An investigation of nonlexical reading impairments

Word and nonword reading ability was tested in a group of 11 patients with varying levels of language impairments. For the least impaired patients, the probability of grapheme-phoneme association affected nonword reading ability. An advantage reading nonwords that sound like words (pseudo-homophones) was found for six patients, and was unrelated to the severity of patients' nonlexical reading impairments. All patients showed evidence of impairment to all three processing components hypothesised to be necessary for nonlexical reading. A focused study of the phonological processing abilities of the five subjects with mildest impairment uncovered differential influences of segment size and lexicality on patients' ability to combine aurally-presented sound segments. Results are interpreted as indicating multiple sources of impairment to a number of cognitive operations that are specialised to support nonlexical reading.