Developmental Eye Movement Research Articles

Developmental Eye Movement Test: What is it Really Measuring?

The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool. However, while the DEM test ratio has been reported to correlate with horizontal saccadic eye movements, there have been no published comparative studies of the DEM test and objective eye movement measures. The aim of this study was to compare DEM test performance with explicit quantification of saccadic eye movements, reading performance, symptomatology and visual processing speed, to assess the validity of the DEM test in clinical practice. One hundred fifty-eight children aged 8 to 11 years completed the DEM test and a battery of eye movement tasks, recorded by a Microguide 1000 infrared eye tracker. All subjects completed a symptomatology survey. Reading performance and visual processing data was collected for 77 and 75 children, respectively. One hundred twenty-nine of the 158 subjects (81.65%) passed the DEM test. There was no significant correlation between any component of DEM test performance and quantitative eye movement parameters (gain, latency, asymptotic peak velocity, and number of corrective saccades) or symptomatology. There were significant correlations between DEM test outcome and reading performance, and with visual processing speed. DEM test performance does not correlate with saccadic eye movement skills or symptomatology. However, it is related to reading performance and visual processing speed. This study suggests that although DEM test times may not correlate directly with eye movement parameters, they do correlate with aspects of reading performance and thus may serve a diagnostic role in clinical practice.

Paper Tools for Assessing Visual Function

Instruments for assessing visual function are valuable tools for optometry, ophthalmology, vision science, education, and public health. Inspired by my observations in the Teller lab, with Dobson, on the process of developing a useful clinical tool from laboratory work, I present four examples of functional vision tests that are made of paper and currently used in the field: the Amsler Grid, the Pelli-Robson Contrast Sensitivity Chart, the Teller Acuity Cards, and the Developmental Eye Movement Test. All are characterized by ease of use and rigorous design. All are either being used with children or have the potential to be so. Each tool is reviewed in terms of its development, with a view toward similarities in the steps or process taken. The goal is to encourage the further development of the functional vision assessments already in existence, and to urge scientists and clinicians alike to consider ways in which their own work can be translated into clinically useful, simple paper tools.

Relationship between oculomotor scanning determined by the DEM test and a contextual reading test in schoolchildren with reading difficulties

The relationship between oculomotor scanning and reading in poor readers of primary school age is not well known. This study was designed to assess this relationship by determining mean Developmental Eye Movement (DEM) test times and reading speeds in a Spanish non-clinical population of children with poor reading skills but without dyslexia. We conducted a cross-sectional study on 81 poor readers (8-11 years of age) in the third to fifth grades recruited from 11 elementary schools in Madrid, Spain. In each subject with best spectacle correction, oculomotor scanning was measured using the DEM test, and reading speed (words per minute) was assessed by a standardized Spanish contextual reading test. Mean horizontal DEM times were higher than normative values for children in the third, fourth and fifth grades, by 20 seconds, 12 seconds, and 3 seconds respectively. Mean reading speeds were 18 words per minute lower than the norm for the third and fourth grades respectively, and 30 words per minute lower than the norm for the fifth grade. Reading speeds were significantly related to horizontal DEM times (r = -0.53, p < 0.0001). Thus, children showing a longer, or worse, horizontal DEM time achieved lower reading speeds. Poor readers showed poor horizontal scanning as assessed by the DEM test that was related to a slow reading speed. This test should be used by optometric clinicians as a screening tool to help identify poor reading skills in school children at an early stage.

Saccadic tracking skills of poor readers in high school

Background Oculomotor control has been implicated as a factor when reading is poor, but few studies exist for adolescents. Methods The saccadic eye movement efficiency of 684 ninth grade students, identified as poor readers in 5 California high schools, was quantified using the Developmental Eye Movement test. Frequency distributions were produced from scores on vertical and horizontal components, and gender and test-retest factors were considered during analysis. Results Vertical times were within 1 standard deviation of normal for eighth grade. However, horizontal (saccadic) times were typical of grade 3, and the average number of errors on the horizontal test was typical of grade 2. Boys and girls performed similarly. Results of retests showed slightly improved horizontal times and fewer errors, but the grade level equivalents remained dramatically low. Overall, fewer than 10% of students scored above the 50th percentile for eighth grade. Conclusion The results indicate that poor readers in high school may be at high risk for poor saccadic tracking skill.

An optometric approach to patients with sensory integration dysfunction

Background Sensory integration dysfunction is a neurologic condition that can cause children to process environmental sensations in an inappropriate way. As a result, they may either seek out strong sensations or avoid even mild sensations. Some of the characteristics of these children may be hyperactivity, poor awareness of pain, high risk taking, listening to loud sounds, clumsiness, poor fine motor skills, poor gross motor skills, poor visual tracking, problems with sequencing, and problems with balance. Sensory integration dysfunction often is related to children with developmental disabilities, autism, and attention deficits. Methods Two children from the same family were examined for general eye examinations because of a history of sensory integration problems. J.H., an 11-year-old girl, and her 6-year-old half-brother, A.T., returned to the clinic for visual-perceptual testing: the Test of Variables of Attention (TOVA), the Developmental Eye Movement Test (DEM), and the Visagraph (Compevo AB, Stockholm, Sweden). The use of yoked prisms with these children was also explored. Results Both children showed oculomotility problems based on the DEM and Visagraph results. Whereas J.H. performed well on the visual-perceptual profile overall, A.T. showed problems in many areas such as reversals, visual spatial relations, visual sequential memory, visual form constancy, and attention. Both children were low hyperopes and showed positive postural and balance changes when tested with yoked prisms. Conclusions Children with sensory integration dysfunction can have a number of signs and symptoms that may bring them to the optometrist’s office. It is important to thoroughly test their visual, perceptual, and oculomotor systems to determine the best way to help these patients. The use of vision therapy and yoked prisms can be beneficial treatment options for many of these patients.

