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Cochrane Database Syst Rev. 2010 May; 2010(5): CD003925.
Published online 2010 May 12. doi:10.1002/14651858.CD003925.pub3
PMCID: PMC7138242
PMID: 20464725
Monitoring Editor: Gianni Virgili, Gary Rubin, and Cochrane Eyes and Vision Group
University of Florence, Department of Specialised Surgical Sciences, Via le Morgagni 85, FlorenceItaly, 50134
Institute of Ophthalmology, Bath Street, LondonUK, EC1V 9EL
Gianni Virgili, Email: ti.ifinu@iligriv.innaig.
Author information Copyright and License information PMC Disclaimer
This article is an update of "Orientation and mobility training for adults with low vision." onpageCD003925.
Abstract
Background
Orientation and mobility (O&M) training is provided to people who are visually impaired to help them maintain travel independence. It teaches them new orientation and mobility skills to compensate for reduced visual information.
Objectives
The objective of this review was to assess the effects of O&M training, with or without associated devices, for adults with low vision.
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, 2010, Issue 3), MEDLINE (January 1950 to March 2010), EMBASE (January 1980 to March 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to March 2010), System for Information on Grey Literature in Europe (OpenSIGLE) (March 2010), the metaRegister of Controlled Trials (mRCT) (www.controlled‐trials.com) (March 2010), ClinicalTrials.gov (http://clinicaltrials.gov) (March 2010), ZETOC (March 2010) and the reference lists of retrieved articles. There were no language or date restrictions in the search for trials. The electronic databases were last searched on 31 March 2010.
Selection criteria
We planned to include randomised or quasi‐randomised trials comparing O&M training with no training in adults with low vision.
Data collection and analysis
Two authors independently assessed the search results for eligibility, evaluated study quality and extracted the data.
Main results
Two small studies satisfied the inclusion criteria. They were consecutive phases of development of the same training curriculum and assessment tool. The intervention was administered by a volunteer on the basis of written and oral instruction. In both studies the randomisation technique was inadequate, being based on alternation, and masking was not achieved. Training had no effect in the first study but tended to be beneficial in the second but not to a statistically significant extent. Reasons for differences between studies may have been: the high scores obtained in the first study, suggestive of little need for training and small room for further improvement (a ceiling effect), and the refinement of the curriculum allowing better tailoring to patients' specific needs and characteristics, in the second study.
Authors' conclusions
The review found two small quasi‐randomised trials with similar methods, comparing training to physical exercise and assessing O&M physical performance by means of a volunteer or a professional, which were unable to demonstrate a difference. Therefore, there is little evidence on which type of O&M training is better for people with low vision who have specific characteristics and needs. Orientation and mobility instructors and scientists should plan randomised controlled trials (RCTs) to compare the effectiveness of different types of O&M training. A consensus is needed on the adoption of standard measurement instruments of mobility performance which are proven to be reliable and sensitive to the diverse mobility needs of people with low vision. For this purpose, questionnaires and performance‐based tests may represent different tools that explore people with low vision's subjective experience or their objective functioning, respectively. In fact, it has to be observed that low vision rehabilitation research is increasingly shifting towards the use of quality of life questionnaires as an outcome measure, sometimes with the aim to study complex and multidisciplinary interventions including different types of education and support, of which O&M can be a component. An example of this is an ongoing cluster RCT conducted by Zijlstra et al. in The Netherlands. This trial is designed to compare standardised O&M training with usual O&M care not only for its effectiveness, but also its applicability and acceptability. This study adopts validated questionnaires for patients' subjective assessment of performance during activities of daily living. As performance assessment does not need to be made by an O&M trainer, this allows for masking of assessors and a patient‐centred outcome measure.
Plain language summary
Orientation and mobility training for people with low vision
Progressive visual impairment often affects people as they age. Training is used to help people with low vision maintain travel independence, with new orientation and mobility skills to compensate for reduced visual information. Orientation is the ability to recognise one's position in relation to the environment, whereas mobility is the ability to move around safely and efficiently. Orientation and mobility (O&M) training teaches people to use their remaining vision and other senses to get around. Canes and optical aids may also be used.
We found two small studies with a total of 63 people comparing O&M training delivered by a trained volunteer to physical exercise. These studies did not show a difference between the two interventions, but they had little power to do so because of the small sample size and poor methodological quality. There were no adverse effects of O&M training in these studies.
There is little evidence from randomised controlled trials on which type of O&M training is better for people with low vision who have specific characteristics and needs.
Summary of findings
Background
Description of the condition
The World Health Organization (WHO) has established criteria for low vision which are used in the International Classification of Diseases (WHO 1992). Visual impairment is defined as a best‐corrected visual acuity of less than 0.5 logMAR (Snellen 6/18 or 20/60) but equal to or better than 1.3 logMAR (3/60 or 20/400) in the better eye. Blindness is defined as a best‐corrected visual acuity of less than 1.3 logMAR or a remaining central field of 20 degrees diameter. In the United States, legal blindness is defined as a visual acuity of 1.0 logMAR (6/60 or 20/200) or less in the better eye.
Blindness is one of the most common disabilities (Congdon 2003). An estimated 40 million people were blind a decade ago, the time of the last accurate assessment. Among persons older than 40 years in 2002 in the USA, 937,000 were blind. Figures for both the developing world, where 90% of world blindness exists, and the developed world are expected to increase significantly during the next decades as the world's population ages.
Causes of blindness in the USA depend on race and ethnicity (EDPRG 2004). Age‐related macular degeneration is the most common cause in white people whereas cataract, glaucoma and diabetic retinopathy are the leading causes in Hispanic and black people. Treatable or preventable conditions are the most frequent causes of blindness in developing countries: infectious disease, nutritional deficiency, cataract and refractive error (Congdon 2003).
One of the most significant handicaps produced by visual impairment is the limit it imposes on the ability to travel independently (Golledge 1991). During travel we receive the majority of the information about our environment through our visual system (Soong 2001b). Many aspects of routine life may be affected by difficulty or inability to travel, such as opportunities to participate in social activities and to find or retain employment (Long 1996). Loss of vision may, therefore, have a major effect on the individual's overall quality of life, either directly or indirectly (Soong 2001b).
The SEE Project (West 2002b) showed that disability, defined as deficit in performance relative to a population, cannot be characterised on the basis of a single cut‐off value of visual acuity. In fact, for most daily living tasks performance gradually declines with progressive visual loss. Moreover, given tasks require specific levels of visual function. In the SEE Project reading and face recognition were very demanding in terms of visual function as they were found to be impaired in most people with even mild visual loss (0.5 or less, Snellen 6/12 or 20/40). On the other hand, the mobility tasks considered in the study were affected in almost half of people when visual acuity approached 0.1 (Snellen 6/60 or 20/200) (West 2002b).
Vision functions other than standard visual acuity may affect day‐to‐day functioning of older adults. In most eye diseases loss of contrast sensitivity and the extent of visual field damage are correlated with mobility impairment at least as much as is visual acuity (West 2002a; West 2002b). Loss of peripheral visual field is particularly prominent in people with retinitis pigmentosa, 80% of whom experienced mobility difficulty based on a questionnaire in one study (Geruschat 1998). Finally, environmental factors are critical to mobility tasks (Kuyk 1996). The ability of visually impaired persons to avoid obstacles is significantly impeded under mesopic (reduced) illumination. Object contrast and location are also factors determining success in avoiding obstacles on the travel path (Kuyk 1996).
