title: Real-space path integration is impaired in Alzheimer's disease and mild cognitive impairment.
abstract: Path integration (PI) is an important component of spatial navigation that integrates self-motion cues to allow the subject to return to a starting point. PI depends on the structures affected early in the course of Alzheimer's disease (AD) such as the medial temporal lobe and the parietal cortex.
  
  
  
  To assess whether PI is impaired in patients with mild AD and amnestic mild cognitive impairment (aMCI) and to investigate the role of the hippocampus, entorhinal and inferior parietal cortex in this association.
  
  
  
  27 patients with aMCI, 14 with mild AD and 18 controls completed eight trials of Arena Path Integration Task. The task required subjects with a mask covering their eyes to follow an enclosed triangle pathway through two previously seen places: start-place1-place2-start. Brains were scanned at 1.5T MRI and respective volumes and thicknesses were derived using FreeSurfer algorithm.
  
  
  
  Controlling for age, education, gender and Mini-Mental State Examination score the aMCI and AD subjects were impaired in PI accuracy on the pathway endpoint (p=0.042 and p=0.013) compared to controls. Hippocampal volume and thickness of entorhinal and parietal cortices explained separately 36-45% of the differences in PI accuracy between controls and aMCI and 28-31% of the differences between controls and AD subjects.
  
  
  
  PI is affected in aMCI and AD, possibly as a function of neurodegeneration in the medial temporal lobe structures and the parietal cortex. PI assessment (as a part of spatial navigation testing) may be useful for identification of patients with incipient AD.
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Mokrisova
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic. Electronic address: janlaczo@seznam.cz.
authors.forename: J
authors.initials: J
authors.lastname: Laczo
authors.affiliation: International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; School of Aging Studies, University of South Florida, Tampa, FL, USA.
authors.forename: R
authors.initials: R
authors.lastname: Andel
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Gazova
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Vyhnalek
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: Z
authors.initials: Z
authors.lastname: Nedelska
authors.affiliation: Department of Neurophysiology of Memory, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: D
authors.initials: D
authors.lastname: Levcik
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Cerman
authors.affiliation: International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurophysiology of Memory, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic. Electronic address: kamil@biomed.cas.cz.
authors.forename: K
authors.initials: K
authors.lastname: Vlcek
authors.affiliation: Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Hort
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000150:complications* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D013028:Space Perception / Q000502:physiology*
keywords: Alzheimer disease; Hippocampus; Mild cognitive impairment; Path integration; Spatial navigation