The present work was performed in The Catholic University of Portugal, Lisboa, Portugal. (1) Institute of Health Sciences, The Catholic University of Portugal, Lisboa, Portugal.
(2)Department of Clinical Neurosciences (UNIC), Lisbon Faculty of Medicine, Hospital de Santa Maria, Portugal. Conflict of interests: No
Authors’ contribution: ITR main researcher, conception and design, provision of study material, collection and assembly of data, data analysis and interpretation, manuscript writing; MGL: supervisor,data analysis and interpretation, manuscript writing, final approval of manuscript.
Correspondence adress: Inês Tello Milheiras Rodrigues. Alameda António Sérgio, 6, 7ºC, 1750-033 Lisboa, Portugal. E-mail: inestellorodrigues@gmail.com Received: 5/4/2013; Accepted: 10/7/2013
Portuguese translation and psychometric properties of
the portuguese version of the Stroke and Aphasia Quality
of Life Scale-39 (SAQOL-39)
Tradução portuguesa e análise de aspetos psicométricos da escala
“Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39)”
Inês Tello Rodrigues1, Maria Gabriela Leal2
ABSTRACT
Purpose: The main goals of this study were to translate and assess the psychometric properties and reliability of the Portuguese version of the SAQOL-39 in a group of chronic aphasia patients. Methods: We used the translation and retroversion method from the original scale to ensure conceptual uniformity. The instrument was administered to 33 aphasia patients. Internal consistency was assessed with Cronbach´s alpha and test-retest reliability was explored (n=12). We also used Pearson´s and Spearman´s correlation coefficients to determine the correlations be-tween the SAQOL-39 domains and other social and clinical variables. Results: The translation process from the original scale was completed without difficulties. Cronbach´s alpha for SAQOL-39 was 0.953 and for each subdomain ranged from 0.882 (Psychosocial) to 0.971 (Physical). The test-retest reliability for total SAQOL-39 was 0.927 and for each subdomain ranged from 0.80 to 0.97. The global scores show neither floor nor ceiling effect and there were no missing data. There was no significant association between the total SAQOL-39 score and either age or years of education. We found a significant correlation between the Communication domain mean score and the Aphasia Quotient ou-tcome (r=0.62, p=0.000). Conclusion: Despite the small sample size, the Portuguese version of the SAQOL-39 showed good internal consistency and test-retest reliability. This study also showed preliminary evidence for good acceptability, feasibility and reliability of this adaptation. The importance of communication ability in perceiving the quality of life in patients with aphasia has also been highlighted.
Keywords: Aphasia; Stroke; Evaluation; Quality of Life; Speech, Lan-guage and Hearing Sciences
RESUMO
Objetivo: Efetuar a tradução e analisar os aspetos psicométricos da adaptação portuguesa da Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39). Esta escala possui 4 domínios (Físico, Psicossocial, Co-municação e Energia) e foi criada especificamente para pacientes com afasia. Métodos: Foi efetuada a tradução e retroversão a partir da escala original. A versão portuguesa foi aplicada 33 pacientes com afasia. A avaliação da consistência interna foi obtida através do Alfa de Cronbach e foi efetuado um teste-reteste em 12 pacientes. Foram igualmente utilizados os coeficientes de Pearson e Spearman para correlacionar os subdomínios da prova e os diferentes dados clínicos e biográficos. Resultados: A versão portuguesa da SAQOL-39 manteve o mesmo formato em tamanho e conteúdo semântico que a original. O alfa de Cronbach da SAQOL-39 foi 0,953 e variou entre 0,882 (domínio psicossocial) e 0,971 (domínio Físico). Os resultados do teste-reteste referentes à SAQOL-39 foram de 0,927 e variaram entre 0,80 a 0,97 entre os diferentes subdomínios. Não se verificou efeito de teto e não existiram dados omissos. Não foram encon-tradas diferenças significativas entre o total da SAQOL-39 e a idade ou a escolaridade. No entanto, evidenciou-se uma correlação significativa entre o Quociente de Afasia e a o subdomínio Comunicação (r=0,62, p=0,000). Conclusão: Apesar do tamanho reduzido da amostra a versão portuguesa da SAQOL-39 apresentou bons valores psicométricos. Este estudo mostra igualmente dados preliminares de uma boa aceitabilidade e fiabilidade desta adaptação e realça a importância da avaliação da qualidade de vida em pacientes com alterações graves de linguagem.
