Corpus callosum surgery and recent memory. A review.

A number of clinical reports have cited memory disturbances in surgical cases involving section of the corpus callosum. This review, however, shows that persistent impairment of recent memory has tended to occur only in cases where there has been concurrent extracallosal damage, particularly to the fornix and its connections. Both the timing and sensitivity of psychometric tests as well as the availability of preoperative baselines are all important factors in determining the reliability of memory assessment following callosal surgery. A minimal delay of one year between surgery and final memory testing is needed because intellectual functions have been shown to improve markedly during the 12 months following callosal section. The use of discriminating psychometric tests with comparisons before and after operation is desirable, since global memory tests are relatively insensitive to disorders of recent memory.