Direct and indirect measures of contextual information in brain-injured patients

Several investigators have suggested that amnesics fail to encode contextual information. Support for this approach was derived from studies that tested the recall or recognition of different aspects of contextual information. In the present study, we tested the possibility that contextual information is encoded by patients with memory impairment but cannot be retrieved by direct methods. The distinction between direct and indirect recall of context is an important one that has not been sufficiently addressed with regard to brain-injured patients. Fifteen brain-injured (BI) patients and 19 non-brain-injured (NBI) subjects participated in this study. The results show that when contextual information was tested directly the NBI group outperformed the BI group. However, both groups benefited from the contextual cues (i.e., indirect measure). Results are interpreted in terms of the theoretical distinction between implicit and explicit memory regarding contextual information; implicit memory is shown to be preserved in patients with memory impairment.