Phase Synchronization Index of Vestibular System Activity in Schizophrenia

Schizophrenia is a severe mental illness associated with multiple neuropathological and neurochemical abnormalities. The aim of this study is to examine if patients with schizophrenia exhibit any abnormality in the level of functional connectivity between the neuronal centers responsible for the processing of vestibular information in the left and right side of the head. Signals were recorded simultaneously in response to tilt stimuli by a special hydraulic chair via a pair of electrodes inserted in the left and right ear canals to rest on tympanic membrane. Using the complex Morlet wavelet transform, we compared instantaneous phase synchronization indices on a set of recordings collected from a group of control subjects (n=24) against schizophrenia group (n=11). Our results show differences between groups in the level and duration of synchrony mostly during dynamic rather than static phases of the tilts. Larger study sample is required to verify these findings.