title: A smaller amygdala is associated with anxiety in Parkinson's disease: a combined FreeSurfer-VBM study.
abstract: BACKGROUND
  Up to 50% of all patients with Parkinson's disease (PD) suffer from anxiety symptoms, a much higher percentage than in the general population. This suggests that PD associated pathological alterations partly underlie these symptoms, although empirical evidence is limited.
  
  
  METHODS
  Here we investigated the association between anxiety symptoms measured with the Beck Anxiety Inventory (BAI) and hippocampal and amygdalar volume in 110 early-stage patients with PD. Measures of anxiety in PD are often obscured by overlap with the somatic symptoms. We therefore also used a subscale of the BAI, established by our recent factor analysis, that reflects 'psychological' anxiety symptoms and is independent of the severity of PD-related motor and autonomic symptoms. We used FreeSurfer and voxel-based morphometry for the volumetric analyses.
  
  
  RESULTS
  Both software packages showed a negative correlation between the 'psychological' subscale of the BAI, but not total BAI and volume of the left amygdala, independent of the severity of motor symptoms, autonomic dysfunction and dopaminergic or anxiolytic medication status.
  
  
  CONCLUSIONS
  These results confirm studies in non-PD samples showing lower left amygdalar volume in anxious patients. The results also indicate that the 'psychological' BAI subscale is a better reflection of neural correlates of anxiety in PD. Whether the left amygdalar volume decrease constitutes a premorbid trait, a PD-associated neurobiological susceptibility to anxiety or arises as a consequence of chronic anxiety symptoms remains to be determined by future prospective longitudinal studies. Nonetheless, we speculate that the Parkinson pathology is responsible for the reduction in amygdalar volume and the concomitant development of anxiety symptoms.
authors.affiliation: Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Chris
authors.initials: C
authors.lastname: Vriend
authors.affiliation: Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands.
authors.forename: Premika S W
authors.initials: PS
authors.lastname: Boedhoe
authors.affiliation: Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Sonja
authors.initials: S
authors.lastname: Rutten
authors.affiliation: Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Henk W
authors.initials: HW
authors.lastname: Berendse
authors.affiliation: Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
authors.forename: Ysbrand D
authors.initials: YD
authors.lastname: van der Werf
authors.affiliation: Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands.
authors.forename: Odile A
authors.initials: OA
authors.lastname: van den Heuvel
mesh_terms: D000368:Aged; D000679:Amygdala / Q000473:pathology*; D001007:Anxiety / Q000150:complications* / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D010300:Parkinson Disease / Q000150:complications* / Q000473:pathology*
keywords: MRI; NEUROBIOLOGY; NEUROPSYCHIATRY; PARKINSON'S DISEASE