title: Caudate volumes in public transportation workers exposed to trauma in the Stockholm train system.
abstract: The caudate nucleus is a structure implicated in the neural circuitry of psychological responses to trauma. This study aimed to quantify the volume of the caudate in persons exposed to trauma. Thirty-six subjects under 65 were recruited from transport workers in Stockholm who reported having been unintentionally responsible for a person-under-the-train accident or among employees having experienced an assault in their work (1999-2001) between 3 months and 6 years before MRI scanning. In those exposed to the trauma, a DSM-IV diagnosis of post-traumatic stress disorder (PTSD) was made by an independent psychiatrist, with subjects being classified as PTSD or no PTSD. MRI data were analyzed blindly to all clinical information by an experienced rater using a standardized manual tracing protocol to quantify the volume of the caudate. Within-group comparisons of PTSD (n=19) and no PTSD (n=17) found the right caudate nucleus to be significantly (9%) larger than the left: a right hemisphere baseline asymmetry. A multivariate analysis of covariance (MANCOVA) was conducted to assess the volume of the caudate nucleus (right and left) in relation to the diagnosis of no PTSD (n=17) or PTSD (n=19). After adjustment for the covariates (age, sex, intracranial volume, years since trauma, and number of trauma episodes), there was a significant difference in raw right caudate nucleus volume between subjects with PTSD compared with those without PTSD. Volume of the left caudate nucleus was not significantly different between the PTSD and no PTSD groups. The right caudate volume in the PTSD group was 9% greater compared with the no PTSD group. There is a larger right hemisphere volume of the caudate within those exposed to trauma with active PTSD compared with those without PTSD, superimposed upon a baseline caudate asymmetry.
authors.affiliation: Research Centre for the Neurosciences of Ageing, Academic Unit of Psychological Medicine, Australian National University Medical School, The Canberra Hospital, Canberra, Australia. jeffrey.looi@act.gov.au
authors.forename: Jeffrey Chee Leong
authors.initials: JC
authors.lastname: Looi
authors.forename: Jerome Joseph
authors.initials: JJ
authors.lastname: Maller
authors.forename: Marco
authors.initials: M
authors.lastname: Pagani
authors.forename: Göran
authors.initials: G
authors.lastname: Högberg
authors.forename: Olof
authors.initials: O
authors.lastname: Lindberg
authors.forename: Benny
authors.initials: B
authors.lastname: Liberg
authors.forename: Lisa
authors.initials: L
authors.lastname: Botes
authors.forename: Eva-Lena
authors.initials: EL
authors.lastname: Engman
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Leif
authors.initials: L
authors.lastname: Svensson
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
mesh_terms: D000328:Adult; D002421:Caudate Nucleus / Q000473:pathology* / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008016:Life Change Events; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D016273:Occupational Exposure; D009929:Organ Size / Q000502:physiology; D011890:Railroads; D012016:Reference Values; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D013548:Sweden