Congenital vs acquired deafness: differences in reading and mathematics levels

Measures of reading ability and math skills were taken in 22 adults who were either congenitally deaf or had acquired deafness in the second or third year of life. Both groups were equivalent with respect to I.Q., education level and degree of loss. The following tests were administered: (1) the performance scale of the Weschler Adult Intelligence Scale, (2) the math section of the Wide Range Achievement Test, (3) the Reading Comprehension subtest of the Peabody Individual Achievement Test, and (4) the Raven Test of Progressive Matrices. There were no significant differences between the two groups on reading level, but a significantly higher math level was found in the congenital group. It was suggested that the pathology in the acquired group may have affected other neural centers in addition to the auditory, or that the acquired group may have been handicapped by the possibility of switching from one coding system (auditory) to another (visual), while in the congenital group the coding remained confined to the visual mode.