title: Obesity-specific neural cost of maintaining gait performance under complex conditions in community-dwelling older adults.
abstract: Recent evidence of obesity-related changes in the prefrontal cortex during cognitive and seated motor activities has surfaced; however, the impact of obesity on neural activity during ambulation remains unclear. The purpose of this study was to determine obesity-specific neural cost of simple and complex ambulation in older adults.
  
  
  
  Twenty non-obese and obese individuals, 65years and older, performed three tasks varying in the types of complexity of ambulation (simple walking, walking+cognitive dual-task, and precision walking). Maximum oxygenated hemoglobin, a measure of neural activity, was measured bilaterally using a portable functional near infrared spectroscopy system, and gait speed and performance on the complex tasks were also obtained.
  
  
  
  Complex ambulatory tasks were associated with ~2-3.5 times greater cerebral oxygenation levels and ~30-40% slower gait speeds when compared to the simple walking task. Additionally, obesity was associated with three times greater oxygenation levels, particularly during the precision gait task, despite obese adults demonstrating similar gait speeds and performances on the complex gait tasks as non-obese adults.
  
  
  
  Compared to existing studies that focus solely on biomechanical outcomes, the present study is one of the first to examine obesity-related differences in neural activity during ambulation in older adults. In order to maintain gait performance, obesity was associated with higher neural costs, and this was augmented during ambulatory tasks requiring greater precision control. These preliminary findings have clinical implications in identifying individuals who are at greater risk of mobility limitations, particularly when performing complex ambulatory tasks.
authors.affiliation: Department of Environmental and Occupational Health, Texas A&M University, 1266 TAMU, College Station, TX 77843, USA.
authors.forename: Olufunmilola
authors.initials: O
authors.lastname: Osofundiya
authors.affiliation: Department of Environmental and Occupational Health, Texas A&M University, 1266 TAMU, College Station, TX 77843, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Benden
authors.affiliation: Department of Health Promotion and Community Health Sciences, Texas A&M University, 1266 TAMU, College Station, TX 77843, USA.
authors.forename: Diane
authors.initials: D
authors.lastname: Dowdy
authors.affiliation: Department of Environmental and Occupational Health, Texas A&M University, 1266 TAMU, College Station, TX 77843, USA. Electronic address: rmehta@tamu.edu.
authors.forename: Ranjana K
authors.initials: RK
authors.lastname: Mehta
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D002531:Cerebellum / Q000378:metabolism*; D003071:Cognition; D005260:Female; D005684:Gait / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D010100:Oxygen / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D016138:Walking / Q000502:physiology*
chemical_list: D006454:Hemoglobins; D010100:Oxygen
keywords: BMI; Brain activity; Dual task; Precision gait; Walking; fNIRS