Efficacy of the DEM test as a predictor of reading difficulty

This study aimed to evaluate the relationship between the DEM test and reading speed, its diagnostic accuracy (sensitivity and specificity), and its usefulness as a screening tool for reading difficulties. We also examined how reading speed is associated with other optometric measures.

A retrospective study was conducted involving children aged 7 and 8 years. Reading speed was assessed using the PROLEC test. The optometric evaluation included visual acuity, stereopsis, accommodative facility, near point of convergence, cover test, retinoscopy, and eye movements assessed with the DEM test. The standard DEM parameters were analyzed. In addition, given the aim of the study, a new outcome variable was introduced: the total time, calculated as the sum of the vertical and adjusted horizontal times.

A total of 48 children participated in the study. When both age groups were analyzed together, all DEM parameters showed significant correlations with reading speed (vertical time, r=-0.52,p < 0.01; adjusted horizontal time, r=-0.63,p < 0.01; ratio, r=-0.48,p < 0.01; and total time, r=-0.58,p < 0.01). The best sensitivity-specificity combination for detecting below-age PROLEC scores was obtained using the adjusted horizontal time (whole sample: 80 %/45 %). AUC ranged from 0.59 (ratio) to 0.79 (total time). A significant association was also found between reading speed and accommodative function (p = 0.02).

The application of the DEM test for detecting reading difficulties should be approached with caution. Although DEM results show a correlation with reading speed and demonstrate high sensitivity, specificity remains low regardless of the DEM measure used.