Stammering occurs in every language and culture throughout the world at 1% of the adult population. People who stammer have the same range of personality and intellectual traits as those who do not, although there are suggestions in the research that they may be more sensitive than is the norm.
Current research is clear that the cause of stammering has a physiological basis in the brain structure. BSA:Research has the details of all the latest research and information. Research is ongoing and complex but this statement by Anne Smith of Purdue University (2008) attempts to draw together current thinking. Her work is discussed in the research section of the BSA web site.
Stuttering (UK usage: stammering) is a neurodevelopmental disorder involving many different brain systems active for speech - including language, motor, and emotional networks. Each infant is born with a genetic makeup that contributes to his or her probability of stuttering, however whether stuttering will develop depends upon experience. To learn to speak fluently, a child's brain must develop many different neural circuits, and these circuits must interact in very precise and rapid ways. Stuttering emerges in childhood as a symptom that the brain's neural circuits for speech are not being wired normally. For this reason, early intervention is critical, because by shaping the child's experience, we can affect the ongoing wiring process in the child's rapidly developing brain. The longer the stuttering symptoms persist in early childhood, the more difficult it is for us to change the brain's wiring, and stuttering becomes a chronic, usually lifelong problem.
There is no single or definite 'cure' and there is no single best strategy for supporting children as they all have individual needs. Parents cannot cause stammering but there is thought to be a family link in some cases, as where a close adult relative is stammering a young child is more likely to stammer. Some research suggests also that precocious language development may be a risk factor for stammering, but not one that as yet differentiates persistent from transient stammering. (Yairi & Ambrose, 2005).
The same research suggested from a sample of young children that 85% of stammering onset occurred prior to the age of 3.5 years and that children past the age of 4 face a relatively low risk for stammering. There is some evidence also that if the parent or sibling stammers then the young child’s stammering is more likely to persist (Davis).
While the underlying cause of stammering is now understood what is also certain is that stammering speech is also affected by a complex combination of environmental, inherited, linguistic and physical factors that are unique to the individual in their form and effects. For children small modifications in the speaking and listening environment at home and in school, which make the child feel supported, can lower anxiety levels, and may help with fluency.
Stammering can emerge at any childhood stage, but most commonly between the ages of 2 and 5 when about 1 in 20 children may stammer. This of course coincides with a period of the rapid development of language skills. At first it affects twice as many boys as girls. Later, as more girls than boys recover, boys who stammer outnumber girls by as much as 5 to 1. It can emerge gradually, but sometimes develops very suddenly. Early Intervention gives the best chance of recovery.
In older children and adults the confirmed condition usually has developed to become more than just a speech difficulty. Feelings and emotions about the stammer and about themselves as people usually become an integral part of the condition and it is essential that support for the management of the stammering is provided.
Parents do not cause stammering
Years ago it was though that parents' behaviour caused the child to stammer. Now research proves that parents do not cause stammering and that this old fashioned view was wrong, although it may still be held by some uninformed people and cause parents considerable distress. Parents do not cause stammering, and with Early Intervention there is an excellent chance of recovery, with some children recovering as late as 7 or 8 years old.
However, we do know that parents play a vital role in helping their child by managing the speaking and listening environment in order to reduce the impact of the stammer.