Change of perspective in discourse comprehension: encoding and retrieval processes after brain injury

Damage to frontal areas has been associated with nonaphasic language disturbances in which word and sentence level processes remain largely intact but text level processes are impaired. Most studies providing evidence for these language deficits have concentrated on text production. To study text comprehension of nonaphasic patients, we adopted the paradigm of Anderson and Pichert (1978) that was developed to separate encoding from retrieval processes. Subjects read a story under one of two alternative perspectives and subsequently recalled it. After this first recall, they were instructed to now adopt the second perspective and to recall the story once more. Twenty-four brain-injured patients participated. Each patient's lesion was evaluated with respect to the involvement of right- and/or left-frontal regions. Seven patients showed unilateral left-frontal lesions, five patients unilateral right-frontal lesions, four patients had bilateral frontal damage, and the lesions of the remaining eight patients did not involve frontal areas. The only factor predicting behavioral results was the presence of a left-frontal lesion. For patients without frontal lesions and patients with unilateral right-frontal lesions, we replicated previously reported results. Encoding relevant information was recalled better than other information. Furthermore, the switch of perspective aided recall of perspective relevant information during the second recall. In contrast, patients with left-frontal or bilateral frontal lesions could not make use of the perspective instructions. While they showed comparable recall performance, as well as sensitivity to the relative ease of information, neither the encoding instructions nor the switch instructions had an impact on the recall patterns. These results suggest that left-frontal damage leads to an impairment of goal directed text processing skills.