Description of the intervention
Travel in the environment involves skills of orientation and mobility (O&M). Orientation is the ability to recognise and establish position in relation to environment. Mobility is the physical ability to move in an orderly, efficient and safe manner through the environment (Novi 1998). To maintain travel independence it is essential for a visually impaired adult to learn new (O&M) skills to be able to compensate for reduced visual information (Jacobson 1993; Seybold 1990).
Orientation and mobility training aims to teach visually impaired people to ambulate and negotiate the environment safely and independently (Blasch 1997; Peterson 1998). Instructors must prepare clients to manage various risks associated with everyday life (Banja 1994), especially if they undertake independent travel in uncontrolled environments (Marsh 2000). Through O&M training, visually impaired individuals are taught to enhance their mobility performance by using their remaining vision and other senses, such as hearing and touch (Guth 1997; LaGrow 1994). The senses are supplemented by the use of devices such as long canes and support canes (LaGrow 1994).
The use of a cane by people with visual impairment, as a device that can help them move about independently, was reported as long ago as in the Bible and in Greek mythology (Blasch 1995). In 1872, Levy proposed a technique for moving a cane, known as 'the touch technique,' in an article that was reprinted in 1949 (Levy 1949). In 1946, Hoover proposed a modified technique in which the cane touches the ground in front of the trailing foot rather than the forward foot (Hoover 1946). The aim is to touch where the next foot is to be placed, facilitating detection of holes, drop offs and other changes in levels of terrain. After World War II, increasing awareness of the potential of these techniques, together with the need to offer rehabilitation to young blind veterans, prompted most agencies to establish 'travel training' programs to incorporate this technique, even for people with usable residual vision. Optical aids including bioptic telescopes have been used in conjunction with O&M training with the aim of improving central visual function (Corn 1990; Feinbloom 1997; Korb 1970; Szlyk 1998; Szlyk 2000).
How the intervention might work
Enhancing the ability of low vision people to safely navigate their home and the external environment is the aim of O&M services. People are taught how to cope with vision loss to maximise the ability to live independently. Given the fact that O&M training is an established practice, the most interesting question to people with low vision and O&M therapists is which techniques are more effective.
Orientation and mobility training may be a component of multidisciplinary rehabilitation delivered by some low vision services. An ongoing Cochrane review focusses on such complex interventions (Langelaan 2007), and therefore these interventions will not be the purpose of our review. Another Cochrane review underway is currently investigating the effect of environmental and behavioural interventions for reducing activity limitation and improving quality of life in community dwelling visually impaired older people. Our review focusses on objective performance whilst the other two Cochrane reviews adopt quality of life as the primary outcome measure.
Why it is important to do this review
The Academy for Certification of Vision Rehabilitation and Education Professionals performed a survey among O&M training specialists in order to evaluate the knowledge, skill and ability required in their profession (Wiener 2000). This survey established a ranking of importance of professional competencies according to the opinion of 200 O&M experts that responded to the questionnaire. However, current assessment and rehabilitation techniques are not standardised and to date there has not been a systematic review of the evidence for the effectiveness of the various interventions used by O&M training specialists.
Objectives
The objective of this review was to assess the effects of orientation and mobility training for adults with low vision, with or without associated devices.
Methods
Criteria for considering studies for this review
Types of studies
We planned to include all relevant randomised or quasi‐randomised trials.
Types of participants
Participants in the trials were people aged 16 or over with low vision. We excluded trials of people with multiple disabilities, such as hearing loss, neurological or musculoskeletal disorders.
Types of interventions
Interventions included in this review were any type of orientation and mobility (O&M) training compared to no training or control, including different types of O&M training.
Types of outcome measures
The following outcome measures were considered.
Primary outcomes
1. Performance in travel activities of daily life, such as ability to reach predetermined destinations walking independently through known and unknown, indoor or outdoor environments; ability to use public transportation such as buses and trains.
Secondary outcomes
1. Performance obtained in predetermined laboratory or real‐world routes. This was considered as either the crude walking speed or as the percentage preferred walking speed (PPWS), defined as speed on the mobility course divided by preferred walking speed (Soong 2000; Soong 2001b).
2. Ability to use guide dogs during outdoor travel.
3. Social interaction, such as ability to meet relatives or friends at their homes or in public places; ability to live alone at home; the need for help from relatives or friends for travel‐related daily tasks such as shopping.
4. Score obtained in quality of life questionnaires that measure psychological well‐being and score in psychiatric questionnaires that evaluate depression.
5. Participants' perceptions of the effect of O&M training on their lives relative to expectance, acceptance, satisfaction and impact in the short and in the long term.
Finally, O&M training is not free of risk as increased mobility causes people to be exposed to potentially serious harm (Banja 1994; Marsh 2000). We aimed to collect information on adverse effects including accidental falls, undesired contact with people and objects, or any trauma related to indoor or outdoor independent travel.
Search methods for identification of studies
Electronic searches
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, 2010, Issue 3), MEDLINE (January 1950 to March 2010), EMBASE (January 1980 to March 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to March 2010), System for Information on Grey Literature in Europe (OpenSIGLE) (March 2010), the metaRegister of Controlled Trials (mRCT) (www.controlled‐trials.com) (March 2010), ClinicalTrials.gov (http://clinicaltrials.gov) (March 2010) and ZETOC (March 2010). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 31 March 2010.
See: Appendices for details of search strategies for CENTRAL (Appendix 1), MEDLINE (Appendix 2), EMBASE (Appendix 3), LILACS (Appendix 4), OpenSIGLE (Appendix 5), mRCT (Appendix 6), ClinicalTrials.gov (Appendix 7) and ZETOC (Appendix 8).
Searching other resources
We searched the references from retrieved articles. We did not manually search conference proceedings or journals specifically for this review.
Data collection and analysis
Selection of studies
Two authors assessed the titles and abstracts resulting from the electronic searches. We obtained the full copies of all relevant or potentially relevant trials and both authors assessed these according to the 'Criteria for considering studies for this review'. The authors were not masked to the names of the authors, the institutions, journal of publication or results when making their assessments. We resolved disagreements about whether a trial should be included by discussion and forming consensus. In cases where additional information was needed before we could decide whether to include a trial, we attempted to obtain this information from the study authors.
Data extraction and management
Two authors independently extracted data using a form developed by the Cochrane Eyes and Vision Group. We resolved discrepancies by discussion. We contacted trialists to obtain missing data and to verify data.
Assessment of risk of bias in included studies
Two review authors independently assessed the included trials for bias according to the methods described in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2009a). The following parameters were assessed: sequence generation; allocation concealment; masking (blinding) of participants, personnel and outcome assessors; incomplete outcome data; selective outcome reporting. These items were evaluated for each outcome measure or class of outcome measure as specified in the latest version of the Cochrane Handbook. As reported in the Handbook, other sources of bias were: risk of bias related to the specific study design used; or trial stopped early due to some data‐dependent process (including a formal‐stopping rule); or an extreme baseline imbalance; or the study claimed to have been fraudulent.
If the information available in the published trial reports was inadequate to assess methodological quality, we contacted the trial authors for clarification. If they did not respond within a reasonable period of time, we assessed the trial based on the available information.
Each parameter was assessed as Yes (low risk of bias), No (high risk of bias) or Unclear.
Measures of treatment effect
We conducted data analysis according to Section 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2009). The mean and standard deviations were obtained. We summarised results across studies using the difference in means (fixed‐effect model).