INTRODUCTION
Quality measures are essential to any health care service. One crucial goal of stroke intervention is to improve the health--related quality of life (HRQOL) of stroke patients, ensuring that they are able to accomplish their roles and purpose in life after the occurrence. Although all of the existing instruments are sufficient to describe HRQOL after stroke(1), the adaption
of HRQOL assessments to specific populations is imperative to provide a more accurate measurement and to assess particular aspects that could be disregarded in other general health-related questionnaires are measured. In this context, unfortunately, the majority of quality of life instruments are not appropriate for aphasia patients. People with aphasia experience verbal and comprehension problems, such that providing answers to standardized questions is difficult or might even be impossible. The Stroke and Aphasia Quality of Life Scale – 39 (SAQOL-39) was created in order to evaluate quality of life in this specific population(2,3).
Measuring quality of life in aphasia patients is not a sim-ple task, mainly due to the existence of a very different range of language impairments, the variation between each type of aphasia and the number of possible co-morbidity deficits. In fact, many studies of HRQOL after stroke simply exclude patients with aphasia because of their linguistic impairment. Furthermore, aphasia has been found to impact social participa-tion(4), friendships(5) and is often associated with depression(6).
All these aspects introduce major changes and daily challenges to establishing and maintaining a satisfying quality of life. In addition, some authors(7) confirm, with a systematic review, that
social participation of people with aphasia has not been studied systematically. Thus, it is important to use specific instruments to measure the quality of life of patients with aphasia but also to include these patients in larger samples of stroke related quality of life studies.
The primary goal of this study was to report the Portuguese translation and subsequent translate and assess the psychome-tric properties and reliability of the Portuguese version of the SAQOL. The secondary goal of this study was to analyze a number of socio-demographic, clinical and functional factors that influenced the different domains of SAQOL-39 among our aphasia participants.
METHODS
SAQOL-39
The SAQOL-39 consists of an interviewer-administered self-reporting instrument that results from a 53-item modified scale(2). This scale modification was made with the intention of
making the instrument more accessible to aphasia and stroke patients. The original authors(3) provided good evidence for
acceptability, reliability and validity of the SAQOL-39 in people
with chronic aphasia. It has also been tested in a generic stroke population(8) with good psychometric results. This instrument
has been translated into several languages, particularly to Spanish(9), Italian(10), Greek(11) and Slovene(12) .
It is a scale that is appropriate to use with a large range of aphasia patients as it can be used with moderate or mild com-prehension impaired patients with any kind of output severity(2).
This questionnaire comprises 39 items distributed among four subdomains, namely Physical (17 items), Psychosocial (11 items), Communication (7 items) and Energy (4 items). The time reference used in the interview for all items is “the past week”.
This scale has two response formats based on the five point Likert scale, the first format corresponding to 1 = Could not do it at all and 5 = No trouble at all, and the second format
corresponding to 1 = Definitely yes to 5 = Definitely no. The
total score is calculated by counting all item values and dividing them by the number of items. Higher scores indicate better perception of life quality. This method facilitates interpretation and inter-individual comparisons.
According to the original authors of the scale(2), during
the assessment the clinicians can use several strategies to improve the comprehension or expression of the person with aphasia. For instance, patients can respond verbally, with gestures or by pointing to a graphic scale. In the current study we used a color scale and a smile scale to assist or confirm the patient´s answers.
Translation procedures
Participants
The study sample comprised 33 patients with long-term aphasia. Participants were recruited from four speech and language therapy centers/service providers from different geographic regions. Subjects completed the SAQOL-39 in an interview format with a speech and language therapist who had expertise in assessment and treatment of aphasia patients. The scoring consistency across examiners was ensured with examiner’s training sessions. Inclusion criteria were as follows: aphasia resulting from a single stroke of at least one year post--onset, absence of psychiatric or other neurological diseases prior to stroke, living at home before the stroke, and being right handed. The exclusion criteria were: cognitive decline, major depression, severe concomitant disease or being illiterate. The native language of all participants was Portuguese.
The study was approved by an Ethical Committee and has been conducted in accordance with APA ethical guidelines and in agreement with the recommendations of the Declaration of Helsinki (1964). The clinicians provided written and verbal information about the study to the patient. All study participants provided informed, written consent.
