title: Brain structural imaging correlates of olfactory dysfunction in obsessive-compulsive disorder.
abstract: Olfactory dysfunction has been described in obsessive-compulsive disorder (OCD). Brain regions involved in smell processing partially overlap with structures included in the neurobiological models of OCD, although no previous studies have analyzed the neuroanatomical correlates of olfactory dysfunction in this disorder. The aim of our study was to examine the association between regional gray matter volume, as assessed by a voxel-based morphometry analysis of magnetic resonance images (MRI), and olfactory function, as assessed by the Sniffin' Sticks test (SST). Olfactory function was assessed in 19 OCD patients and 19 healthy volunteers. All participants were also scanned in a 1.5-T magnet to obtain T1-weighted anatomical MRIs, which were pre-processed and analyzed with SPM8. Three different correlation models were used to study the association between regional gray matter volumes and olfactory function in the domains assessed by the SST: detection threshold, discrimination, and identification. OCD patients showed a significant impairment in all the domains assessed by the SST. Voxel-based mapping revealed a positive association in healthy controls between detection threshold and the gray matter content of a left anterior cingulate cortex cluster. In OCD patients, a positive correlation was observed between identification errors and the gray matter volume of the left medial orbital gyrus. In a post hoc analysis, these two gray matter regions were shown to be enlarged in OCD patients. Our findings support the idea that olfactory dysfunction in OCD is associated with volumetric changes in brain areas typically implicated in the neurobiology of the disorder.
authors.affiliation: OCD Clinical and Research Unit, Department of Psychiatry, Hospital de Bellvitge, Bellvitge University Hospital, c/Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain, csegalas@bellvitgehospital.cat.
authors.forename: Cinto
authors.initials: C
authors.lastname: Segalàs
authors.forename: Pino
authors.initials: P
authors.lastname: Alonso
authors.forename: Arantxa
authors.initials: A
authors.lastname: Orbegozo
authors.forename: Eva
authors.initials: E
authors.lastname: Real
authors.forename: Marta
authors.initials: M
authors.lastname: Subirà
authors.forename: Clara
authors.initials: C
authors.lastname: López-Solà
authors.forename: Ignacio
authors.initials: I
authors.lastname: Martínez-Zalacaín
authors.forename: Javier
authors.initials: J
authors.lastname: Labad
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Jesús
authors.initials: J
authors.lastname: Pujol
authors.forename: José M
authors.initials: JM
authors.lastname: Menchón
authors.forename: Narcís
authors.initials: N
authors.lastname: Cardoner
authors.forename: Carles
authors.initials: C
authors.lastname: Soriano-Mas
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000150:complications* / Q000188:drug therapy; D000857:Olfaction Disorders / Q000150:complications* / Q000188:drug therapy / Q000473:pathology*; D012903:Smell / Q000502:physiology; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents