title: Neurological Gait Abnormalities Moderate the Functional Brain Signature of the Posture First Hypothesis.
abstract: The posture first hypothesis suggests that under dual-task walking conditions older adults prioritize gait over cognitive task performance. Functional neural confirmation of this hypothesis, however, is lacking. Herein, we determined the functional neural correlates of the posture first hypothesis and hypothesized that the presence of neurological gait abnormalities (NGA) would moderate associations between brain activations, gait and cognitive performance. Using functional near-infrared spectroscopy we assessed changes in oxygenated hemoglobin levels in the pre-frontal cortex (PFC) during normal walk and walk while talk (WWT) conditions in a large cohort of non-demented older adults (n = 236; age = 75.5 ± 6.49 years; female = 51.7 %). NGA were defined as central (due to brain diseases) or peripheral (neuropathic gait) following a standardized neurological examination protocol. Double dissociations between brain activations and behavior emerged as a function of NGA. Higher oxygenation levels during WWT were related to better cognitive performance (estimate = 0.145; p < 0.001) but slower gait velocity (estimate = -6.336, p < 0.05) among normals. In contrast, higher oxygenation levels during WWT among individuals with peripheral NGA were associated with worse cognitive performance (estimate = -0.355; p < 0.001) but faster gait velocity (estimate = 14.855; p < 0.05). Increased activation in the PFC during locomotion may have a compensatory function that is designed to support gait among individuals with peripheral NGA.
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA. roee.holtzer@einstein.yu.edu.|Ferkauf Graduate School of Psychology of Yeshiva University, Bronx, NY, USA. roee.holtzer@einstein.yu.edu.
authors.forename: Roee
authors.initials: R
authors.lastname: Holtzer
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.|Department of Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.
authors.forename: Joe
authors.initials: J
authors.lastname: Verghese
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.|Department of Clinical Neurosciences, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Gilles
authors.initials: G
authors.lastname: Allali
authors.affiliation: School of Biomedical Engineering, Drexel University, Philadelphia, PA, USA.
authors.forename: Meltem
authors.initials: M
authors.lastname: Izzetoglu
authors.affiliation: Department of Epidemiology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.
authors.forename: Cuiling
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.
authors.forename: Jeannette R
authors.initials: JR
authors.lastname: Mahoney
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000150:complications* / Q000473:pathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D010108:Oxyhemoglobins / Q000378:metabolism*; D011187:Posture / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D016138:Walking
chemical_list: D010108:Oxyhemoglobins
keywords: Aging; Brain; Locomotion; Near-infrared spectroscopy