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A mechanism in the brain which controls tics in children with Tourette Syndrome (TS) has been discovered by scientists at The University of Nottingham.
The work was funded with a £150,000 grant from the
James Tudor Foundation and was carried out by PhD student Amelia Draper.
Professor Stephen Jackson, in
the University’s School of Psychology, said: “This new study is very important
as it indicates that motor and vocal tics in children may be controlled by
brain changes that alter the excitability of brain cells ahead of voluntary
movements. You can think of this as a bit like turning the volume down on an
over-loud motor system. This is important as it suggests a mechanism that might
lead to an effective non-pharmacological therapy for Tourette Syndrome.”
Brain re-structuring
The neurological condition TS
affects around one child in every 100 and usually starts during early
childhood. Scientists believe that the tics that affect children with TS are
caused by faulty wiring in the brain that leads to hyper excitability in the
brain regions controlling motor function.
In adolescence, there is a period
of ‘pruning back’ in which redundant brain connections are removed and other
structural and functional brain changes occur.
During this time, around
one-third of children with TS will find that their tics disappear and another
third are able to more effectively control their tics. Unfortunately, the
remaining third of individuals will see little or no change in their tics and
are likely to remain troubled by their TS symptoms into adulthood.
This clinical observation
suggests that there are mechanisms in the brain that are involved in
controlling tics and undergo development or re-organisation during the teenage
years.
Amelia Draper added: “The research
is based on the general hypothesis that an area in the brain called the
striatum is overactive as a result of alterations in the early development of
the brain. As a result, the signals that are relayed to the brain’s cortex
region lead to hyper-excitability and cause tics to occur.
“We have looked at how that
hyperactivity and the resultant tics might be controlled by finding a way to
‘turn down the volume’ on that ‘cortical excitability’. This is potentially
extremely important as the parents of children with tics are desperate to find
a safe and effective therapy that is an alternative to drug treatments.”
Unwanted movements
In the current study the team
used a method called Transcranial Magnetic Stimulation (TMS) in which a
magnetic field is passed over the brain to produce a weak electrical current
which stimulates motor function to induce a twitch response.
By delivering TMS at
different points in time as participants were about to undertake a hand
movement, the researchers were able to measure alterations in brain
excitability ahead of the movement and chart the differences between each
person.
The study showed that
subjects with TS, unlike those of a similar age without the condition, were
least able to modulate the hyperactivity in the brain.
Professor Jackson said: “If
there is a relationship between this cortical excitability or hyperactivity and
tics then this is really important as it means that there may be something that
we might be able to do to help children with TS to better control these
unwanted movements.”
Further research by the team
has involved the use of a similar type of brain stimulation called transcranial
direct current stimulation (TDCS) to study the brains of children with TS.
Early results suggest that TDS can be applied to decrease neuronal excitability
and this may be effective in suppressing tics for extended periods. In
addition, if another form of TDCS is applied, one that increases neuronal
excitability, it may act to improve learning and memory function, particularly
in the context of behavioural therapies. Following use of these treatments
lasting effects can be applied to the brain.
Effective and longer lasting
If proven to be effective,
the technology could be adapted into a TENS machine-style device that would
offer a cheap, portable and individualised therapy for children with TS.
Professor Jackson added: “For
the one-third of people who aren’t going to get better this could offer them a
much needed assistance with controlling their tics, while relying less on other
conventional pharmaceutical therapies which can have associated side effects
such as weight gain or tiredness.
“It can be applied at home while
the child is watching TV or eating their cornflakes so it would reduce the
amount of school they would miss and potentially we can use the TDCS to both
control the tics and make that control more effective and longer lasting.”
As part of her work Amelia
Draper is also using MRI scanning technology to examine the potential
relationship between cortical excitability and a brain chemical that appears to
be strongly linked to neuronal excitability in TS.
Rod Shaw, Chief Executive of
the James Tudor Foundation, said: “We’re glad to see that the funding we have
given to this project is producing some interesting and potentially useful
results.”
Professor Jackson’s research is
a key project within the University’s appeal, Impact: The Nottingham Campaign,
which is delivering the University’s vision to change lives, tackle global
issues and shape the future. Find out more about our research and how you can
support us at http://tiny.cc/UoNImpact
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Notes to editors: The University of Nottinghamhas 43,000 students and is ‘the nearest Britain has to a truly global university, with campuses in China and Malaysia modelled on a headquarters that is among the most attractive in Britain’ (Times Good University Guide 2014). It is also the most popular university among graduate employers, the world’s greenest university, and winner of the Times Higher Education Award for ‘Outstanding Contribution to Sustainable Development’. It is ranked in the World's Top 75 universities by the QS World University Rankings.
Impact: The Nottingham Campaign, its biggest-ever fundraising campaign, is delivering the University’s vision to change lives, tackle global issues and shape the future. More news…