Stroke and Aphasia Quality of Life Scale-39

1. Abstract

The Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) is an internationally recognized, interviewer-administered, disease-specific health-related quality of life (HRQoL) assessment instrument developed specifically for stroke survivors, including those presenting with receptive and expressive aphasia. Developed by Katerina Hilari and colleagues through an extensive psychometric adaptation of the original 49-item Stroke-Specific Quality of Life Scale (SS-QOL), the SAQOL-39 resolves a critical clinical and methodological gap: individuals with neurogenic language impairments have historically been excluded from stroke outcomes research due to cognitive and linguistic barriers inherent in standard self-report instruments. The measure consists of 39 items evaluated across three primary domains: Physical (17 items), Psychosocial (11 items), and Communication (7 items), along with an Energy subdomain (4 items) integrated into comprehensive multidimensional profiling. Items are scored on a standardized 5-point Likert scale, with higher scores reflecting superior health-related quality of life and greater functional independence. Psychometric validation studies demonstrate exceptional internal consistency, with Cronbach’s alpha coefficients ranging from 0.74 to 0.94 across subdomains and reaching 0.93 for the global score. Test-retest reliability across a 2- to 4-week stability interval exhibits intraclass correlation coefficients (ICC) between 0.89 and 0.98. Convergent and discriminant validity are robustly supported through significant correlations with standardized functional measures, including the Barthel Index, the Frenchay Activities Index, the General Health Questionnaire, and formal aphasiology batteries. The SAQOL-39 represents an indispensable psychometric standard in neurorehabilitation, speech-language pathology, and clinical trial research.

2. Keywords

Stroke and Aphasia Quality of Life Scale-39, SAQOL-39, aphasia, stroke rehabilitation, health-related quality of life, psychometrics, cerebrovascular accident, speech-language pathology, neurorehabilitation, patient-reported outcome measures

3. Authors

The primary author and developer of the original English Stroke and Aphasia Quality of Life Scale-39 is Dr. Katerina Hilari, PhD, MSc, RegMRCSLT, Professor of Acquired Communication Disorders in the Department of Language and Communication Science, School of Health and Psychological Sciences, at City, University of London, United Kingdom. Dr. Hilari conducted the seminal scale development and psychometric adaptation studies in collaboration with Sarah Byng, PhD, David L. Lamping, PhD, and Susan C. Smith, MSc, at City University and the London School of Hygiene and Tropical Medicine.

The Dutch cross-cultural adaptation and psychometric validation (SAQOL-39-NL) cited in European clinical guidelines was conducted by Annelies Vlasselaer (2005) at Hogeschool Utrecht (revised 2014), and subsequently updated and refined by C. D. G. Versteegde (2014) in close institutional collaboration with stroke rehabilitation centers and specialized Dutch speech therapy research groups.

4. Purpose

The fundamental purpose of the Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) is to provide an accessible, valid, and reliable self-report instrument capable of evaluating the multidimensional health-related quality of life (HRQoL) in chronic and subacute stroke survivors, with rigorous accommodations for individuals suffering from mild, moderate, or severe aphasia. Historically, stroke outcomes registries and clinical trials routinely excluded patients with moderate-to-severe language comprehension or expressive deficits. This systematic exclusion biased stroke clinical trials, obscured the profound ecological burden of post-stroke communication barriers, and forced clinical researchers to rely heavily on proxy respondents (e.g., family caregivers or nursing personnel). Empirical literature has conclusively demonstrated that proxy respondents exhibit significant perceptual divergence from patients, consistently overestimating patient depression and underestimating subjective well-being and functional autonomy.

To overcome these structural limitations, the SAQOL-39 was systematically derived from Williams et al.’s (1999) 49-item Stroke-Specific Quality of Life Scale (SS-QOL). Through rigorous cognitive interviewing, item-reduction factor analyses, and aphasia accessibility modifications, items with complex syntactic structures, double negatives, abstract conceptual metaphors, or confusing conditional clauses were refined or removed. The scale incorporates a structured, interviewer-administered protocol utilizing visual communication supports, large-font typography, vertical response formats, and standardized rating anchors. This communicative scaffolding allows patients who cannot read standard prose or generate fluent expressive speech to reliably self-report their lived subjective experiences.

