title: Impaired attention modulation of the blink reflex R3 component in Parkinson's disease: a non-task warning paradigm study.
abstract: OBJECTIVE
  the aim of this experimental study was to evaluate the attention modulating actions on the polysynaptic component of blink reflex responses and especially of the R3 component in patients suffering from Parkinson's Disease (PD). To this end, a non-task warning paradigm was adopted.
  
  
  METHODS
  attention processing was evaluated by means of a non-task paradigm in 55 patients suffering from PD. Subjects were presented with a visual 'warning' prestimulus and the blink reflex (BR) analyzed with special regard for any modulation of its polysynaptic components (R2-R3).
  
  
  RESULTS
  The mean amplitude of the post-warning R3 component (PW-R3c) of 'de novo' PD patients was 62% of the corresponding component following unannounced stimuli, a figure which differs significantly from both treated PD patients (18.9%) and control subjects (15.4%). De novo patients subsequently started on L-dopa therapy exhibited a more pronounced inhibition of the R3 component after warning stimulus, as the PW-R3c percentage decreased. Inversely, treated patients whose therapy was withheld showed decreased inhibition of this component. Regarding R2, the mean PW-R2c in the de novo patients differed slightly from that of the treated patients (P<0.05), but not from that of the control subjects. Such a finding may be attributable to a specific effects on the excitability of the polysynaptic responses.
  
  
  CONCLUSIONS
  Attention disorders in PD have been well documented by means of this kind of non-task warning paradigm, which appears to probe the modulation of the BR R3 component, even if the interpretation of this R3 changes suggesting a specific alteration of attention processing must be put forward extremely carefully, because something similar, but less evident, appears also for R2.
authors.affiliation: Section of Neurology, Department of Neuroscience, University of Pisa, Via Roma 67, 56100 Pisa, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Gabrielli
authors.forename: Paolo
authors.initials: P
authors.lastname: Nocita
authors.forename: Carlo
authors.initials: C
authors.lastname: Pasetti
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Bonuccelli
authors.forename: Grazia
authors.initials: G
authors.lastname: Dell'Agnello
authors.forename: Maria
authors.initials: M
authors.lastname: Chiara Carboncini
authors.forename: Bruno
authors.initials: B
authors.lastname: Rossi
mesh_terms: D000368:Aged; D001288:Attention / Q000502:physiology*; D001767:Blinking / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*