Methods for future updates
For dichotomous data we will present the risk ratio. The risk difference or the number needed to treat will also be given. If continuous data can be pooled, we will calculate the weighted mean difference or the difference between treated and control arms weighted by the inverse of the variance. If the outcome was measured using different instruments but they are similar enough to be combined we will present the standardised mean difference. We will only analyse the means if the data are approximately normally distributed.
Unit of analysis issues
We do not expect there will be unit of analysis issues in the updates of this review since individuals, not eyes, are the unit of analysis and cluster randomised trials are unlikely to be conducted.
Dealing with missing data
In the updated version of this review, given further guidance available in the Cochrane Handbook (Higgins 2009a), we considered that missing outcome data are not a problem if loss to follow‐up is both balanced in the study arms and causes of loss to follow up are documented and judged to be unrelated to outcome in both study arms. When causes of missingness were not available, we planned to use Stata 10.2 software (StataCorp, College Station, Tx) user written function metamiss to take into account missing data and conduct sensitivity meta‐analyses if sufficient studies were found. The underlying theory and a link to download metamiss are provided in White 2008.
Assessment of heterogeneity
Although the same two studies were included in the current and in the previous version of this review, we decided to present results in meta‐analyses in this version of the review mainly with the purpose of presenting results in the Summary of Findings table. This also reflected a change in perspective on heterogeneity, since it is difficult to investigate with few studies in the meta‐analyses (Higgins 2009b). The updated Cochrane Handbook (Deeks 2009) provides overlapping bands of I2 values as categories of heterogeneity, which should be used considering the magnitude and direction of effects and heterogeneity Chi2 P‐value or I2 confidence intervals. However, I2 confidence intervals are typically very wide in many systematic reviews that include a few trials (Ioannidis 2007), making it difficult to assess statistical heterogeneity. Thus we commented on differences between trials, also considering the P‐value of the heterogeneity Chi2 and the overlap of individual studies' confidence intervals. We also present 99% confidence intervals as found in RevMan since their coverage approaches a conservative Bonferroni approach that takes into account multiplicity of outcome measures in the two included studies (total score and three subscales) such as done in the previous version of this review. In fact 98.75% confidence intervals are obtained applying this method to four outcomes (P = 0.05 divided by four comparisons: P = 0.0125).
If more than three studies can be pooled in future updates of this review, we will follow the guidance given in the updated Handbook version (Deeks 2009) and also consider I2 95% confidence interval calculated from the Q value given by RevMan and the appropriate degrees of freedom by means of the heterogi Stata software routine.
Assessment of reporting biases
If more than 10 studies are found in future updates, we will examine funnel plot asymmetry as a potential index of publication bias.
We investigated selective outcome reporting by doing an "outcome matrix" and classifying missing outcomes according to the following classification (adapted from a list provided by Paula Williamson at a Cochrane training workshop on selective outcome reporting bias, Edinburgh, March 2009).
A: States outcome analysed but only reported the P‐value > 0.05 i.e. NS.
B: States outcome analysed but only reported that P‐value < 0.05.
C: Clear that outcome was analysed but insufficient data presented to be included in meta‐analysis or full tabulation.
D: Clear that outcome was analysed but no results reported.
E: Clear that outcome was measured (for example, includes structurally related outcomes) but not necessarily analysed.
F: States that outcome was not measured.
G: Not mentioned but clinical judgement says likely to have been measured.
H: Not mentioned but clinical judgement says unlikely to have been measured.
I: Other (give details).
Data synthesis
Data analysis was conducted according to Section 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2009). The mean and standard deviations were obtained. Results were summarised across studies using the difference in means (fixed‐effect model). We did not use the standardised mean difference (SMD) in this review because the measurement tools were similar and differences in standard deviation probably reflect true differences between samples rather than between measurement tools.
Subgroup analysis and investigation of heterogeneity
We will undertake the following subgroup analyses:
1. Severity of low vision, people with no residual vision or light perception only versus people with some residual vision useful to help them orientate (at least hand‐motion);
2. Level of independent mobility at baseline, which may limit the effect of the intervention if the level of independent mobility in the home is already good;
3. Type of visual field defect: central loss versus peripheral loss;
4. Use versus no use of non‐optical mobility devices in conjunction with O&M training, such as long canes;
5. Use versus no use of optical devices as long‐distance low vision aids (such as telescopes) to enhance central residual vision or optical devices useful to widen peripheral visual field (such as amorphic lenses).
Sensitivity analysis
We will undertake the following sensitivity analyses:
1. Excluding studies of lower methodological quality (scoring No on any parameter of methodological quality);
2. Excluding unpublished studies.
Results
Description of studies
Results of the search
The original search identified 200 titles and abstracts. We obtained the full text of twenty‐four articles. Two of these were controlled studies. One further study in which a control group was present was identified from the references of one of the controlled studies. Because no random assignment was mentioned in the text we contacted the authors of the three controlled studies (Soong 2001; Szlyk 1998; Szlyk 2000) to obtain more information about the assignment procedure. All trial authors confirmed that participants were matched for age and for relevant visual variables but were not randomised. In Soong 2001 treated and control participants were recruited at two different clinics. The characteristics of the three controlled studies are summarised in the 'Discussion' section.
Search updates
Updates to the searches in 2005 retrieved a further 348 titles and abstracts. Two articles were obtained as full text (Straw 1991a; Straw 1991b). These studies used alternate allocation of participants to groups as the method of allocation and were therefore considered quasi‐randomised controlled studies and were included in the review.
Searches undertaken in 2006 and in 2009 retrieved a further 225 and 156 reports of studies, respectively, but no new studies about O&M training were identified.
The most recent search in March 2010 retrieved a further 75 reports of studies. We identified one ongoing study Zijlstra 2009 which will be included in the review when outcome data are available.
Included studies
See 'Characteristics of included studies' table for further details. Both studies were conducted in the USA. They adopted similar inclusion and exclusion criteria, type of intervention and outcome measures since Straw 1991b was developed on the basis of Straw 1991a.
Participants
Straw 1991a included 48 people aged 60 or over. They were legally blind participants who still maintained some degree of independent mobility but with indoor O&M needs. Because this was a US‐based study, legal blindness should have corresponded to a visual acuity of 20/200 or less bilaterally. To be included the participants must have had sufficient cognitive functioning to comprehend verbal communication. Thirteen persons were lost to follow up, mainly due to illness. There were 13 females and 22 males among the 35 people who completed the study (mean age was 76 years). Loss to follow up was balanced in the treatment and control groups since 18 versus 17 people completed the follow up respectively. Vision had been impaired for nine years on average and was mainly due to glaucoma. Of 35 people, 37% were totally blind and 40% had light perception only; only nine participants had some cognitive impairment. Nineteen people did not have balance problems and did not use devices such as canes; four had some balance problems; eight used a cane and four needed a wheelchair. People mostly resided in apartments in retirement complexes, single‐dwelling family or nursing homes.
Straw 1991b included 40 people with a minimum age of 58 years. People had to be functionally blind (not using vision for mobility), have indoor O&M needs yet have some degree of independent mobility. Eight of them could not complete the study; illness being the main reason for this. Out of 32 participants who completed the program, 20 were male and 12 were female (mean age was 77 years); 50% were totally blind and 34% had light perception only; with visual impairment lasting from 12 years on average and mainly due to glaucoma. Fourteen people had some cognitive impairment. Eleven did not have balance problems and did not use devices such as canes; eight had some balance problems (frail), eight used a cane; one a walker and four needed a wheelchair. The most common housing was in a nursing home, followed by private home.
