Abstract
Abstract: :
Purpose: The Visagraph has gained popularity as a standard, objective, infrared method to assess reading eye movements and by inference global reading ability in both children and adults. However, guidelines for the proper determination of a valid and stable baseline for comparative purposes have yet to be established. Methods: Thirty visually-normal adult subjects (mean age of 28 years, range of 20-59; 10 males and 20 females) without self-reported reading disability read five standardized high school/college level Visagraph paragraphs in consecutive trials within a single session. Habitual refractive correction for near was worn during all testing. Eye movements were computer analyzed and compared to Taylor's normative database with respect to grade level equivalent and reading rate. Results: Trend analysis of these two aforementioned parameters revealed four response patterns: those who (1) remained at a constant reading grade level across trials (63%), (2) shifted either up or down in a single step-like manner after one or two paragraphs (13%), (3) progressively decreased and plateaued (17%), or (4) progressively increased and plateaued (7%). Conclusions: These results suggest that patients should be provided with multiple practice paragraphs prior to formal testing for diagnostic and/or therapeutic purposes to obtain valid baseline results. This is supported by the finding that one third of the subjects required more than one test paragraph to attain a stable baseline level. However, since one does not know who these individuals might be prior to testing, it is recommended that at least three practice paragraphs be used with all adult patients. Moreover, it is proposed that in young children, in whom greater response variability is predicted, these measurements may need to be repeated at a separate test session to assure baseline accuracy.
Keywords: eye movements • reading • eye movements: recording techniques