Developmental Eye Movement (DEM) Test in Adults: Age-Related Changes and Italian Normative Data

Abstract

The developmental eye movement (DEM) test is a paper-based tool used to assess ocular motor skills in children. By naming numbers in a simple and easy simulated reading task, the DEM test provides an oculomotor efficiency score without complex eye-tracking equipment. Studies have shown that its usefulness can be extended to adults, despite its name suggesting that it is used primarily for developmental ages. However, for a broader application in the adult population in a clinical setting, there are no adult-specific norms. This study aimed to develop adult normative data for the Italian-speaking population and assess whether the DEM scores were influenced by age. In this study, 521 healthy Italian adults, aged 20 to 79 years, participated. Normative data were obtained by using a regression-based framework with demographic variables as predictors. Results show that age influences all sub-measures of time such as Vertical Time (VT), Adjusted Horizontal Time (AHT), and the Ratio score, but did not influence the error score. This is in line with the processing speed reduction in aging. Errors were influenced by education and gender. DEM norms, defined and scored using percentiles and equivalent scores, allow the assessment of oculomotor efficiency in adults, making this test suitable for use in all clinical settings, particularly in neuropsychological and neurological ones.

Keywords: DEM test; concussion; neuropsychological test; norms; oculomotor dysfunction.

Figure 1

Mean scores among age groups for all DEM subtests separately. VT = Vertical Time; AHT = Adjusted Horizontal Time. Bars represent ± 1 SEM.