VISUAL FUNCTION AND EXECUTION OF MICROSACCADES RELATED TO READING SKILLS, IN CEREBRAL PALSIED CHILDREN

This article investigates the ability of cerebral palsied (CP) children to execute microsaccades. One-hundred and five congenitally CP school aged children (6 to 15 years old), without severe mental retardation, were classified into three groups: those with spastic quadriplegi, spastic diplegics, and spastic hemiplegics on the basis of: (1) patient anamnesis, (2) IQ estimation, (3) evaluation of the microsaccadic skills with the Developmental Eye Movement test (DEM). Their performance in these tests was compared with a control group from the general pediatric population. IQ of the CP children ranged between 70 and 100; the microsaccadic skills were severely affected: only 19% of the CP children had normal function, 20.9% of the CP children appeared with a pure oculomotor problem, 32.4% of the CP children had a visual-perceptual problem, and 27.7% of the CP children had a combined oculomotor and visual perceptual problem. CP children, in the absence of severe mental retardation, have disturbed visual skills and visual perception that usually leads to reading difficulties. It is also suggested that microsaccadic skills of CP children is an identifiable factor compounding the adverse effects of mental retardation on reading skills.

Developmental Eye Movement Test: reliability and symptomatology

The Developmental Eye Movement Test (DEM) is a widely used visual skill test, especially in the context of a vision therapy evaluation. It is intended to diagnose oculomotor dysfunction (OMD) and can also identify deficient rapid automatized naming. As such, its reliability and associated symptomatology are important. The DEM test-retest reliability was investigated within two populations: a group of 53 office patients who were participating in vision therapy evaluation in a private optometry practice, and a smaller group of 13 subjects at their school. One to four weeks separated the test and retest for both groups. We also studied the relationship between results on a questionnaire of symptoms associated with OMD and DEM test performance in these two populations. The first administration of the DEM significantly correlated with the second for all four of its scores for both groups. The office group had higher intra-class correlation coefficients than the school group. There was good agreement between test and re-test in terms of pass-fail classification for the office group. Symptomatic subjects performed poorer than asymptomatic subjects on the DEM. Failing the DEM Ratio, the score used to diagnose OMD, identified 90% of the subjects who were symptomatic. The DEM has good intra-subject test-retest reliability for all four of its scores when it is administered in an office setting to patients participating in a vision therapy evaluation. It also has good consistency in classifying patients as pass or fail. Performance on the DEM relates to certain symptoms that are associated with OMD.

Spatial load factor in prediction of reading performance

Abstract This study investigated whether there is a relationship between reading age and clinical optometric tests that have varying degrees of spatial loading in their design. Spatial loading in this context is the demand on the visual system to process information about the relative position and orientation of stimuli. A total of 112 children aged 8-11 years were assessed using saccadic eye movement and rapid naming tasks with varying spatial loads. All were subtests of Garzia's Developmental Eye Movement test and Liubinas' SeeRite Reading Diagnostic Programme. Variability in load was achieved by comparing rapid naming of numerals vs the spatially loaded letters p, d, b, q; and by comparing the speed of reading numerals presented in increasingly complex arrays. Reading Age was assessed independently and results were analysed by multiple logistic regression. Spatially loaded naming tasks performed at speed exposed a Spatial Loading Factor which clearly differentiates children at risk with reading.

Evolution of accommodative function and development of ocular movements in children.

The evolution of the accommodative function and development of ocular movement are evaluated in a non-clinical paediatric population (1056 subjects) aged 6-12 years, providing means for each age in the optometric tests that evaluate the accommodative amplitude, accommodative facility, accommodative response (lag), and saccadic movements. A comparison of these values between ages (anova) established three distinct trends in the behaviour of these parameters. The accommodative amplitude, measured by modified dynamic retinoscopy, and the evaluation of the saccadic movements by the development of ocular movements [developmental eye movement (DEM)] test showed continuous change with age. The values for monocular and binocular accommodative facility, measured by +/-2.00 D flippers, indicated the need to divide the population into two age groups (6-7 and 8-12 years). Finally, the means of accommodative response, measured by monocular estimation model (MEM) retinoscopy, and the direct observation of saccadic movement revealed no significant differences between ages, establishing a single mean reference value for the age group studied.

Correlation between reading skills and different measurements of convergence amplitude

Purpose. To find correlations between convergence amplitude and reading ability, as assessed in various methods. Methods. Convergence of 66 children aged 8-10 years was evaluated using 1) Non-accommodative target at near and distance; 2) A near computerized stereogram; and 3) Measurement of near point of convergence (NPC). Reading ability was examined by: 1) a reading comprehension test and 2) the Developmental Eye Movement Test (DEM), which evaluates saccadic speed and accuracy. Results. Convergence amplitudes on a distant target and on a near stereogram were correlated with the DEM score (P = 0.005/0.02, r = –0.38/–0.32 and P < 0.001/0.002, r = –0.53/–0.53 for break/recovery respectively), while NPC and convergence on a near non-accommodative target did not. Reading comprehension test score was not correlated with any of the convergence measurements. Conclusion. Convergence amplitude measured while accommodation is controlled was correlated with the DEM score, which evaluates saccadic speed and accuracy. Further study to evaluate whether improvement in vergence control improves DEM scores is needed.

The Presumed Influence of Attention on Accuracy in the Developmental Eye Movement (DEM) Test

The Presumed Influence of Attention on Accuracy in the Developmental Eye Movement (DEM) Test

The Presumed Influence of Attention on Accuracy in the Developmental Eye Movement (DEM) Test

The Presumed Influence of Attention on Accuracy in the Developmental Eye Movement (DEM) Test