title: Interactions of Subjective and Objective Measures of Fatigue Defined in the Context of Brain Control of Locomotion.
abstract: Fatigue adversely impacts quality of life in old age. The relationship between subjective and objective measurements of fatigue, however, is poorly understood. We examined whether subjective fatigue moderated the expression of objective fatigue during locomotion. Associations between objective and subjective measures of fatigue were predicted to manifest only under dual-task conditions that maximized cognitive demands.
  
  
  
  Participants were 314 nondemented older adults (age = 76.8±6.7 years; % female = 56). Functional near-infrared spectroscopy was used to assess oxygenated hemoglobin (HbO2) levels during walking. A 4×14-foot Zeno electronic walkway was utilized to assess stride velocity (cm/s). Objective fatigue was operationalized as attenuation in HbO2 levels and decline in stride velocity (cm/s) during six continuous straight walks under single- (normal-walk) and dual-task (walk-while-talk) conditions. The Brief Fatigue Inventory assessed subjective fatigue.
  
  
  
  Worse subjective fatigue was associated with attenuated increase in HbO2 levels (estimate = 0.175; p < .05) but not with decline in stride velocity (estimate = 0.394; p > .05) from normal-walk to walk-while-talk conditions. Objective fatigue did not manifest and was not associated with subjective fatigue during the course of normal-walk. Worse subjective fatigue was associated with attenuated HbO2 levels in the fourth (estimate = -0.178; p < .05), fifth (estimate = -0.230; p < .01), and sixth (estimate = -0.231; p < .01) straight walks compared to the first during walk-while-talk.
  
  
  
  Dual-task walking paradigms provide a unique environment to simultaneously assess different facets of fatigue. The prefrontal cortex subserves both subjective and objective measurements of fatigue as defined in the context of attention-demanding locomotion.
authors: Department of Neurology.|Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, New York.
authors: Roee
authors: R
authors: Holtzer
authors: Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, New York.
authors: Jennifer
authors: J
authors: Yuan
authors: Department of Neurology.|Department of Medicine, and.
authors: Joe
authors: J
authors: Verghese
authors: Department of Neurology.
authors: Jeannette R
authors: JR
authors: Mahoney
authors: School of Biomedical Engineering, Drexel University, Philadelphia, Pennsylvania.
authors: Meltem
authors: M
authors: Izzetoglu
authors: Department of Epidemiology, Albert Einstein College of Medicine, Bronx, New York.
authors: Cuiling
authors: C
authors: Wang
mesh_terms: D000368:Aged; D001921:Brain / Q000502:physiology*; D059026:Diagnostic Self Evaluation; D005221:Fatigue / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008124:Locomotion; D008297:Male; D016138:Walking
keywords: Aging; Brain; Fatigue; Locomotion