Performance of Balance Impaired Elders on Three Balance Tests under Two Visual Conditions

Performance of Balance Impaired Elders on Three Balance Tests under Two Visual Conditions

Huang, Min

ABSTRACT

Purpose: This study compared differences in balance measures among elderly adults with different degrees of balance impairments under different visual conditions. Methods: This study was conducted on 89 adults (> 60 years) with balance impairments. Subjects were divided into 3 groups based on the initial Tinetti score: low risk of fall (LRF, n=29), moderate risk of fall (MRF, n=30) and high risk of fall (HRF, n=30). Three balance measures-Tinetti, Timed-up and Go (TUG), and Functional Reach-were tested with 2 different visual conditions: eyes open with normal vision (EONV) and eyes open with blurred vision (EOBV). All data were analyzed using repeated measures analysis of variance. Results: Subjects with EOBV had significantly decreased Tinetti (P .05) scores. Conclusion: Blurred vision significantly altered all 3 balance measure scores in all risk groups. However, blurred vision had a greater influence on Tinetti and TUG scores than Functional Reach scores in subjects with higher risk of falls.

Key Words: aging, balance, vision, fall

INTRODUCTION

Falls are a major problem among older adults. At least one-third to one-half of the population aged 65 and older fall each year1-5 and these falls often result in serious injury. The majority of the falls by elderly persons appear to be multi-factorial in etiology, including cognitive impairment, muscle weakness, postural hypotension, visual impairment, balance and gait abnormalities, foot problems, and medications.6’9 Of all these, balance disorders appear to be the primary factor in falls.1013 There is general agreement that the ability of a person to maintain balance highly depends on the integration of the somatosensory, vestibular, and visual systems.14 A deficit in any of these systems can lead to postural instability, balance disorder, and falls.

Postural control is the ability to control the body position in space. Postural sway is a corrective body movement resulting from the control of body position. Therefore, any increase in postural sway indicates poor postural control and poor balance.15 Researchers have reported that postural sway increases with aging. Increased postural sway is associated with an increased risk of falls among community-dwelling elders.16-18

The role of vision in the maintenance of postural control and balance is crucial. Some investigators19·20 have reported that postural sway is affected by viewing visual scenes that rotate or create a tunnel effect, with amplitude of sway being influenced by the frequency of the moving visual scene. Baloh et al21 reported that changing visual input alone can increase postural sway. Similarly, Maki et al22 noted that lateral sway with eyes closed was the single best measure from a battery of clinical and laboratory balance tests for predicting falls in 100 community-dwelling older persons. Vision plays an even greater role in postural control and balance when somatosensory and vestibular sensory input are reduced.23

While many of the previous studies focused on the effects of vision on postural sway and static balance, there is little research on the effect of vision on clinical balance measures. Therefore, the purpose of this study was to determine whether altered vision influenced 3 clinical balance measures [Tinetti, Timed-upandGo(TUG),and Functional Reach] in elderly adults with different degrees of balance impairments. The following hypotheses were tested: (1) the subjects in the low risk of fall (LRF) group will perform better in all balance tests than those in the moderate risk of fall (MRF) and high risk of fall (HRF) groups, (2) blurred vision will impair all balance measure scores.

METHODS

Subjects

This study was performed on 89 elderly adults (12 males, 77 females, mean age =79 ± 8 years, range = 60 to 97). Subjects in the LRF (n = 29) group were recruited from a retirement center. Subjects in the MRF (n = 30) and HRF (n = 30) groups were recruited from a long-term care facility in Jackson, Mississippi. Subjects were screened for medical problems that would prevent their participation. Inclusion criteria were: (1) ≥ 60 years of age, (2) ability to ambulate at least 6 meters with or without an assistive device (28 subjects used walkers, 6 subjects used canes, and 55 used no assistive devices). Exclusion criteria included: (1 ) inability to stand with both feet on floor; (2) demonstration of visual deficits not corrected with corrective lenses; (3) evidence of limited range of motion (range of motion was not within normal functional limit) at key joints including trunk and bilateral shoulders, elbows, wrists, hips, knees, and ankles; (4) presence of orthopedic problems with weight bearing status less than full weight bearing; or (5) failure to answer questions in a consistent manner. This study was approved by the Institutional Review Board (IRB) of the University of Mississippi Medical Center to ensure protection of human subjects. Prior to the data collection, each subject volunteered to participate in this study and signed an informed consent document that explained the tests and the risks involved.

Procedure

Subjects were divided into 3 groups according to their initial Tinetti score: (1) LRF (total Tinetti score: 25-27/28), (2) MRF (total Tinetti score: 19-24/28), and (3) HRF (total Tinetti score

Tinetti test comprised a series of tests that measured subjects’ gait and balance. Subjects were scored O to 2 on the individual items, with O representing the most impairment and 2 representing independence. The individual items were combined into 3 measures: (1) an overall gait score (12 points), (2) an overall balance score (16 points), and (3) a gait and balance score (28 points). Subjects who scored 25 to 27 were classified as low risk of falls (LRF).Those who scored 19 to 24 points were classified as moderate risk of falls (MRF) and 18 or below were classified as high risk of falls (HRF).2426

The TUG test consisted of the subject rising from an armchair and walking 3 meters and returning to the chair to sit while a researcher recorded the time.27 Instructions given to the participants were: “sit in this chair with your back against the chair and your arms resting on the chair arms; when I say ‘go/ scoot to the edge of the seat, and place your feet flat on the floor close to the front edge of the chair; use armrests of the chair to push up into standing and walk at your normal speed to the line on the floor; then turn around, return to the chair, and sit down carefully.” Timing began on the word ‘go’ and ended when the subjects returned to the start position with their back against the chair.

