Unravelling the mysteries of stuttering
Reprinted from *Canterbury – Volume 5, No 1, Winter 2008
Jeanette Colman – 27/06/08
British Prime Minister Winston Churchill, scientist Isaac Newton, author Lewis Carroll and movie star Marilyn Monroe all shared one trait – they stuttered.
Considered one of the best orators in parliament, Churchill discreetly hummed to get his vocal fold vibrating ahead of giving a speech. Newton once asked that the windows of Parliament be closed so the public would not hear his stuttering. Carroll had hoped to become a priest but was not allowed to because of his stuttering.
Monroe was taught by a speech coach to use exaggerated mouth movements and a breathy affected speaking style to control her stuttering.
Reports of stuttering date back to the Roman Emperor Claudius (10 BC to 54 AD), as well as King Louis II of France (843-879). Despite the well documented occurrence of stuttering, the precise cause of the disorder remains unknown.
Stuttering – described as unusually frequent disruptions in the flow of speech – affects around 42,000 New Zealanders. The peculiarity of the disorder is undeniable and is probably the most identifiable of the vast range of communication disorders noticed by both trained and untrained listeners.
Stuttering develops in early childhood, typically around the age of 3 years. Symptoms include consonant, syllable, or word repetitions, sound prolongations, and airflow or voicing blocks. For many sufferers, just the anticipation of having to speak is enough to spark fear. People who stutter tend to show increased levels of anxiety compared to people who do not stutter, especially in regard to communication. This communication apprehension appears to worsen with age and stuttering severity.
Research by the University of Canterbury’s Department of Communication Disorders is challenging the notion that stuttering in children could be linked to personal anxiety.
Bianca Phaal, who recently graduated with a Master of Speech and Language Therapy with Distinction, has thrown new light on the role of anxiety in stuttering.
She has looked at the anxiety levels of a group of three and four-year-olds experiencing the onset of stuttering and compared these with a control group of non-stuttering children.
To date, research specific to anxiety in children who stutter has been limited. The type of research undertaken has been mainly dominated by questionnaire studies administered to parents of children who stutter or direct questioning of the children themselves.
Phaal sought to quantify anxiety associated with speaking by collecting saliva samples from stuttering and non-stuttering children. The children were repeatedly sampled over a 2-week period as they engaged in a variety of speaking and non-speaking situations.
At the conclusion of each activity saliva samples were collected by having the children chew on a dental roll. The saliva was later extracted following centrifugation and analysed using radioimmunoassays to measure the steroid levels of a substance called “cortisol”.
Cortisol is the main glucocorticoid hormone in humans and is released from the adrenal cortex during periods of stress and physiological arousal.
Phaal also conducted communication apprehension tests with the children and surveyed their parents, asking them to rate their children’s anxiety levels in different situations.
Working with biochemist Dr John Lewis (Steroid and Immunobiochemistry Laboratory, Canterbury District Health Board), Phaal found no higher anxiety levels in children who stutter compared to non-stuttering children.
“There were no significant differences between the children who stutter and those who don’t according to either of the measures of anxiety or the communication apprehension measure neither was there any relationship between stuttering severity and anxiety or communication apprehension,” Phaal said.
“Results of this study suggested that generalised anxiety and communication apprehension are not associated with early childhood stuttering, therefore it is unlikely anxiety is the root cause of stuttering.
“However, should early childhood stuttering persist, negative experiences in speaking situations could lead to the development of communication apprehension and perhaps generalised anxiety. Early intervention for stuttering may thus be crucial in preventing this development.”
Since announcing the findings of her research, Phaal, who now works as a speech-language therapist at Waikato Hospital, has been fielding inquiries from academics and medical professionals from around the world. In May she presented her research to the Reflecting Connections Conference in Auckland, a joint conference of the New Zealand Speech-Language Therapists Association and Speech Pathology Australia.
Professor Mike Robb of the Department of Communication Disorders said the study’s findings were important in better understanding the condition that affects about one per cent of New Zealanders.
“There is a long history of research in stuttering and its relationship to personal anxiety, with some theorists believing that anxiety ’causes’ stuttering or that anxiety is an ‘outcome’ of stuttering. In any event, people feel as though anxiety is a core feature of stuttering.
“In this particular case, accepting the null hypothesis has important theoretical and clinical implications concerning the aetiology of stuttering. To my knowledge, this study is the first of its kind to quantitatively examine the role of anxiety in children who are at the cusp of developing this particular communication disorder.
“Bianca has also demonstrated how biochemistry can serve a role in research examining communication disorders,” Robb said.
*“Canterbury” is the magazine for alumni and friends of the University of Canterbury.