In both studies, the Pfeiffer Short Portable Mental Status Questionnaire was used to evaluate simple cognitive abilities (10 questions) of the participants. There is no mention in these studies about the level of independence at baseline when moving in the home. This could influence the effect of the intervention if sufficient skills have been acquired by most participants.
Interventions
In Straw 1991a the intervention consisted of a series of scripted lessons administered by a volunteer. The O&M instruction programme was personalised according to the level of physical functioning of the participant, and specifically according to the type of device used. The volunteer received both written and oral instructions that enabled her or him to perform simple indoor O&M techniques with the participant during one hour of orientation to the project. The volunteer‐participant pairs worked on the program for 90 minutes a week for 10 to 12 weeks.
Items included in a subscale were used both as a training framework and as an assessment tool and were:
1. Orientation skills subscale: sound localisation, concepts, landmarks, turns, tactual discrimination (hands and feet), systematic search patterns and dropped objects.
2. Mobility skills, independent subscale: motor balance, seating, stairs, trailing, diagonal cane, elevator, squaring off and straight line, self‐protection positions.
3. Mobility skills, sighted guide subscale: basic position, narrow spaces, changing sides, doors, stairs.
Not all participants completed all items as this depended on their own characteristics and needs. The control group received programmed fitness exercises according to Ross 1984.
The intervention delivered in Straw 1991b was an evolution of that presented in Straw 1991a, which was modified to improve the applicability to the individual circumstances. To achieve this many sections of the programs were rearranged. In particular, an item corresponding to route travel within the living environment was added.
The reliability of the assessment instrument was assessed in both studies by an independent grader on a subset of participants. Crude agreement was reported to be high.
Outcomes
Straw 1991a used an assessment instrument administered by the volunteer and consisted of an Orientation scale and a Mobility scale. The Orientation and Mobility scales provided the outcome measures, recorded as the percentage of correct behaviours performed out of those possible for that participant. Therefore, the score ranged between 0 and 100, the latter being the higher score or the better performance. Not all activities could be performed by all participants and some scales were not delivered as they were inappropriate for certain participants. The scores were added to obtain a total score. There were two versions of the instrument: for people using, or not using, a device such as cane, walker or wheelchair.
The assessment instrument adopted in Straw 1991b was developed on the basis of that used for Straw 1991a. The main changes were the introduction of subjective assessment of the ability to complete four routes in order to rate the visually impaired person on safe and effective travel within the living environment. Furthermore, assessment was performed by a trained professional to try to improve its sensitivity.
In both studies, the skills on which the total score and the subscales were calculated could be classified as corresponding to the definition of the primary outcome measure considered for this review. In fact, the assessment instrument measured skills that were related to travel activities of daily life. The three subscales that were created by the authors represent different aspects of O&M training. The Orientation scale includes skills related predominantly to the person's understanding of the information to interpret the environment, spatial relationships, and movement. The two Mobility scales depended primarily on the person's physical movements within the indoor living environment. The Independent subscale included skills that were necessary for autonomous travel, while skills in the Sighted Guide scale referred to the interaction with a seeing guiding person during travel.
The score was expressed as the percentage of behaviours performed out of the number of behaviours appropriate for that person (Straw 1991b).
Excluded studies
Excluded studies are presented in the 'Characteristics of excluded studies' table, along with the reason for exclusion, which was lack of use of randomisation to form treatment and control group in three studies.
When updating this review we discussed the inclusion of an additional study (Campbell 2005) which compared a home safety program to an exercise program to prevent falls and injuries. This study is already included in a Cochrane review dedicated to fall prevention in the elderly (Gillespie 2009).
Risk of bias in included studies
The results of the assessment of methodological quality are shown in the 'Characteristics of included studies' table and summarised in Figure 1.
Methodological quality summary: review authors' judgements about each methodological quality item for each included study.
Allocation
Both Straw 1991a and Straw 1991b used alternate allocation of participants to groups rather than randomisation and were thus considered as having inadequate quality with respect to potential selection bias.
Blinding
Straw 1991a did not mask outcome assessors. In particular, the same volunteers providing care collected the outcomes. In Straw 1991b persons assessing outcome were independent professionals but it was unclear if masking occurred. It has to be said that masking individuals can be difficult for these types of physical interventions, and outcome assessors are also difficult to mask if they are aware of the intervention components, e.g. because the use of a cane is part of the experimental intervention, but not of the control intervention.
Incomplete outcome data
The exact number of people missing in each arm was not available in the reports. Therefore, we scored the quality of this parameter as unclear. We attempted to contact the authors to clarify unclear issues but we could not get additional data.
Selective reporting
We believe there were no selective reporting issues since one measurement tool was used and both total score and three subscales' scores are reported.
Other potential sources of bias
We could not identify other sources of bias.
Effects of interventions
See: Table 1
Summary of findings for the main comparison
Orientation & Mobility training compared to physical exercise for adults with low vision
Orientation & Mobility training compared to physical exercise for adults with low vision | ||||||
Patient or population: patients with adults with low vision Settings: Intervention: Orientation & Mobility training Comparison: physical exercise | ||||||
Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
Assumed risk | Corresponding risk | |||||
physical exercise | Orientation & Mobility training | |||||
Total score (using structured skills assessment) 0 to 100. Scale from: 0 to 100. | The mean total score (using structured skills assessment) ranged across control groups from 61 to 85 percentage of behaviours performed out of the number of behaviours appropriate for that person | The mean Total score (using structured skills assessment) in the intervention groups was 2.9 higher (6.9 lower to 12.6 higher) | 67 (2 studies) | ⊕⊝⊝⊝ very low1,2,3,4,5 | ||
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; | ||||||
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. |
1 Alternation used to assign patients and outcome assess unmasked to assignment
2 Heterogeneity is difficult to asses with two studies in the review.
3 Findings from two small studies conducted by the same review group cannot be assumed to be generalisable
4 Each study could not exclude an effect size close to 1 based on 95%CIs.
5 We believe that studies published on grey literature can be difficult to retrieve in this field.
The authors of the two included studies reported analyses of the total score (Analysis 1.1) as well as analyses of three subscales (Analysis 1.2, Analysis 1.3, Analysis 1.4). Since this was a training and assessment instrument, grouping of similar skills in the subscales should have been pre‐planned which would avoid the risk of "post hoc" analyses but as yet we have not had this confirmed by the authors. Since discussing statistical heterogeneity of two small studies is questionable, we provide a meta‐analysis for descriptive purposes and discuss clinical heterogeneity issues.
Analysis
Comparison 1 Orientation & Mobility training versus physical exercise, Outcome 1 Total score (using structured skills assessment).
Analysis
Comparison 1 Orientation & Mobility training versus physical exercise, Outcome 2 Orientation subscale (using structured skills assessment).
Analysis
Comparison 1 Orientation & Mobility training versus physical exercise, Outcome 3 Sighted guide subscale (using structured skills assessment).
Analysis
Comparison 1 Orientation & Mobility training versus physical exercise, Outcome 4 Independent subscale (using structured skills assessment).
An issue in Straw 1991a was the good functioning of most individuals, either because they already had some independent mobility in their living environments, or because of the characteristics of the measurement tool (too easy for the people included). In fact, baseline scores were in general high, from 73 up to 95 in all scales, which may have limited the ability to detect an improvement (ceiling effect). The score was a percentage of tasks done correctly; high scores were markedly skewed when plotted as a continuous outcome variable. Taking into account these limitations, there was no statistically significant difference between groups in any score at the final examination (Analysis 1.1; Analysis 1.2; Analysis 1.3; Analysis 1.4).
