Speeded processing of grammar and tool knowledge in Tourette's syndrome.
Tourette's syndrome (TS) is a developmental disorder characterized by motor and verbal tics. The tics, which are fast and involuntary, result from frontal/basal-ganglia abnormalities that lead to unsuppressed behaviors. Language has not been carefully examined in TS. We tested the processing of two basic aspects of language: idiosyncratic and rule-governed linguistic knowledge. Evidence suggests that idiosyncratic knowledge (e.g., in irregular past tense formation; bring-brought) is stored in a mental lexicon that depends on the temporal-lobe-based declarative memory system that also underlies conceptual knowledge. In contrast, evidence suggests that rule-governed combination (e.g., in regular past tenses; walk+-ed) takes place in a mental grammar that relies on the frontal/basal-ganglia-based procedural memory system, which also underlies motor skills such as how to use a hammer. We found that TS children were significantly faster than typically developing control children in producing rule-governed past tenses (slip-slipped, plim-plimmed, bring-bringed) but not irregular and other unpredictable past tenses (bring-brought, splim-splam). They were also faster than controls in naming pictures of manipulated (hammer) but not non-manipulated (elephant) items. These data were not explained by a wide range of potentially confounding subject- and item-level factors. The results suggest that the processing of procedurally based knowledge, both of grammar and of manipulated objects, is particularly speeded in TS. The frontal/basal-ganglia abnormalities may thus lead not only to tics, but also to a wider range of rapid behaviors, including the cognitive processing of rule-governed forms in language and other types of procedural knowledge.
Walenski
Matthew
M
Brain and Language Lab, Department of Neuroscience, Georgetown University, Washington, DC 20057-1464, USA.
Mostofsky
Stewart H
SH
Ullman
Michael T
MT
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007804:Language Development; D007807:Language Tests; D008037:Linguistics; D008297:Male; D011930:Reaction Time / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values; D018709:Statistics, Nonparametric; D005879:Tourette Syndrome / Q000503:physiopathology*; D014706:Verbal Learning / Q000502:physiology*