[Saccadic system plasticity mechanisms in Parkinson disease patients].
BACKGROUND
Voluntary or reactive saccades predominate in rapid eye movements. Their goal is to preserve an active and optimal visual perception of the environment. Saccades cannot be guided once launched. Oculomotor plasticity, or saccadic adaptation, is still partially unknown, in particular the role played by the basal ganglia. New neuro-ophthalmological rehabilitation techniques require understanding the neurophysiological basis and demonstrating the neuronal structures involved in this plasticity.


OBJECTIVE
This study assessed the reactive saccade adaptation in patients with idiopathic Parkinson disease, as a model of basal ganglia dysfunction. We predicted that saccadic adaptation would be preserved in this pathology.


METHODS
Five patients with mild idiopathic hemi-Parkinson disease were included, as well as four age-matched controls. Reactive saccade adaptation was studied using the double-step target paradigm, in patients with OFF-Dopa treatment and in controls.


RESULTS
Group analysis demonstrated that patients had a lower level of adaptation than the controls (p<0.05). Individually, two patients did not adapt for bilateral saccades and one for ipsilateral (compared to Parkinson motor clinical syndrome) saccades. Two additional patients adapted on both sides but with a deficit in contralateral saccades when compared to the control group.


CONCLUSIONS
These preliminary results suggest basal ganglia involvement in reactive saccadic adaptation, which remains to be clarified.
Inserm U1028, CNRS UMR5292, équipe Impact, centre de recherche en neurosciences de Lyon, 95, boulevard Pinel, 69500 Bron, France. lucieabouaf@gmail.com
L
L
Abouaf
M
M
Panouillères
S
S
Thobois
V
V
Majerova
A
A
Vighetto
D
D
Pélisson
C
C
Tilikete
D000222:Adaptation, Physiological / Q000502:physiology; D000368:Aged; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009473:Neuronal Plasticity / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D011930:Reaction Time; D012438:Saccades / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology