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Author Notes:

AGS and SRF contributed equally to this work.

The authors have no financial conflicts related to the contents included in this manuscript.

Subjects:

Research Funding:

AS is supported by grant from Dystonia Medical Research Foundation and Dystonia Coalition.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Clinical Neurology
  • Neurosciences
  • Neurosciences & Neurology
  • Microsaccades
  • Gaze holding
  • Vision
  • Tics
  • Basal ganglia
  • MICROSACCADE GENERATION
  • REFLEXIVE SACCADES
  • BASAL GANGLIA
  • ABNORMALITIES
  • NEURONS
  • FOVEAL
  • SCALE
  • TASK

Fixational eye movements in Tourette syndrome

Tools:

Journal Title:

Neurological Sciences

Volume:

Volume 38, Number 11

Publisher:

, Pages 1977-1984

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Studies of saccadic eye movements in subjects with Tourette syndrome (TS) have provided additional evidence that there is a link between TS symptoms and deficits in fronto-striato-thalamic networks. These studies revealed impaired timing and inhibition of saccades. We compared fixational eye movements, such as microsaccades and ocular drifts, in subjects with TS and healthy controls.We measured horizontal and vertical eye positions with video-oculography in 14 subjects with Tourette syndrome. We found reduced microsaccade amplitude but increased time between adjacent microsaccades (intersaccadic interval). Hence, the rate of microsaccades was reduced in subjects with TS compared to controls. Measure of ocular stability during intersaccadic intervals revealed increased drift velocity and increased variance in eye position. We hypothesize that increased activity of the direct fronto-striatal pathway and the resulting reduction in basal ganglia outflow targeting the superior colliculus fixation zone affect the rate and amplitude of microsaccades in subjects with TS. The resulting impairment in frontal eye field fixation leads to increased drifts during intersaccadic interval in subjects with TS. Possible clinical implication for these results is that fixational eye movements can be objective biological markers of TS.

Copyright information:

© 2017, © US Government (outside the USA).

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