Developmental Eye Movement test and dyslexic children: A pilot study with eye movement recordings

Abstract

The goal of this study is to explore eye movement recordings during the Developmental Eye Movement (DEM) test in dyslexic and non-dyslexic children. Thirteen children with dyslexia, 13 non-dyslexic chronological age- and IQ-matched children and 13 non-dyslexic reading age- and IQ-matched children were examined. Test C of the DEM test was performed with and without eye movement recordings (eye tracker by SuriCog). The results of the three groups were compared. Children with dyslexia and non-dyslexic children of equivalent reading age have significant longer fixation time and take longer to read Test C of the DEM test than non-dyslexic children of similar chronological age. A significant correlation was also found between the fixation time and the number of words read in one minute with the total time to read Test C of the DEM test. DEM test is a useful test for exploring the oculomotor behavior of dyslexic children during reading. The maturation of cortical structures controlling fixation capability appears to play a crucial role in reading skills.

Visual fixations rather than saccades dominate the developmental eye movement test

“…Both vertical and horizontal DEM times strongly related to the visual processing speed measured in the SA test as well as the eye fixation durations measured in the DEM. These findings agree with the results of Ayton et al 10 and Moiroud et al 20 for the horizontal DEM, and extend the results to the vertical DEM. Additionally, we found that faster performance on the horizontal DEM coincided with fewer, but typically larger saccades.…”

“…3 a bottom; r = 0.39, p = 0.018), but the median amplitude of return sweep saccades was not age-dependent (r = 0.21, p = 0.23). Based on previous research 10 , 20 , we expected a decrease in fixation durations with improved performance. The median fixation duration indeed decreased with improving DEM times but only during the number identification epochs (Fig.…”

“…First, as the purpose of saccades is to rapidly redirect gaze, we found that the contribution of saccade time (the sum of saccade durations) to the total time spent on number identification is small, and almost negligible compared to the overall DEM time. It is not surprising, therefore, that saccade parameters measured under different task conditions did not correlate significantly with horizontal DEM performance 10 , 19 , 20 . Second, visual search can take place with or without eye movements 37 – 39 , as humans are capable of shifting attention without redirecting their eyes.…”

“…They found that the horizontal DEM, but not the vertical DEM or the DEM ratio, correlated significantly to the number and average duration of fixations in the reading task. To the best of our knowledge, Ayton et al 10 and Moiroud et al 20 were the only groups to measure eye movements during the horizontal DEM. Both studies found a significant correlation between fixation durations and the time needed to complete the test.…”

Clinical Characterization of Oculomotricity in Children with and without Specific Learning Disorders

“…Similarly, DEM outcomes obtained in the CG differed significantly from those obtained in the OAG and LDG. As in previous studies [43], significantly longer times for reading sheet C was observed in the group with specific learning disorders. Furthermore, higher DEM pattern values and ratios, as well as a lower percentile for horizontal time, were found in the LDG compared to the CG.…”