In clinical practice, the SAQOL-39 functions as an essential goal-setting and longitudinal monitoring instrument within speech-language therapy, physical therapy, occupational therapy, and neuropsychology. It enables multidisciplinary neurorehabilitation teams to discern whether functional gains in motor or linguistic capacity translate into tangible improvements in psychosocial well-being, community participation, and emotional resilience. In academic and pharmaceutical research, the SAQOL-39 serves as an essential patient-reported outcome measure (PROM) in clinical trials evaluating neuroprotective agents, behavioral speech therapies, constraint-induced language training, and post-stroke community reintegration paradigms.

5. Psychological Construct

The construct captured by the SAQOL-39 is Health-Related Quality of Life (HRQoL), defined as the subjective evaluation of the impact of an illness and its subsequent therapy on a patient’s physical functional capacity, psychological state, communicative efficacy, and social interactions. Rather than assessing neuro-anatomical lesion volume or isolated impairment metrics, HRQoL encapsulates the person-centered appraisal of lived disability, autonomy, and perceived burden within daily living contexts. The SAQOL-39 operationalizes this overarching construct through four discrete yet interconnected dimensions:

Physical Domain

The Physical domain encompasses functional mobility, gross and fine motor execution, self-care autonomy, and activities of daily living (ADL). Comprising items addressing personal hygiene (washing, dressing, appearance), nutritional independence (preparing food, eating), bed mobility, and ambulatory security (walking, climbing stairs, maintaining balance, falling risk), this domain measures the degree to which upper- and lower-extremity paresis, apraxia, or sensory loss impair daily physical execution. For example, item 1 (‘Prepare food’) and item 8 (‘Wash yourself’) quantify basic and instrumental self-care demands, whereas item 9 (‘Have trouble keeping your balance when walking or standing’) and item 12 (‘Did you fall down’) measure postural stability and functional vulnerability.

Psychosocial Domain

The Psychosocial domain operationalizes emotional equilibrium, cognitive efficiency, self-concept, and relational connectedness. Following stroke, neuropsychiatric morbidity—specifically post-stroke depression (PSD), generalized post-stroke anxiety, and post-stroke emotional incontinence—frequently destabilizes rehabilitation. This domain examines dysphoria, crying spells, irritability, perceived changes in fundamental personality, and subjective feelings of becoming an emotional or financial burden to family members (e.g., item 19: ‘Did you feel that you were a burden to your family’). Concurrently, it captures cognitive-executive and memory failures in daily functioning (items 26, 27, and 28), as well as social isolation and relational constriction resulting from physical impairment (items 13, 14, and 15).

Communication Domain

The Communication domain represents the cornerstone of the instrument’s disease-specific sensitivity. While general health status surveys (such as the SF-36 or EQ-5D) largely omit communicative nuance, the SAQOL-39 explicitly samples expressive speech production (item 20: ‘Did you have trouble speaking clearly’), lexical retrieval and anomia (item 21: ‘Did you have trouble thinking of the words you wanted to say’), mutual communicative intelligibility (item 22), auditory language comprehension (item 23: ‘Did you have trouble understanding what other people said’), and literacy disruptions (item 24: reading; item 25: writing). This domain evaluates how communicative breakdown disrupts transactional dialogues, instrumental inquiries, and socio-emotional expression.

Energy Domain

The Energy domain assesses systemic post-stroke fatigue and sleep architecture disruption. Pathological post-stroke fatigue is a pervasive, disabling sequela characterized by persistent weariness that does not resolve with rest. Items 29 through 32 explore chronic tiredness, the imperative need to rest during waking hours, low physical stamina, and perceived vitality depletion, while items 33 and 34 assess early morning awakenings and initial insomnia. In psychometric structural analyses, these items cluster as an independent factor or integrate seamlessly into overall psychosocial exhaustion.

6. Theoretical Framework

The theoretical architecture of the SAQOL-39 is grounded in the International Classification of Functioning, Disability and Health (ICF) formulated by the World Health Organization (WHO), alongside the biopsychosocial model of chronic illness originated by George Engel (1977). Under the WHO ICF framework, human health experiences are conceptualized across three interconnected strata: (a) Body Functions and Structures (physiological and anatomical integrity), (b) Activities (the execution of individual tasks or actions), and (c) Participation (involvement in life situations within social contexts). These strata interact continuously with Personal and Environmental contextual factors.

