Paper based DEM vs computerized DEM test : printed and computerized DEM test in Nepali adults in varying directions of reading

Abstract

Background: Measurement of an eye movements during reading provides an optometrist with a piece of valuable information about visual information processing. Developmental eye movement test (DEM) is a number naming paper-based saccadic eye movements test that has been developed for children between 6-14 years old. The goal of our study was first to compared paper-based and computer-based DEM test in young adults’ population. Secondly, to establish a relationship between the DEM test result and eye movements parameter that was measured using an eye tracker. Finally, to addresses the impact of reading direction on DEM performance. Methods: It is a cross-sectional study comprising 23 young Nepali adults studying in Norway. The participant’s age was between 25-32 with a mean age 27.56±1.92. Participants who meet our study criteria were enrolled for the study. All participants completed both paper and computer DEM tests. Eye movements measurement were recorded with SMI Remote Eye-tracking Device (RED) at a sampling rate of 250 Hz. Result: No highly significant correlation was found between paper and computer DEM except for DEM subtest C. Highly significant correlation (r=0.83) was found between Test C, tested on the right to left reading direction. A moderate correlation was found between the DEM test result and eye movement parameter (i.e total number of fixation and total fixation duration). There was statistically significant difference in DEM result (i.e. Test C time and ratio score) between left to right (L-R) and right to left (R-L) reading direction. Conclusion: This study suggests that the paper and computer DEM test is not appropriate to use interchangeably. Secondly, the study establishes that the DEM test performance is fast in habitual reading direction. The fixational (i.e. number and duration) and saccadic (i.e. number and duration) eye movements parameters are higher in unhabitual reading direction. Finally, this study shows that using eye-tracker DEM test could be a useful tool for investigating the fixational eye movement parameter (total number of fixation and total fixation duration). Further research with a large sample size is necessary to establish this relationship.