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Study protocol
Improving balance and mobility in people over 50 years of age with vision impairments: can the Alexander Technique help? A study protocol for the VISIBILITY randomised controlled trial
  1. Michael Gleeson1,
  2. Catherine Sherrington2,
  3. Ewa Borkowski3,
  4. Lisa Keay1
  1. 1Injury Division, The George Institute for Global Health, The University of Sydney, Sydney, New South Wales, Australia
  2. 2Musculoskeletal Division, The George Institute for Global Health, The University of Sydney, Sydney, New South Wales, Australia
  3. 3Sydney East Client Services, Guide Dogs NSW/ACT, Sydney, New South Wales, Australia
  1. Correspondence to Michael Gleeson, Injury Division, The George Institute for Global Health, PO Box M201, Missenden Rd, NSW 2050, Australia; mgleeson{at}georgeinstitute.org.au

Abstract

Background Falls are an increasingly important and costly public health problem. Vision is key to postural stability as we age and this puts adults with visual impairments at greater risk of falls. Physical interventions improve balance in the general population and in older adults with visual impairments in residential care. They also prevent falls in the general community but to date have not been shown effective in community-dwelling adults with visual impairments.

Objective To investigate, with a randomised controlled trial, whether the Alexander Technique (AT) can improve balance and mobility in the community-dwelling population with visual impairments and thus reduce the risk of falls. The AT is a form of physical re-education that has recently received attention for its possible value in rehabilitation.

Method and design One hundred and twenty people with visual impairments over 50 years of age will be recruited from Guide Dogs New South Wales/Australian Capital Territory (NSW/ACT). Participants will be independently mobile and cognitively able to take part in the programme. After baseline assessment participants will be randomly assigned to two groups. The control group will receive usual care from Guide Dogs NSW/ACT, and the intervention group will receive 12 weekly home-based lessons in the AT in addition to usual care. The primary outcome measures will be physical measures from the short physical performance battery at 3 months. Secondary outcome measures will be balance, mobility, social participation and emotional well-being at 3 and 12 months.

Trial registration number: The protocol is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000634077).

https://doi.org/10.1136/injuryprev-2012-040726

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    Introduction

    Around one-third of adults over 65 years of age fall at least once a year,1–3 and in Australia hospitalisation rates due to fall related injuries rose by 5.6% between 2007–8 and 2008–9.4 Falls are the most common cause of injury death among Australians over 75 years of age owing to the high susceptibility to trauma in this age group.5 The risk of injury is higher for people with visual impairment.6 ,7 About 12% of falls lead to serious injuries8 and the Auckland Hip Fracture Study9 found that 40% of fractures could be attributed to poor visual acuity or lack of stereopsis.

    A study in the UK found that about 618 000 adults over 75 years of age had moderate or worse visual impairment, which is just over 1% of the total population and about 14% of the population over 75 years of age.10 Another study in the UK using national data from accident and emergency departments found that 21% of the cost of treating falls was spent on the visually impaired population.11 The high burden of falls in our community and the over-representation of older people with visual impairments make verified strategies for prevention of falls for this group a pressing concern.

    A study of balance in young adults with visual impairments found that they did not fully adapt to their vision loss with respect to maintaining postural stability.12 Recent work on falls in young and middle-aged adults in the general population has found that even in these age groups, falls resulting in admission to hospital can have a significant effect on long-term health and functioning.13 Changes in equilibrium control have been noted in the general population after the fifth decade,14 adding to the existing impact of visual impairment on the physical functioning of this population. Lower femoral-neck bone mineral density has been reported in middle-aged women with visual impairments,15 which coupled with reduced balance can compound the risk of fracture. These differences in balance control in the visually impaired population as they age, highlight the need for continued research into this area.

