Correlation of Magnocellular Function with Measurements of Reading in Children

Abstract

Purpose: Children with reading disability frequently exhibit reduced sensitivity to motion, as assessed by coherent motion thresholds (CMT) and critical flicker frequency (CFF). A retrospective analysis was conducted to evaluate whether there was a correlation between reading fluency as measured by the Test of Silent Word Reading Fluency (TOSWRF), reading rate (as measured with the Visagraph II Eye Movement System), and pseudoword decoding (as measured with the pseudoword decoding subtest of the Wechsler Intelligence Achievement Test, WIAT-II), and these two visual motion sensitivity tests. Methods: 68 children between the ages of 7-16 years presented to the principal investigator’s optometric practice for a vision therapy evaluation between June 1st 2010 and March 31st 2011. As part of the standard protocol for vision therapy evaluations, they were assessed using the CMT, CFF, TOSWRF, WIAT-II (pseudoword decoding subtest), and Visagraph II. The patients were divided into reading ability groups based on the published recommendations from the TOSWRF manual. Individuals at the 25% or below level were labeled as poor fluency, individuals in the 26th to 74th% level were labeled average fluency, and those in the 75% or higher level were labeled as good fluency. Results: Pearson correlations were computed between the dependent variables revealing several important relationships: Fluency (TOSWRF) correlated significantly with all of the dependent measures selected for study. Of these measures, the WIAT-II subtest score correlated the most strongly at a moderate level (r = +0.569). Reading rate (Visagraph II) was the next strongest correlate of fluency, with changes in rate accounting for 26.5% of the variance in fluency. The variables of CMT and CFF were combined with rate in two follow-up, logistic regressions to determine whether their inclusion added to the classification accuracy of rate. Both variables improved the specificity of rate, which has a high likelihood of false positives. CMT maintained the sensitivity of rate while boosting specificity, whereas CFF caused a decline in the sensitivity of rate while greatly improving specificity. Reading rate with CFF and with CMT both had an overall accurate prediction of fluency of 84%. Conclusions: Silent word reading fluency correlated with CMT, CFF, reading rate, and WIAT-2. Combining reading rate with a motion sensitivity test (either CMT or CFF) maintained good sensitivity, while greatly improving specificity. Clinicians should consider adding a motion sensitivity test to the Visagraph II reading rate assessment when evaluating school-age children who may be at risk for reading fluency deficits.