title: Basic visual dysfunction allows classification of patients with schizophrenia with exceptional accuracy.
abstract: Basic visual dysfunctions are commonly reported in schizophrenia; however their value as diagnostic tools remains uncertain. This study reports a novel electrophysiological approach using checkerboard visual evoked potentials (VEP). Sources of spectral resolution VEP-components C1, P1 and N1 were estimated by LORETA, and the band-effects (BSE) on these estimated sources were explored in each subject. BSEs were Z-transformed for each component and relationships with clinical variables were assessed. Clinical effects were evaluated by ROC-curves and predictive values. Forty-eight patients with schizophrenia (SZ) and 55 healthy controls participated in the study. For each of the 48 patients, the three VEP components were localized to both dorsal and ventral brain areas and also deviated from a normal distribution. P1 and N1 deviations were independent of treatment, illness chronicity or gender. Results from LORETA also suggest that deficits in thalamus, posterior cingulum, precuneus, superior parietal and medial occipitotemporal areas were associated with symptom severity. While positive symptoms were more strongly related to sensory processing deficits (P1), negative symptoms were more strongly related to perceptual processing dysfunction (N1). Clinical validation revealed positive and negative predictive values for correctly classifying SZ of 100% and 77%, respectively. Classification in an additional independent sample of 30 SZ corroborated these results. In summary, this novel approach revealed basic visual dysfunctions in all patients with schizophrenia, suggesting these visual dysfunctions represent a promising candidate as a biomarker for schizophrenia.
authors.affiliation: Departments of Neurophysiology and Psychiatry, "Hermanos-Ameijeiras" Hospital, University of Medical Science of Havana, Cuba; Department of Psychiatry and Psychotherapy, University of Münster, Germany. Electronic address: joseconchyalt@gmail.com.
authors.forename: J A
authors.initials: JA
authors.lastname: González-Hernández
authors.affiliation: Department of Psychiatry, "Manuel Fajardo" Hospital, University of Medical Science of Havana, Cuba.
authors.forename: C
authors.initials: C
authors.lastname: Pita-Alcorta
authors.affiliation: Departments of Neurophysiology and Psychiatry, "Hermanos-Ameijeiras" Hospital, University of Medical Science of Havana, Cuba.
authors.forename: A
authors.initials: A
authors.lastname: Padrón
authors.affiliation: Departments of Neurophysiology and Psychiatry, "Hermanos-Ameijeiras" Hospital, University of Medical Science of Havana, Cuba.
authors.forename: A
authors.initials: A
authors.lastname: Finalé
authors.affiliation: Departments of Neurostatistics and Neuroinformatics, Cuban Neuroscience Center, Havana, Cuba.
authors.forename: L
authors.initials: L
authors.lastname: Galán
authors.affiliation: Departments of Neurostatistics and Neuroinformatics, Cuban Neuroscience Center, Havana, Cuba.
authors.forename: E
authors.initials: E
authors.lastname: Martínez
authors.affiliation: Departments of Neurostatistics and Neuroinformatics, Cuban Neuroscience Center, Havana, Cuba.
authors.forename: L
authors.initials: L
authors.lastname: Díaz-Comas
authors.affiliation: Faculty of Computer Sciences and Mathematic, University of Havana, Cuba.
authors.forename: J A
authors.initials: JA
authors.lastname: Samper-González
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Münster, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Lencer
authors.affiliation: Departments of Neurophysiology and Psychiatry, "Hermanos-Ameijeiras" Hospital, University of Medical Science of Havana, Cuba.
authors.forename: M
authors.initials: M
authors.lastname: Marot
mesh_terms: D000328:Adult; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D012372:ROC Curve; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000145:classification* / Q000150:complications*; D014786:Vision Disorders / Q000175:diagnosis* / Q000209:etiology*; D055815:Young Adult
keywords: Biomarker; EEG; LORETA; Spectral resolution; VEP