Amplitude criteria and anticipatory saccades during smooth pursuit eye movements in schizophrenia

Psychophysiology. 1999 Jul;36(4):464-8.

Abstract

Increased frequency of anticipatory saccades during smooth pursuit eye movements is a potential marker of genetic risk for schizophrenia even in the absence of clinical symptomology. The operational definition of anticipatory saccades has often included an amplitude criterion; however, these amplitude criteria have often differed across studies. This study reports on the effect of varying amplitude criteria on the effect size in a comparison of 29 schizophrenic adults and 29 normal subjects during a 16.7 degrees/s constant velocity task. The inclusion of small amplitude anticipatory saccades, with amplitudes of 1-4 degrees, consistently increased effect size (largest effect size = 1.61). The inclusion of large anticipatory saccades, with amplitudes of 4 degrees or greater, had an inconsistent impact on effect size. The separation of anticipatory saccades into leading saccades (anticipatory saccades with amplitude 1-4 degrees) and large anticipatory saccades (amplitude > 4 degrees) deserves further exploration.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Case-Control Studies
  • Chi-Square Distribution
  • Female
  • Genetic Markers
  • Humans
  • Male
  • Predictive Value of Tests
  • Psychophysics
  • Pursuit, Smooth / physiology*
  • Reference Values
  • Saccades / physiology*
  • Schizophrenia / genetics
  • Schizophrenia / physiopathology*

Substances

  • Genetic Markers