title: Freezing of gait in Parkinson's disease: the paradoxical interplay between gait and cognition.
abstract: BACKGROUND
  Freezing of gait is a disabling episodic gait disturbance common in patients with Parkinson's disease. Recent evidences suggest a complex interplay between gait impairment and executive functions. Aim of our study was to evaluate whether specific motor conditions (sitting or walking) influence cognitive performance in patients with or without different types of freezing.
  
  
  METHODS
  Eight healthy controls, eight patients without freezing, nine patients with levodopa-responsive and nine patients with levodopa-resistant freezing received a clinical and neuropsychological assessment during two randomly performed conditions: at rest and during walking.
  
  
  RESULTS
  At rest, patients with levodopa-resistant freezing performed worse than patients without freezing on tests of phonological fluency (p = 0.01). No differences among the four groups were detected during walking. When cognitive performances during walking were compared to the performance at rest, there was a significant decline of verbal episodic memory task (Rey Auditory Verbal Learning Test) in patients without freezing and with levodopa-responsive freezing. Interestingly, walking improved performance on the phonological fluency task in patients with levodopa-resistant freezing (p = 0.04).
  
  
  CONCLUSIONS
  Compared to patients without freezing, patients with levodopa-resistant freezing perform worse when tested while seated in tasks of phonological verbal fluency. Surprisingly, gait was associated with a paradoxical improvement of phonological verbal fluency in the patients with levodopa-resistant freezing whilst walking determined a worsening of episodic memory in the other patient groups.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy; Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Lucia
authors.initials: L
authors.lastname: Ricciardi
authors.affiliation: Department of Neurology and Parkinson Centre Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Bastiaan R
authors.initials: BR
authors.lastname: Bloem
authors.affiliation: Department of Neurology and Parkinson Centre Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Anke H
authors.initials: AH
authors.lastname: Snijders
authors.affiliation: Department of Neurology, Catholic University of Sacred Heart, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Daniele
authors.affiliation: Department of Neurology, Catholic University of Sacred Heart, Rome, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Quaranta
authors.affiliation: Department of Neurology, Catholic University of Sacred Heart, Rome, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Bentivoglio
authors.affiliation: Movement Disorders Center, Toronto Western Hospital, UHN, Division of Neurology, University of Toronto, 399 Bathurst St, 7 Mc412, Toronto, Ontario M5T 2S8, Canada. Electronic address: alfonso.fasano@gmail.com.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Fasano
mesh_terms: D000368:Aged; D003071:Cognition / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005684:Gait; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000523:psychology
keywords: Cognition; Executive functions; Freezing of gait; Gait; Parkinson's disease