Word processing in Parkinson's disease is impaired for action verbs but not for concrete nouns.
Recent studies have demonstrated that processing of action words recruits cortical motor regions that are also involved in the planning and execution of the actions words refer to. The functional role of these regions in word understanding remains, however, to be clarified. The present study investigates this issue by examining the impact of Parkinson's disease (PD) on lexical decision performance for action words, relative to concrete nouns, in a masked priming paradigm. Priming effects for the two word categories were measured in non-demented PD patients off and on dopaminergic treatment, and in healthy participants. Our results revealed that although overall performances did not differ between verbs and nouns, priming effects showed a clear dissociation between word categories. While priming for concrete nouns was not affected by Levodopa intake, it dissociated as a function of treatment for action verbs. No priming was actually obtained for action verbs in PD patients off dopaminergic treatment. Following Levodopa intake, this deficit recovered, however, because priming effects for verbs became comparable to those for concrete nouns and similar to performance of healthy participants. Overall, this study thus brings compelling evidence that processing lexico-semantic information about action words depends on the integrity of the motor system.
Boulenger
Véronique
V
L2C2-Institut des Sciences Cognitives, UMR 5230 CNRS/Université Claude Bernard Lyon I, 67 boulevard Pinel, 69675 Bron Cedex, France. boulenger@isc.cnrs.fr
Mechtouff
Laura
L
Thobois
Stéphane
S
Broussolle
Emmanuel
E
Jeannerod
Marc
M
Nazir
Tatjana A
TA
D000368:Aged; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D003463:Cues; D005260:Female; D006801:Humans; D007806:Language Disorders / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D009048:Motor Skills; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012016:Reference Values; D012660:Semantics; D009626:Terminology as Topic
D000978:Antiparkinson Agents; D007980:Levodopa