All baseline scores were much lower in Straw 1991b (range: 47 to 70), suggestive of less O&M skills in these people who had more room for improvement. At the final assessment, all the scores in the treated group increased, but the difference between comparison groups was close to statistical significance only for the Independent subscale (Analysis 1.4). The authors observed anecdotally that blind persons with no O&M experience benefit more, while those living in their homes for years already had skills. Participants with less severe visual impairment did not have O&M needs.
Apart from the inclusion of people with more severe disability in Straw 1991b compared to Straw 1991a, a further difference was the use of trained professional outcome assessors in the former, which the authors believed may have improved measurement sensitivity.
Discussion
Summary of main results
The two small quasi‐randomised controlled studies included in this review (Straw 1991a; Straw 1991b) could not find a significant difference between O&M training, delivered by a volunteer and physical exercise. Straw 1991a and Straw 1991b evaluated the effects of orientation and mobility (O&M) training in adults with low vision, comparing it to physical exercise. The studies were consecutive phases of development and implementation of the same training curriculum and assessment instrument. No difference between O&M training and physical exercise was found in Straw 1991a. In Straw 1991b O&M training tended to be better than physical exercise, but only the difference for the independent subscale of the training/ assessment instrument was close to statistical significance. This scale assessed the ability to travel indoors independently.
The differences between the two studies may have been due to the improvement of the intervention and assessment instrument, which was developed to be tailored to a patient's needs and characteristics in the second study. An important limitation of Straw 1991a was the high baseline scores obtained by the participants, close to the maximum achievable with that instrument (ceiling effect). Another difference between these studies could be greater O&M abilities of participants before training. Very low vision was slightly less common among participants in Straw 1991a as compared to Straw 1991b (77% versus 84%), and the authors observed that there is little need for O&M training among those using vision for travel. Even differences among blind people may exist, since those who are very familiar with their home environment already have such skills, but no details are available in the articles.
Overall completeness and applicability of evidence
Given the complexity of O&M interventions and the small size of the two studies in this review, as well as the fact that they were conducted by the same study group, we cannot assume that our findings are applicable to other settings. The precision obtained in each study is low since analysing data as standardised mean difference (i.e. the effect size) could not exclude a large effect size, i.e. approaching 1, based on 95% confidence interval limits.
From the researchers' point of view, these two studies suggest that it is possible to develop an O&M training curriculum coupled with an assessment tool that is able to capture change with time for at least some O&M skills. Nonetheless, this message can be less useful today, given the shift towards the use of quality of life questionnaires as an outcome measure and towards complex rehabilitation or support models as an intervention.
Quality of the evidence
The size of the studies (which are small) and the inadequate method of randomisation place these studies at risk of selection bias and confounding. Masking of recipients of care and care providers could not be achieved and indeed this may be difficult or impossible when delivering an O&M intervention. In at least one study the outcome assessors were not masked. On the other hand, the choice of outcome measures that allow masking of at least outcome assessors is important when scoring O&M performance. The shift from objective to subjective outcomes, i.e. from scoring physical performance to self‐perceived performance or quality of life measured with validated questionnaires, would change the perspective from that of the trainer to that of the patient, thus allowing masking of both assessors and a patient‐centred outcome measure. Such a choice has been made in the ongoing study Zijlstra 2009. This study is validating a standardised O&M training model in The Netherlands while assessing its acceptability and efficacy compared to standard care.
Agreements and disagreements with other studies or reviews
In this update of the review we have pooled the results of the two studies for descriptive purposes. However, the limitations in the analyses remain, particularly the fact that data were markedly skewed in Straw 1991a, making the use of parametric tests improper. The I2 value was more than 60% for two subscales, but, as reported above, we decided not to make formal analyses of statistical heterogeneity in the update of this review because it cannot be reliably calculated with few studies in the meta‐analyses (Higgins 2009b; Ioannidis 2007).
Since we found little literature that met the more stringent criteria for this review, we provided a description of three non‐randomised controlled studies found by the electronic searches that have evaluated the effects of this intervention, to delineate the most recently used investigation methods.
Szlyk 1998 compared the performance of eight people who received both bioptic amorphic lenses and O&M training with that of seven people who received neither, during an observation period of three months. All participants were affected by peripheral visual field loss and the aim of the lenses was to expand their visual field. No randomisation procedure was reported but the authors state that the participants were matched as much as possible for ocular disease, level of visual impairment and age. The group that served as a control in the first three months received the same intervention during the second trimester. All participants were evaluated with clinical, psychophysical, laboratory and O&M assessment, which included driving skills, at baseline and at three and six months. A merit of this study is that the authors explored the feasibility of using a number of laboratory and real‐world tests grouped in six fundamental visual skills that are relevant to O&M (recognition, peripheral detection, scanning, tracking, visual memory and mobility). The authors provided examples of such tasks. Examples of recognition tasks were counting the number of people in a passing car; locating building addresses; reading posted prices of items within a cafeteria. As an index of mobility, participants were graded on their ability to cross intersections, walk stairs, and negotiate crowded public places. Scanning tasks included finding particular items on a store shelf, finding a particular entrance in the student union building, and locating the "deli station" in a cafeteria. Tracking tasks included watching moving vehicles as they pass down the street and following particular individuals in public places. The certified O&M specialist coded performance on the mobility tests using a scale from 1 (not able to perform) to 5 (no difficulty). On each task, either performance or speed or both were coded. To define a trained person as improved in a particular task they had to obtain an increase in score of at least the average change recorded in the observation group after three months. With this definition, there was a reported 25% to almost 50% improvement of performance, depending on the type of task, after both immediate and delayed training. The investigators found that the amount of improvement was larger in those with narrower visual field. Data on reliability of the measures are not provided.
Szlyk 2000 used a similar battery of assessment methods and study design to evaluate the effectiveness of bioptic lenses with or without O&M training in people with central vision loss. Participants were assigned to receive bioptic telescopes with training (n = 9), telescopes alone (n = 8) or no intervention (n = 8). This last group was offered delayed use of lenses and training from three to six months. No method of randomisation was used but the authors state that groups were matched and statistically equivalent in age, sex, central scotoma size, visual acuity and letter contrast sensitivity. As in the former study, the authors defined an improvement in a task as an increase in score by more than the average of the test‐retest difference (baseline versus three months) for the untreated group. Since they found no difference between the improvement obtained with immediate versus delayed training, they combined data of those given lenses and training initially with those who received the intervention in the second trimester only; these individuals had served as controls in the first trimester. They found a statistically significant effect of training plus lenses compared to lenses alone for some visual tasks, such as recognition (P = 0.05, t‐test), peripheral identification (P = 0.02), scanning (P = 0.03), but not for mobility (P = 0.06), tracking (P = 0.15) or visual memory (P = 0.07), although all comparisons favoured the intervention. When driving related tasks were evaluated separately from other O&M tasks a statistically significant effect of training was observed for this task (P = 0.02). This work shows that differences between treatment groups can be elicited based on numerous and complex psychophysical, laboratory and real‐world tests but statistical methods used to analyse them are not reported in detail in the paper. One statistical issue is the failure to take into account multiple testing, which increases the likelihood of finding a statistical significance by chance. As an example, performing 20 comparisons adopting the conventional level of statistical significance (P=0.05), leads to a probability of (1 to 0.9520) or 64% to obtain one or more significant findings only by chance.