    For many older adults, vision loss leads to a decrease in physical activity, which then affects their general health and well-being. Higher rates of depression have been reported,16–18 and significant associations have also been found between vision function and poor performance on physical tests.19 Older adults with visual impairment more often have breathing problems, diabetes, heart problems, hypertension, joint symptoms, low back pain and stroke,20 and many of these comorbid conditions are associated with difficulties in walking, climbing steps, shopping and socialising. Visual impairment has also been reported to contribute to frailty3 ,21 and increased rates of mortality.22

    Nerve conduction speed and central nervous system integration slow with age, forcing older adults to rely more on vision, especially for balance control during movement.23 ,24 At the same time, the ability to rely on vision also declines with age,25 further compounding the difficulty of maintaining upright balance. This pushes older adults with visual impairments to the edge of their ability to maintain balance under challenging conditions, and increases fall rates.26

    Interventions known to improve balance in the general population27 have also been shown to improve balance in the visually impaired population when delivered effectively. Two recent studies of visually impaired people in residential care in Hong Kong showed that programmes could be delivered in a way that maximised attendance and compliance because the classes took place in the residential care homes. An exercise programme provided three times a week improved balance compared with controls,28 and a 16-week Tai Chi course significantly improved knee proprioception and balance.29

    There is evidence that exercise programmes reduce falls in older adults in the general population,30 ,31 particularly programmes which challenge balance, including group Tai Chi classes in community settings. However, programmes delivered in a community group setting are difficult to access for people with visual impairments and their ability to participate effectively is also limited owing to their need for more individual attention. A trial of older people with significant visual impairments found that a home safety programme reduced falls but the home-based exercise intervention, which had been shown to benefit older adults in the general population, did not reduce falls in this population.32 The authors found that fall rates were highest in those with lowest adherence to the programme protocol and this suggests that compliance might have been a problem with the exercise intervention. There is a need to tailor interventions to suit specific populations, and an individually delivered physical intervention that takes account of visual impairment might be better suited to reducing risk of falls in community-dwelling older adults with visual impairments.

    The Alexander Technique (AT) was developed in the 1890s and although it has been widely used in the performing arts, it has developed outside the mainstream medical model and is only now being investigated for its possible therapeutic benefits.33 The AT uses manual guidance and verbal feedback in everyday activities such as sitting, standing and walking to teach people how to better organise their balance and mobility by reducing largely unnoticed habitual muscular tension that may be interfering with an easier overall coordination. Although the physiological rationale behind the AT has yet to be clearly established, a case–control study of Alexander teachers and matched controls found that lessons in the AT reduce axial stiffness through the spine and enhance dynamic modulation of muscle tone.34 Because it does not require learning of unfamiliar exercises or movement patterns, and uses manual guidance, it may be ideal for people with visual impairments. Randomised controlled trials of the AT have been shown to benefit people with Parkinson's disease35 and back pain,36 but it has not been used in studies to improve balance and mobility in the visually impaired population until now.

    Objective

    The objective of this study is to determine if home-based lessons in the AT can improve balance and mobility in community-dwelling older adults with visual impairments, as these are key risk factors for falls.

    Methods

    Design

    The VISIBILITY study is a two-armed randomised controlled trial (see figure 1). Ethical approval for the study was granted by the human research ethics committees at the University of Sydney (Protocol No 12985) and the University of New South Wales (HREC10277). The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000634077).

    Figure 1
    Figure 1

    The VISIBILITY randomised controlled trial design.

    Recruitment and randomisation

    The study is a collaboration with Guide Dogs New South Wales/Australian Capital Territory (NSW/ACT) in Sydney, Australia, and all participants will be recruited from the database at Guide Dogs NSW/ACT. The organisation provides community-based services to enhance the mobility and independence of people within NSW and the ACT with visual impairments. Programmes are tailored to individual needs and can include training in the use of canes, guide dogs and electronic travel aids, together with safe strategies for pedestrian and public transport travel.

    General information about the study will be included in an audio-format client newsletter called ‘Soundtracks’ to inform clients that the study is being established. Additionally, eligible adults aged ≥50 years with visual impairments in the Sydney region will be identified by Guide Dogs NSW/ACT from their client database. People from a range of socioeconomic and cultural backgrounds are represented in the database. Eligible subjects will be contacted by Guide Dogs NSW/ACT using their preferred mode of communication. The database identifies people's preferred communication medium and the options include: standard font size (clients may have a visual field restriction but good central acuity); large print (clients can designate the font size); email (many clients have text to voice software or can resize documents electronically); audio CD or Braille.

