Journal of Physiotherapy 60 (2014) 130–135
Journal of
PHYSIOTHERAPY journal homepage: www.elsevier.com/locate/jphys
Research
Exercise and physical training improve physical function in older adults with visual impairments but their effect on falls is unclear: a systematic review Michael Gleeson, Catherine Sherrington, Lisa Keay Sydney Medical School, The George Institute for Global Health, The University of Sydney, Australia
K E Y W O R D S
A B S T R A C T
Visual impairment Falls risk Falls Ageing Exercise Mobility
Question: Can exercise or physical training improve physical function and prevent falls in older adults with visual impairments? Design: Systematic review of randomised controlled trials with metaanalysis. Participants: Older adults ( 60 years) with visual impairments. Intervention: Individual or group exercise or physical training classes in any settings. Outcome measures: Mobility, balance, strength and proprioception measured with performance tests or questionnaires and/or falls with calendars or incident reports. Results: Four eligible trials with a total of 522 participants were identified. Multimodal group exercise (n = 50 and 41) and Tai Chi (n = 40) improved physical function among residents of care settings. Meta-analysis of data from two trials indicated a significant positive impact of multimodal exercise on the Berg Balance Score (weighted mean difference 3.9 points, 95% CI 1.8 to 6.0), but not on the Timed Up and Go test (weighted mean difference 1.5 seconds, 95% CI –1.7 to 4.6). One trial (n = 41) found that multimodal exercise reduced the time to first fall (p = 0.049). A factorial trial (n = 391) among community dwellers did not find a significant effect on falls from a home-based exercise intervention, although clinically relevant effects in either direction were not excluded by the study (incidence rate ratio = 1.15, 95% CI 0.82 to 1.61). Conclusion: Exercise interventions in residential care settings improve performance on some tests of physical function that are risk factors for falls but the impact on falls is not yet clear. The impact of exercise and training on physical function and falls in community-dwelling older adults with visual impairments also warrants further investigation. [Gleeson M, Sherrington C, Keay L (2014) Exercise and physical training improve physical function in older adults with visual impairments but their effect on falls is unclear: a systematic review. Journal of Physiotherapy 60: 130–135] ß 2014 Australian Physiotherapy Association. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
Introduction Falls are a leading cause of morbidity and mortality. At least 30% of people aged 65 and over fall each year.1–3 Older adults with visual impairment are 1.7 times more likely to fall than their sighted peers and 1.9 times more likely to have multiple falls.4 Visual impairment has been found to be an independent risk factor for falls, particularly with relation to impaired edge-contrast sensitivity and depth perception.5,6 People with visual impairment are at a particularly high risk of falls due to impaired balance7 and difficulty detecting environmental hazards. With normal ageing, conduction speed and central nervous system processing slows down,8 forcing balance control mechanisms to rely more heavily on visual input to maintain stability,9 particularly during single limb balance.10 This has obvious implications for older adults with visual impairments. Deterioration in balance control in older people is primarily in the medio-lateral direction11 and reduced visual input has been shown to have a greater impact on lateral balance control,12 which amplifies the deterioration in the older population with visual impairments on mobility tasks involving single-limb balance. Travel in the community presents additional hazards for older people with visual impairment. Environmental preview involves
scanning the environment ahead with sufficient time to recognise potential hazards and avoid them. Glare can interfere with environmental preview in people with visual impairment. High levels of glare sensitivity are reported in individuals with glaucoma13 and recovery from glare exposure is slower in people with age-related macular degeneration.14 Fluctuations in environmental light can divide attention and reduce the available reaction time to hazards for this population. When attention is divided, older adults have a decreased ability to avoid obstacles in the environment, compared to younger adults.15 Individuals with visual impairments may also rely on memorised aspects of the environment and often employ a mobility aid as they travel. If the individual is using a long cane as a mobility aid, the cane is detecting the next footfall, giving little warning before a hazard is encountered. Attention allocated to route memory and mobilityaid use, in addition to postural stability and hazard avoidance, could thus overload attention resources and further increase the risk of falls in people with visual impairment. A Cochrane review by Gillespie et al16 identified several effective approaches to fall prevention for the general population of older adults living in the community, including exercise, home safety, medication management and interventions targeting multiple risk factors. The latest update of that review included
http://dx.doi.org/10.1016/j.jphys.2014.06.010 1836-9553/ß 2014 Australian Physiotherapy Association. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/3.0/).
