Stroke Specific Quality of Life Scale (SS-QOL)

Original Editor - Kyrstal_Tan

Top Contributors - KRYSTAL TAN, Alexandra Stead and Vidya Acharya  

Introduction

The Stroke Specific Quality of Life Scale (SS-QOL) is a stroke-specific, patient-reported outcome measure designed to assess health-related quality of life (HRQOL) in stroke survivors. It was developed because generic HRQOL instruments were considered insufficiently sensitive to the specific problems experienced by people after stroke. The scale comprises 49 items across 12 domains: energy, family roles, language, mobility, mood, personality, self-care, social roles, thinking, upper extremity function, vision, and work/productivity. Items are rated on a 5-point Likert scale, and domain scores are calculated as an unweighted average of item scores; an overall total score is also calculated as an unweighted average of domain scores, with higher scores indicating better HRQOL.

A principal component analysis of the 12 SS-QOL domains identified two broader components. Ten of the twelve domains loaded onto these components: a Physical Health (PH) component, comprising self-care, mobility, work/productivity, and upper extremity function, and a Cognitive-Social-Mental (CSM) component, comprising thinking, personality, family roles, mood, social roles, and energy. The remaining two domains, vision and language, did not correlate strongly with either component and were excluded from the component structure. Reporting PH and CSM component scores alongside the total score can highlight specific rehabilitation needs that may otherwise be masked in the overall total.

SS-QOL is the most frequently used stroke-specific HRQOL patient-reported outcome measure (PROM) in the research literature, used more often than the Stroke Impact Scale (SIS) or the Stroke and Aphasia Quality of Life scale (SAQOL).

Intended Population

The SS-QOL was developed for, and has since been validated across, a range of stroke and stroke-related populations:

• Adults who have had an ischaemic or haemorrhagic stroke
• Has also been validated in people with aneurysmal subarachnoid haemorrhage
• Has been used and validated in stroke survivors up to and beyond four years post-stroke, including in community-dwelling cohorts
• Has been cross-culturally adapted and validated in multiple languages, including Danish, Norwegian, German, Brazilian Portuguese, Chinese, and Yoruba, for use in diverse stroke populations
• A modified 39-item version (SAQOL-39) exists for stroke survivors with Aphasia

Method of Use

The SS-QOL takes approximately 10–15 minutes to complete and can be administered by interview (in person or by telephone) or as a self-report questionnaire. No specialised training is required. Patients respond to each item with reference to how they have felt over the past week.

Scoring

The SS-QOL uses a straightforward unweighted scoring system: individual item scores are averaged within each domain, and domain scores are then averaged to produce a total score, meaning no domain is weighted more heavily than another. Scores range from 1 to 5 at both the domain and total level. In summary:

• Each of the 49 items is rated on a 5-point Likert scale (1 = worst function/most difficulty, 5 = best function/no difficulty)
• Domain scores are the unweighted average of the items within that domain
• The total SS-QOL score is the unweighted average of the 12 domain scores
• Higher scores indicate better HRQOL
• Optionally, domain scores can be grouped into the Physical Health (PH) and Cognitive-Social-Mental (CSM) component scores described above, which may better reflect specific rehabilitation needs than the total score alone

Evidence

Reliability

The original development study reported excellent internal consistency across all 12 domains (Cronbach's α ≥0.73 for every domain). Cross-cultural adaptations have reported similarly strong internal consistency: the Norwegian version reported Cronbach's α ranging 0.79–0.93 and the Danish version 0.81–0.94 across domains. Test-retest reliability has also been reported as good to excellent, including when administered by telephone, with Spearman's rho ranging 0.67–0.94 (Norwegian version) and 0.65–0.99 (Danish version).

Validity

Construct validity was established in the original development study by comparing SS-QOL domain scores with similar domains from established generic and stroke-specific measures, including the Short Form-36 Health Survey (SF-36), a widely used generic measure of health-related quality of life, the National Institutes of Health Stroke Scale (NIHSS), a clinician-rated measure of neurological impairment and stroke severity, and the Barthel Index, with most domains moderately correlated with comparable domains of these measures (r² range 0.3–0.5). Validity has since been confirmed across multiple populations and cultural adaptations, including patients with aneurysmal subarachnoid haemorrhage.

