The table-top visual search ability test for children and young people: normative response time data from typically developing children.
Five table-top tasks were developed to test the visual search ability of children and young people in a real-world context, and to assess the transfer of training related improvements in visual search on computerised tasks to real-world activities. Each task involved searching for a set of target objects among distracting objects on a table-top. Performance on the Table-top Visual Search Ability Test for Children (TVSAT-C) was measured as the time spent searching for targets divided by the number of targets found. 108 typically developing children (3-11 years old) and 8 children with vision impairment (7-12 years old) participated in the study. A significant correlation was found between log-transformed age and log-transformed performance (R2 = 0.65, p = 4 x 10-26) in our normative sample, indicating a monomial power law relationship between age and performance with an exponent of -1.67, 95% CI [-1.90, -1.43]. We calculated age-dependent percentiles and receiver operating characteristic curve analysis indicated the 3rd percentile as the optimal cut-off for detecting a visual search deficit, giving a specificity of 97.2%, 95% CI [92.2%, 99.1%] and sensitivity of 87.5%, 95% CI [52.9%, 97.8%] for the test. Further studies are required to calculate measures of reliability and external validity, to confirm sensitivity for visual search deficits, and to investigate the most appropriate response modes for participants with conditions that affect manual dexterity. Additionally, more work is needed to assess construct validity where semantic knowledge is required that younger children may not have experience with. We have made the protocol and age-dependent normative data available for those interested in using the test in research or practice, and to illustrate the smooth developmental trajectory of visual search ability during childhood.