    An invitation letter will be sent by Guide Dogs NSW/ACT to eligible people who, initially, will be asked to contact the researchers within a defined time period if they are interested in participating or require further information before making a decision. They will be informed in the invitation letter that a follow-up phone call will be made to those who do not respond within the initial time period. Orientation and mobility (O&M) instructors employed by Guide Dogs NSW/ACT working in the community will be given a standard information sheet enabling them to answer basic questions about the study during unrelated visits but asked to refer the person to the researchers for further information and provide the appropriate contact details. Confidentiality, impartiality and the voluntary nature of participation will be emphasised by all staff at every step.

    Inclusion criteria

    The inclusion criteria are as follows:

    1. People over 50 years of age with visual impairments that affect their mobility will be eligible for recruitment to the study.

    2. Their visual impairment must be such that they have received mobility training from O&M instructors at Guide Dogs NSW/ACT within the past 5 years to maintain their independent mobility.

    3. Mobility aids may include identification canes, long white canes, support canes, walking frames and guide dogs.

    4. Participants must live in greater metropolitan Sydney.

    5. They must have conversational English.

    Exclusion criteria

    The exclusion criteria are as follows:

    1. Any clients who require an interpreter will be excluded as conversational English is necessary for participation in the intervention arm of the study.

    2. Clinically diagnosed dementia or a short mental status questionnaire37 score of <8, as the intervention is a re-education process requiring cognitive ability, and this could place unnecessary stress on such subjects.

    3. Those not independently mobile with the aids already mentioned. This would exclude people confined to wheelchairs, stationary chairs or beds.

    4. Those planning cataract surgery in the next 12 months are also excluded as this can significantly improve their vision and mobility.

    Baseline assessment

    The baseline assessment will be conducted by trained O&M instructors from Guide Dogs NSW/ACT. The instructors have all completed a Master of Special Education (sensory disability) and regularly supervise clients in complex situations requiring attention to balance and safety when providing mobility-related services. Additionally the O&M instructors will attend a 2-day training course on the study assessment procedures with one of the researchers, who will accompany them on their first assessment before randomisation to ensure conformity to protocol.

    Demographic information on participants will be collected at the initial visit before screening and assessment. Information on mobility status, visual impairment, residence type, living arrangement, country of birth, primary language and level of education will be used to characterise the population. Additional comorbidities38 and medication status will also be collected at baseline and at the 3- and 12-month assessments to follow their health status over time.

    Primary outcome measures

    The three physical ability measures from the short physical performance battery (SPPB)39 will be used as individual primary outcome measures and investigated as a change from baseline. The study is not powered to use the three tests as a composite score. The SPPB has been validated in a large study within the general older population as a measure of lower limb function which can distinguish risk of future nursing home admission.39 It can be administered by a single investigator in the person's home, takes about 10 min to complete and has been found to be reliable and sensitive to change.40 The SPPB comprises the following:

    1. Timed five times sit-to-stand test.

    2. Timed 4 m walk.

    3. A standing balance test which includes side-by-side, semi-tandem, tandem and single limb balance test.

    4. Tests will be administered before randomisation and after the 12-week intervention period by a trained O&M instructor from Guide Dogs NSW/ACT who is unaware of group allocation.

    Secondary outcome measures

    The secondary outcome measures are as follows:

    1. The three tests from the SPPB used as a primary outcome will be re-administered at 12 months as a secondary outcome and an indicator of the duration of any effect.

    2. The postural sway test and maximal balance tests from the physiological profile assessment41 will also be used as secondary outcome measures at the 3- and 12-month time points. The extent of sway during 30 s of standing will be measured with four conditions: on floor with eyes open, on floor with eyes closed, on a foam mat with eyes open and on a foam mat with eyes closed. All measurements are taken on a grid paper and body sway excursions will be measured in millimetres for analysis.

    3. Fall rates will be measured by falls calendars. The study will be too small to detect an effect on fall rates but will give a useful indication of the presence and size of an effect on falls, which will assist with sample size calculations for future larger trials in this study population and could be made available for future meta-analysis.

