title: Quantitative Timed-Up-and-Go Parameters in Relation to Cognitive Parameters and Health-Related Quality of Life in Mild-to-Moderate Parkinson's Disease.
abstract: BACKGROUND
  The instrumented-Timed-Up-and-Go test (iTUG) provides detailed information about the following movement patterns: sit-to-walk (siwa), straight walking, turning and walk-to-sit (wasi). We were interested in the relative contributions of respective iTUG sub-phases to specific clinical deficits most relevant for daily life in Parkinson's disease (PD). More specifically, we investigated which condition-fast speed (FS) or convenient speed (CS)-differentiates best between mild- to moderate-stage PD patients and controls, which parameters of the iTUG sub-phases are significantly different between PD patients and controls, and how the iTUG parameters associate with cognitive parameters (with particular focus on cognitive flexibility and working memory) and Health-Related-Quality of Life (HRQoL).
  
  
  METHODS
  Twenty-eight PD participants (65.1 ± 7.1 years, H&Y stage 1-3, medication OFF state) and 20 controls (66.1 ± 7.5 years) performed an iTUG (DynaPort®, McRoberts BV, The Netherlands) under CS and FS conditions. The PD Questionnaire 39 (PDQ-39) was employed to assess HRQoL. General cognitive and executive functions were assessed using the Montreal Cognitive Assessment and the Trail Making Test.
  
  
  RESULTS
  The total iTUG duration and sub-phases durations under FS condition differentiated PD patients slightly better from controls, compared to the CS condition. The following sub-phases were responsible for the observed longer total duration PD patients needed to perform the iTUG: siwa, turn and wasi. None of the iTUG parameters correlated relevantly with general cognitive function. Turning duration and wasi maximum flexion velocity correlated strongest with executive function. Walking back duration correlated strongest with HRQoL.
  
  
  CONCLUSIONS
  This study confirms that mild- to moderate-stage PD patients need more time to perform the iTUG than controls, and adds the following aspects to current literature: FS may be more powerful than CS to delineate subtle movement deficits in mild- to moderate-stage PD patients; correlation levels of intra-individual siwa and wasi parameters may be interesting surrogate markers for the level of automaticity of performed movements; and sub-phases and kinematic parameters of the iTUG may have the potential to reflect executive functioning and HRQoL aspects of PD patients.
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Janet M T
authors.initials: JM
authors.lastname: Van Uem
authors.affiliation: McRoberts, The Hague, The Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Walgaard
authors.affiliation: McRoberts, The Hague, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Ainsworth
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Hasmann
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Heger
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Nussbaum
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Hobert
authors.affiliation: McRoberts, The Hague, The Netherlands.|MOVE Research Institute Amsterdam, Department of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Encarnación M
authors.initials: EM
authors.lastname: Micó-Amigo
authors.affiliation: McRoberts, The Hague, The Netherlands.
authors.forename: Rob C
authors.initials: RC
authors.lastname: Van Lummel
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Berg
authors.affiliation: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.|DZNE, German Center for Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Maetzler
mesh_terms: D000368:Aged; D000465:Algorithms; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010300:Parkinson Disease / Q000503:physiopathology*; D004856:Postural Balance; D011446:Prospective Studies; D011788:Quality of Life; D013997:Time Factors