title: Time Course of Lexicalization During Sentence Production in Parkinson's Disease: Eye-Tracking While Speaking.
abstract: Growing evidence suggests that sentence formulation is affected in Parkinson's disease (PD); however, how speakers with PD coordinate sentence planning and speaking remains unclear. Within 2 competing models of sentence production, this study examined whether speakers with PD show advanced buffering of words to minimize disfluencies and increased demands during speech or whether they plan one word at a time, compromising accuracy and fluency of speech.
  
  
  
  Participants described 3 computer-displayed pictures using the sentence "the A and the B are above the C." Name agreement (codability) was varied to be high (clock) or low (sofa/couch) for each object position (A, B, C), affecting difficulty of lexical selection. Participants' gaze durations to each object were recorded.
  
  
  
  Speakers with PD showed incremental word-by-word planning, retrieving only the first lexical item (A) before speech onset, similar to controls. However, they produced greater word-finding errors and disfluencies compared to controls for the low-codable pictures, but not for high-codable pictures.
  
  
  
  These findings suggest that by following word-by-word incremental production, speakers with PD compromise fluency and accuracy of speech to a greater extent than healthy older speakers and that PD is associated with impaired inhibitory control during lexical selection.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN.
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Lee
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D053483:Eye Movement Measurements; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007266:Inhibition, Psychological; D007807:Language Tests; D008037:Linguistics; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology; D010775:Photic Stimulation; D013060:Speech; D013068:Speech Production Measurement; D013997:Time Factors