Research
no new trials that provided physical training for communitydwelling older adults with untreatable visual impairments. A Cochrane review by Cameron et al17 identified that Vitamin D prescription reduces falls in residential care facilities and that interventions targeting multiple risk factors may also do so, but it included no trials that provided physical training for older adults with visual impairments in care facilities and hospitals. It is believed that the present study is the first systematic review to address this question. Older adults with visual impairments are affected by agerelated deterioration in balance to an even greater extent than the general population.18 Thus, exercise and physical training warrant particular investigation as fall prevention strategies for people with visual impairment living in the community, as well as in residential care settings. Mobility, balance, strength and proprioception are aspects of physical function that have been identified as risk factors for falls. Thus, the impact of exercise on these factors, as well as on falls themselves, was investigated. Therefore, the research questions for this review were: 1. Does exercise or other physical training improve physical function in older adults with visual impairments? 2. Does exercise or other physical training prevent falls in older adults with visual impairments?
Method Identification and selection of studies A search of the literature was conducted in February 2013 of MEDLINE, Embase, CINAHL and the Cochrane Register of Controlled Trials (CENTRAL). The MEDLINE search strategy used is shown in Appendix 1 (see eAddenda) and this was adapted for other databases. Supplementary searches of the Physiotherapy Evidence Database (PEDro), the WHO International Clinical Trials Registry and Literatura Latino-Americana e do Caribe em Cieˆncias da Sau´de (LILACS) were also undertaken. The searches sought trials of exercise and training to improve physical function or reduce falls in older adults with untreatable visual impairments. The inclusion criteria are summarised in Box 1. Assessment of study characteristics The researchers were not blinded to any aspects of the papers. Study titles and abstracts were independently screened by two investigators (MG and LK) for inclusion in the review and any discrepancies were resolved by discussion with a third investigator (CS). Data were extracted by one investigator (MG) and checked by a second investigator (CS) and any discrepancies resolved by
Box 1. Inclusion criteria. Design Randomised controlled trials or trials with factorial design Participants Older adults 60 years of age Uncorrectable visual impairment Intervention Exercise Physical training other than exercise, such as Tai Chi, Yoga, dance Outcome measures Measures of physical function with performance tests or questionnaires Falls with calendars or incident reports Comparisons Exercise program designed to enhance physical function compared with control program or usual care
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discussion. Data extracted included: the settings in which the trials were conducted; the characteristics of the participants (age, gender and visual status); the programs provided to the intervention and control groups; and outcome measures. Quality The studies had already been assessed for quality using the PEDro scale,19 which includes items related to risk of bias and completeness of reporting, and reported on PEDro (http:// www.pedro.org.au). Studies were not excluded on the basis of the rating. Design Only published, randomised trials were eligible. Language of publication was not an exclusion criterion. Participants This review focused on studies in older adults with untreatable visual impairments, and so excluded studies of people with visual disturbance relating to cataract surgery, refractive correction and medication. The study populations were required to be primarily aged 60 or older. Trials that included younger participants were considered eligible if the mean age of participants minus one standard deviation was over 60 years. Interventions Eligible interventions included strength and balance training, and physical training such as dance, Tai Chi and other complementary therapies. Comparisons in eligible studies were between the intervention group and either a usual care or control group, and studies with factorial designs comparing more than one intervention were also included. Outcome measures Included studies measured physical function with performance tests or questionnaires