Central auditory function following anterior sectioning of the corpus callosum

This paper describes auditory findings for eight patients with anterior sections of the corpus callosum. Peripheral (pure tone and speech recognition) and five central auditory tests were administered to each of the eight patients prior to surgery and then again approximately 2 weeks after surgery. The central tests administered included a low-pass filtered speech test, the frequency patterns perception test, and three dichotic speech tests. Mean scores for the peripheral tests fell grossly within the normal range preoperatively and showed little change postoperatively. Similarly, scores on the central tests, though somewhat more variable, did not show any obvious differences upon pre- and postsurgical comparison. A comparison of these results with those reported previously for patients with complete commissurotomies (Musiek, Kibbe, and Baran. Semin Hear 1984;5:219-29) revealed that as a group, patients with anterior sections of the corpus callosum showed fewer postsurgery deficits than did the subjects with complete commissurotomies. The lack of an apparent auditory effect in the anterior group is believed to have an anatomical basis.