Abnormalities in the processing of emotional prosody from single words in schizophrenia

Background: Abnormalities in emotional prosody processing have been consistently reported in schizophrenia and are related to poor social outcomes. However, the role of stimulus complexity in abnormal emotional prosody processing is still unclear. Method: We recorded event-related potentials in 16 patients with chronic schizophrenia and 16 healthy controls to investigate: 1) the temporal course of emotional prosody processing; and 2) the relative contribution of prosodic and semantic cues in emotional prosody processing. Stimuli were prosodic single words presented in two conditions: with intelligible (semantic content condition—SCC) and unintelligible semantic content (pure prosody condition—PPC). Results: Relative to healthy controls, schizophrenia patients showed reduced P50 for happy PPC words, and reduced N100 for both neutral and emotional SCC words and for neutral PPC stimuli. Also, increased P200 was observed in schizophrenia for happy prosody in SCC only. Behavioral results revealed higher error rates in schizophrenia for angry prosody in SCC and for happy prosody in PPC. Conclusions: Together, these data further demonstrate the interactions between abnormal sensory processes and higher-order processes in bringing about emotional prosody processing dysfunction in schizophrenia. They further suggest that impaired emotional prosody processing is dependent on stimulus complexity.
This work was supported by two grants awarded to A.P.P.: Post-Doctoral Grant no. SFRH/BD/35882/2007 funded by Fundacao para a Ciencia e a Tecnologia (FCT, Portugal); and research grant no. PTDC/PSI-PCL/116626/2010, funded by FCT and FEDER (Fundo Europeu de Desenvolvimento Regional) through the European programs QREN (Quadro de Referencia Estrategico Nacional) and COMPETE (Programa Operacional Factores de Competitividade). It was additionally supported by two grants from the National Institute of Mental Health (no. RO1 MH 040799 awarded to R.W.M. and no. RO3 MH 078036 awarded to M.A.N.).