Merging Attentional Focus and Balance Training to Reduce Fall Risk in Older Adults

Overview

Approximately 15 million older adults fall every year in the United States and fall prevention programs have only been moderately successful in arresting fall rates. This proposal uses motor learning principles derived from the attentional focus literature to determine whether training someone where to focus their attention during a balance task enhances balance control and reduces fall risk. Older adults (N=90) who are classified as fallers (one or more falls in the past 12 months) will be recruited. A series of balance control, clinical metrics of fall risk, and patient-reported outcomes will be assessed prior, during, and after a 12-week intervention to examine changes in performance and fall risk. The 12-week intervention will emphasize directing the participants' attention either internally or externally during a series of balance tasks. Empirical evidence and our preliminary data leads us to hypothesize that an external focus of attention training will positively influence balance control. This will be the first study to will examine balance control changes over 12-week balance intervention using an attentional focus paradigm and we will relate the balance control changes to clinical metrics that indicate fall risk and patient-reported outcomes. Further, our proposal includes a novel model of entropy in postural sway, a metric that has been proposed to relate to balance ability, to help explain the hypothesized enhancement in balance. Thus, this proposal will merge motor learning principles with a 12-week balance intervention to determine if fall risk is reduced in older adults. Specific Aim 1 compares balance performance within each trial/session throughout the 12 weeks of balance training to evaluate whether the attentional focus groups (external vs. internal) differ in their motor learning trajectory with respect to the balance task. Specific Aim 2 compares the motor ability outcome measures that relate to fall-risk between the groups (external focus, internal focus, or control) before, during, and after the 12-week balance intervention. Specific Aim 3 compares the patient-reported outcome measures of fear of falling, functional health and well-being, and fear of injury from movement between the groups (external focus, internal focus, or control) before, during, and after the 12-week balance intervention.

Falls due to poor balance are common and costly in older adults. Unfortunately, traditional balance interventions show mixed results in reducing falls. Balance is controlled by a complex system that depends on a host of cognitive functions, including attention. While attention has different meanings in different research areas, this proposal will examine attention defined as a performer's conscious perception of information for a task, which can be focused internally or externally. An internal focus of attention is directed at the performer's own body movements, while an external focus is directed at the effects a particular movement has on the environment. Fall prevention interventions typically emphasize an internal focus of attention. However, mounting evidence from laboratory settings indicates that an external focus of attention improves balance control. For example, participants in one study were asked to balance on a stabilometer, which is an unstable device that swings forward or backward when someone is out of balance. Participants were asked to focus on keeping their feet level (i.e., an internal focus) or keeping the surface of the stabilometer level (i.e., an external focus). When the participants adopted an external focus, their balance was enhanced. That is, they had fewer deviations from their starting position (i.e., less variability in their motion). Follow-up research also showed that participants were able to respond faster to their change in body position during a balance task when they adopted an external focus. Both of these characteristics would be beneficial for an older adult population with a history of falls. The theoretical explanation of these findings is the constrained-action hypothesis, which suggests that an internal focus of attention constrains the system in a way that does not allow it to find an optimal solution. For example, instructions that ask a participant to focus internally by keeping their feet level may constrain other parts of the body and actually diminish balance control. In contrast, instructions that ask a participant to focus externally by keeping a balance apparatus level allow the body to find the optimal way to perform the task. This small change in instruction has been repeatedly shown to significantly enhance performance. Thus, emphasizing an external focus of attention may be critical to the optimization of strategies designed to improve balance and reduce fall risk in older adults. This approach does not require a re-tooling of all clinical practice, just a modification of current delivery, making the cost-benefit ratio of the approach appealing to clinical practitioners and administrators. The goal of this proposed study, therefore, is to extend this line of research to determine the efficacy of using an external focus of attention to enhance balance control and decrease fall risk in older adults. To show proof-of-concept, we conducted 2 preliminary studies. The 1st preliminary study showed that older adults who adopted an external focus of attention during a balance task had greater postural control complexity, which is typically interpreted as a more adaptable and less fall-prone behavior. The 2nd preliminary study showed that an external focus of attention increases the time-in-balance for older adults standing on a wobble board. By altering the attentional focus, our data show that the external focus instructions lead to more stable postural control. This is consistent with the plethora of literature showing the positive effect of adopting an external focus of attention on motor control performance. These preliminary results give us confidence that a 12-week balance intervention that emphasizes an external focus of attention will be superior to a similar intervention that utilizes an internal focus of attention (i.e., what is used in traditional balance interventions). Balance control, clinical metrics of fall risk, and patient-reported outcomes of functional ability will be recorded before, during, and after a 12 week balance training intervention in a cohort of 90 older adults with a history of falls. There are three specific aims for this proposal: SPECIFIC AIM 1: Compare balance performance within each trial/session to evaluate whether the attentional focus groups (external vs. internal) differ in their motor learning trajectory with respect to the balance task. Hypothesis 1: The external focus group will exhibit a faster rate of motor learning toward stable balance. SPECIFIC AIM 2: Compare the motor ability outcome measures that relate to fall-risk between the groups (external focus, internal focus, or control) before, during, and after the 12 week balance intervention. Hypothesis 2a: The external focus group will exhibit a greater reduction in fall-risk during mid- and post-testing relative to the internal focus and control groups. Hypothesis 2b: Sensory information (vision, vestibular, and somatosensory scores) and attention will be related to fall risk, but mediated through entropy of postural sway. SPECIFIC AIM 3: Compare the patient-reported outcome measures of fear of falling, functional health and well-being, and fear of injury from movement between the groups (external focus, internal focus, or control) before, during, and after the 12 week balance intervention. Hypothesis 3: The external focus group will have a significantly lower fear of falling, enhanced functional health and well-being, and lower fear of injury from movement during mid- and post-testing relative to the internal focus and control groups.