MRI- and MRS-derived hippocampal correlates of quantitative locomotor function in older adults

Molly E. Zimmerman, Richard B. Lipton, Jullie W. Pan, Hoby P. Hetherington, Joe Verghese

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Gait measures have been shown to predict cognitive decline and dementia in older adults. Investigation of the neurobiology associated with locomotor function is needed to elucidate this relationship with cognitive abilities. This study aimed to examine magnetic resonance imaging (MRI; hippocampal volume)- and proton magnetic resonance spectroscopy (MRS; N-acetylaspartate to creatine (NAA/Cr) ratios)-derived hippocampal correlates of quantitative gait function (swing time (seconds), stride length (cm), and stride length variability (standard deviation)) in a subset of 48 nondemented older adults (24 males; mean age = 81 years) drawn from the Einstein Aging Study, a community-based sample of individuals over the age of 70 residing in Bronx, New York. Linear regression analyses controlling for age were used to examine hippocampal volume and neurochemistry as predictors of gait function. We found that stride length was associated with hippocampal volume (β = 0.36, p = 0.03; overall model R2 = 0.33, p = 0.01), but not hippocampal neurochemistry (β = 0.09, p = 0.48). Stride length variability was more strongly associated with hippocampal NAA/Cr (β = - 0.38, p = 0.01; overall model R2 = 0.14, p = 0.04) than hippocampal volume (β = - 0.33, p = 0.08). Gait swing time was not significantly related to any neuroimaging measure. These relationships remained significant after accounting for memory and clinical gait impairments. These findings suggest that nondemented older adults exhibit increased stride length variability that is associated with lower levels of hippocampal neuronal metabolism, but not hippocampal volume. Conversely, decreased stride length is associated with smaller hippocampal volumes, but not hippocampal neurochemistry. Distinct neurobiological hippocampal substrates may support decreased stride length and increased stride length variability in older adults.

Original languageEnglish (US)
Pages (from-to)73-81
Number of pages9
JournalBrain Research
Volume1291
DOIs
StatePublished - Sep 21 2009

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Keywords

  • Aging
  • Hippocampus
  • Locomotion
  • Memory
  • Motor processing
  • Neuroimaging

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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