Prototype Measurement System for the Eye-Hand Coordination Test of the Developmental Test of Visual Perception

Abstract

The current version of the Developmental Test of Visual Perception (DTVP-3) is one of the most commonly used tests to identify the presence and degree of visual-perceptual and visual-integration deficits in children from 4 to 12 years of age. This test consists of five main sub-tests including a eye-hand coordination test (EHCT). Currently, the EHCT is based on observations by a therapist and requires a post-hoc analysis using the DTVP normative data, a time-consumption task that is not free of therapist error. Thus, a medical device is needed to automatically measure, score and report the test scores obtained from the DTVP-3. This device will lead to an overall decrease in the time taken for the post-hoc analysis and an improvement in the accuracy of the EHCT score. We determined that the device must allow a stylus position to be tracked in two dimensions with a resolution of 1 mm and the system must be small in size in order not to interfere with the test. In this study, we proposed a system based on Hall-effect technology sensors, which allows distances from the magnetic field magnitudes to be indirectlyestimated using small sensors. A first prototype consisted of a matrix array of sensors. A radial basis function was used to model the magnitude-distance response of each sensor. The model was estimated by using a multivariate linear regression, and it was found that the proposed model for 1 mm resolution tests, had an average r² of 99%.