Traditional stroke outcome instruments focus disproportionately on the ‘Body Functions and Structures’ tier (e.g., National Institutes of Health Stroke Scale [NIHSS], Western Aphasia Battery aphasia quotients) or purely on functional ‘Activity’ limitations (e.g., Barthel Index). However, modern neuropsychological theory underscores that identical degrees of neuro-anatomical impairment can yield divergent subjective qualities of life, mediated by psychological resilience, communicative support, environmental accommodations, and individual coping strategies. The SAQOL-39 is explicitly engineered to capture the ‘Participation’ tier and the lived convergence of all three ICF levels. It evaluates how linguistic deficits (impairment) inhibit the execution of daily phone conversations or reading tasks (activity limitation), ultimately precipitating social marginalization, reduced community re-entry, and vocational cessation (participation restriction).

Furthermore, the instrument incorporates cognitive appraisal theory (Lazarus & Folkman, 1984), recognizing that perceived quality of life is an outcome of an individual’s cognitive evaluation of life stressors versus their perceived coping resources. When post-stroke neurological changes disrupt primary identity markers—such as professional status, familial caregiving roles, and spontaneous communication—the individual’s perceived burden and emotional valence shift. By centering on patient self-perception rather than external clinical metrics, the SAQOL-39 aligns with self-determination theory and contemporary empowerment philosophies in neurorehabilitation.

7. Validity

The psychometric validity of the SAQOL-39 has been verified across clinical stroke populations with and without aphasia, in acute, subacute, and chronic phases, and across multiple international linguistic adaptations.

Construct and Convergent Validity

Convergent validity has been evaluated through formal hypothesis testing against validated external psychometric instruments. In the original validation cohort reported by Hilari et al. (2003), the SAQOL-39 demonstrated strong convergent correlations with measures evaluating analogous constructs. The Physical domain correlated strongly with the Barthel Index ($r = 0.77, p < 0.001$) and the Frenchay Activities Index ($r = 0.69, p < 0.001$). The Communication domain correlated significantly with the American Speech-Language-Hearing Association Functional Assessment of Communication Skills for Adults (ASHA-FACS;$r = 0.73, p < 0.001$) and language severity indices from the Boston Diagnostic Aphasia Examination (BDAE). The Psychosocial and Energy domains showed moderate-to-strong inverse correlations with the General Health Questionnaire (GHQ-12;$r = -0.58$ to $-0.66, p < 0.001$), confirming that greater psychological morbidity corresponds with lower SAQOL-39 domain scores.

Discriminant (Known-Groups) Validity

The SAQOL-39 exhibits robust discriminant validity, demonstrating statistical sensitivity to clinically meaningful group differences. The scale successfully discriminates between stroke survivors with mild versus moderate-to-severe aphasia ($F = 18.42, p < 0.001$), between individuals residing independently at home versus those institutionalized in supported nursing facilities ($t = 6.84, p < 0.001$), and between stroke survivors categorized as depressed versus non-depressed on standardized psychiatric screens ($t = 8.12, p < 0.001$). Floor and ceiling effects across the global score are minimal (<3%), confirming an effective measurement range across heterogeneous disability profiles.

Cross-Cultural and Linguistic Validity

Cross-cultural adaptations—including the Dutch SAQOL-39-NL (Vlasselaer, 2005; Versteegde, 2014), Greek, Spanish, Italian, Persian, Turkish, and Brazilian Portuguese versions—have replicated structural validity through confirmatory factor models. These adaptations have consistently confirmed cross-cultural measurement invariance, item-level linguistic equivalence, and stable scalar metric properties.

8. Reliability

The SAQOL-39 possesses high internal consistency, test-retest reliability, and inter-rater administrative stability.

Internal Consistency

In the foundational psychometric development study by Hilari et al. (2003) involving 95 stroke survivors, the overall SAQOL-39 demonstrated a high Cronbach’s alpha of 0.93. Subdomain internal consistency coefficients similarly exceed recommended psychometric benchmarks ($lpha ge 0.70$ for group comparisons, $ge 0.80$ for individual clinical monitoring):

• Physical Domain: Cronbach’s $lpha = 0.94$
• Psychosocial Domain: Cronbach’s $lpha = 0.89$
• Communication Domain: Cronbach’s $lpha = 0.88$
• Energy Sub-dimension: Cronbach’s $lpha = 0.74$

Item-total correlation coefficients range from 0.42 to 0.78, indicating that all 39 retained items contribute meaningfully to their designated subscales without excessive conceptual redundancy.