A structured content review comparing the SS-QOL, SIS, and SAQOL against the International Classification of Functioning, Disability and Health (ICF) Stroke Core Sets found that 80% of SS-QOL items could be linked to an ICF code, and more than 75% of the measure's content was represented in the Comprehensive Stroke Core Set, supporting its content validity. However, the SS-QOL had the highest proportion of "non-codable" items among the three measures (20%, mainly items on feelings or general quality of life that ICF does not capture), and, like the SIS and SAQOL, contained few items relevant to work/employment, community life, relationships, or use of technology, despite these being recognised as important post-stroke concerns.

A four-year follow-up study examining construct validity against neuropsychological testing found that the Cognitive-Social-Mental (CSM) component of the SS-QOL was significantly associated with reaction time (ρ = .47), verbal memory (ρ = .42), and fine motor coordination (ρ = .39), while the Physical Health (PH) component was associated only with fine motor coordination (ρ = .49); no significant associations were found for language, visuospatial ability, working memory, or executive functions. This supports the distinction between the PH and CSM components and indicates that cognitive and psychosocial functioning, not physical recovery alone, contributes meaningfully to long-term HRQOL after stroke.

Responsiveness

In the original development study, most SS-QOL domains were responsive to change between 1 and 3 months post-stroke, with standardised effect sizes >0.4. The Danish version has also demonstrated adequate responsiveness and sensitivity to change. A later clinometric study established the minimal detectable change (MDC95) and clinically important differences (CIDs) for the physical-function subscales in stroke rehabilitation: MDC95 values of 5.9 (mobility), 4.0 (self-care), and 5.3 (upper extremity function) points, with minimal CID ranges of 1.5–2.4, 1.2–1.9, and 1.2–1.8 points respectively. This means a patient's change score must reach these MDC thresholds to be confident the change is real and not measurement error, and must reach the CID range to be considered clinically meaningful.

Additional Considerations

A shorter, 12-item version of the SS-QOL has also been developed and validated for more time-efficient use in stroke research while retaining acceptable validity and reliability. Family/proxy assessments of the SS-QOL have shown only moderate agreement with patient self-report, particularly for domains involving mood and cognition, so proxy versions should be interpreted with caution.

A comparison of subacute rehabilitation service organisation across two Scandinavian regions found that individual patient factors, such as older age, pre-stroke dependency, greater initial stroke severity, anxiety, and depression, were more strongly associated with SS-QOL scores than regional differences in how rehabilitation services were organised, and that both cohorts reported more difficulty in cognitive, social, and emotional domains than in physical domains. This suggests that clinicians should prioritise addressing cognitive, emotional, and social functioning in long-term stroke rehabilitation planning, not only physical recovery.

Limitations

The SS-QOL relies on patient self-report, which may be difficult to complete for stroke survivors with significant aphasia, cognitive impairment, or reduced insight; a modified version (SAQOL-39) is available for this reason. Family or proxy versions show only moderate agreement with patient self-report, particularly for domains involving mood and cognition, so they should be interpreted with caution rather than treated as interchangeable with patient self-report. The scale also has a relatively high respondent burden, with 49 items across 12 domains taking up to 15 minutes to complete, which may limit its use in time-constrained clinical settings or with fatigued patients. Cross-cultural adaptations show generally strong psychometric properties, but findings from one language or healthcare setting should not automatically be assumed to generalise to others without local validation.

Summary

The SS-QOL is a 49-item, stroke-specific, patient-reported outcome measure covering 12 domains of health-related quality of life, including physical function, cognition, mood, and social participation. It was developed specifically because generic quality-of-life tools were considered insufficiently sensitive to the problems stroke survivors experience. Domain scores can be interpreted individually, summed into a total score, or grouped into Physical Health and Cognitive-Social-Mental component scores to highlight where a patient's rehabilitation needs are concentrated. The scale has demonstrated strong reliability and validity across multiple stroke populations and cultural adaptations, making it a useful tool for both clinical monitoring of rehabilitation progress and stroke research. When using or interpreting the SS-QOL, clinicians should be mindful of its reliance on self-report, the moderate agreement of proxy versions, and the value of considering the PH and CSM components separately rather than relying on the total score alone.

Resources

Original SS-QOL scale and scoring instructions (Strokengine)