A longitudinal case study of a Hyperlexic child

Abstract

This thesis is a longitudinal study of a hyperlexic child ZA, who is now 10 years 8 months old. ZA is an autistic child who initially presented with features which are typical of hyperlexia. Now at 10 years 8 months of age, he appears to be outgrowing the label hyperlexia, although he still exhibits some subtle comprehension deficits at both the word and text level. The thesis traces the development of this child's decoding, comprehension and language skills over the last seven years. The data collected from a wide range of standardized and non standardized tests are presented. In spite of well developed decoding skills from a very early age, ZA had no detectable phonemic awareness when first tested. Even when phonemic awareness did develop it appeared to be driven by orthography rather than phonological analysis. The dissociation between decoding and comprehension in cases of hyperlexia is more evident in some tests than others. Standardized comprehension tests suggest that ZA's comprehension was relatively well developed by the time he was in Grade 2 (92 months old). However, his poor scores when presented with sustained stretches of material indicate otherwise, and the adequacy of comprehension measures is discussed. Those skills which underlie successful comprehension were examined during the course of the study. Two hypotheses attempt to explain how a child might learn to read without phonemic awareness: The Knowledge Sources Theory (ISRs) and privileged access theory.