    4. Fear of falling will be assessed with the Falls Efficacy Scale—International42 at baseline, 3 and 12 months.

    5. Mood will be assessed with the Geriatric Depression Scale,43 the Positive and Negative Affect Scale,44 and the Emotional Well-Being subscale of the Impact of Vision Impairment Scale45 at baseline, 3 and 12 months.

    6. Functional mobility will be assessed with the Perceived Visual Ability Scale46 at baseline, 3 and 12 months.

    7. Community participation will be assessed with the Keele Assessment of Participation47 at baseline, 3 and 12 months.

    Sample size

    A sample size of 60 individuals in each of the two groups will give the study adequate power to detect a 15% between-group difference at a 5% level of significance with a power of 80% allowing for 15% drop-out during the 12 month study. The power calculations are based on data from a study in a similar population group.48 The estimates of between-group differences used in power calculations for the three primary outcomes measures are as follows:

    1. Five times sit-to-stand (effect 3.6 s, SD 9.0, correlation between baseline and final measure 0.7).

    2. Timed 4 m walk (effect 0.1 m/s, SD 0.25, correlation between baseline and final measure 0.7).

    3. Standing balance test (effect 3.6 s, SD 9.0, correlation between baseline and final measure 0.7).

    Substudy

    A subgroup of participants will undergo movement analysis of their walking style using a GAITrite pressure-sensitive mat in the laboratory before randomisation and after the 12-week intervention period of the study. The reliability of the GAITrite system as a measure of averaged and individual step parameters used in gait analysis has been demonstrated,49 ,50 and the data collected will be used as a pilot study to determine whether gait analysis would be of value in future studies of the AT.

    Discussion

    Ageing populations in industrialised countries have seen an increase in the prevalence of age-related visual impairments that affect physical ability, postural stability and social functioning and increase the risk of falls. Projections for Australia show that in the over-40 population the rate of vision impairment will rise from 5.4% in 2004 to 6.5% by 2024, and the rate of blindness is projected to increase by 73% from 50 000 in 2004 to 87 000 in 2024.51 Fall prevention programmes based on well-designed exercise programmes have reduced falls in the general population, but to date the only intervention that has been shown to be effective in the community-dwelling visually impaired population is a home modification programme.32 ,52 Many fall prevention programmes are community-based group activities and this limits their suitability for older adults with visual impairments. Home-based programmes that take account of visual impairment may be better suited to improving balance and mobility in this population.

    Falls costs more than one billion dollars in medical treatment, disability, lost output and mortality in Australia each year.53 As no strategy has been proved to be effective in the community-dwelling population with visual impairments, there is an urgent need to identify interventions that are tailored to, and suitable for, the growing number of older adults whose lives are complicated by failing vision. Fall prevention programmes are being made available to the general population and these services need to be provided in a range of formats so that they are accessible to all sections of the population at risk.

    Because the AT uses manual guidance and verbal feedback, it does not require vision to learn, and so may be a useful approach for people with visual impairments. The VISIBILITY study has been designed to determine whether the AT can improve balance and mobility in this population. If shown to be effective, a further larger study would be required to determine whether this would result in reduced fall rates within the population with visual impairments.

    Acknowledgments

    The authors would like to acknowledge Guide Dogs NSW/ACT for their support for this study.

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    Footnotes

    • Contributors MG, CS, and LK were responsible for the conception and design of the study. MG and EB were responsible for the study management and data acquisition. MG, CS, LK and EB were all involved in the drafting, revision and final approval of the paper.

    • Funding Guide Dogs NSW/ACT provided substantial ‘in-kind’ support. The Australian Society of Teachers of the Alexander Technique and the FM Alexander Trust (UK) both provided small grants to support the study. MG received an Australian postgraduate award scholarship from the Australian Federal Government.

    • Competing interests None.

    • Ethics approval Human research ethics committees at the University of Sydney (Protocol No 12985) and the University of New South Wales (HREC10277).

    • Provenance and peer review Not commissioned; internally peer reviewed.