title: Auditory hallucinations and reduced language lateralization in schizophrenia: a meta-analysis of dichotic listening studies.
abstract: Reduced left-hemispheric language lateralization has been proposed to be a trait marker for schizophrenia, but the empirical evidence is ambiguous. Recent studies suggest that auditory hallucinations are critical for whether a patient shows reduced language lateralization. Therefore, the aim of the study was to statistically integrate studies investigating language lateralization in schizophrenia patients using dichotic listening. To this end, two meta-analyses were conducted, one comparing schizophrenia patients with healthy controls (n = 1407), the other comparing schizophrenia patients experiencing auditory hallucinations with non-hallucinating controls (n = 407). Schizophrenia patients showed weaker language lateralization than healthy controls but the effect size was small (g = -0.26). When patients with auditory hallucinations were compared to non-hallucinating controls, the effect size was substantially larger (g = -0.45). These effect sizes suggest that reduced language lateralization is a weak trait marker for schizophrenia as such and a strong trait marker for the experience of auditory hallucinations within the schizophrenia population.
authors: Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway. sebastian.ocklenburg@psybp.uib.no
authors: Sebastian
authors: S
authors: Ocklenburg
authors: René
authors: R
authors: Westerhausen
authors: Marco
authors: M
authors: Hirnstein
authors: Kenneth
authors: K
authors: Hugdahl
mesh_terms: D000161:Acoustic Stimulation; D004007:Dichotic Listening Tests; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006212:Hallucinations / Q000209:etiology*; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012559:Schizophrenia / Q000150:complications*; D012565:Schizophrenic Psychology