title: Hippocampal volume, early cognitive decline and gait variability: which association?
abstract: BACKGROUND
  In contrast to its prominent function in cognition, the involvement of the hippocampus in gait control is still a matter of debate. The present study aimed to examine the association of the hippocampal volume with mean values and coefficients of variation (CoV) of spatio-temporal gait parameters among cognitively healthy individuals (CHI) and patients with mild cognitive impairment (MCI).
  
  
  METHODS
  A total of 90 individuals (47 CHI with a mean age of 69.7±3.6years and 48.9% women, and 43 MCI individuals with a mean age of 70.2±3.7years and 62.8% women) were included in this cross-sectional study. The hippocampal volume was quantified from a three-dimensional T1-weighted MRI using semi-automated software. Mean values and CoV of stride time, swing time and stride width were measured at self-selected pace with a 10m electronic portable walkway (GAITRite®). Age, gender, body mass index, number of drugs daily taken, Mini-Mental State Examination (MMSE) score, history of falls, walking speed and white matter signal-intensity abnormality scoring with Manolio scale were used as covariates.
  
  
  RESULTS
  Patients with MCI had a lower MMSE score (P<0.001), a higher CoV of stride time (P=0.013) and a lower hippocampal volume (P=0.007) compared with CHI. Multiple linear regression models showed that CoV of stride time was specifically associated with higher hippocampal volume among CHI (P<0.05) but not among patients with MCI (P>0.650).
  
  
  CONCLUSIONS
  Our findings revealed a positive association between a greater (i.e., better morphological structure) hippocampal volume and a greater (i.e., worse performance) stride time variability among CHI, but not among MCI individuals.
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, University Memory Clinic of Angers, UPRES EA 4638, University of Angers, UNAM, Angers, France. Electronic address: olbeauchet@chu-angers.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Beauchet
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, University Memory Clinic of Angers, UPRES EA 4638, University of Angers, UNAM, Angers, France.
authors.forename: Cyrille P
authors.initials: CP
authors.lastname: Launay
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, University Memory Clinic of Angers, UPRES EA 4638, University of Angers, UNAM, Angers, France; Center for Functional Metabolic Mapping, Robarts Research Institute, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, Canada.
authors.forename: Cédric
authors.initials: C
authors.lastname: Annweiler
authors.affiliation: Department of Neurology, Geneva University Hospital and University of Geneva, Switzerland; Department of Neurology, Division of Cognitive & Motor Aging, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, USA.
authors.forename: Gilles
authors.initials: G
authors.lastname: Allali
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait; D006624:Hippocampus / Q000033:anatomy & histology*; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male
keywords: Gait; Hippocampus; Magnetic resonance imaging; Mild cognitive impairment; Motor control; Older adults