title: Multimodal imaging evaluation of excessive daytime sleepiness in Parkinson's disease.
abstract: OBJECTIVE
  The multimodal imaging investigation of excessive daytime sleepiness (EDS) in Parkinson's disease (PD). The role of dopaminergic treatment and other clinical parameters was also evaluated.
  
  
  METHODS
  Seventeen non-demented PD patients with EDS (PD-EDS) and 17 PD patients without EDS were enrolled. Clinical, treatment and MRI data were acquired. Gray matter (GM) volume was examined with voxel-based morphometry, while white matter (WM) integrity was assessed with diffusion tensor imaging by means of fractional anisotropy, mean diffusivity, axial diffusivity (AD) and radial diffusivity measures.
  
  
  RESULTS
  Increased regional GM volume was found in the PD-EDS group bilaterally in the hippocampus and parahippocampal gyri. Increased AD values were also shown in the PD-EDS group, in the left anterior thalamic radiation and the corticospinal tract and bilaterally in the superior corona radiata and the superior longitudinal fasciculus. Levodopa equivalent dose differed significantly between the groups and was the only predictor of EDS, while the only predictor of the Epworth sleepiness scale score in the PD-EDS group was the dopamine-agonist dose. Increased frequency of gamblers was also observed in the PD-EDS group.
  
  
  CONCLUSIONS
  Regional GM increases and increased AD values in certain WM tracts were found in the PD-EDS group. The changes could result from disinhibited signaling pathways or represent compensatory changes in response to anatomical or functional deficits elsewhere. The study findings support also the contribution of the total dopaminergic load in the development of EDS, while the dose of dopamine agonists was found to predict the severity of the disorder.
authors.affiliation: a Department of Neurology.
authors.forename: Maria
authors.initials: M
authors.lastname: Chondrogiorgi
authors.affiliation: b Department of Radiology.
authors.forename: Loukia C
authors.initials: LC
authors.lastname: Tzarouchi
authors.affiliation: b Department of Radiology.
authors.forename: Anastasia K
authors.initials: AK
authors.lastname: Zikou
authors.affiliation: c Department of Medical Physics, Medical School , University of Ioannina , Ioannina , Greece.
authors.forename: Loukas G
authors.initials: LG
authors.lastname: Astrakas
authors.affiliation: b Department of Radiology.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Kosta
authors.affiliation: b Department of Radiology.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Argyropoulou
authors.affiliation: a Department of Neurology.
authors.forename: Spiridon
authors.initials: S
authors.lastname: Konitsiotis
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D006970:Disorders of Excessive Somnolence / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D066128:Gray Matter / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010300:Parkinson Disease / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D066127:White Matter / Q000473:pathology / Q000503:physiopathology
keywords: Parkinson’s disease; axial diffusivity; diffusion tensor imaging; excessive daytime sleepiness; neuroradiology