Comparison of executive functions in stuttering and normal children

Dissertation for Master's Degree Department of Psychology and Education of Exceptional Children

Abstract:

The aim of the present study is to compare the executive functions of children with and without stuttering disorder. This research was of a causal-comparative type, the sample of this research includes 60 children aged 7-11, 30 normal children were selected from among boys' elementary schools in District 16 of Tehran city as a simple random sampling, and 30 children with stuttering were selected as accessible sampling by referring to speech therapy centers in Tehran. The tools used were Wechsler's intelligence test for children (small test of numerical memory, sub-test of image adjustment) and Andre Ray's test. In order to analyze the data, independent samples t-test was used. The analysis of the information obtained using the t-test for independent groups showed that the organization-planning ability of children with disorders is weaker than the group without disorders (p<0.05), but children with stuttering disorders in executive functions (working memory, inhibition, There was no difference between the Andrey test and the normal group. Based on this, it can be concluded that children with stuttering have problems in some executive functions. These findings can be used in diagnosis and treatment. Key words: executive functions, working memory, response inhibition, organization-planning, children with stuttering, normal children. We rarely pause and think about it. Conversations with family, friends, and acquaintances are usually so effortless and pleasant that it's hard to imagine being problematic. Most of us feel doubtful about the adequacy of our speech and language only in unusual and stressful social situations, situations such as giving a speech to a large number of listeners or in a job interview (Halahan & Kaufman, 2003; translated by Alizadeh, Saberi, Hashemi & Mohiuddin, 2019).  

Communication disorders are damage in context, sending, processing and understanding concepts or symbols of the verbal, non-verbal and pictorial system. The communication disorder may occur in the process of hearing, language, and speech, or it may range in severity from mild to severe. It may also be developmental or acquired. Individuals may exhibit one or a combination of communication disorders. It is possible to have a communication disorder alone or with another disability (Halahan and Kaufman, 2003; translated by Alizadeh, Saberi, Hashemi and Mohiuddin, 2019). Not all communication disorders are related to speech disorders. All speech disorders, like stuttering, do not hinder social interactions, and stuttering is not the most common speech disorder. Out of every hundred people, it affects only one person, and that only in childhood. But stuttering is a kind of mystery, a phenomenon that continues to be theorized about. Although stuttering has attracted the attention of speech and language pathologists for years, the causes and treatment remain largely unknown (Carly and Siegel, 1997).

One of the types of communication disorders is speech disorders. Speech disorders include voice disorders, voice production and expression, and fluency of speech, which are described as follows: a) Disorder in the expression and production of speech sounds, abnormal production of speech sounds, which is characterized by substitutions, deletions, increases or distortions and interferes with the clarity of speech. b) Voice disorder is characterized by abnormal production or lack of quality, pitch, loudness, reverberation, or delay of the voice, which is not suitable for the age and gender of the person, and c) Speech disorder is a disruption in the flow of speaking, which is characterized by the rate, rhythm, and unusual repetitions in sounds, parts, words, and paragraphs. This problem may be associated with increased tension and secondary fighting behaviors (Halahan and Kaufman, 2003; quoted by Alizadeh, Saberi, Hashemi and Mohiuddin, 2013). 

Stuttering [1] is very important among speech disorders. Stuttering is a fluid disorder of verbal expression, which is characterized by involuntary repetitions and prolongations, voiced or voiceless, during the release of small speech units, i.e. sounds, individual syllables, or word syllables. These disorders are very common and are not easily controlled. According to the statistical and diagnosis guide[2], the main characteristic of stuttering is a normal fluid disorder and a speaking tone that is inappropriate for the person's age.This disorder is associated with repetitions and lengthening of sounds and syllables, as well as other speech fluency disorders (Diagnostic and Statistical Manual of Mental Disorders, translated by Nik Joe, Ava Dis Yanes, 2013).

Some pathological theories consider physiological factors to be effective in the onset of stuttering; Such as bilateral dominance, right hemisphere dominance for speech, brain damage, neuro-muscular or neuro-psychological dysfunctions, laryngeal dysfunctions and central auditory system dysfunctions, and today, recent advances in imaging techniques have led us to pay attention to neurological or physiological factors to explain how stuttering begins or the cause of stuttering (Ambrose and Yairi[3], 2002; Bernstein Ratner[4], 2004; Guitar and Marchin Eski [5], 2001).

Barclay (1997) in his theory about attention deficit/hyperactivity disorder, pointed out the deficiency in executive functions as the main core of the breakdown of processing processes in cognitive tasks. Executive functions are the higher functions of the cognitive system, which are a set of cognitive abilities including self-management, self-initiation and inhibition, strategic planning, cognitive flexibility, and impulse control (Wyant and Willis [6], 1994). In fact, functions such as organization, decision-making, working memory, retention and conversion [7], motor control, feeling and perception of time [8], predicting the future, reconstruction [9], inner language and problem solving can be considered among the most important executive functions that help people in life and doing learning tasks and intelligence functions (Barclay, 1998).

Although executive functions have been primarily studied from a neurological perspective; But in recent years, their evolution and pathology has been the topic of interest for many experts. Evolutionary investigations of executive functions have shown that these functions: a) emerge from the very early period of development (probably the end of the first year of life); b) They grow gradually and in the years two to five very important changes occur in them and at around 12 years of age the child's performance becomes very similar to the performance of adults, c) it is possible to determine the child's failure to perform executive functions based on the complexity of tasks, d) a distinction can be made between the development of relatively "hot[10]" emotional aspects in executive functions and, on the other hand, the evolution of pure cognitive "cold[11]" aspects. (Zalazo and Muller [12], 2002; quoted by Alizadeh, 2015).

2-1- Statement of the problem

Stuttering is a permanent disorder that affects the progress and career, social, academic and emotional achievements of people with stuttering (Bladashtin and Kancher [13], 1995; quoted by Dehghan, 1385). This disorder is a combination of broken words, slurred speech, repeating the first sound of words, stuttering, and locking, but none of these alone is stuttering (Hajdeh [14], 1995; quoted by Dehghan, 2015). Usually, stuttering starts in children before the age of 8, and about 70-80% of them recover without specific formal treatments. About one percent of them remain among children after the age of 6, and if its impact on the life and daily activities of people with stuttering is not destructive, it is very obvious and striking (Yaros and Kancher [15], 1995). For many years, stuttering was thought to be due to structural disorders such as defects in the tongue or larynx. However, surgical interventions and manipulation of these organs had no effect on stuttering recovery. Until the works of Orton [16] (1927) and Travis [17] (1931) in the 20th century caused a huge change in the understanding of stuttering. They believed that stuttering is due to abnormal brain activity. The new findings of brain PET scan [18] have shown that in people with stuttering, a decrease in brain activity is observed in the areas of the speech cortex [19] and striatum [20]. Similar researches have shown that the speech areas of the left hemisphere in people with stuttering have less activity compared to the same areas of the right hemisphere. Sommer [21] (2002), showed that increased activity in the right hemisphere is possible in people with stuttering. In addition, there is a possibility of a timing problem between the left frontal cortical areas [22] and the central areas involved in speech. Therefore, according to the said material, we can point to executive functions, which is one of the discussed factors related to stuttering and seems to play a role in it. Pennington and Uzonov [23] (1996; cited by Alizadeh, 2015) consider executive functions to be a special field of abilities that include organization in space, selective inhibition, response preparation, goal orientation, planning, and flexibility.