Validity and reliability of the Persian version of the Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39)

ABSTRACT

Background: Aphasia is one of the frequent consequences of stroke. The Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) is a commonly used instrument for measuring the quality of life in persons with aphasia following stroke.

Aims: The aim of this study was twofold: (1) to examine the reliability and validity of the Persian version of the SAQOL-39, and (2) to examine the agreement between the self- and proxy-report versions of the scale.

Methods and procedures: This cross-sectional study included 30 stroke people with aphasia in Tehran, Iran from January to April 2018. The SAQOL-39, 12-Item Short Form Health Survey (SF-12), Visual Analogue Scale (VAS), Barthel index (BI), and Modified Rankin Scale (MRS) were administered to all patients. In addition, the proxy version of SAQOL-39 was completed by the patients’caregivers. Tests of data quality included descriptive statistics of the data, ceiling and floor effects, internal consistency reliability, test-retest reliability, convergent validity, and agreement between self-report and proxy-report versions of the SAQOL-39.

Outcomes and results: The mean SAQOL-39 total scores for the self- and proxy-report versions were 3.19 (SD = 0.79) and 3.38 (SD = 0.83) respectively. There were no significant floor and ceiling effects for both self- and proxy-report versions of the SAQOL-39 and its subscales. Both self- and proxy-report versions of the SAQOL-39 demonstrated satisfactory internal consistency (Cronbach’s alpha>0.7) and test-retest reliability (intraclass correlation coefficient>0.7). Convergent validity of the SAQOL-39 was supported by its moderate to strong correlation with SF-12 (r = 0.701 for the self-report and r = 0.432 for proxy-report version). The intraclass correlation coefficient and visual inspection of a Bland-Altman plot demonstrated satisfactory agreement between self- and proxy-report versions.

Conclusions: The Persian version of the SAQOL-39 demonstrated satisfactory reliability and validity; these results support its use to measure quality of life for Persian stroke people with aphasia.

KEYWORDS:

• Stroke
• aphasia
• saqol-39
• quality of Life
• validity
• reliability

Acknowledgments

We thank all patients and caregivers who participated in this study. Authors thank specially Dr.Katerina Hilari for supporting us with her questionnaires. This study was supported by Tehran University of Medical Sciences.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.