A Comparative Study of the Cognitive Function of the Hearing-Impaired and Non-Hearing Impaired in Two Primary Schools in Lagos State, Nigeria

Background: The study was carried out in two primary schools in Lagos State, Nigeria using 302 respondents aged 6-20 years. The study compared the cognitive function of pupils from Wesley School for the hearing-impaired with pupils from Onitolo Primary School, a main stream public school to see if similarities or differences existed in their cognitive function and to highlight the factors determining their performance on a standard non-verbal test. Method: The instrument of data collection was the Raven’s Standard Progressive Matrices, a standard, non-verbal intelligence test. Statistical association using Chi-Square was used to test for associations between categorical variables. Kruskal-Wallis was used to test for association in variables that were not normally distributed. Regression Coefficient was used to examine linear relationships between selected independent variables and the scores on the standardized test. As it was impossible to individually match human subjects in this study, the variables of class, sex, age and parents’ occupations were adjusted for matching by multiple regression analysis. Multiple regression analysis was used to examine which variables were significant predictors of performance taking possible confounders into consideration. Results: Respondents from Wesley School were much older than respondents from the public main-stream school, class for class. There was no statistically significant difference in their cognitive functions. The mean score difference between the two schools was 0.54 with respondents from Wesley School scoring higher (P > 0.05). Age, sex and class in primary school were determinants of score (P < 0.05). Males scored higher than females. Respondents of skilled parents had the highest scores. There was no relationship between the time the child became hearing-impaired and their scores (P > 0.05). The mean score difference between children that became hearing-impaired by their first year of life and children that became hearing-impaired after the first year of life was 1.83 (P > 0.05). The children that became hearing-impaired before their first year of life scored higher (P > 0.05) than those that became hearing-impaired after their first year of life. Conclusion: There was no statistically significant difference in the cognitive functions between the hearing-impaired and the non-hearing- impaired pupils. Age, sex and class were determinants of score (P < 0.05). In Nigeria, children that are hearing-impaired should be given equal opportunities especially in education.