vendex and Schizophrenia

There is evidence that patients with psychotic conditions display greater center of pressure (CoP) displacement during quite standing than healthy subjects, but the underlying impairments in the control mechanisms are uncertain. The aim of this study was to identify the nature of possible impairments in the control of posture by modulation of visual and kinesthetic information during quiet standing. Center of pressure (CoP) data and whole-body kinematics of the center of mass (CoM) were recorded during quite standing on a firm surface with eyes open and with eyes closed, and standing with eyes open on a yielding surface. During all three conditions, patients displayed greater migration of CoM and CoP-CoM, a measure related to ankle joint torque, whereas CoP-frequency (MPF) was similar in patients and healthy subjects. Our results suggested that greater postural sway in patients may depend on disproportionally large ankle joint torque without corresponding increase in frequency. Furthermore, interactions between groups and conditions suggested that the patients made less use of visual information for postural control than the healthy subjects.

Topics: Adult; Biomechanical Phenomena; Case-Control Studies; Female; Humans; Kinesthesis; Male; Postural Balance; Pressure; Psychomotor Performance; Psychotic Disorders; Schizophrenia; Schizophrenia, Paranoid; Torque; Visual Perception; Young Adult

Anatomical asymmetry may be altered in schizophrenia, but the changes are subtle and in some studies undetected perhaps due to methodological limitations.. In a postmortem MRI study (23 patients, 20 controls), we used a geometric mesh technique to define the cortical surface and to separate two components of brain asymmetry: hemisphere shift, conceived as the position of an entire hemisphere relative to the other (which may be reversed in situs inversus), and the distribution of tissue within the hemisphere along the antero-posterior axis ("volume torque").. Only volume torque was changed in schizophrenia-in comparison subjects, the coronal section of maximal left hemisphere volume was more anteriorly placed than on the right [and correlated with left superior temporal gyrus (STG) volume], and, in patients, it was more posterior (showing a reversed correlation with left STG volume).. The findings validate a new approach to cerebral asymmetry. Assessments of cerebral asymmetry in psychosis should account for, or exclude, hemisphere shift, which is not changed, and focus on the second component, A-P volume distribution; the findings point to an anomaly of relative hemispheric development that may have pathophysiological significance.

Topics: Adult; Brain; Cadaver; Female; Frontal Lobe; Functional Laterality; Humans; Magnetic Resonance Imaging; Male; Occipital Lobe; Schizophrenia; Torque