Electrovestibulography biomarkers differentiate schizophrenia from healthy controls: implications for the dopamine hypothesis

OBJECTIVES: Previous studies have demonstrated that Electrovestibulography (EVestG) biomarkers for Parkinson's Disease are sensitive to dopamine levels. Given the dopamine hypothesis of Schizophrenia (SCZ), we recorded EVestG signals from 45 individuals with SCZ and 36 healthy controls to evaluate whether EVestG can differentiate these populations. METHODS: Features derived from field potentials (FP) and firing pattern interval histograms (IH33)-the two primary EVestG outcomes-were extracted and used to classify the two groups. RESULTS: We achieved a 78% cross-validated accuracy using a Naïve Bayes classifier. This classification performance was achieved despite nearly all SCZ participants being on antipsychotic medications with most on high (n = 21) or partial (n = 4) dopamine D2 receptor affinity, which would be expected to attenuate the dopaminergic signal. The exploratory separation of SCZ the sub-groups on high (N = 15) and low affinity (N = 15) D2 medications was achieved for the FP feature (p = 0.027). CONCLUSIONS: Features derived from both static and dynamic segments of the EVestG signal were altered in SCZ; features from dynamic segments-which impose greater metabolic demand on the vestibular system-showed more pronounced group differences than those from static segments.