Development of a Symbol Cancellation Test to Evaluate Attention in a School-aged Zambian Population.

Objective: The assessment of child cognitive health in Sub-Saharan developing countries poses significant challenges, including the paucity of valid diagnostic tools. We report the development and the initial validation of the Zambia Symbol Cancellation Test (ZSCT), a psychometric test to evaluate selective attention in a pediatric, school-aged population.

Design: ZSCT reliability and validity were assessed in a field trial. A total of 409 children, aged 5 to 17 years, were recruited at multiple Zambian clinical sites and schools. The ZSCT provides a visuomotor processing index (VMPI), a measure of effortful processing to deliver accurate task response.

Results: The VMPI reliability estimate at test-retest was found to be adequate for a clinical use (intraclass correlation coefficient [ICC]: 0.79, ICC-95% confidence interval [CI]: 0.69-0.86). Age showed a large effect on VMPI (n=323, r=-0.62, p=0.000). Impaired visuo-perceptual-motor processing, as measured by VMPI, was associated with poor health status (i.e., chronic neurologic or medical disease or prolonged exposure to psychosocial stress and deprivation). A two-way ANOVA found significant and small health status and age group effects [F (7, 408): 33.24, p=0.0000, η²=0.367]; the main effect of health status [F (1, 408): 37.79, p=0.000, η²=0.09], age group [F (3, 408): 35.06, p=0.000, η²=0.21], and their interaction was not significant (p=0.364).

Conclusion: Study findings indicate that the ZSCT has satisfactory reliability, validity, and clinical utility to evaluate cognitive development and the effect of health conditions on attention. Study results warrant further research to validate its use in healthcare and clinical research settings.