Assessment(s)
Socio-demographic and clinical data were collected from previous interviews and from clinical reports. A speech and lan-guage therapist made a previous lanlan-guage assessment of each participant, ensuring that the original instructions, items and scoring materials were clearly expressed.We used a Portuguese adaptation of the Multilingual Aphasia Examination named Bateria de Avaliação da Afasia de Lisboa (BAAL)(13-15). The
BAAL proved to have similar psychometric properties com-pared to the Western Aphasia Battery(16). None of the patients
could score less than 20% or more than 85% in the Aphasia Quotient (AQ) obtained from the sum of scores from the four major language tasks: verbal fluency, naming, word repetition and oral comprehension. The AQ indicates overall severity of language impairment.
Evaluation of depression was performed using the Portuguese version of the Center for Epidemiologic Studies Depression Scale (CES-D)(17). Other evaluations included
aver-age results from Raven´s Colored Progressive Matrices(18) and
the Barthel Index(19) to measure performance in basic activities
of daily living.
Statistical analyses
Internal consistency of the Portuguese version of the SAQOL-39 was evaluated using a Cronbach´s alpha threshold of 0.70(20). Reliability is an assessment of reproducibility of
the scale(21). Test-retest reliabilitywas evaluated by assessing
Pearson´s correlation coefficients using a threshold of 0.70,
according to the Scientific Advisory Committee of the Medical Outcomes Trust(21). Acceptability was assessed in terms of a
floor/ceiling effect of less than 20%. Feasibility was determined by the amount of time required to complete the questionnaire and the percentage of missing values less than 10%. We also used Pearson´s and Spearman´s correlation coefficients to determine the correlations between the SAQOL-39 domains and other social and clinical variables. The Statistical Package for the Social Sciences (SPSS – version 18.0) was used for all statistical analyses. A significance level of p≤0.05 was used.
RESULTS
Characterization of the sample
The socio-demographic and clinical characteristics of the participants are summarized in Table 1. There were no signi-ficant differences in terms of gender so the two groups could be validly compared.
Reliability and acceptability
Cronbach´s alpha was calculated for all item sets to exami-ne internal consistency (Table 2). Cronbach´s alpha for total SAQOL-39 score, demonstrated very good internal consistency. Cronbach´s alpha for each of the subdomains extended from 0.882 (Psychosocial) to 0.971 (Physical). Test-retest data
Table 1. Socio-demographic and clinical characteristics of participants
Variable n (%)
Gender Female Male
16 (48.5) 17 (51.5)
Age Mean (SD) Range
67.5± 10.7 49 - 86
Time post-onset (moths) Mean (SD)
Range
32 ± 29.9 11 - 120
Stroke type Ischemic Haemorrhagic
31 (93.9) 2 (6.1)
Aphasia Type Global Broca Anomic Wernicke Conduction Transcortical motor Transcortical sensorial
5 (15.2) 9 (27.3) 10 (30.3)
2 (6.1) 5 (15.2)
1 (3) 1 (3)
Aphasia quotient Mean (SD) Range
57.3 ± 16.2 20.1 - 85
were collected from 12 subjects with socio-demographic and clinical characteristics representative of the overall sample. The test-retest reliability score was also very high for the total SAQOL-39 and for the subdomains. The global score showed no floor or ceiling effects.
Feasibility
The scale application lasted between 12 and 50 minutes, although the original authors(8) predicted that the interview
could be completed over more than one session (for example, due to fatigue). All participants were able to complete the ques-tionnaire in the presence of a speech and language therapist, and there were no missing data.
Results from SAQOL-39
The mean total SAQOL-39 score ranged from 2.45 for the Communication domain to 3.65 for the Energy subscale. The details can be found in Table 3. No differences were observed between men and women. Other results include a lack of signi-ficant association between total SAQOL-39 score and years of education (r=0.40, p=0.18) or age (r=0.77, p=0.670) (Table 3).
Pearson’s product-moment correlation coefficient was computed to assess the relationship between the AQ and the SAQOL-39 total score. We determine a statistical significant correlation between these two variables. More specifically, when we analyzed the correlation in each subdomain, we found a significant correlation between the Communication domain mean score and the AQ outcome but there were no other sig-nificant correlations between the AQ and the other SAQOL-39 domains. The main results, regarding the Person´s correlations, are summarized in Table 4.
