Head motion analysis during cognitive fMRI examination: Application in patients with schizophrenia

OBJECTIVES Functional MRI (fMRI) has become an important imaging modality for analyzing the neural mechanisms underlying schizophrenia. Earlier studies indicate that patients with schizophrenia tend to generate involuntary and unnecessary head motion during visual tasks. Since head motion can deteriorate the quality of fMRI data, an investigation was needed to examine the type and extent of head motion from patients with schizophrenia undergoing fMRI. METHODS Patients with schizophrenia and demographically-matched healthy comparison subjects underwent fMRI examination involving visual working memory tasks. We obtained head movement parameters (three translational and three rotational) through mathematical realignment of the volumetric image data, and transformed these parameters into head displacement indices to quantify the subject's head motion in space. RESULTS We found no group difference in displacement indices between the two groups. Group comparison of movement parameters indicated that the patient group showed reduced head motion along the superior-inferior direction when compared to healthy individuals. CONCLUSION These results suggest that cognitive fMRI examination in patients with schizophrenia can be successfully conducted without the deteriorative effects of head motion.