title: Resting state functional MRI reveals abnormal network connectivity in orthostatic tremor.
abstract: Very little is known about the pathogenesis of orthostatic tremor (OT). We have observed that OT patients might have deficits in specific aspects of neuropsychological function, particularly those thought to rely on the integrity of the prefrontal cortex, which suggests a possible involvement of frontocerebellar circuits. We examined whether resting-state functional magnetic resonance imaging (fMRI) might provide further insights into the pathogenesis on OT. Resting-state fMRI data in 13 OT patients (11 women and 2 men) and 13 matched healthy controls were analyzed using independent component analysis, in combination with a "dual-regression" technique, to identify group differences in several resting-state networks (RSNs). All participants also underwent neuropsychological testing during the same session. Relative to healthy controls, OT patients showed increased connectivity in RSNs involved in cognitive processes (default mode network [DMN] and frontoparietal networks), and decreased connectivity in the cerebellum and sensorimotor networks. Changes in network integrity were associated not only with duration (DMN and medial visual network), but also with cognitive function. Moreover, in at least 2 networks (DMN and medial visual network), increased connectivity was associated with worse performance on different cognitive domains (attention, executive function, visuospatial ability, visual memory, and language). In this exploratory study, we observed selective impairments of RSNs in OT patients. This and other future resting-state fMRI studies might provide a novel method to understand the pathophysiological mechanisms of motor and nonmotor features of OT.
authors.affiliation: Department of Neurology, University Hospital "12 de Octubre", Madrid Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) Department of Medicine, Complutense University, Madrid, Spain Department of Neurology, Yale School of Medicine Department of Chronic Disease Epidemiology, Yale School of Public Health Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine and Yale School of Public Health, New Haven, CT, USA Neuroimaging Laboratory, Center for Biomedical Technology, Rey Juan Carlos University, Móstoles Department of Radiology, Hospital Ruber International Faculty of Biosanitary Sciences, Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA Movement Disorders Laboratory, HM CINAC, HM Hospitales, Móstoles (Madrid), Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Benito-León
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
authors.forename: Eva
authors.initials: E
authors.lastname: Manzanedo
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Hernández-Tamames
authors.forename: Juan
authors.initials: J
authors.lastname: Álvarez-Linera
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Molina-Arjona
authors.forename: Michele
authors.initials: M
authors.lastname: Matarazzo
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Romero
authors.forename: Cristina
authors.initials: C
authors.lastname: Domínguez-González
authors.forename: Ángela
authors.initials: Á
authors.lastname: Domingo-Santos
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Sánchez-Ferro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology*; D015331:Cohort Studies; D004244:Dizziness / Q000175:diagnosis / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology*; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D011187:Posture / Q000502:physiology; D012016:Reference Values; D014202:Tremor / Q000175:diagnosis / Q000503:physiopathology*