IMPACT OF FATIGUE ON POSTURAL STABILITY AND BRAIN WAVE ACTIVITY

Abstract

BACKGROUND: To maintain postural control, the brain is required to integrate visual and sensory information within the sensorimotor systems. Increases in fall risk are influenced by many factors such as age, fatigue, and neural dysfunction (e.g., Parkinson’s Disease). While it is known these factors increase fall risk, the relationship between fatigue and neurological function in postural control is still unclear and the effects of fatigue are still unknown. The aim of this study was to directly analyze the effects of neural brain activity and postural control of healthy individuals following volitional fatigue. METHODS: Nine healthy participants, ages 18 to 38, were chosen. Individuals with any previous history of concussions or major lower-extremity injuries were excluded as these conditions may affect postural control. After providing informed consent, the participants were outfitted with a Pedar in-sole pressure distribution system and a g-tec EEG system. The pre-test consisted of three trials, each involving 30 seconds of standing with eyes open and 30 seconds with eyes closed. After, the participant was asked to wear an HTC VIVE virtual reality (VR) headset and do three rounds of 30 seconds in the VR still room, 30 seconds in the VR moving room, and 30 seconds in recovery after the moving room. Next, they underwent a volitional fatigue protocol. Fatigue was defined as reaching a rate of perceived exertion (RPE) of 13 or 76% of their target heart rate. Once the fatigue protocol was completed, the pre-fatigue protocol was repeated to assess any changes in the force plate and brain activity. Data was processed using customized MATLAB scripts and EEGLAB, and a repeated-measures ANOVA was conducted to compare pre- and post-fatigue indicators. RESULTS: Fatigue will impair postural control and increase neural activity in brain regions responsible for balance. These effects are shown to be more pronounced during a visual perturbation and when sensory information is inaccurate.