World First in Childhood Stuttering Research
By Dr. Paul Sowman
Stuttering can emerge in children between the ages of two and five years. For 70% the problem resolves spontaneously before puberty. For 1% of the population, however, stuttering becomes chronic.
"Stuttering occurs as children move from using individual words to constructing sentences but in most cases brain development catches up and stuttering disappears," explains Dr. Paul Sowman, a member of Macquarie University's Department of Cognitive Sciences and the ARC Centre of Excellence in Cognition and its Disorders.
"A lot of stuttering studies have been done with adults, particularly in the US, UK and Finland, but the brain changes over time so the original issue may be masked," he said.
"Speech can contain six syllables per second and involve up to 100 muscles in the tongue, neck, jaws, chest and diaphragm. Then there's the feedback from the ears. It's an amazing feat of coordination."
Since 2009, Dr. Sowman and his colleagues have been using a unique MEG, or magnetoencephalography, system designed specifically for young children-the first child-sized MEG system ever to be built.
The brain imaging technique measures the magnetic field generated whenever information is processed by the brain - in this case as a child watches and responds to a series of pictures in short sessions, or as they watch a DVD and listen to a series of sounds.
The MEG captures measurements every 1/1000 second even though the brain's magnetic fields are 100 million times smaller than the earth's and 1 million times smaller than those produced in an urban environment. To guarantee accuracy the MEG system is located in a multi-tonne, shielded room with thick walls specially constructed to block out external magnetic fields. "It's been likened to trying to pick up the footsteps of an ant at a rock concert," said Dr. Sowman.
"Unlike electroencephalography (EEG) which depends on electrodes placed on the scalp to measure electrical activity produced by the brain, MEG uses a helmet-like device with extremely sensitive sensors. We can see how a child's brain responds when she or he is looking at pictures or reading." He adds, "The MEG system is a 'passive' device and completely safe and non-invasive. The research proposal was closely scrutinised by the University's Ethics Committee before we began."
To make the child MEG experience friendlier from the outset, the researchers have created a "Space Adventure" with the children boarding the "space ship", wearing a "space helmet" and travelling to another planet. Their mission is to listen to the instructions from ground control through earphones within the space ship while observed at all times by a video camera. Parents are invited to accompany them but many children prefer to "travel" with a substitute teddy after the initial visit.
The youngest child to slip into the MEG space helmet to date was aged two years but researchers have found children aged three or more have a better attention span and are more likely to remain still enough for the required data collection over two sessions. Children above age four usually require only one session of about 20 minutes.
"The child MEG system allows us to explore language acquisition and auditory processing in children who are too young to participate in behavioural studies. We now have a window of opportunity to learn more about the earlier stages of development when the brain is most plastic."
Data from several studies is still being analysed, but initial results have shown that the amount of activation and the timing is slightly different to those in control groups, said Dr. Sowman.
The child MEG system was developed by the Kanazawa Institute of Technology (KIT) in Japan, which also jointly funded the development of the KIT Macquarie Brain Research Laboratory, and a second MEG system designed for adults. The child MEG system is the first of its kind in the world and the MEG facility at Macquarie University is one of only two in Australia.
Now an ARC Research Fellow at Macquarie, Dr. Sowman has an NHMRC grant to fund his work on brain anomalies and the movement control pathways implicated in stuttering in adults. He and his colleagues are investigating how we might potentially use these movement control pathways to overcome stuttering or other movement disorders.
About Dr. Paul Sowman
Dr. Sowman and his colleagues are currently seeking children participants between the ages of three and nine. They are mostly seeking boys and girls who stutter, but also need children who have never stuttered to act as controls. Adult family members who stutter are also needed for other studies. Participants are paid a small amount (usually around $40 per visit) and receive free parking. If you are interested or have questions, you may contact Dr. Sowman.
Dr. Paul Sowman
P: 02 9850 6732