and/or falls with calendars or incident reports. Eligible aspects of physical function were mobility, balance, strength and proprioception. Data analysis Random-effects meta-analyses were conducted using commercial softwarea to compare the impact on the outcomes of interest of programs designed to enhance physical function or prevent falls with control programs or usual care. The weighted mean difference (WMD) was calculated using the pre-intervention and postintervention means and standard deviations. Statistical heterogeneity was quantified with the I2 and Q statistics. Results Flow of studies through the review The electronic database search identified 3451 records after removal of duplicates. After screening by title and abstract, full articles were then obtained for 10 trials and their eligibility assessed against the inclusion criteria. After more detailed investigation, three papers were excluded because they were not randomised controlled trials, one because the participants were not visually impaired, one because there was no physical intervention and one because it was another report of an included trial. Four trials were deemed to fit the inclusion criteria and results from two trials were combined in a meta-analysis. Figure 1 shows the flow of search results through to the selection for meta-analysis. Characteristics of studies The four studies included in the review were randomised controlled trials published in English. Their quality scores are
[(Figure_1)TD$IG]
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Titles and abstracts screened (n = 3451)
Papers excluded after screening titles/abstracts (n = 3441) Potentially relevant papers retrieved for evaluation of full text (n = 10)
Papers excluded after evaluation of full text (n = 6) • research design not RCT (n = 3) • participants not visually impaired (n = 1) • intervention not a physical intervention (n = 1) • secondary paper describing the intervention in more detail (n = 1) Papers included in review (n = 4)
Papers included in meta-analysis (n = 2) Figure 1. Flow of studies through the review.
presented in Table 1, and their designs, participant characteristics, interventions and outcome measures are summarised in Table 2. The VIP trial by Campbell and colleagues20 was a 12-month, 2 x 2 factorial community-based trial involving men and women over 75 years of age with visual impairment. The remaining three trials were undertaken in residential care settings. The trial by Chen and colleagues21 ran for 16 weeks and stratified the randomisation based on gender, age and level of visual impairment. Cheung and colleagues22 assessed women over 70 years of age in a 12-week trial, and Kova´cs and colleagues23 assessed women over 60 years of age in a 6-month trial. There were 522 participants in total in the included studies, but data from only 91 participants could be pooled for meta-analysis. Effect of the intervention Physical function outcomes Three trials21–23 measured physical function as the primary outcome. One used Tai Chi as the intervention21 and the other two used group multimodal exercise, which incorporated both strength and balance training.22,23 The Tai Chi trial of Chen and colleagues21 used a passive knee joint repositioning test,24 the Sensory Organisation Test,25 and concentric isokinetic strength of the knee flexors and extensors of the dominant leg as outcome measures. This trial showed a significant decrease (p = 0.032) in the percentage change of
absolute angle error of passive knee joint repositioning, measured with a Cybex Norm dynamometer, in the intervention group (26 29%) compared to the control group (4 31%). There was an overall significant difference in favour of the intervention group on the Sensory Organisation Test (p = 0.024), but there were also significant differences in the vestibular and visual ratios between the two groups. The intervention group achieved a greater (p = 0.048) percentage improvement in the vestibular ratio (33 40%) compared to controls (–18 57%) and a greater (p = 0.006) percentage change of visual ratio (58 42%) compared to the control group (–2 29%). There was no significant difference between the two groups in muscle strength in the dominant leg. Kova´cs and colleagues23 and Cheung and colleagues22 both reported outcomes using the Timed Up and Go test26 and the Berg Balance Score27 so these data were pooled for meta-analysis. Forest plots and weighted mean differences for the Berg Balance Scale are presented in Figure 2 and for the Timed Up and Go test in Figure 3. In both