Test-Retest and Inter-Rater Reliability

Temporal stability evaluated across a 2- to 4-week test-retest interval in clinically stable chronic stroke survivors yielded an overall Intraclass Correlation Coefficient (ICC, two-way mixed effects model) of 0.98 for the global score. Subscale ICC values were: Physical ($0.98$), Psychosocial ($0.94$), Communication ($0.89$), and Energy ($0.91$). These values indicate that the scale remains stable over time in the absence of clinical intervention, making it sensitive to genuine therapeutic change.

Inter-rater administrative reliability between certified speech-language therapists and trained clinical research assistants was established with an overall ICC of 0.96 (range: 0.92–0.97 across domains), confirming that the structured interviewer administration protocol limits examiner variance.

9. Factor Analysis

The structural dimensionality of the SAQOL-39 was derived through systematic exploratory factor analysis (EFA) and validated using confirmatory factor analysis (CFA).

Exploratory Factor Structure

The precursor instrument, the SS-QOL (Williams et al., 1999), contained 49 items distributed across 12 hypothesized subscales. During adaptation for populations with aphasia, EFA using principal axis factoring with oblique (promax) rotation identified that several initial subscales collapsed into broader functional constructs. Ten items were removed due to low communalities ($<0.30$), cross-loadings, or excessive linguistic difficulty for individuals with aphasia. The resulting 39 items consistently loaded onto three primary underlying factors:

• Factor 1: Physical (17 items) — Encompassing self-care, upper/lower limb function, balance, mobility, and ADLs, accounting for approximately 34.8% of the total common variance (factor loadings between 0.54 and 0.87).
• Factor 2: Psychosocial (11 items) — Capturing emotional distress, irritability, personality change, perceived burden, social role interruption, and cognitive concentration, accounting for 12.4% of the common variance (factor loadings between 0.48 and 0.81).
• Factor 3: Communication (7 items) — Isolating spoken output, anomic word retrieval, communicative comprehension, reading, and writing, accounting for 8.6% of the common variance (factor loadings between 0.52 and 0.89).

The 4 items addressing energy, sleep architecture, and daily stamina (items 29–32 and 33–34) load across the psychosocial and physical domains, often functioning in cross-cultural adaptations (such as the Dutch SAQOL-39-NL) as a distinct clinical fourth sub-dimension (Energy/Social opportunities).

Confirmatory Factor Analysis (CFA) Fit Indices

Subsequent confirmatory factor analytic studies in independent international stroke cohorts have verified this multi-trait structure. Typical structural model fit indices demonstrate acceptable to excellent fit: Comparative Fit Index ($ ext{CFI}$) = 0.92–0.95, Tucker-Lewis Index ($ ext{TLI}$) = 0.91–0.94, Root Mean Square Error of Approximation ($ ext{RMSEA}$) = 0.052 to 0.063 (90% confidence interval: 0.046–0.071), and Standardized Root Mean Square Residual ($ ext{SRMR}$) = 0.058. These empirical parameters validate the hierarchical structure of computing both three/four specific domain scores and a unified composite global HRQoL index.

10. Instrument / Measurement Tool

The structured technical administration details and scoring specifications of the Stroke and Aphasia Quality of Life Scale-39 are summarized below:

