Methodological issues need to be considered carefully if research on persons with hidden mobility disabilities is to be useful and relevant. Below is a discussion of the most common methodological issues and how they might be addressed.
Defining Hidden Mobility Disabilities
In keeping with the social model of disability and based on the definition of disability in the 2006 United Nations Convention on the Rights of Persons with Disabilities, a hidden mobility disability can be defined as:
a disability that results from the interaction between persons with mobility impairments that shorten the distance they can walk comfortably or the time that they can stand without pain and attitudinal and environmental barriers that hinder their full and effective participation in society on an equal basis with others.
The attitudinal barriers faced by persons with hidden mobility disabilities include dismissiveness, pity, irritation or anger that a slow moving person is blocking their way, and even criticism that such people should not have disabled parking permits because they can walk. The environmental barriers include:
- Distance to be walked
- Impediments such as slopes, unstable or shifting ground, or uneven ground that make walking more of an effort
- Going up and down stairs
- Time standing unsupported
Focus of Measurement
Most data on mobility disabilities come from census surveys that measure prevalence – i.e., how many people have a mobility disability, broadly defined with some breakdown into categories of disability. More detailed questioning is typically in one or more of the following areas:
- Degree of difficulty experienced (none/mild/moderate/severe/extreme or can’t do) OR (none/some/a lot/ can’t do)
- Frequency of activity limitation (never/rarely/sometimes/often/always)
Prevalence, participation difficulty, and frequency of activity limitation are relevant to hidden mobility disabilities, but hidden mobility disability is typically not a category of focus.
Because of the historic focus on visible mobility disabilities where the person always uses a mobility aid, census survey questions have been limited to walking and going up and down stairs. Both measurements are relevant to persons with hidden mobility disabilities, as long as the appropriate response categories are included.
Most census surveys also ask about standing, although they do not include difficulty standing in their definition of disability. For persons with a hidden mobility disability, questions about how long the person can stand unsupported are particularly relevant. If a person with a hidden mobility disability does not realize that they will have to stand in line and therefore bring a seat cane or walker with them, they may be faced with a situation where they are unable to stand for the length of time required.
Assumptions about the Point of Difficulty
“Short distance”: Those without a hidden mobility disability tend to vastly overestimate what constitutes a “short distance” and may assume that 30.5 m (100 feet) to 61.0 m (200 feet) “should” pose no problem. For example, the WHO Model Disability Survey asks, “How much of problem is walking a short distance such as 100 m [328 feet, or a city block] for you?” The WHO Disability Assessment Schedule 2.0 (WHODAS) refers to one kilometer (3,281 feet) as being the measure of a “long distance”. SPARC BC will issue a disabled parking decal to persons who cannot walk more than 328 feet (100 m). The U.S. Census Bureau asks about the ability to walk one-quarter of a mile, or 1,320 feet (402.3 m). Data from the Survey on Hidden Mobility Disabilities indicate that for most persons with hidden mobility disabilities, a comfortable “short” distance is 35 feet or 10.7 meters.
Time standing: Those without a hidden mobility disability also tend to vastly overestimate the length of time that is a “comfortable” time to stand unsupported. The WHO Disability Assessment Schedule 2.0 (WHODAS) refers to 30 minutes as a “long period” to stand. For persons with hidden mobility disabilities due to joint degeneration, pressure on the joints from standing can become painful very quickly. Data from the Survey on Hidden Mobility Disabilities confirm that standing for two minutes or less would be considered a “brief time” and standing for more than five minutes can become unbearably painful.
The Challenge of Measuring Distance
It can be very challenging for people to gauge the distance they can walk comfortably. In the Washington Group’s Extended Set of Questions on Functioning, the following references are used:
- 100 meters = 1 football field or 1 city block
- ½ kilometer = 5 football fields or 5 city blocks
These measurements are not satisfactory as people have difficulty relating them to their own walking experience. As well, measurements need to be expressed in both feet and meters. Statistics Canada addressed this issue in its Disability Short Questions by switching the focus to the length of time that people could walk on a flat surface; however, gauging the length of time walked (when not walking as part of a specific exercise regime) can also be challenging for people.
Based on an approach adopted by the U.S. Supreme Court, the Survey on Hidden Mobility Disabilities uses the standard school bus as the unit of measure. The standard school bus is 35 feet (or 10.7 meters) long, and most people can visualize their walking in relation to the length of a school bus.
Support for Variability and Recovery
In contrast to some other disabilities, hidden mobility disabilities are most often variable. One day a person may be able to comfortably walk 50 feet, while the next day severe pain could begin at 20 feet. It is not uncommon for a person with a hidden mobility disability to begin walking across a large expanse or down a long hallway and suddenly become immobilized with pain.
Existing census surveys assume that the use of assistive devices will solve access issues, and they often ask questions about which assistive devices are used and when. Data from the Survey on Hidden Mobility Disabilities confirm that two-thirds of persons with hidden mobility disabilities never use a wheelchair, electric scooter, or walker. Wheelchairs are used temporarily by 22.5 percent of respondents for long distances, such as in airports. The most commonly used mobility aid is a cane, used by 20.7 percent of respondents.
None of the existing census surveys examine the supports needed to recover once severe pain or shortness of breath sets in. The most common accommodation needed, but not asked about, is bench seating at frequent intervals.