Soong 2001b investigated the effect of O&M training on mobility performance of 19 visually impaired individuals compared to 18 people who were matched as closely as possible for ocular disease, level of visual impairment and age. No randomisation procedure was adopted. All the participants were physically active and went out of their homes with or without other people. Sixteen people in the treated group were prescribed long canes or support canes or identity canes. All participants were tested at two visits four weeks apart. At each visit, the person's mobility performance was assessed twice as walking efficiency (Percentage Preferred Walking Speed (PPWS)) and error score on an indoor obstacle course. The error score improved at the second visit only in the treated group but not to a statistically significant extent, while PPWS improved only in the untrained group. The authors comment that the mental effort spent by trained participants trying to use the new techniques may have compromised their walking efficiency. Also the design of the walking path may be critical and future studies should consider other outcome measures such as self reported mobility performance and mental effort needed.
The studies presented above as well as the literature obtained in our search point out that trials considering O&M training may use very different tests to measure participants' performance. The objective of our review was not to find and discuss all the studies that have used or evaluated O&M assessment instruments. Nonetheless, we recognise that the discussion of this issue is critical for those who plan to conduct RCTs in this field of research. Therefore, we provide some examples that are useful for this purpose. Soong 2001b used an indoor laboratory course with obstacles set up along the course and measured time and errors made while completing the task. Szlyk 1998 used 41 indoor and outdoor tests exploring six visual skills categories (recognition, peripheral detection, scanning, tracking, visual memory and mobility). Geruschat 1989 used total time and mobility incidents on real‐world routes. Straw 1991a and Straw 1991b developed an assessment instrument for assessing O&M in older visually impaired adults, which has been described above and which they claimed to have acceptable inter‐observer reliability.
The complexity of an O&M intervention and its evaluation is such that assessment instruments will usually focus on several aspects of the performance rather than on a single objective measure. While objective measurements of performance have theoretically better properties, being easier to standardise, their use and interpretation may not be straightforward. As an example, Soong 2001b used PPWS and error score to evaluate mobility. They could not demonstrate a benefit from training with respect to the control group, although there was a trend in favour of treated people for the error score outcome.
The authors state that it may be necessary to assess mobility performance after a longer period, such as at three and six months after training, to allow visually impaired adults to have sufficient practice in adopting new travel skills. It must also be considered that O&M instructors specifically teach clients to vary walking speed and to increase the duration of preview while walking through an unfamiliar area so that faster may not always be better for some real‐world tasks. In addition, many of the participants in the training group used a long cane on the post‐test, but not the pre‐test. This may have further slowed their progress as they would have been relatively inexperienced with the cane and would have had to use it to manoeuvre round the confined and cluttered obstacle course that was being used to assess performance. This could explain the opposite direction of training effect on PPWS and error score in treated and control participants in the study by Soong 2001b. Even if such effects were demonstrated, how they relate to a person's quality of life is not clear. Indeed, if laboratory mobility tests are used they should both be sensitive to meaningful changes in performance and correlate with real‐world tasks. An advantage of using laboratory tests is that they can be described in detail, as in Soong 2001b, and possibly replicated by others. Finally, tests arranged in a laboratory may not be comparable across studies because of differences in their construction, such as number and positioning of obstacles along the path, their characteristics or positioning of light and glare sources.
The training and assessment methods of the studies presented in this discussion indicate that, despite the apparent lack of standard measures of the effect of O&M training, several travel‐related activities which are relevant to a person's life should be considered as primary outcome measures and the training should also be personalised according to patients' needs and characteristics. It may also be expected that enhanced mobility will have an impact on a person's wellbeing and self‐esteem and on their relationship with other people. Results from laboratory‐based mobility tests can be considered as surrogate outcome measures as they are expected to relate to performance in daily life. Specifically designed quality of life questionnaires may also be suitable to measure the effect of O&M intervention. The advantages of these tools are the ability to capture not only physical, but also mental and social dimensions of health using measures of both functionality and well‐being based on self‐evaluation. One example of such instruments is the Independent Mobility Questionnaire (IMQ), developed by Turano et al. (Turano 1999) for people with retinitis pigmentosa. An overview on quality of life and other types of visual function assessment questionnaires is offered in Massof 2001.
Authors' conclusions
Implications for practice
The clinical practice of O&M instructors suggests that the need for mobility training of people with low vision is self evident. Nonetheless, the possibility of quantitative assessment of the effect of training is needed to study which techniques are more useful. Such results would help O&M instructors choose the most appropriate techniques, as well as guiding social health programmes in deciding to support this intervention in an era of cost‐containment.
Two small quasi‐randomised controlled studies could not find a significant difference between O&M training, delivered by a volunteer, and physical exercise.
Implications for research
More research is needed on O&M training for low vision adults. The complexity and diversity of patients' needs makes it necessary to adapt any training curriculum to individual patients' profiles, as pointed out by the authors of the studies retrieved in this review. The O&M community should develop standard, yet flexible methods to objectively test O&M performance which are valid and reliable. The complexity of the relationship between O&M training and a person's experiences suggests that instruments that capture more fully subjective perceptions of health, such as questionnaires on quality of life that are specific to these tasks, could also be useful tools for assessing the outcome of O&M training.
Finally, we report here a few key questions for future O&M research which have been formulated in the discussion of the update of this review.
How much instruction is required before treatment effects are seen (dosage issue)?
How does the type and degree of vision loss affect the number of units of service that are required?
Of the various philosophies of care, which one is most effective?
What are the characteristics of subjects who benefit from the different philosophies of care?
What are the measures of mobility performance that are needed to assess the diverse needs of people with low vision?
What's new
Date | Event | Description |
---|---|---|
14 April 2010 | New citation required but conclusions have not changed | Review substantially updated including new assessment of risk of bias and preparation of summary of findings tables. |
14 April 2010 | New search has been performed | Issue 5, 2010: New search yielded one ongoing trial. |
History
Protocol first published: Issue 4, 2002
Review first published: Issue 4, 2003
Date | Event | Description |
---|---|---|
24 October 2008 | Amended | Converted to new review format. |
31 March 2006 | New citation required and conclusions have changed | Substantive amendment |
Acknowledgements
The Cochrane Eyes and Vision Group editorial team prepared and executed the electronic searches for this review. Jennifer Evans and Anupa Shah provided editorial support during the development of the review. We are grateful to Duane Geruschat for peer review comments on both the protocol and review. We thank Roberta Scherer, Catey Bunce, Ruthy Acosta and Thomas Kuyk for their comments on the review.
Appendices
Appendix 1. CENTRAL search strategy
#1 MeSH descriptor Vision, Low
#2 MeSH descriptor Vision Disorders
#3 MeSH descriptor Visually Impaired Persons
#4 (low* or handicap* or subnormal* or impair* or partial* or disab*) near/3 (vision or visual* or sight*) 1422 edit delete
#5 (#1 OR #2 OR #3 OR #4)
#6 MeSH descriptor Rehabilitation
#7 MeSH descriptor Activities of Daily Living
#8 (rehabilitat*) near/3 (navigat* or mobility or travel* or walk* or moving or movement or driv* or teach* or train*) 860 edit delete
#9 (cane*) near/3 (long or support)
#10 orientat* and mobili*
#11 way near/3 find*
#12 dog*
#13 (#6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12)
#14 (#5 AND #13)
Appendix 2. MEDLINE search strategy
1. randomized controlled trial.pt.
2. (randomized or randomised).ab,ti.
3. placebo.ab,ti.
4. dt.fs.
5. randomly.ab,ti.
6. trial.ab,ti.
7. groups.ab,ti.
