Sunday, May 11, 2025
5/11/2025
Neural and Behavioral Indices of Balance Performance in Individuals with sensory loss - ABSTRACT People with unilateral vestibular hypofunction (VH, peripheral disease of the inner ear) are thought to develop visual dependence. They get dizzy and off balance in complex visual environments. They sway more with dynamic visuals compared to static or with eyes closed compared to open. Individuals with UHL are not regularly assessed for balance function, but those with at least moderate hearing loss show increased risk for falls. Data from mechanistic studies in our lab have demonstrated that individuals with UHL do not increase postural sway in the presence of complex visual scenes as much as healthy controls, suggesting they are not as reliant on visual input to maintain their balance. Based on these findings, we hypothesize that individuals with UHL may reallocate attentional resources to motor control of balance (conscious movement processing) to compensate for the loss of auditory cues. To test the hypotheses of visual dependence in VH and conscious movement processing in UHL, this proposal will combine behavioral assessments of balance with analyses of network-based functional connectivity from resting-state functional magnetic resonance imaging (fMRI). The long-term goal of this research is to identify the neurobiological index explaining balance behavior and develop an intervention approach targeting functional connectivity differences that maximizes functional mobility gains in people with sensory loss. In the current project we will address the following Specific Aims: Aim 1: Identify balance profiles for people with VH and UHL. Individuals with VH, UHL and controls (N=24 each) will perform a battery of balance measures including static, dynamic, gait, and tests targeting sensory and cognitive aspects of balance. We will also analyze their postural sway from force plate data as they are tested in a virtual reality environment. Aim 2: Identify internetwork functional connectivity differences in VH, UHL, and healthy controls. Resting-state fMRI data will be acquired from VH and UHL (N=12 each) and compared to a distribution of healthy control data. Aim 3: Determine the extent to which balance performance (Aim 1) correlate with neurobiological data (Aim 2) in VH and UHL. We will calculate correlations between postural sway data and ratio of attention-motor connectivity to attention-vision connectivity. If we accomplish our aims, we will identify which balance domains are most affected by vestibular and hearing loss and whether people with UHL should be regularly screened for balance performance. We will establish which brain connections are altered by sensory loss and the implications for balance. This knowledge will have important implications to public health for improved assessment of balance and development of future interventions in VH and UHL.
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