Spearman’s correlation coefficient was used to determine the correlation between SAQOL-39 and time after onset. Although this correlation was significant (r=0.45, p=0.007), a more detailed analysis of each domain showed that only the Physical domain demonstrated significance (r=0.46, p=0.007), diverging from all other domains, in particular Communication (r=0.14, p=0.416), Psychosocial (r=0.36, p=0.366) and Energy (r=0.53, p=0.768).
DISCUSSION
We report results from the Portuguese translation and some psychometric aspects of SAQOL-39. Internal consis-tency of the Portuguese version of SAQOL-39 was supported by strong values that were similar to those of the original(3),
Spanish(9), Italian(10) and Greek(11) versions. The reliability of
the present adaptation was also high. The mean total score of the SAQOL-39 and its subdomains were also similar to previous studies.
The feasibility of using the Portuguese SAQOL-39 in people with aphasia is supported by the fact that all participants were able to complete the questionnaire in the presence of a speech and language therapist and there were no missing data.
The most affected SAQOL-39 domain was Communication, as expected in a sample of subjects with aphasia. This result is in accordance to former investigations namely to a preli-minary Portuguese version of SAQOL-39(22). Furthermore,
the Communication domain demonstrates the only significant correlation with aphasia quotient, since it´s directly related to language deficits. In this line, we found no other signifi-cant correlations between the AQ and the other SAQOL-39 domains and these results are consistent with those reported recently(23).
As with other studies(24,25), there was no significant
association between perceived quality of life and years of education. Additionally, there was no correlation between the Communication, Psychosocial and Energy domain scores and time after onset. This could be interpreted as consistent with the observation that people tend to increase in their acceptance to impairment and use more coping strategies along time after stroke. This finding is corroborate by some investigations(26,27).
As other authors that used this scale(28), we consider the use Table 4. Person´s correlations between AQ-BAAL values and SAQOL-39 domains
r p-value
SAQOL-39 Communication Physical Psychosocial Energy
0.46 0.62 0.31 0.57 0.48
0.006 0.000 0.433 0.063 0.081
Person´s correlations (r) (p≤0.05)
Table 3. Mean scores of SAQOL-39 and its four subdomains
Mean (SD) Range
SAQOL-39 Physical Communication Psychosocial Energy
3.17 SD 0.75 3.31 SD 1.05 2.45 SD 0.82 3.21 SD 0.81 3.65 SD 1.07
1.82 - 4.71 1.59 - 4.88 1.05 - 5 1.63 - 5 1.50 - 5
Note: SD = standard deviation
Table 2. Cronbach´s alpha for total SAQOL-39 and its four subdomains
Cronbach´s α
SAQOL-39 Physical Communication Psychosocial Energy
0.953 0.971 0.882 0.863 0.833
Cronbach´s alpha:
of specific instruments to assess quality of life in people with aphasia, such as SAQOL-39, as crucial for targeting appropriate and effective speech and language interventions in a population that is often excluded from clinical trials.
CONCLUSION
Overall, this first study demonstrates good acceptability, feasibility and reliability of the Portuguese translation of the SAQOL-39. Importantly, the study provides preliminary evi-dence that the Portuguese version of the SAQOL-39 represents a good instrument to assess quality of life in patients with long-term aphasia. The psychometric results are promising, although the Portuguese version of the SAQOL-39 requires further psychometric evaluation in a larger sample, with a focus on the assessment of its dimensionality and factor invariance. Its implications in the clinical field could be very interesting for people with aphasia. Subsequently, SAQOL-39 could provide a new instrument to explore functional outcomes during speech and language therapy and after clinical discharge in chronic phase as a follow-up-study. It´s also a promising measure to identify better predictors of quality of life and to evaluate the effectiveness of health care in general and of language therapy interventions in particular. These predictors could help speech and language therapists to be more precise when choosing therapy goals, aiming for the development of more accurate coping strategies and aiding the patients’ adjustments to life with aphasia.
ACKNOWLEDGEMENTS
We would like to thank Dr. Katerina Hilari for the permis-sion to translate and study SAQOL-39 in Portuguese popu-lation. We would also like to express our gratefulness to Dr. Clara Loureiro and Dr. Raquel Gil Gouveia for their valuable contribution to the translation of the SAQOL-39 as well as to our colleagues for helping collecting the clinical data. For copies of the Portuguese translation of the SAQOL-39 please contact: maria.leal@hsm.min-saude.pt
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