The role of fundamental frequency and duration in the perception of linguistic stress by individuals with brain damage

Two tests of ability of individuals with left-hemisphere damage (LHD) and right-hemisphere damage (RHD) and non-brain-damaged participants to identify phonemic and emphatic stress contrasts were undertaken. From a set of naturally produced base stimuli, two additional stimulus sets were derived. In one, fundamental frequency (F-0) cues to stress were neutralized, whereas in the other duration cues were effectively neutralized. Results demonstrated that individuals with IHD were unable to identify phonemic stress contrasts with better-than-chance accuracy; individuals with RHD performed worse than normal participants but significantly better than the patients with LHD-particularly with the original full-cue stimuli. All groups performed better on the emphatic stress subtest, with the scores of only the patients with LHD at chance level for the F-0-neutralized stimuli. The findings are considered in relation to hypotheses concerning the hemispheric lateralization of prosodic processing, particularly with respect to a hypothesis that posits differential lateralization for specific acoustic parameters.