For the Functional Reach test, a 48-inch ruler was attached to a wall at the level of the subject’s acromion. Subjects were asked to extend their arm to 90° and reach forward as far as possible without losing their balance or taking a step.28

To ensure safety, one researcher guarded the subject during the test period for all tests, while another researcher recorded the results. All balance measures were tested by 2 experienced physical therapy faculty and 3 senior physical therapy students. Prior to testing, all examiners had a practice session together to ensure all examiners were using the same technique and instructions. All data were collected in either the retirement center (for LRF group) or the long-term care facility (for MRF and HRF groups).

Data Analysis

Performance on each balance test was summarized using the mean, standard deviation, and confidence intervals. Repeated measures analysis of variance (ANOVA) procedures were performed to determine if there were significant differences in each of the balance measures between the 3 risk groups under the 2 visual conditions. Post-hoc Student-Neuman-Keuls were used to test differences between risk groups. P

RESULTS

The balance measures from theTinetti,TUG, and Functional Reach tests are presented by fall risk group and visual condition in Table !.Results of ANOVA procedures are summarized in Table 2.TheTinetti scores in LRF group were significantly higher than those in MRF (P

DISCUSSION

Findings of this study indicated significant interactions between vision and risk groups in Tinetti (P

On the other hand, there was no interaction between vision and the risk group in Functional Reach test (P > .05). As shown in Figure 1C, Functional Reach scores from all 3 groups were parallel, indicating all 3 risk groups had a similar response to the changes in vision. The exact reason for the different effect of blurred vision on the 3 clinical balance measures is not known. A potential explanation may be that the different visual effect on the clinical balance measures might be associated with the specific components of each test itself. Both the Tinetti and TUG tests were involved with gait and other multiple components.24″ 27.29 Whereas,the Functional Reach test involved an anterior and posterior displacement of center of gravity and had no gait component.10·28 Therefore, the Tinetti and TUG tests are more dynamic than the Functional Reach test.The results of the present study suggested that blurred vision has greater influence on dynamic balance measures (Tinetti and TUG) than static balance measure (Functional Reach).

Tinetti,TUG, and Functional Reach test are commonly used for the measurements of balance impairment in physical therapy clinics.24 2S Based on the study of Abbruzzese,26 the Tinetti test was used to classify different degrees of balance impairments. The TUG and Functional Reach tests were chosen as the assessment tools in this study because both tests are widely used, require minimal time to complete, require no sophisticated equipment, are easy to administer, and yield measurements that have known reliability and validity.10,27-29 The results of the present study indicate that all 3 balance tests are useful tools for discriminating balance between fall risk groups and visual conditions because all subjects in the LRF group performed better in all 3 tests than MRF (P

The hypothesis that blurred vision would impair all balance measure scores was supported by study results. Subjects with blurred vision demonstrated significantly (P

There were a number of limitations associated with this study. A learning curve may occur between the repeated measurements under 2 different visual conditions although authors do not believe the learning curve will affect the interpretation of the results because subjects performed balance tests with a normal vision followed by blurred vision. Intra-rater and inter-rater reliability of the testers were not assessed. Multiple measurements and multiple testers involved in this study could have created a larger variability in different test scores in different groups. The number of trials given to subjects to perform different balance tests was not consistent. The subjects had only 1 trial forTinetti and TUG.This occurred because some of the subjects in HRF group could not tolerate 2 trials of all balance tests. However, 2 trials were given to subjects to perform Functional Reach. This occurred because a greater variation between the repeated trials in Functional Reach tests was observed in the pretrial test. Finally, balance impairment was totally determined by initial Tinetti scores. The actual number of falls related to the balance scores and balance impairments was not assessed.

Many clinical balance tests are available to determine the presence of balance impairments in elderly adults. However, research is lacking concerning how to select a proper test for a patient with balance impairment plus visual impairment. Blurred vision had greater influence on dynamic balance measures with a gait component (Tinetti and TUG) than static balance measure without a gait component (Functional Reach). Therefore, the findings of the present study may support the concept that dynamic balance measures with a gait component may be superior to static balance measures without a gait component for elderly adults with different degrees of balance impairment during visual impairment. Based on the fact that vision plays an important role in determining the balance score, we recommend that clinicians consider the correction of visual problem as an essential part of treating elderly adults with balance and visual impairments.

CONCLUSION

Blurred vision significantly altered all 3 balance measures in older adults with different degrees of balance impairments, suggesting that the visual system plays an important role in balance assessment. Blurred vision had a greater influence on Tinetti and TUG than Functional Reach tests, suggesting that dynamic balance measures with a gait component are better balance indicators than static balance measure without a gait component in elderly adults with both blurred vision and balance impairment.

ACKNOWLEDGMENTS

The authors wish to thank the following physical therapy students for assisting with preliminary data collection in this study: Daniel Henderson, Leslie Nagel, and Abbey Wright.

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Min Huang, PT, MD, PhD;1 Ruth Burgess, PT, MHS, PhD;1 Mark Weber, PT, PhD;1 Neva F Greenwald, PT, MSPH1

1 Department of Physical Therapy, School of Health Related Professions at the University of Mississippi Medical Center, Jackson, MS

Address all correspondence to: Dr Huang, Department of Physical Therapy, School of Health Related Professions, The University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216, Ph: 601-815-4037, Fax:601-815-1715 (mhuang@shrp.umsmed.edu).

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