title: Alterations of mean diffusivity of pedunculopontine nucleus pathway in Parkinson's disease patients with freezing of gait.
abstract: BACKGROUND
  Although freezing of gait (FOG) is a common and disabling symptom in Parkinson's disease (PD), the underlying mechanism of FOG has not been clearly elucidated. Using analysis of diffusion tensor imaging (DTI), we investigated anatomic structures associated with FOG in PD patients.
  
  
  METHODS
  We enrolled 33 controls and 42 PD patients (19 patients with FOG and 23 without FOG). DTI data were compared between PD patients and controls, and also between PD patients with and without FOG. Whole brain voxel-based analysis and regions of interest analysis in the pedunculopontine nucleus were used for DTI analysis.
  
  
  RESULTS
  Compared with normal controls, PD patients showed microstructural changes in various subcortical structures (substantia nigra, globus pallidum and thalamus), frontal and insula cortex. PD patients with FOG demonstrated altered mean diffusivities in subcortical structures connected with pedunculopontine nucleus, such as basal ganglia, thalamus and cerebellum in voxel-based analysis. Using region of interest analysis of pedunculopontine nucleus, fractional anisotropy values were reduced and mean diffusivity values were increased bilaterally in PD patients with FOG. In correlation analysis, the fractional anisotropy value of the right pedunculopontine nucleus was moderately correlated with the severity of FOG.
  
  
  CONCLUSIONS
  Based on our results, microstructural changes of pedunculopontine nucleus and connected subcortical structures are closely related with FOG in PD patients.
authors.affiliation: Department of Neurology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Youn
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea.
authors.forename: Hunki
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Department of Neurology, Soonchunhyang University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Sun
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Neurology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Tae Ok
authors.initials: TO
authors.lastname: Son
authors.affiliation: Department of Neurology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: jinwhan.cho@samsung.com.
authors.forename: Jin Whan
authors.initials: JW
authors.lastname: Cho
mesh_terms: D000368:Aged; D016880:Anisotropy; D056324:Diffusion Tensor Imaging; D046352:Freezing Reaction, Cataleptic / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D045042:Pedunculopontine Tegmental Nucleus / Q000473:pathology*; D012720:Severity of Illness Index
keywords: Diffusion tensor; Freezing; Gait; Parkinson's; Pedunculopontine