Language disturbances, such as impoverishment, disorganization and dysregulation, are a prominent feature of schizophrenia. Several neuroimaging studies have suggested the superior temporal gyrus (STG) as a likely anatomical substrate of language deficits in schizophrenia. The aim of this study was to verify a correlation between structural measures of STG and Heschl's gyrus (HG) and language dimensions.

An extensive language examination battery, which included narrative and conversational expressive tasks, and syntactic and pragmatic comprehension tests, was administered to 23 schizophrenia patients (mean age±SD= 40.30±11.60) and 21 normal controls (mean age±SD= 42.19±11.05). All subjects also underwent a 1.5T MRI session, and STG and HG were manually traced and volumes were obtained, bilaterally, using Brains2.

Specific language deficits were shown in subjects with schizophrenia compared to healthy individuals (p<0.001), particularly in verbal fluency, syntactic complexity, lexical diversity and metaphor/idiom comprehension. Interestingly, speech fluency significantly directly associated with left STG gray matter volumes in controls (r=0.46, p=0.03) but not in patients (r=-0.27, p=0.21). In contrast, complex syntax and word diversity significantly correlated, respectively, with left and right HG volumes in schizophrenia patients (r=0.45, p=0.02; r=-0.47, p=0.02), but not in controls (p>0.05).

This study confirmed a widespread impairment of language in schizophrenia. Interestingly, distinct language dimensions differently correlated with STG-HG volumes in patients with schizophrenia and controls, particularly with regard to verbal fluency and syntactic measures.