title: Neuroimaging and neurocognitive abnormalities associated with bipolar disorder in old age.
abstract: OBJECTIVE
  Cognitive dysfunction is prevalent in older adults with bipolar disorder (BD). High white matter hyperintensity (WMH) burden, a marker of white matter disease, detected on T2/fluid-attenuated inversion recovery brain magnetic resonance imaging (MRI) has been consistently reported in BD across all age ranges, including older adults. Yet, whether high WMH burden is related to the excess cognitive impairment present in older adults with BD is unknown. Therefore, we examine whether higher WMH burden is related to worse cognitive function in older adults with BD.
  
  
  METHODS
  This is a cross-sectional study of 27 non-demented BD patients aged ≥50 years and 12 similarly aged mentally healthy comparators (controls). Subjects underwent both brain MRI and comprehensive neurocognitive assessment. We employed correlational analyses to evaluate the burden of WMH and the relationship between WMH and cognitive function.
  
  
  RESULTS
  Although BD subjects had worse performance in all cognitive domains, BD subjects had less total WMH burden (t[13.4] = -3.57, p = 0.003). In control subjects, higher WMH was related to lower global cognitive function (ρ = -0.57, n = 12, p = 0.05). However, WMH did not correlate with neuropsychological performance in BD subjects. Further, BD and control subjects did not differ with respect to total gray and hippocampal volumes.
  
  
  CONCLUSIONS
  Cognitive dysfunction in late-life BD does not appear to be due primarily to processes related to increased WMH or reduced gray matter volume. Future longitudinal studies should examine other potential neuroprogressive pathways such as inflammation, mitochondrial dysfunction, serum anticholinergic burden, and altered neurogenesis.
authors.affiliation: Department of Psychiatry, McGill University, Montreal, QC, Canada.
authors.forename: Soham
authors.initials: S
authors.lastname: Rej
authors.forename: Meryl A
authors.initials: MA
authors.lastname: Butters
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Aizenstein
authors.forename: Amy
authors.initials: A
authors.lastname: Begley
authors.forename: Jawad
authors.initials: J
authors.lastname: Tsay
authors.forename: Charles F
authors.initials: CF
authors.lastname: Reynolds
authors.forename: Benoit H
authors.initials: BH
authors.lastname: Mulsant
authors.forename: Ariel
authors.initials: A
authors.lastname: Gildengers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001714:Bipolar Disorder / Q000473:pathology / Q000503:physiopathology; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged
keywords: aging; bipolar disorder; cognition; neuroimaging