Structural brain correlates of defective gesture performance in schizophrenia

Publication date: Available online 10 March 2016
Source:Cortex
Author(s): Katharina Stegmayer, Stephan Bohlhalter, Tim Vanbellingen, Andrea Federspiel, Jeanne Moor, Roland Wiest, René Müri, Werner Strik, Sebastian Walther
IntroductionThe neural correlates of impaired performance of gestures are currently unclear. Lesion studies showed variable involvement of the ventro-dorsal stream particularly left inferior frontal gyrus (IFG) in gesture performance on command. However, findings cannot be easily generalized as lesions may be biased by the architecture of vascular supply and involve brain areas beyond the critical region. The neuropsychiatric syndrome of schizophrenia shares apraxic-like errors and altered brain structure without macroanatomic lesions. Schizophrenia may therefore qualify as a model disorder to test neural correlates of gesture impairments.MethodsWe included 45 schizophrenia patients and 44 healthy controls in the study to investigate the structural brain correlates of defective gesturing in schizophrenia using voxel based morphometry. Gestures were tested in two domains: meaningful gestures (transitive and intransitive) on verbal command and imitation of meaningless gestures. Cut-off scores were used to separate patients with deficits, patients without deficits and controls. Group differences in GM volume were explored in an ANCOVA.ResultsPatients performed poorer than controls in each gesture category (p < 0.001). Patients with deficits in producing meaningful gestures on command had reduced gray matter (GM) predominantly in left IFG, with additional involvement of right insula and anterior cingulate cortex. Patients with deficits differed from patients without deficits in right insula, inferior parietal lobe and superior temporal gyrus.ConclusionsImpaired performance of meaningful gestures on command was linked to volume loss predominantly in the praxis network in schizophrenia. Thus, the behavioral similarities between apraxia and schizophrenia are paralleled by structural alterations. However, few associations between behavioral impairment and structural brain alterations appear specific to schizophrenia.



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