8. or/1‐7
9. exp animals/
10. exp humans/
11. 9 not (9 and 10)
12. 8 not 11
13. exp low vision/
14. exp vision disorders/
15. exp visually impaired persons/
16. ((low$ or handicap$ or subnormal$ or impair$ or partial$ or disab$) adj3 (vision or visual$ or sight$)).tw.
17. or/13‐16
18. exp rehabilitation/
19. exp activities of daily living/
20. (rehabilitat$ adj3 (navigat$ or mobility or travel$ or walk$ or moving or movement or driv$ or teach$ or train$)).tw.
21. (cane$ adj3 (long or support)).tw.
22. (orientat$ or mobili$).tw.
23. (way adj3 find$).tw.
24. dog$.tw.
25. or/18‐24
26. 17 and 25
27. 12 and 26
The search filter for trials at the beginning of the MEDLINE strategy is from the published paper by Glanville et al (Glanville 2006).
Appendix 3. EMBASE search strategy
1. exp randomized controlled trial/
2. exp randomization/
3. exp double blind procedure/
4. exp single blind procedure/
5. random$.tw.
6. or/1‐5
7. (animal or animal experiment).sh.
8. human.sh.
9. 7 and 8
10. 7 not 9
11. 6 not 10
12. exp clinical trial/
13. (clin$ adj3 trial$).tw.
14. ((singl$ or doubl$ or trebl$ or tripl$) adj3 (blind$ or mask$)).tw.
15. exp placebo/
16. placebo$.tw.
17. random$.tw.
18. exp experimental design/
19. exp crossover procedure/
20. exp control group/
21. exp latin square design/
22. or/12‐21
23. 22 not 10
24. 23 not 11
25. exp comparative study/
26. exp evaluation/
27. exp prospective study/
28. (control$ or prospectiv$ or volunteer$).tw.
29. or/25‐28
30. 29 not 10
31. 30 not (11 or 23)
32. 11 or 24 or 31
33. exp visual disorder/
34. exp visual impairment/
35. ((low$ or handicap$ or subnormal$ or impair$ or partial$ or disab$) adj3 (vision or visual$ or sight$)).tw.
36. or/33‐35
37. exp rehabilitation/
38. exp daily life activity/
39. (rehabilitat$ adj3 (navigat$ or mobility or travel$ or walk$ or moving or movement or driv$ or teach$ or train$)).tw.
40. (cane$ adj3 (long or support)).tw.
41. (orientat$ or mobili$).tw.
42. (way adj3 find$).tw.
43. dog$.tw.
44. or/37‐43
45. 36 and 44
46. 32 and 45
Appendix 4. LILACS search strategy
vision, low [Subject descriptor]andrehab$ or navigat$ or mobility or travel$ or walk$ or moving or movement or driv$ or teach$ or train$ or cane$ or dog$
Appendix 5. OpenSIGLE search strategy
((keyword:low$ or keyword:handicap$ or keyword:subnormal$ or keyword:impair$ or keyword:partial$ or keyword:disab$) AND (keyword:vision or keyword:visual$ or keyword:sight) AND (keyword:rehabilitat$ or keyword:navigat$ or keyword:mobility or keyword:travel$ or keyword:walk$ or keyword:moving or keyword:movement or keyword:driv$ or keyword:teach$ or keyword:train$))
Appendix 6. metaRegister of Controlled Trials search strategy
(mobility or orientation) AND vision
Appendix 7. ClinicalTrials.gov search strategy
(mobility or orientation) AND vision
Appendix 8. ZETOC search strategy
low vision mobility
low vision orientation
Notes
New search for studies and content updated (no change to conclusions)
Data and analyses
Comparison 1
Orientation & Mobility training versus physical exercise
Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
---|---|---|---|---|
1 Total score (using structured skills assessment) | 2 | 67 | Mean Difference (IV, Fixed, 99% CI) | 2.88 [‐6.87, 12.64] |
2 Orientation subscale (using structured skills assessment) | 2 | 67 | Mean Difference (IV, Fixed, 99% CI) | 1.54 [‐7.94, 11.01] |
3 Sighted guide subscale (using structured skills assessment) | 2 | 65 | Mean Difference (IV, Fixed, 99% CI) | 0.65 [‐7.35, 8.64] |
4 Independent subscale (using structured skills assessment) | 2 | 66 | Mean Difference (IV, Fixed, 99% CI) | 7.15 [‐7.48, 21.77] |
Characteristics of studies
Characteristics of included studies [ordered by study ID]
Straw 1991a
Methods | Method of allocation: Assignment stratified by level of functioning. First participant assigned by flipping a coin, the following by alternation. Masking: Participant ‐ not used in this review; Provider ‐ not used in this review. Outcome: Pre‐testing could be masked because it was performed before randomisation; post‐testing not masked because performed by the same volunteer who delivered the intervention. Losses to follow‐up: 13; mostly due to illness. | |
Participants | Country: USA Number randomised: 43 Age: 60+ (mean 76) Sex: 22 F, 13 M among 35 who completed the program. Inclusion criteria: Age 60+, legally blind, have indoor O&M needs, have some degree of independent mobility, have sufficient cognitive functioning to comprehend verbal communication, be willing to participate. Participant characteristics: 19 did not have balance problems and did not use devices such as canes; 4 had some balance problems; 8 used a cane and 4 needed a wheelchair. Visual impairment from 9 years average, mainly due to glaucoma. 37% were totally blind and 40% had light perception only. 9 participants had some cognitive impairment. | |
Interventions | The intervention consisted of a series of scripted lessons to be administered by a volunteer. The O&M instruction programme was personalised according to the level of physical functioning of the participant, specifically according to the type of device used. The volunteer received both written and oral instruction that enabled her/him to perform with the participant simple indoor O&M techniques during one hour of orientation to the project. The fields of instruction corresponded to the activities described in the Outcomes section. The volunteer‐participant pairs worked on the program for 90 minutes a week for 10 to 12 weeks. | |
Outcomes | Assessment instrument delivered by the volunteer and consisting of Pfeiffer Short Portable Mental Status Questionnaire, an Orientation scales, a Mobility scales; some scales may not have been delivered if inappropriate for certain participants. The Orientation and Mobility scales provided the outcome measures. Two versions of the instrument (for people using or not using a device, such as cane, walker or wheelchair). Outcome measures: percent of correct behaviours performed out of those possible for that participants (not all activities could be performed by all participants). Scores of 24 skills were summed‐up for 3 subscales (orientation, sight guided, independent). A total score could be compared. | |
Notes | The authors provide a discussion of several issues in the instrument development: ‐ the delivery of assessment and training by inexperienced healthy volunteers, including ‐ the absence of criteria to determine the acquisition of a skill ‐ having tested participants in their own environment, where they had already gained independence in most cases ‐ ceiling effect in some tasks, such as the seating skills | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Adequate sequence generation? | High risk | First participant assigned flipping a coin, then by alternation. |
Allocation concealment? | High risk | Alternation was used, which allows investigators to foresee treatment assignment. |
Blinding? All outcomes | High risk | Masking patients and care providers is impossible in this field of research; outcome assessors were masked at baseline but not during follow‐up. The latter type of masking can also be impossible to achieve if participants randomised to O&M training use a cane as a part of the intervention. |
Incomplete outcome data addressed? All outcomes | Unclear risk | 35 out of 43 people completed follow‐up, but the loss in each assignment arm is not reported. |
Free of selective reporting? | Low risk | Subscales of a questionnaire are the primary outcome. |
Free of other bias? | Low risk | No other sources of bias are identified. |
Straw 1991b
Methods | Method of allocation: assignment stratified by level of functioning. First participant assigned by flipping a coin, the following by alternation. Masking: participant ‐ none; provider ‐ none. Outcome: pre‐testing could be masked because it was performed before randomisation; post‐testing not masked because performed by the same volunteer who delivered the intervention. Losses to follow‐up: 8, mostly due to illness. | |
Participants | Country: USA, 1988 to 1989 Number randomised: 40 Age: 58+ (mean 77) Sex: 20 female, 12 male among 32 who completed the program. Inclusion criteria: age 58+, functionally blind (not using vision for mobility), have indoor O&M needs, have some degree of independent mobility, have sufficient cognitive functioning to comprehend verbal communication, be willing to participate. Participant characteristics: 11 did not have balance problems and did not use devices such as canes; 8 had some balance programs (frail); 8 used a cane, 1 a walker and 4 needed a wheelchair; most common housing: 14 in nursing home, 12 in private home. Visual impairment from 12 years on average, mainly due to glaucoma. 50% were totally blind and 34% had light perception only. 14 participants had some cognitive impairment. | |
