World Health Organization (WHO) has explained “health” with emphasizing on its vast dimensions including complete physical, social and mental welfare in 1948. Base on this description, WHO explains health is not merely the lack of disease (
1). It describes quality of life (QOL) as an individual comprehension from one’s own life status, culture and system of values in where one lives and also in relation to objectives, expectations and one’s own standards (
2). In fact, QOL ideally assesses the health in physical, mental, environmental and social dimensions (
2,
3). On the other hand, American speech and hearing association (ASHA) believes that one of the speech and language pathologist’s duty is to attempt to improve QOL of individuals by reducing functional and structural deficits to one’s body, decreasing limitations in activities and communications (
4).
Thus, survey of QOL is not merely to comprehend people’s life experience but also plays an important role in treatment process in patients with speech and language disorders. Also, it is necessary to mention that most studies on QOL have been conducted on diseases, which deal with mortality or have deep impressions on the society such as cancers, diabetes, drug abuse etc. (
5-
10). However, it seems that no adequate studies have been performed on QOL in disorders and disabilities that do not lead to mortality (
11-
14).
One of the impairments on which limited QOL studies have been done is stuttering which is a kind of disorder in fluency of speech which mostly appears in childhood and its prevalence is about 1% of total population (
15-
18). Stuttering includes various forms of involuntary disruptions in speech such as repetition of syllables, prolongation, blocking of sounds, substitution and avoiding of words (
15-
17). This speech disorder is a communicational and social problem, which has negative impacts on mental and emotional health and various aspects of the adults' life (
15-
17). Therefore, in most people who stutter, daily activities are affected and in some cases stuttering causes problems in communication during speech activities including making a call or talking in front of others. And most often, communication problems will occur in a wide range of activities at school, at home or at work (
16-
20).
Most studies have shown that stuttering has a significant relation with the level of social anxiety (
20-
25), so that the levels of tiredness, mental and emotional disorders will be increased in them and on the contrary, their social activities will be decreased (
14,
26). Some studies show that one factor causes anxiety in people with stuttering is stuttering return after treatment and most of adults who stutter (AWS) have experienced this situation (
18,
27,
28). Thus, it causes them a negative attitude toward themselves (
22). Such attitude causes them to encounter problems in employment, seeking career, and keeping a job. These are social and mental items in QOL assessment (
15-
17,
29).
Klompas and Ross (2004) studied QOL in AWS and found negative impacts of stuttering on emotion, self-esteem, self-image, and work performance (
30). Yaruss et al. (2010) using Overal Assessment of the Speaker's Experience of Stuttering (OASES) questionnaire to study QOL of people with stuttering before and after treatment considered that stuttering had negative impression on QOL; however, life quality increased after treatment (
31). In Craig’s study (2009) on QOL of AWS and normal adults, results showed that stuttering had negative impression on social and emotional activities and mental health. The more frequency of stuttering, the more emotional function was affected. And frequency of stuttering (the percentage of syllables stuttered ) had no relationship with dimensions of QOL (
14). Andrade et al. (2008) reported in their study that both mild and severe stuttering had negative effects on QOL (
32), while Koedoot et al. (2011) reported that moderate to severe stuttering had negative effects on overall QOL (
33). Bramlett et al. (2006) mentioned stuttering had negative impressions on QOL and the severity of stuttering had negative impact on QOL (
34).
In Iran, Mohammadi et al. (2011) studied QOL of 59 Kurdish speaking AWS lived in Kermanshah City and 73 equal normal cases in sex, education, job and marital status by using Brief form of The World Health Organization Quality of Life (WHOQOL-BREF) questionnaire. They reported that QOL scores of people with stuttering was lower than normal peers in aspects of physical and mental health and also social interactions, but the significant difference was only observed in the domain of physical health. Also, there was a negative correlation between stuttering severity and the domains of physical, mental and environment health (
35). Mansuri et al. (2013) studied QOL in Tehran City in 25 AWS and compared the results with 25 normal pairs with equal sex, age and education level using the WHOQOL-BRIEF questionnaire. Data analysis indicated that there was a significant difference in overall score of QOL and scores of physical, mental and environmental health between AWS and AWDNS. No significant difference was seen in domain of social relationship (
36).