Perception and production of facial and prosodic emotions by chronic CVA patients

Variable etiology, limited testing of emotions and inclusion of patients in acute and chronic phases have made it difficult to specify the extent of right hemisphere involvement in the processing of emotional material. In addition, there is an absence of data concerning CVA patients' long-term abilities to process emotional information. Two groups of subjects with unilateral brain damage (15 RBD, 17 LBD), matched for chronicity (minimum 12 months post-CVA), etiology (ischemic CVA), duration of hospitalization and other variables, and an appropriate control group participated in two experiments to address these concerns. In the first experiment, subjects were given a series of tasks (discrimination, identification, imitation, production on request) to assess their processing of facial expressions of the six universal emotions [P. Ekman, W. Friesen, Unmasking the face, Prentice-Hall, Englewood Cliffs, 1975]. The results showed that three emotions (surprise, happiness, fear) discriminate between RBD and LBD patients and controls, with RBD subjects performing worse than the other groups on the identification task only. Using tasks of the same nature, the second experiment investigated the processing of emotional prosody. The results showed that three emotions (fear, sadness, anger) discriminate between RBD and LBD patients and controls, with RBD subjects again performing worse than the others on the discrimination, imitation and production on request tasks. LBD subjects performed as well as normal controls on almost all tasks. The RBD subjects were the only ones who showed relatively consistent impairment in the processing of both facial and prosodic emotional information. Taken together, these data strongly suggest that the right hemisphere is preferentially involved in processing emotional information in the chronic phase of brain damage.