title: Classification of first-episode psychosis in a large cohort of patients using support vector machine and multiple kernel learning techniques.
abstract: First episode psychosis (FEP) patients are of particular interest for neuroimaging investigations because of the absence of confounding effects due to medications and chronicity. Nonetheless, imaging data are prone to heterogeneity because for example of age, gender or parameter setting differences. With this work, we wanted to take into account possible nuisance effects of age and gender differences across dataset, not correcting the data as a pre-processing step, but including the effect of nuisance covariates in the classification phase. To this aim, we developed a method which, based on multiple kernel learning (MKL), exploits the effect of these confounding variables with a subject-depending kernel weighting procedure. We applied this method to a dataset of cortical thickness obtained from structural magnetic resonance images (MRI) of 127 FEP patients and 127 healthy controls, who underwent either a 3Tesla (T) or a 1.5T MRI acquisition. We obtained good accuracies, notably better than those obtained with standard SVM or MKL methods, up to more than 80% for frontal and temporal areas. To our best knowledge, this is the largest classification study in FEP population, showing that fronto-temporal cortical thickness can be used as a potential marker to classify patients with psychosis.
authors.affiliation: UOC Psychiatry, Azienda Ospedaliera Universitaria Integrata Verona (AOUI), Italy; InterUniversity Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Squarcina
authors.affiliation: Department of Informatics, University of Verona, Verona, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Castellani
authors.affiliation: UOC Psychiatry, Azienda Ospedaliera Universitaria Integrata Verona (AOUI), Italy; InterUniversity Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Bellani
authors.affiliation: InterUniversity Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy; Department of Public Health and Community Medicine, Section of Clinical Psychology, University of Verona, Verona, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Perlini
authors.affiliation: UOC Psychiatry, Azienda Ospedaliera Universitaria Integrata Verona (AOUI), Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lasalvia
authors.affiliation: UOC Psychiatry, Azienda Ospedaliera Universitaria Integrata Verona (AOUI), Italy; InterUniversity Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Dusi
authors.affiliation: Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bonetto
authors.affiliation: Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy.
authors.forename: Doriana
authors.initials: D
authors.lastname: Cristofalo
authors.affiliation: Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy.
authors.forename: Sarah
authors.initials: S
authors.lastname: Tosato
authors.affiliation: InterUniversity Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy; Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Rambaldelli
authors.affiliation: Neuroradiology Department, Azienda Ospedaliera Universitaria, Verona, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Alessandrini
authors.affiliation: Neuroradiology Department, Azienda Ospedaliera Universitaria, Verona, Italy.
authors.forename: Giada
authors.initials: G
authors.lastname: Zoccatelli
authors.affiliation: Department of Radiology, G.B. Rossi Hospital, University of Verona, Verona, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pozzi-Mucelli
authors.affiliation: Department of Psychiatry, CSM AULSS 21 Legnago, Verona, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Lamonaca
authors.affiliation: Department of Mental Health, Hospital of Montecchio Maggiore, Vicenza, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Ceccato
authors.affiliation: Department of Mental Health, Azienda ULSS Bologna, Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pileggi
authors.affiliation: Department of Mental Health, Modena, Italy.
authors.forename: Fausto
authors.initials: F
authors.lastname: Mazzi
authors.affiliation: Department of Neuroscience, University of Padova, Padova, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Santonastaso
authors.affiliation: UOC Psychiatry, Azienda Ospedaliera Universitaria Integrata Verona (AOUI), Italy; Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy.
authors.forename: Mirella
authors.initials: M
authors.lastname: Ruggeri
authors.affiliation: Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy; Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, TX, USA. Electronic address: paolo.brambilla1@unimi.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Brambilla
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D000069550:Machine Learning; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011618:Psychotic Disorders / Q000000981:diagnostic imaging*; D060388:Support Vector Machine; D055815:Young Adult
keywords: Affective psychosis; Cortical thickness; Frontal; MRI; Schizophrenia; Temporal cortex