Australian normative data for the Overall Assessment of the Speaker's Experience of Stuttering

Abstract

People who stutter often report negative impacts on their wellbeing as a result of their chronic fluency disorder. The need for a comprehensive assessment of the wellbeing and experience of stuttering should be a prime consideration when measuring treatment outcomes. One such measure designed to evaluate wellbeing and aspects of the individual's experience of his or her stuttering is the Overall Assessment of the Speaker's Experience of Stuttering (OASES). Normative data for the OASES Adult version (OASES-A; and hereafter referred to simply as the OASES) has begun to be collected over the past 10 years, though none are available for an Australian population. This paper presents Australian normative data for the OASES for 200 adult males and females who stutter, aged between 18 and 85 years. Additionally, the influence of age, sex, and frequency of stuttering on the Australian OASES scores are also presented. No significant relationships between OASES scores were found for sex and age, which is in keeping with the USA original dataset. However, those participants who had more severe stuttering were more likely to have higher negative impacts for ‘General Information’, Communication in Daily Situations,’ and for the overall OASES score. Implications for further research are discussed.

Educational objectives: The reader will be able to: (i) describe the purpose of the Overall Experience of the Speaker's Experience of Stuttering for Adults (OASES), (ii) evaluate the relevance of the OASES to treatment planning and the evaluation of stuttering treatment outcomes in the adult population, and (iii) compare Australian normative dataset with the USA and Dutch normative datasets for the OASES.

Introduction

The ability to communicate effectively is an integral part of an individual's life (Kagan et al., 2008, Yaruss, 2004). Consequently, it is possible that a communication disorder could result in psychosocial problems that may negatively impact quality of life (Costa and Kroll, 2000, Craig et al., 2009, Shapiro, 1999, Treon et al., 2006). Stuttering is a fluency disorder that can have negative psychological, emotional, and social repercussions (Bothe et al., 2006, Craig et al., 2003, Messenger et al., 2004, Prins and Ingham, 2009, Yaruss et al., 2002a, Yaruss et al., 2002b). Typical problems include elevated levels of social anxiety (Blumgart et al., 2010a, Iverach et al., 2009), a reduced capacity to function in the work environment (Klein and Hood, 2004, Klompas and Ross, 2004), and physical and emotional fatigue from having to constantly monitor speech in an effort to control stuttering. These aspects contribute to the individual's perception of his or her quality of life (QOL; Craig et al., 2009).

The notion underlying QOL investigation is that physical improvement resulting from treatment is no longer considered the only treatment goal. Rather, the individual's perceptions of their personal wellbeing, ability to participate freely in daily activities and levels of self-confidence, are considered equally important to any physical improvement post-treatment (Garratt, 2009, McCabe and Priebe, 2002, Pope and Tarlov, 1991, Yaruss, 2010). While it has been noted that QOL is an important measure when estimating the impact of communication disorders and the efficacy of treatment (Klompas and Ross, 2004, Yaruss and Quesal, 2006), unfortunately QOL research in stuttering is only recently being conducted (Blumgart et al., 2010b, Bramlett et al., 2006, Craig et al., 2009, Franic and Bothe, 2008, Klompas and Ross, 2004, Yaruss and Quesal, 2006). Although generic or general measures of QOL have been widely used to determine QOL impact, there is a need for stuttering specific QOL measures (Franic and Bothe, 2008, Yaruss and Quesal, 2006).

The Overall Assessment of the Speaker's Experience of Stuttering (OASES; Yaruss and Quesal, 2006, Yaruss and Quesal, 2010) is the first published psychometric measure designed to examine functional communication difficulties and QOL from the perspective of individuals who stutter (Yaruss & Quesal, 2006). The measure consists of 100 items in four separate parts or sections: ‘General Information,’ ‘Reactions to Stuttering,’ ‘Communication in Daily Situations’ and ‘Quality of Life’. A detailed description of the development, nature, and ongoing use of the OASES in research has been described elsewhere (Yaruss, 2001, Yaruss and Quesal, 2004, Yaruss and Quesal, 2006). Items are rated on a Likert scale, from 1 to 5 (Likert, 1932). Higher scores for the OASES indicate higher levels of impact. All response choices require an estimate of impact. The scores provide an indication of the extent to which stuttering impacts aspects of the speaker's life. This scoring method does not allow for a zero impact rating. This could be seen as a design shortcoming as it assumes that all people who stutter will experience some impact. The OASES provides an impact rating and impact score, calculated out of 100.

The design of the OASES was based on the World Health Organization's original International Classification of Impairments, Disabilities, and Handicaps (ICIDH; WHO, 1980, WHO, 1993) and current ICF International Classification of Functioning, Disability and Health frameworks (ICF: WHO, 2001). It was developed using a varied sample of individuals who stutter aged from 7 years to almost 80 years. The OASES is a comprehensive, pen and paper, self-report measure. It was designed as a descriptive outcome measure to supplement other clinician-administered measures of stuttering in order to provide a more complete account of the speaker's experience of stuttering. The contribution of the OASES lies in serving as a monitoring tool in the evaluation of stuttering treatment outcomes.

Empirical data have provided preliminary support for the reliability and validity of the OASES, based on samples collected in the United States (Yaruss & Quesal, 2006). Analyses have revealed a high degree of test–retest reliability for impact scores, with mean differences ranging from 2.1 to 3 (standard error ranged from 1.9 to 2.6). Comparison between impact ratings revealed strong reliability between initial and follow-up administration of the OASES. The authors concluded that the OASES demonstrates acceptable reliability and validity sufficient to support its use in the evaluation of treatment outcomes.

Available normative data for the OASES over the past decade has come exclusively from a North American cohort of 173 adults who stutter, aged 18–78 years. This cohort was drawn primarily from the National Stuttering Association (NSA) database and several clinics throughout the USA. Owing to the likelihood that different English speaking populations as well as culturally diverse populations may have different attitudes towards stuttering (ASHA, 1986, Bebout and Arthur, 1992, Finn and Cordes, 1997, Holland and Forbes, 1986, Leith, 1988), the authors have called for further collaborative normative data worldwide (Yaruss, 2010). Normative data for a Dutch cohort of 138 adults who stutter were investigated (Koedoot, Versteegh, & Yaruss, 2011). This paper reports on the translation process of the OASES from English into Dutch and evaluates the psychometric performance of a Dutch version of the OASES (n = 138). Clearly, additional normative data are required for the OASES, and to date the OASES has not been standardized on an Australian population. The current investigation was designed to provide an Australian normative dataset for the OASES. Specific research aims for this study are: (i) to determine the distribution of the Australian normative dataset for the OASES, (ii) to ascertain whether the USA and Australian OASES datasets are comparable, and (iii) to reveal if a relationship exists between sex, age, and percent syllables stuttered with the OASES.