Clinical NeuroscienceReliability of visual orienting response measures in children with and without visual impairments

- Orienting responses are a quantitative measure of visual information processing.
- Response times and fixation accuracies are stable over time in young children.
- The method has good test-retest reliability in children with visual impairments.
- The orienting eye movement responses provide a criterion for reliable data.

BackgroundFrom the need for a quantitative method to examine visual processing in young children, we measured ocular orienting responses to visual stimuli (form, motion, expansion, color, contrast, cartoons). Reliability and applicability of this method were assessed.New method80 children (1-12 years) with visual impairments and a reference group of 118 typically developing children (1-6 years) completed two sessions. Test-retest reliability was measured by calculating differences in reaction time and fixation accuracy between the two sessions. For applicability, the cumulative percentage of children that fell within a pre-defined reliability interval was plotted against the mean number of responses.ResultsIn typically developing children none of the outcome measures significantly differed between sessions. In the children with visual impairments similar results were obtained, except for motion. This stimulus elicited significantly faster reaction times in the second session. In at least 80% of the children reliable reaction times could be calculated if 4 responses to a cartoon stimulus and 1 or 2 responses to the other stimuli were measured.Comparison with existing method(s)The existing method to quantify visual information processing has been refined: the range of visual functions was extended and a criterion for reliable assessment of orienting response times was established.ConclusionsObjective measurement of orienting responses is a reliable method to test the initial stage of visual processing in children with and without visual impairments. A set minimum number of responses for each stimulus warrants the reliability of measurements obtained with this functional method in clinical practice.