Parkinsonism is associated to fronto-caudate disconnectivity and cognition in schizophrenia

The present work studies the possible relation of parkinsonism and fronto-caudate dysconnectivity, as well as its relation to cognition in schizophrenia patients. We assessed parkinsonism using Simpson-Angus scale and prefronto-caudate connectivity using diffusion magnetic resonance in 22 schizophrenia patients (11 first-episodes) and 14 healthy controls. Fractional anisotropy was calculated for the white matter tracts directly linking rostral middle prefrontal (RMPF) and superior medial prefrontal (SMPF) regions with caudate nucleus. Cognition was assessed using the Brief Assessment of Cognition in Schizophrenia Scale (BACS). Total parkinsonism scores were negatively related to fractional anisotropy in the right SMPF-caudate tract in patients, which was also found in the first-episode patients alone, but not in controls. Parkinsonism was also inversely associated in patients to performance in social cognition, verbal memory, working memory and performance speed tests. In conclusion, our data support the involvement of fronto-striatal dysconnectivity in parkinsonism in schizophrenia.