect to their performance on the shift and non-shift elements. Also, the right hemisphere damaged subjects did worse on both shift and non-shift items than left hemisphere-damaged subjects. In addition, while the right hemisphere-damaged patients scored lower than the control group on the non-shift items, there was no meaningful difference between the performance of normal individuals and left hemisphere-damaged patients.
Conclusion: Both groups of brain-damaged patients were almost at the same level in terms of their cognitive abilities. However, the right hemisphere-damaged subjects performed considerably weaker than the left hemisphere-damaged subjects in the syntactic experiment. Therefore, the present study is in accordance with research in English and Italian languages in indicating the important role of the right hemisphere in processing shift and non-shift syntactic structures.
Type of Study:
Research |
Subject:
Special Received: 2007/10/20 | Accepted: 2008/01/17 | Published: 2008/03/20