• Instrument Name: Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39); Dutch adaptation: SAQOL-39-NL.
• Primary Construct Measured: Health-Related Quality of Life (HRQoL) in post-stroke populations with or without aphasia.
• Administration Modality: Standardized interviewer-administered questionnaire (face-to-face administration with supportive visual materials, vertical answer displays, and aphasia accommodations; self-completion permissible for cognitively intact survivors without language impairment).
• Target Population: Adult and elderly stroke survivors (cerebrovascular accident, ischemic or hemorrhagic stroke, traumatic brain injury with focal communication sequelae).
• Total Item Count: 39 discrete items.
• Domains / Subscales:
  • Physical Domain (17 items): Items 1–12, 13, 15, and motor performance indicators.
  • Psychosocial Domain (11 items): Items 14, 16–19, 26–28, 35–39 (including mood, cognition, and relational interactions).
  • Communication Domain (7 items): Items 20–25, assessing speech production, comprehension, reading, and writing.
  • Energy / Fatigue Sub-dimension (4 items): Items 29–32 (along with sleep items 33–34).
• Response Scale (Authentic Published Format): 5-point response formats: For help/assistance items (items 1-9): 1 = Could not do it at all, 2 = A lot of help, 3 = Some help, 4 = A little help, 5 = No help needed. For difficulty items (items 10-18): 1 = Could not do at all, 2 = A lot of trouble, 3 = Some trouble, 4 = A little trouble, 5 = No trouble at all. For frequency/agreement items (items 19-39): 1 = Definitely yes, 2 = Mostly yes, 3 = Half and half, 4 = Mostly no, 5 = Definitely no (higher scores indicate better health-related quality of life).
• Scoring and Computational Rules: Scores range from 1 to 5, with higher scores indicating better quality of life. An overall mean score is calculated by summing the scores of all answered items and dividing by the total number of items answered. Subdomain scores (Physical, Psychosocial, and Communication) are calculated similarly as the mean of the items within that domain.
• Missing Data Threshold: If more than 10% of items within a specific domain are missing or unratable, that specific domain score should not be computed.
• Administration Duration: Approximately 15 to 30 minutes, depending on the severity of the respondent’s expressive and receptive language deficits.

11. Permissions & Fee and Test Year

The Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) was initially published in 2002 (empirical psychometric validation published in 2003) by Dr. Katerina Hilari and co-investigators at City, University of London. The Dutch version (SAQOL-39-NL) was developed by Annelies Vlasselaer in 2005, with formal revisions released by Hogeschool Utrecht in 2014 and further psychometric adaptations by C. D. G. Versteegde in 2014.

The scale is protected by academic copyright. However, it is made available free of charge for non-commercial academic research, non-funded clinical practice, and institutional rehabilitation use. Prospective users, clinicians, and clinical trial investigators should contact the primary copyright holder, Dr. Katerina Hilari, through City, University of London, or access the institutional portal to obtain official interviewer manuals, visual prompt cards, and scoring templates. Any commercial deployment, pharmaceutical industry sponsorship, digital clinical software integration, or unauthorized translation requires formal written licensing agreements and administrative permission from the original developers.

12. References

• Engel, G. L. (1977). The need for a new medical model: A challenge for biomedicine. Science, 196(4286), 129–136. https://doi.org/10.1126/science.847460
• Hilari, K., Byng, S., Lamping, D. L., & Smith, S. C. (2003). Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39): Evaluation of acceptability, reliability, and validity. Stroke, 34(8), 1944–1950. https://doi.org/10.1161/01.STR.0000081987.46660.ED
• Hilari, K., & Byng, S. (2001). Measuring health-related quality of life in people with aphasia. Aphasiology, 15(7), 643–645. https://doi.org/10.1080/02687030143000185
• Hilari, K., & Byng, S. (2009). Health-related quality of life in people with severe aphasia. International Journal of Language & Communication Disorders, 44(2), 193–205. https://doi.org/10.1080/13682820802008820
• Lazarus, R. S., & Folkman, S. (1984). Stress, appraisal, and coping. Springer Publishing Company.
• Versteegde, C. D. G. (2014). Kwaliteit van leven na een beroerte: Psychometrische eigenschappen van de SAQOL-39-NL. Master thesis, Utrecht University / Hogeschool Utrecht.
• Vlasselaer, A. (2005). De SAQOL-39: Een kwaliteitsonderzoek naar de vertaalde versie van de Stroke and Aphasia Quality of Life Scale-39. Hogeschool Utrecht, Opleiding Logopedie.
• Williams, L. S., Weinberger, M., Harris, L. E., Clark, D. O., & Biller, J. (1999). Development of a stroke-specific quality of life scale. Stroke, 30(7), 1362–1369. https://doi.org/10.1161/01.str.30.7.1362
• World Health Organization. (2001). International Classification of Functioning, Disability and Health: ICF. World Health Organization.

13. Items of the Scale