Monday, 3 September 2007

Children with Tourette's show superior grammatical ability

Children with Tourette's syndrome, the motor disorder characterised by involuntary tics, are more skilled than healthy control children at processing certain forms of grammar. That's according to Matthew Walenski at the Brain and Behaviour Lab at Georgetown University and colleagues, writing in Neuropsychologia.

The researchers presented eight children with Tourette's and eight control children with sentences containing a verb in the present tense. The children's task was to produce the correct past tense form of the verb as accurately and quickly as possible. The children were also asked to name pictures of objects that are either 'manipulable' (e.g. a hammer) or not (an elephant).

The children with Tourette's responded more quickly than the controls on those aspects of the tasks that were considered to depend on procedural memory – such as when producing past tenses of regular verbs and naming objects that can be manipulated, but they responded with similar speed to the controls when performance depended on declarative memory – such as when giving the past tense of irregular verbs or naming non-manipulable objects.

Procedural memory is rooted in the frontal/basal ganglia circuits of the brain and these areas are known to be structurally abnormal in people with Tourette's. The researchers said it was likely this association explained the superior performance of the children with Tourette's.

Past studies involving children and adults with Tourette's have tended to focus on their involuntary verbal tics, rather than investigating their actual language abilities. Co-researcher professor Michael Ullman said: 'These children were particularly fast, as well as largely accurate, in certain language tasks. This tells us that their cognitive processing may be altered in ways we have only begun to explore, and moreover in a manner that may provide them with performance that is actually enhanced compared to that of typically-developing children.'

The new findings follow a study published last year that showed people with Tourette's have enhanced cognitive control relative to healthy participants, as shown by their ability to switch task sets without the usual reaction time cost.

This item is taken from the news section of The Psychologist magazine, another serving from the table of the British Psychological Society.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.


Anonymous said...

Well isn't a grp of 8 people too small a sample group?

Anonymous said...

One would think a sample size of eight to be too small to show significance, but with a large enough effect size it is doable. I would need to see the particular statistical analysis in this study to see if the results are legitimate, but obviously the authors thought so. The typical way such an issue is vetted is by peer review. If the article was published in a recognized journal then it should be valid.

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