Conceptualization and definition of QOL

Although the term “goodness of life” (Baker & Intagliata 1982) seems appropriate to express the overall concept of quality of life (QOL), its apparent simplicity hides a multidimensional concept that is among the most difficult one to define and to translate into a functioning and operating reality. Nonetheless, 2 main conceptualizations of QOL are well-accepted: (1) the subjective approach whose focal point is the person’s emotional or cognitive assessment of the congruence between his/her life expectations and achievement, usually associated with life satisfaction or well-being and (2) the objective approach, based on one’s characteristics that can be objectively measured by an external appraiser or outsider (Dijkers 2003). The latter includes the concept of Health-related Quality of Life (HRQOL) that focuses mostly on physical and mental health, social and role achievements, and thus it is more oriented toward functional performance than is subjective QOL (Wood-Dauphinee et al. 2002).

As the HRQOL tends to address dimensions that influence subjective QOL (health status, functioning), Post et al. proposed a superordinate construct of QOL that includes both HRQOL and well-being which was operationalized from the International Classification Functioning, Disability and Health (ICF) (Post et al. 1999; WHO 2001; Post & Noreau 2005). This approach is quite useful for the rehabilitation community as it permits to integrate most of the dimensions that might be measured to cover the construct of QOL in the field of disability and rehabilitation.

Thus QOL tools are either investigator-determined enabling statistical comparisons between an experimental and control group or they are more individualized allowing the participating subject to weigh the value (importance) of any individual field in the self-assessment of their own QOL.

Measurement issues

On an operational basis, Dijkers (2003) nicely summarized that QOL measures focus on three dimensions: 1) the person’s achievements (performance) or 2) expectations, or 3) the reaction to the congruence between his/her life expectations and achievements. The HRQOL measures mainly (but not exclusively) focus on achievement as the subjective QOL measures address the reaction (or satisfaction) regarding the achievements.

The current review focuses on a number of HRQOL and subjective measures that were previously reported in the field of SCI for which psychometric testing has been published and assessed as adequate or excellent. Most of the measures are not disability-specific, meaning that they have not been specifically developed for the context of people with disability in general or specifically for individuals with SCI. As such, psychometric properties are usually stronger with general population or groups having conditions other than SCI.

Recommendations (HRQOL)

Three generic instruments addressing the concept of HRQOL are recommended despite some limitations: The short version of the World Health Organization Quality of Life Assessment (WHOQOL-BREF), the Sickness Impact Profile (SIP-68), and the MOS 36-Item Short-Form Health Survey (SF-36) or its shorter form (SF-12). The WHOQOL (BREF) is a promising instrument with a strong conceptualization but its psychometric testing in SCI is limited. Despite their wide use, SIP-68 and SF-36 should be used with caution as limitations were previously reported (Andresen & Meyers 2000; Post & Noreau 2005). For example, the SF-36 physical functioning scale has been found inappropriate in individuals with mobility impairments because several items refer to climbing or walking. Post et al. (1996) found the SIP68 valid for use in persons with SCI but had to develop a recoding procedure to deal with several questions about walking difficulties that are not applicable to persons who cannot walk. Moreover, to answer the questions ‘in the context of health’can be problematic as some persons with SCI will distinguish health from disability. People perceive themselves as healthy, defining SCI and its consequences as a disability, and not as a disease.

A utility measure (Quality of Well-being) has been reviewed but little work has been done to establish its psychometric properties in individuals with SCI. Moreover, the usefulness of the concept (utility) in the field of rehabilitation might be limited in regards of clinical purposes. Finally, the Qualiveen a SCI specific measure of urinary related QOL has been reviewed. Despite excellent psychometric properties its scope is limited.

Recommendations (subjective QOL)

Four different instruments focusing on life satisfaction have been  included in the current review: The Satisfaction with Life Scale (SWLS), the Life Satisfaction Questionnaire (LISAT-11), The Quality of Life Index (QLI) and the Quality of Life for Adults with Physical Disabilities (QOLP-PD) With some pros and cons, they addresses the life satisfaction as a whole, or with a few questions focusing on general life dimensions or with a more-in depth assessment of importance and satisfaction regarding life domains. SWLS is quite brief, mostly useful in research setting but does not bring about information that can be assessed as useful for clinical interventions. At the opposite, QLI and QOLP-PD can inform a lot on some areas of life dissatisfaction hut they might be seen as lengthy in some setting. QOLP-PD is a promising instrument with a good conceptualization but it is at an early stage of development with a few psychometric characteristics already tested. The LISAT-11 might be seen a good compromise for research and clinical purposes as it contains items (life dimensions) that are relevant to SCI. Some data has already been published in the field (Post et al. 1998; Schönherr et al. 2005; Kennedy et al. 2006) and it has previously been recommended by an expert committee on QOL (Wood-Dauphinee et al. 2002). Its main limitation remains the lack of psychometric information relative to the field of SCI.

Conclusion   

In the process of selecting tools to assess QOL, one should consider the purposefulness, usefulness and psychometric properties of measures. For example, generic and global outcomes measures might be useful for comparison across populations but might not bring about information for needs related to community interventions. At the opposite, more specific or detailed measures might be seen as too lengthy for some research or survey settings or as having complex scoring procedures. In many situations, the choice might be driven by a ‘trade-off’ between a measure that fully meets one’s needs and another one that will limit the respondent’s burden. But in all cases, a careful evaluation of the psychometric characteristics is mandatory before making the final choice.

The outcome measures reviewed under this category are listed on the right.