Measuring quality of life in Dutch people with aphasia: development and psychometric evaluation of the SAQOL-39NL

Abstract

ABSTRACTBackground: Cross-cultural adaptation of health-related quality of life (HRQL) scales is useful as it allows comparisons of therapy outcomes across different countries to be drawn.Aims: To adapt the English Stroke and Aphasia Quality of Life—39 item generic stroke scale (SAQOL-39g) into Dutch. To investigate the psychometric properties (acceptability, internal consistency, test–retest reliability and construct validity) of the Dutch version (SAQOL-39NL).Methods & Procedures: Established guidelines for cross-cultural adaptation of self-report measures were followed. Individuals with chronic aphasia were recruited from six centres in The Netherlands. Participants completed the SAQOL-39NL and a visual analogue scale on HRQL in an interview format with an aphasia specialist speech and language therapist.Outcomes & Results: The cross cultural adaptation resulted in a consensus version of the SAQOL-39NL, which participants (n = 13) felt was informative and of value in assessing the impact of stroke on their lives. The SAQOL-39NL was acceptable (no missing data; no floor or ceiling effects) to people with chronic aphasia (n = 47). Internal consistency (Cronbach’s alpha = 0.89 for scale; 0.84–0.91 for domains) and test–retest reliability were excellent (ICC = 0.90 for scale, 0.70–0.93 for domains). Internal validity (moderate intercorrelations between domains) and convergent validity (r = 0.45) were good.Conclusions: The SAQOL-39NL is a psychometrically sound measure of HRQL for Dutch speaking people with aphasia. As is common with new measures, its psychometric properties need to be evaluated further; and its appropriateness as a clinical outcome measure needs to be determined. Yet, the SAQOL-39NL is a promising new measure for use in clinical practice, audit and research.