cases the pooled estimates showed a favorable effect of the intervention. The pooled estimate indicated statistically significant differences between intervention and control groups for the Berg Balance Score (WMD 3.9 points, 95% CI 1.8 to 6.0). The pooled estimate of effect for the Timed Up and Go test indicated a between-group difference in favour of the intervention that did not reach statistical significance (WMD 1.5 seconds, 95% CI –1.7 to 4.6). The Berg Balance Scale estimates showed a low level of heterogeneity (I2 = 0%, Q = 0.45), as did the Timed Up and Go test estimates (I2 = 0%, Q = 1.0). Cheung and colleagues22 also used a chair stand test and found that the intervention group showed significant improvement compared with the control group (mean time difference 2.35 seconds, 95% CI 0.03 to 4.67). Kova´cs and colleagues23 used the Barthel Activities of Daily Living Index28 but found no significant difference between intervention and control groups (p = 0.622). Falls outcomes Only the VIP trial by Campbell and colleagues20 collected prospective falls data. The VIP trial was a 2 x 2 factorial design with prospective calendars and 12 months of follow-up. Communitydwelling older adults were randomised into: a home safety assessment and modification program; an exercise program; both the home safety and exercise programs; or social visits. The study found that home safety assessment and modification reduced falls (41% fewer falls, incidence rate ratio = 0.59, 95% CI 0.42 to 0.83). The study did not find a significant effect of the exercise intervention on falls, although clinically relevant effects in either direction were not excluded by the study (incidence rate ratio = 1.15, 95% CI 0.82 to 1.61). The successful home safety aspect of the study is described in a separate paper.29 Kova´cs and colleagues23 used medical records and nursing documentation during the 6-month study period to collect falls data and reported that the risk for falls was reduced by 46% in the intervention group, but the difference did not reach statistical significance (relative risk = 0.54, 95% CI 0.29 to 1.01). This trial found a significant between-group difference in the mean length of time to first fall in favour of the intervention group (p = 0.049). The mean length of time to first fall was 18.5 weeks (95% CI 15.4 to 21.7) for the intervention group and 14.8 weeks (95% CI 11.1 to 18.4) for the control group. As acknowledged by the authors, these results need to be treated with caution due to the small sample size
Table 1 PEDro scores of included studies. Study
Campbell20 Chen21 Cheung22 Kova´cs23 Y = yes, N = no
Random allocation
Concealed allocation
Groups similar at baseline
Participant blinding
Therapist blinding
Assessor blinding
Adequate follow-up
Intention-totreat analysis
Between-group difference reported
Point estimate and variability reported
Total (0 to 10)
Y Y Y Y
Y N Y Y
Y N Y Y
N N N N
N N N N
Y N Y Y
Y N Y Y
Y Y N Y
Y Y Y Y
Y Y Y Y
8 4 7 8
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Table 2 Summary of included studies. Study
Design
Participants
Intervention
Outcome measures
Campbell20
2x2 factorial RCT
n = 391 Age (yr) 75 Gender = 124 M, 267 F Community dwelling Visual acuity 6/24
Exp = 2 x 2 factorial Otago exercise program (multimodal) and home safety. 5 home visits by physiotherapist at 1,2,4,8 wk and 6 mth to progress and encourage independent practice of the Otago exercise program. 30 min x 3/wk and walk x 2/wk if safe to do so for 12 mth, plus Vitamin D supplementation. Con = 2 x 1 hr social visits in first 6 mth.
falls measured with prospective calendars over 12 mth follow-up = 12 mth
Chen21
RCT
n = 40 Age (yr) 70 Gender = M & F but data unavailable Residential facility Visual acuity stratified 3/60, < 6/18 or < 3/60
Exp = Modified 8-form Yang-style Tai Chi in small group with verbal and manual support. 90 min x 3/wk x 16 wk. Con = Social music group - time and duration not stated.
muscle strength = % change of knee muscle strength with Cybex Norm dynamometer proprioception = % change of absolute angle error with Cybex Norm dynamometer Sensory Organisation Test = % change of sensory ratios using sway referencing follow-up = 16 wk
Cheung22
RCT
n = 50 Age (yr) 65 Gender = F only Residential facility Visual acuity 6/120
Exp = Multimodal exercise program with verbal and manual support delivered by physiotherapist. 45 min x 3/wk x 12 wk, plus standard residential exercise program given to control group 45–60 min x 3/wk x 12 wk. Con = Standard residential exercise program 45–60 min x 3/wk x 12 wk.
