Neurological soft signs (NSS), which are minor motor and sensory deficits, e.g., during finger-to-thumb opposition, are frequently found in schizophrenia. The purpose of this study was to investigate differences in the cerebral activation pattern in ten schizophrenic patients and ten healthy volunteers using functional MRI.
Methods: fMRI was performed using a modified FLASH sequence (TR/TE/alpha = 100/60/40 degrees) and a conventional 1.5 T MR scanner. Color-coded statistical parametric maps based on Student's t-test were calculated. Activation strength was quantified using a 5 x 6 grid over-lay.
Results: The volunteers showed a higher activation strength during left hand movement compared to right hand movement. This lateralization effect was reversed in patients who showed overall reduced activation strength.
Conclusions: Disturbed interhemispheric balance in schizophrenic patients during motor task performance can be demonstrated using fMRI. These findings support the hypothesis that changes in the sensorimotor cortex may be involved in the development of NSS.