title: Differences in cerebral perfusion deficits in mild traumatic brain injury and depression using single-photon emission computed tomography.
abstract: BACKGROUND
  Numerous studies have shown decreased perfusion in the prefrontal cortex following mild traumatic brain injury (mTBI). However, similar hypoperfusion can also be observed in depression. Given the high prevalence of depressive symptoms following mTBI, it is unclear to what extent depression influences hypoperfusion in TBI.
  
  
  METHODS
  Mild TBI patients without depressive symptoms (mTBI-noD, n = 39), TBI patients with depressive symptoms (mTBI-D, n = 13), and 15 patients with major depressive disorder (MDD), but no TBI were given 99m T-ECD single-photon emission computed tomography (SPECT) scans within 2 weeks of injury. All subjects completed tests of information processing speed, complex attention, and executive functioning, and a self-report questionnaire measuring symptoms of psychological distress. Between-group comparisons of quantified SPECT perfusion were undertaken using univariate and multivariate (partial least squares) analyses.
  
  
  RESULTS
  mTBI-D and mTBI-noD groups did not differ in terms of cerebral perfusion. However, patients with MDD showed hypoperfusion compared to both TBI groups in several frontal (orbitofrontal, middle frontal, and superior frontal cortex), superior temporal, and posterior cingulate regions. The mTBI-D group showed poorer performance on a measure of complex attention and working memory compared to both the mTBI-noD and MDD groups.
  
  
  CONCLUSIONS
  These results suggest that depressive symptoms do not affect SPECT perfusion in the sub-acute phase following a mild TBI. Conversely, MDD is associated with hypoperfusion primarily in frontal regions.
authors.affiliation: Department of Psychiatry, Sunnybrook Health Sciences Centre , Toronto, ON , Canada.
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Romero
authors.affiliation: Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Health Sciences Centre , Toronto, ON , Canada ; L. C. Campbell Cognitive Neurology Research Unit, Sunnybrook Health Sciences Centre , Toronto, ON , Canada.
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Black
authors.affiliation: Department of Psychiatry, Sunnybrook Health Sciences Centre , Toronto, ON , Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Feinstein
keywords: SPECT; TBI; attention; depression; neuropsychology; partial least squares