Berg Balance Score Timed Up and Go test Chair stand test follow-up = 12 wk
Kova´cs23
RCT
n = 41 Age (yr) 60 Gender = F only Residential facility for visually impaired Excluded if totally blind
Exp = Otago exercise program (multimodal) with verbal and manual support in small group delivered by physiotherapists 30 min x 2/wk x 6 mth, plus standard osteoporosis exercise program given to the control group below x 2/wk x 6 mth. Con = Standard osteoporosis program 30 min x 4/wk x 6 mth.
Berg Balance Score Timed Up and Go test Barthel Activity Index falls follow-up = 6 mth
Con = control group, Exp = experimental group, RCT = randomised controlled trial, M = male, F = female.
[(Figure_2)TD$IG]
Study
Time point
Experimental n, Mean (SD)
Control n, Mean (SD)
Mean difference (95% CI)
Weight (%)
Association measure (95% CI)
Cheung22 12 wk
27, 48.6 (4.4)
23, 44.3 (5.2)
72
4.3 (1.8 to 6.8)
Kovacs23
21, 45.1 (7.4)
20, 43.3 (6.8)
28
2.7 (–1.3 to 6.7)
6 mth
Pooled
3.9 (1.8 to 6.0)
–15
–10
–5
Favours control
0
5
10
15
Favours experimental
Figure 2. Weighted mean differences (95% CI) of effect of multimodal exercise immediately after 12 weeks to 6 months of training on the Berg Balance Scale by pooling data from two studies (n = 91).
[(Figure_3)TD$IG]
Study
Time point
Experimental n, Mean (SD)
Control n, Mean (SD)
Cheung22 12 wk
27, 23.6 (11.3)
23, 26.1 (15.0)
19
4.8 (–2.0 to 11.5)
Kovacs23
21, 17.9 (5.0)
20, 19.3 (4.2)
81
0.7 (–1.9 to 3.3)
6 mth
Mean difference (95% CI)
Weight (%)
Association measure (95% CI)
1.5 (–1.7 to 4.6)
Pooled
–15
–10
–5
Favours control
0
5
10
15
Favours experimental
Figure 3. Weighted mean differences (95% CI) of effect of multimodal exercise immediately after 12 weeks to 6 months of training on the Timed Up and Go Test by pooling data from two studies (n = 91).
(n = 41). Cheung and colleagues22 reported no falls in either group during the three-month study period (n = 50), but did not state how the data were collected. The Tai Chi trial by Chen and colleagues21 did not collect falls data. Due to the differences in settings and follow-up periods a meta-analysis for the falls outcome was not undertaken.
Discussion This systematic review found few studies of mixed quality in this vulnerable population. There was only one community-based trial among older adults with visual impairments.20 It had falls as the primary outcome and it found a protective effect of home
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modification but not exercise. Data from three small trials in residential care settings,21–23 one of which specialised in people with visual impairment,23 indicated that multimodal exercise programs and Tai Chi can improve balance and physical function, and thus may reduce fall risk. This provides a rationale for future larger trials of physical interventions in this population that would measure actual fall rates, given the known effect of visual impairment as an intrinsic risk factor for falls, and its subsequent negative effect on physical function. In the meta-analyses, although both outcome measures were in a direction favouring the intervention, only the Berg Balance Scale reached significance. The Timed Up and Go Test is widely used, but it may not be the most appropriate measure for adults with a visual impairment. It is possible that there is a limit to how much it can be expected that walking speed will increase, given the visual impairment, regardless of the level of physical improvement that the intervention provides. A study of sighted and visually impaired adults, matched for age and gender, found that sighted adults responded faster than those with visual impairments on the Timed Up and Go test and concluded that adults with visual impairments have difficulty with fast-paced movements.30 It should also be kept in mind that the only outcome data reported from these studies were immediately post-intervention, so there was no follow-up period looking at effect duration over time. Three of the trials were conducted in residential care settings, one of which specialised in people with visual impairment; this limits how much can be inferred about these results for a community-dwelling population. Adherence to the study protocol may be easier in the controlled setting of a residential facility, plus, verbal guidance and manual assistance were provided,21–23 which may have improved the precision of the exercise performed compared to a person exercising at home without feedback. Adherence has already been shown to be an issue in home-based programs in this population group20 and group classes in the community are difficult for some people with visual impairments to access. Improving physical ability may not always translate into a reduction in fall rates in the community, as those individuals are likely to be more mobile and may be at a higher risk due to environmental hazards. Providing the level of manual assistance and verbal support available in a residential