Discourse after early-onset hydrocephalus: core deficits in children of average intelligence.
A review of our studies of oral and written language in children with early-onset hydrocephalus suggests that hydrocephalus is associated with specific deficits in discourse as opposed to generalized linguistic deficit. It is proposed that the language skills that are impaired in hydrocephalus are those that require context to derive meaning, while those that are intact may function relatively independent of particular discourse contexts. This hypothesis was tested in two discourse studies comparing children with hydrocephalus of average verbal IQ to age-matched controls. Study 1 investigated narrative economy, syntactic complexity, and semantic content in the retellings of familiar and less familiar fairy tales. Despite producing quantities of story content similar to controls and using syntactic economy similar to controls, the hydrocephalus group produced less of the core semantic content of both familiar and less familiar tales. Study 2 investigated inferencing and figurative language understanding in a narrative comprehension task. Even when prior knowledge was controlled, the hydrocephalus group had difficulty making inferences and recalling factual information from the story. In contrast to their ability to understand idiomatic figurative expressions, the hydrocephalus group had difficulty interpreting novel figurative expressions. The results are compatible with the hypothesis that the core discourse deficits characteristic of children with hydrocephalus are concerned with computing meaning from context. Putative processing features underlying the proposed core discourse deficit are discussed.