Dataset Information

Parametric Covariability in the Standard Model of the Saccadic Main Sequence.

ABSTRACT: SIGNIFICANCE:Saccades present a direct relationship between the size of the movement (SACSIZE) and its peak velocity (SACPEAK), the main sequence, which is traditionally quantified using the model SACPEAK = Vmax × (1 - e). This study shows that Vmax and SAT are not veridical indicators of saccadic dynamics. PURPOSE:Alterations in saccadic dynamics are used as a diagnostic tool. Are the 95% reference ranges (RRs) of Vmax and SAT correctly quantifying the variability in saccadic dynamics of a population? METHODS:Visually driven horizontal and vertical saccades were acquired from 116 normal subjects using the Neuro Kinetics Inc. Concussion Protocol with a 100-Hz I-Portal NOTC Vestibular System, and the main sequence models were computed. RESULTS:The 95% RRs of Vmax, the asymptotic peak velocity, and SAT, the speed of the exponential rise toward Vmax, were quite large. The finding of a strong correlation between Vmax and SAT suggests that their variability might be, in part, a computational interaction. In fact, the interplay between the two parameters greatly reduced the actual peak velocity variability for saccades less than 15°. This correlation was not strong enough to support the adoption of a one-parameter model, where Vmax is estimated from SAT using the regression parameters. We also evaluated the effects of interpolating the position data to a simulated acquisition rate of 1 kHz. Interpolation had no effect on the population average of Vmax and brought a decrease of the average SAT by roughly 8%. CONCLUSIONS:The 95% RRs of Vmax and SAT, treated as independent entities, are not a veridical representation of the variability in saccadic dynamics inside a population, especially for small saccades. We introduce a novel three-step method to determine if a data set is inside or outside a reference population that takes into account the correlation between Vmax and SAT.

SUBMITTER: Busettini C

PROVIDER: S-EPMC6212342 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

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Parametric Covariability in the Standard Model of the Saccadic Main Sequence.

Busettini Claudio C Christy Jennifer Braswell JB

Optometry and vision science : official publication of the American Academy of Optometry 20181101 11

<h4>Significance</h4>Saccades present a direct relationship between the size of the movement (SACSIZE) and its peak velocity (SACPEAK), the main sequence, which is traditionally quantified using the model SACPEAK = Vmax × (1 - e). This study shows that Vmax and SAT are not veridical indicators of saccadic dynamics.<h4>Purpose</h4>Alterations in saccadic dynamics are used as a diagnostic tool. Are the 95% reference ranges (RRs) of Vmax and SAT correctly quantifying the variability in saccadic dyn ...[more]

PMID: 30339645

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Dataset Information

Parametric Covariability in the Standard Model of the Saccadic Main Sequence.

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Parametric Covariability in the Standard Model of the Saccadic Main Sequence.

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