Patients with schizophrenia have difficulties identifying and interpreting other people’s emotions from the tone of their voice. In this study, Pinheiro and colleagues used event-related potentials (ERPs) to shed light on the mechanisms underlying poor emotional prosody recognition in schizophrenia. Specifically, ERPs and behavioral measures were used to track three successive stages of prosody recognition as proposed by Schirmer and Kotz (Schirmer and Kotz, 2006). The N100 ERP was used to track early sensory processing of the auditory signal; the P200 ERP was used to track the detection of emotionally salient cues; and behavioral responses were used to measure the cognitive evaluation of emotional stimuli. The results revealed a complex set of dysfunctions extending from the earliest stages of auditory processing to the later stages of higher-order emotional prosody processing in the patient sample. The N100 and P200 were both smaller in patients compared to controls; accurate behavioral identification of prosody was also impaired. N100 and P200 amplitudes correlated with the number of errors on the behavioral task in both groups.

These findings are clinically relevant, as they demonstrate that dysfunctional processing of prosody in schizophrenia begins at the very basic level of sensory processing. While there have been a handful of studies exploring the link between dysfunctional auditory processing and its impact on prosody in schizophrenia (e.g., Leitman et al., 2007; Leitman et al., 2010), this is the first study to examine ERPs specifically during the processing of prosody. The work by Pinheiro and colleagues demonstrates the downstream consequences of dysfunctional auditory processing on prosody detection. These findings are important because, as Pinheiro et al. note, difficulties in decoding emotional information embedded within the auditory modality may lead to difficulties in social interactions and functional outcome. These results also have implications for clinical or psychosocial interventions to improve prosody recognition in schizophrenia. If deficits in prosody detection occur at the earliest stage of sensory registration, interventions aimed at higher-level processing may not be as effective if the lower-level sensory processing deficits are not addressed as well, as suggested by Javitt (Javitt, 2009).

References:

Javitt, D.C. (2009). When doors of perception close: Bottom-up models of disrupted cognition in schizophrenia. Annual Review of Clinical Psychology 5, 249-275. Abstract

Leitman, D.I., Hoptman, M.J., Foxe, J.J., Saccente, E., Wylie, G.R., Nirenberg, J., Jalbrzikowski, M., Lim, K.O., and Javitt, D.C. (2007). The neural substrates of impaired prosodic detection in schizophrenia and its sensorial antecedents. American Journal of Psychiatry 164, 474-482. Abstract

Leitman, D.I., Sehatpour, P., Higgins, B.A., Foxe, J.J., Silipo, G., and Javitt, D.C. (2010). Sensory deficits and distributed hierarchical dysfunction in schizophrenia. American Journal of Psychiatry 167, 818-827. Abstract

Schirmer, A., and Kotz, S.A. (2006). Beyond the right hemisphere: Brain mechanisms mediating vocal emotional processing. Trends in Cognitive Sciences 10, 24-30. Abstract

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