title: Association of neurobehavioral performance with R2* in the caudate nucleus of asymptomatic welders.
abstract: Welding fumes contain several metals including manganese (Mn) and iron (Fe) that may affect the nervous system. Previous studies of potential welding-related neurotoxicity have focused primarily on Mn exposure. The current study examined neurobehavioral and brain imaging changes in asymptomatic welders and their associations with both Mn and Fe exposure measurements.
  
  
  
  Data were obtained from subjects with (n=46) and without (controls; n=31) a history of welding exposure. Occupational questionnaires estimated recent (HrsW; welding hours and E90; cumulative exposure, past 90days) and lifetime (YrsW; total welding years and ELT; cumulative exposure, lifetime) exposure. Brain MRI pallidal index (PI), R1 (1/T1), and R2* (1/T2*) were measured to estimate Mn and Fe concentrations in the basal ganglia [caudate nucleus (CN), putamen, and globus pallidus], amygdala, and hippocampus. Comprehensive neuropsychological tests were conducted to examine behavioral differences between welders and controls. Correlation analyses were conducted between neuropsychological tests and those exposure measurements that showed significant group differences.
  
  
  
  Compared to controls, welders had significantly higher R2* in the CN and lower performance on the Phonemic Fluency test. Correlation analyses revealed that welders' Phonemic Fluency scores were inversely associated with R2* in the CN, but not with the PI or R1 in any brain region of interest studied.
  
  
  
  The results showed that neurobehavioral performance for the asymptomatic welders in our study was worse than individuals who had not welded, and suggest the differences may be associated with higher Fe accumulation in the CN.
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Lee
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Public Health Sciences, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Radiology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Eslinger
authors.affiliation: Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Flynn
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Daymond
authors.initials: D
authors.lastname: Wagner
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Guangwei
authors.initials: G
authors.lastname: Du
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Pharmacology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Mechelle M
authors.initials: MM
authors.lastname: Lewis
authors.affiliation: Department of Public Health Sciences, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Kong
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Pharmacology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Mailman
authors.affiliation: Department of Neurology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Pharmacology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Radiology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Neurosurgery, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA; Department of Kinesiology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA. Electronic address: xuemei@psu.edu.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism*; D015331:Cohort Studies; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007501:Iron / Q000097:blood / Q000378:metabolism*; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011596:Psychomotor Disorders / Q000139:chemically induced*; D012727:Sex Characteristics; D014706:Verbal Learning; D014896:Welding
chemical_list: D007501:Iron
keywords: Basal ganglia; Caudate nucleus; Cognitive performance; Iron accumulation; Phonemic fluency; Welders