Interventions | The intervention delivered in an evolution of that presented in Straw 1991a, which was modified to improve the applicability to the individual circumstances. Many sections of the programs were rearranged to achieve this. | |
Outcomes | The assessment instrument was developed on the basis of that used in Straw 1991a. The main changes were the introduction of subjective assessment of the ability to complete 4 routes to rate the visually impaired person on safe and effective travel within the living environment. Furthermore, assessment was performed by a trained professional to try to improve its sensitivity. | |
Notes | ||
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Adequate sequence generation? | High risk | First participant assigned flipping a coin, then by alternation. |
Allocation concealment? | High risk | Alternation was used, which allows investigators to foresee treatment assignment. |
Blinding? All outcomes | Unclear risk | Masking patients and care providers is impossible in this field of research; outcome assessors were masked at baseline but its is unclear if they were masked during follow‐up. The latter type of masking can also be impossible to achieve if participants randomised to O&M training use a cane as a part of the intervention. |
Incomplete outcome data addressed? All outcomes | Unclear risk | 32 out of 40 people (16 per each group) completed follow‐up, but the number randomised to each arm is not reported. |
Free of selective reporting? | Low risk | Subscales of a questionnaire are the primary outcome. |
Free of other bias? | Low risk | No other sources of bias are identified. |
O&M ‐ orientation and mobility
Characteristics of excluded studies [ordered by study ID]
Study | Reason for exclusion |
---|---|
Soong 2001 | Participants were not randomised. Authors were contacted and reported that control participants were recruited from one clinic while the experimental participants were recruited from another clinic. The two mobility instructors who assessed both groups of participants were from the same organisation and they used the same guidelines for referring people for orientation and mobility training. Furthermore, authors attempted to match the participants' age and ocular disease. |
Szlyk 1998 | Participants were not randomised. Authors were contacted and confirmed that they used a modified matching design where the groups were statistically equivalent on a number of relevant measures. |
Szlyk 2000 | Participants were not randomised. Authors were contacted and confirmed that they used a modified matching design where the groups were statistically equivalent on a number of relevant measures. |
Characteristics of ongoing studies [ordered by study ID]
Zijlstra 2009
Trial name or title | A parallel group randomised controlled trial developed to evaluate a standardised O&M training in the use of an identification cane (NCT00946062). The trial is conducted in collaboration with the two main organisations for low vision rehabilitation care in The Netherlands: Bartiméus and the VisioSensisDeBrink Group (as of January 2010: Royal Visio). |
Methods | Cluster randomised trial. In 18 local centres, which are scattered over The Netherlands, O&M training is provided to older persons with visual impairment. The centres were randomly allocated to the control group or intervention group stratified by organisation (at that time: Bartiméus – four local centres, Sensis – four local centres, and Visio – 10 local centres). Due to the nature of the trial and the information provided to clients before the start of the trial (required by the Medical Ethical Committee), mobility trainers, researchers and participants are not masked to intervention status. Participants are, however, not informed about their intervention status until the start of the O&M training. Trained outcome assessors who perform the interviews by telephone are masked to intervention status. Data for the effect evaluation are collected at baseline, and at five and 17 weeks after the start of the O&M training during 40 minute interviews by telephone. Trained interviewers, who are masked to group allocation, perform the interviews. In addition, a 25 minute interview by telephone is performed at eight weeks after the start of the O&M training to obtain data for the process evaluation from participants in the intervention group as well as the control group. Pre‐structured questionnaires on process aspects are used to gather data from the mobility trainers per participant. Trainers receive this questionnaire before the first session of the participant's O&M training. As recommended by Hollis 1999, non‐compliant participants are approached for all follow‐up assessments. |
Participants | Community‐dwelling older people who ask for support at a rehabilitation centre for people with visual impairment and who are likely to receive an O&M training in using the identification cane are included in the trial (N = 190). |
Interventions | The standardised O&M training aims to facilitate safe and independent participation in the community by optimal use of one's abilities, and to facilitate uptake of old or new activities. To achieve these aims several strategies were added to the regular O&M training, that is: prioritising the client's needs, cognitive restructuring, action planning, contracting, providing direct feedback and stimulating individual problem solving, and finding personal, realistic solutions. The standardised O&M training consists of two face‐to‐face sessions and one telephone session. Compared to the regular O&M training, the standardised O&M training is well structured, yet still tailor made as clients are actively involved in their rehabilitation with respect to mobility. For example, they are encouraged to individualise their training by means of formulating personal goals regarding activities in the community. Trainers were instructed to provide additional O&M training sessions to the clients if needed. Trainers providing care according to the standardised O&M training needed to complete both the two face‐to‐face sessions and the one telephone session before conducting extra training sessions on O&M. Trainers who would provide the standardised O&M training to the intervention group received a two hour instruction by the researcher (GZ). To prepare for the instruction, trainers read the manual of the standardised O&M training. To monitor whether participants received sufficient care, trainers answered two questions as part of the process evaluation. These questions included to what extent the O&M training met the participant's need for mobility support according to the perception of the trainer and whether additional training sessions in the use of the identification cane were needed. |
Outcomes | ADL self care and visual functioning with respect to distance activities and mobility. Secondary outcomes include quality of life, feelings of anxiety, symptoms of depression, fear of falling, and falls history. Data for the effect evaluation are collected by means of telephone interviews at baseline, and at five and 17 weeks after the start of the O&M training. In addition to an effect evaluation, a process evaluation to study the feasibility of the O&M training is carried out. |
Starting date | November 2007. Preliminary findings regarding the evaluation are expected in the course of 2010. |
Contact information | GAR Zijlstra ‐ R.Zijlstra@zw.unimaas.nl; Maastricht University, Faculty of Health, Medicine and Life Sciences, Department of Health Care and Nursing Science, Maastricht, the Netherlands; CAPHRI School for Public Health and Primary Care, P.O. Box 616, 6200 MD Maastricht, the Netherlands |
Notes |
Differences between protocol and review
2010, Issue 5 update
This version of the review is based on the new RevMan 5 format.
We decided that it was of little interest to consider no training as the only comparator, and we included different types of O&M training as control. In fact, our peer‐reviewers pointed out that there is no point in assessing the efficacy of O&M training in itself, given its established use and self‐evident effect.
Contributions of authors
Conceiving the review: GV
Designing the review: GV
Co‐ordinating the review: GV
Screening search results: GV, GR
Screening retrieved papers against inclusion criteria: GV, GR
Writing the review: GV
Commenting on the review: GR
Declarations of interest
None known
References
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