Saving during relearning as an implicit measure of memory in closed-head-injured patients.

Memory disturbance is the most prominent residual deficit after closed-head injury (CHI). Recent studies have demonstrated that CHI patients, just like global amnesic patients, show impaired memory when measured explicitly, but not when measured implicitly. Many theorists have concluded that the saving paradigm introduced by Ebbinghaus in 1885 can be viewed as a measure of implicit memory. Thus, it was hypothesized that saving will be preserved in CHI patients. Thirteen CHI patients and 13 control subjects were tested individually on three word lists. Each list was tested in two phases: learning and relearning. There was a different time delay between the two phases for each list: 1 h, 1 day, and 3 days. The groups were compared on explicit-recall and implicit-saving measures of memory. Time delay from learning to relearning did not affect the performance of either group. As expected, the results show that overall, the control group recalled more words than the CHI group, but the groups did not differ on the overall amount of saving measure. However, when saving was measured just on the initial learning and relearning trials, the groups did differ. The results are discussed in terms of the relationship between saving and implicit memory