ABSTRACT

1. Balance Relates to Visual and Motor Reaction Time and Coordination in Older Adults Jonathan D. Bohner, Maren S. Fragala, Nadia S. Emerson, Kyle S. Beyer, Gabriel J. Pruna, Carleigh H. Boone, Leonardo P. Oliveira, Jay R. Hoffman, FACSM, Jeffrey R. Stout, FACSM Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL USA, RESULTS Cont. ABSTRACT METHODS Cont. PURPOSE Background:Impaired balance can predispose older adults to the higher risk of falls which can lead to catastrophic consequences. The ability to quickly process and integrate visuomotor stimuli and coordinate a response reaction may intercept balance perturbations and prevent a fall. However, it is not known how balance relates to reaction, coordination, or cognition in older adults. PURPOSE:To evaluate the relationship between balance and visuomotor reaction time, coordination, and perceptual cognitive function in older adults. METHODS:Twenty-five older adults (13 men, 12 women; 70.0 ± 6.1 y) performed a series of tests. Balance performance was recorded from a timed single-leg balance test. Perceptual cognitive function (PCF) was assessed using a multiple object tracking device within a three-dimensional environment. Visual and motor reaction times of the upper and lower body were evaluated on interactive displays where individuals responded to light stimuli with hand or foot strikes. Pearson correlation coefficients and step-wise linear regressions were computed to assess the relationship between variables with significance set at p ˂ 0.05. RESULTS: Balance time ranged from 0.38 s to 600.00 s (67.1 ± 123.6 s). Lower body (LB) reaction scores ranged from 9 to 20 hits in 20-seconds (15.4 ± 3.1 hits). Upper body (UB) reaction scores ranged from 35 to 72 hits in 60-seconds(54.2 ± 9.9 hits). PCF threshold ranged from 0.14 to 1.36 (0.58 ± 0.34). Balance time significantly correlated to LB (r=0.48, p=0.015) and UB reaction time (r=0.43, p = 0.034). UB and LB reaction time were significantly correlated (r=0.657, p=0.000). PCF test scores were not correlated to balance or reaction time. Step-wise regression indicated that LB reaction time was the single greatest predictor of balance (R=.481, SEE=110.692, p=.015) CONCLUSION:Balance ability is related to visual motor coordination and reaction time in older adults, with the strongest predictor of balance being the LB reaction and coordination test. Therefore, interventions to improve balance may benefit from visual motor coordination and reaction time training exercises. Further evaluation is necessary to determine how situational awareness in a 3-D environment may impact balance and function in older adults. • To observe and evaluate balance and it’s relationship with visuomotor reaction time, coordination, and perceptual cognitive function in older adults. • To discover which test is the greatest predictor of balance performance in older adults. Table 3. Correlations of reaction tests and perceptual cognitive function with Balance • QuickBoard • Participants performed a single, twenty second test responding to visual stimuli with their feet to assess lower body reaction time (LB Reaction). No restrictions were placed on which foot was used or what form was adopted. After receiving the countdown, subjects would coordinate their response as quickly as possible by observing the light stimulus in front of them and hitting the corresponding dot with their foot as quickly and correctly as possible. This was scored by correct hits accumulated in the allotted time. • NeuroTracker • Participants performed one perceptual cognitive function (PCF) test, during which one attempts to track four out of eight identical objects in a 3 dimensional environment for eight seconds. This Core level is comprised of twenty trials, varying in difficulty based on individual performance. A score is given as a threshold at the end of the test, depicting a baseline performance given by that individual based on difficulty and consistency at completed levels. * Significant at p < 0.05 Figure 1. Correlations between Reaction Time and Balance METHODS r = 0.43 Participants for this study included men (13) and women (12) who were local to the Central Florida area. Characteristics for this group are further detailed in Table 1. Table 1. Participant Characteristics • Statistical Analysis • Pearson correlation coefficients and step-wise linear regressions were computed to assess the relationship between variables with significance set at p ˂ 0.05. • Balance • Participants balanced on their dominant foot for as long as they could without any assistance from the ground or other objects with their non-dominant leg flexed at 90°. Subjects wore flat shoes. The test was measured in seconds of successful balance. • DynaVision D2 • Participants performed 2 separate tests on the Dynavision to assess upper body reaction time (UB Reaction). The first test was performed with their dominant hand, measuring their visual and motor reaction timeto a light stimulus on one of five buttons displayed in a linear fashion. The second test was performed with both hands, responding to light stimuli constantly for sixty seconds on a coronal plane, responding to one of 64 lights. Test was scored by accumulating as many hits as possible in the allotted time. RESULTS • Balance time was significantly correlated with both upper and lower body reaction time (Table 3, Figure 1.) • The perceptual cognitive function (PCF) test did not significantly correlate with balance or reaction time. • The step-wise regression indicated that lower body reaction time was the single greatest predictor of balance performance (R=0.481; SEE=110.692; p=0.015). INTRODUCTION SUMMARY & CONCLUSIONS • The results of this study demonstrate that there is a correlation between upper and lower body reaction time and balance. These correlations have a number of implications for older adults. The ability to react to a variety of changes such as varied walking surfaces and climbing and descending stairs, is crucial to avoid falling, which has been reported as the primary disabler in older adults (National Safety Council. (2011). Injury Facts®, 2011 Edition.). • Of interest, was the lack of correlation between PCF and reaction time measures. However, it can be explained in the nature of the tests. The PCF test requires tracking multiple objects over eight seconds, and does not require a reflexive response of the motor system. • Future research should investigate the effects of a balance training program on these measures. • For older adults, balance can challenge mobility and their ability to perform basic activities of daily living. • The ability to respond to visual stimuli and coordinate a response could play a major role in preventing a fall or balance related accident. • It is unknown what relationship may exist between upper body reaction time, lower body reaction time, perceptual cognitive function, and single leg balance. Table 2. Balance, Reaction Time, and PCF Results