Normative Data for a Waranka Indigenous Population of Ecuador: the Importance of Using Data Culturally Appropriate

To generate normative data for Waranka indigenous population in a comprehensive neuropsychological battery.400 healthy children from Guaranda-Ecuador were evaluated. Inclusion criteria were: IQ ≥ 80 on the Test of Non-Verbal Intelligence-2, & a score of <19 on the Children's Depression Inventory. 54.5% were girls with an average age of 11.1 ± 3.2 years and mean parental education (MPE) of 8.1 ± 3.3. The battery was composed of 19-test-scores and were normed (subsample = 306) using multiple linear regressions (MLR) and standard deviation of residual values. Age, age2, sex, MPE and interactions were included as predictors. Best model method was used for variable selection, where 2^p combinations of p covariates were potentially related with each test-score. Four step analyses were used to generate norms: 1-the predictive value was obtained, 2-the residual value was obtained, 3-the residual value was standardized, and 4-percentiles were calculated. Wilcoxon signed-rank test was used to compare norms differences using indigenous vs non-indigenous norms, and to determine the low-scores (subsample = 94).The MLR models showed main effects for age linear or quadratic effect in all test-scores. MPE effect was found for Peabody-test and Fruits verbal fluency, while sex effect for Peabody-test and Symbol Digit Modality-Test. Wilcoxon signed-rank test showed significant differences in all test-scores, except for trail making test and Stroop word-color. Compared to non-indigenous norms, indigenous children achieved higher scores and lower number of low-scores when using indigenous norms.This study highlights the great need to use culturally appropriate normative data for the indigenous population in order to avoid possible diagnostic mistakes.