setting, or provision of transport to and from existing fall prevention programs in the community are possible options, but their cost effectiveness has yet to be established. These results suggest that residential care facilities should include visually impaired residents in fall prevention programs when it is possible to provide the additional support necessary to do so. This review found only one trial powered to detect a reduction in falls and this was undertaken in a community setting.20 This trial found that home safety and home modification programs reduce falls in community-dwelling older adults with visual impairments when delivered by an occupational therapist.20,29 Home safety interventions are designed to reduce the presence of extrinsic risk factors in the home environment, along with general advice about fall prevention. To date, this is the only large-scale trial that has implemented non-vision-related interventions for older adults with visual impairments designed to reduce falls. The Otago Exercise Programme, which was used in this trial, is effective in preventing falls in the general community-dwelling population and is also a multimodal program incorporating elements of strength and balance training.31,32 In addition to the home-based exercise program, there was a walking program33 and participants in the exercise groups in the trial were expected to walk at least twice a week for 30 minutes, if it was safe to do so. It is possible that the walking program may have exposed some of the participants in the exercise group to greater risk of falling, given their visual impairment. Falls were also recorded in two of the trials that delivered programs to improve physical function in residential settings.22,23 Data from one small trial (n = 41) suggested a fall prevention effect of multimodal exercise,23 but this was in a specialty residential
facility for the people with visual impairment and needs confirmation in a further study with a larger sample size. At present, no strong conclusions can be drawn regarding the impact of improved physical function on fall rates within residential settings for older adults with visual impairments. There are several limitations to this review. Only four trials qualified for inclusion, and three of these had small sample sizes. Only data from two trials could be combined for meta-analysis, and in addition to this, the difference in setting between the community and residential care-facilities makes it difficult to generalise findings between them. The quality of the studies was generally high, but one study21 only scored 4 out of 10, so those results should be interpreted with caution. In conclusion, it has been shown that exercise programs that include a balance component and Tai Chi can improve physical function in older adults with visual impairments living in residential care, but any effect on fall rates requires larger trials before it can be verified. Translating these results into community settings poses some problems due to the differences in residential and community populations. Home modification and safety programs have been shown to have a protective effect on falls in the communitydwelling, visually impaired population. Apart from the VIP trial,20 which investigated an exercise intervention with falls as the primary outcome, this review found no trials designed to improve strength and balance in visually impaired older adults living in the community, and so appropriate interventions and their method of delivery have yet to be determined. What is already known on this topic: Falls are a leading cause of morbidity in older people; visual impairment in older people increases the risk of falls even more. In older people without visual impairment, exercise training has a range of benefits, including improved physical function and reduced falls risk. What this study adds: In older people with visual impairment, multimodal exercise improves performance on physical function tests that are associated with falls risk. One study involving community-dwelling older people found that an exercise program reduced falls. However, the studies involving institutionalised older people had variable results, making the overall effect on falls unclear.
Footnotes: a Comprehensive Meta-Analysis software, Version 2, Biostsat, Englewood NJ, USA. eAddenda: Appendix 1 can be found online at doi:10.1016/ j.jphys.2014.06.010 Ethics approval: Not applicable. Competing interests: Nil. Source(s) of support: Australian Federal Government Australian Postgraduate Award scholarship (MG); Australian Research Council Postdoctoral Fellowship (LK) and Australian National Health and Medical Research Council Senior Research Fellowship (CS). Acknowledgements: Nil. Correspondence: Michael Gleeson, Injury Division, The George Institute for Global Health, The University of Sydney, Australia. Email:
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Websites www.pedro.org.au
