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Abstract:
Some reports suggest that persistent developmental stuttering
(PDS) is associated with anomalous laterality, characterized by
atypical activation of language and motor regions. The dual-task
paradigm was used to evaluate verbal-manual interference in 50
fluent individuals; 18 individuals with PDS were compared to 27
matched fluent controls. Finger Tapping Rate (FTR) was measured for
both hands under three conditions: at Baseline (no verbal
behavior), during Word Repetition, and during Word Generation
(category exemplars). To assess Motor Interference, Word Generation
was measured both at baseline and while finger tapping with the
left or right hand. Significant effects follow. Fluent sample:
Males exhibited greater FTR than females. FTR was greater for the
writing hand than the non-writing hand. For the Word Repetition
condition, Left (but not Right) FTR was increased relative to
Baseline. No effect of Word Generation on FTR was detected,
however, the presence of Right (but not Left) Finger Tapping was
associated with a significant decrease in number of Words
Generated. Differences between PDS and Matched Controls: The male
FTR advantage was larger for PDS than for controls. For Controls,
Word Generation did not affect FTR, whereas PDS exhibited reduced
FTR while generating words. PDS exhibited a male, rather than
female, advantage for Number of Words Generated. These differences
support the notion that PDS may be related to atypical organization
of neural substrates supporting verbal and manual behavior.
(Support-NIDCD)
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